| Safeguarding
Children's Health: A Major New Health and Nutrition Report For Healthcare Professionals and Parents by Laura Scott, MSc Nutrition – Vegetarian & Vegan Foundation Senior Nutritionist Introduction
by Professor Colin Campbell Copyright:
The Vegetarian & Vegan Foundation Registered Charity: 1037486 Contents Introduction How
Animal Products Affect Children: How
Animal Products Affect Adults: Introduction Professor
Colin Campbell This report – summarising the scientific evidence favouring the health value of a plant-based diet for children – is well done. I have been on several 'expert panels' responsible for recommending health policy positions, both nationally and internationally, and although some may be more voluminous, none is more reliable. This well-referenced document draws heavily on conclusions drawn by other institutions and panels, who have represented considerable collective deliberation, to synthesize their views into a logical and responsible report. It is well nigh time to make clear to the public that even conservative science is strongly trending in the direction of a plant-based diet and a read of this report is a good place to start. Dr Anne
Griffiths MB ChB VVF has brought together, in this report, the overwhelming evidence that vegetarian and vegan diets are not only healthy for children, but preferable to modern meat and dairy-based diets which are a major cause of chronic ill-health and premature death. Here we have the results from over 200 studies, which show conclusively the links between meat and dairy consumption with such diverse diseases as asthma, gastrointestinal problems, cancer, coronary heart disease, hypertension, diabetes and obesity. This information should now be disseminated so that as many parents as possible can make informed choices about what they choose to feed their offspring. Some of us have long-standing beliefs about the importance of meat and dairy products in our diets. We need to challenge these, as individuals and societies. It is imperative that future generations reap the health benefits that a shift towards a plant-based diet can bring. Vegetarian and vegan diets need to be actively promoted as the best diet for all stages of life: pregnant mothers, babies, toddlers, children, adolescents, teenagers and adults. Meat has become the so-called “luxury” we can ill afford. Vegetarian – a person who eats no red meat, white meat, fish or other aquatic animals (prawns, crabs, lobsters etc) or slaughterhouse by-products such as gelatine, animal fat, lard or rennet. Vegan – a person who eats no animal products at all including red and white meat, fish and other water creatures, dairy products (eg cow's or goat's milk or derivatives such as yoghurt or cheese) or eggs. The latest worldwide research on diet and health has led internationally renowned health organisations such as the World Health Organisation (WHO) to recommend a diet very different to the one the majority of people in the West eat today. Diets should be based more on foods such as fruits, vegetables and cereals and less on meat, fat, sugar and salt if killer diseases such as coronary heart disease, diabetes, obesity and cancer are to be reduced. This report documents the evidence which backs up this assertion and concludes that animal produce must be eliminated from the diet as early as possible to promote a long, healthy life. And the evidence is overwhelming. Anthropological studies show that the diet which fuelled most of human evolution was low in fat, very low in sugar and high in fibre and other complex carbohydrates (3), so it is no great surprise that today's high-fat, high-protein, low-fibre diet causes so many health problems and the dietary trends are spreading worldwide. With increased prosperity, the global trend is towards an increasingly unsuitable and unhealthy diet. In less developed countries even modest increases in prosperity are accompanied by major changes in dietary patterns and a dramatic increase in the incidence of diet-related diseases. If such trends continue, the WHO predict a massive rise in cardiovascular disease and cancer in virtually every country in the world (4). So concerned is this august body they are argue for “intervention on a mass scale” to shift dietary patterns closer to a safer diet (5). “Scientific data suggest positive relationships between a vegetarian diet and reduced risk for several chronic degenerative diseases and conditions, including obesity, coronary artery disease, hypertension, diabetes mellitus, and some types of cancer... Vegetarians often have lower morbidity and mortality rates from several chronic degenerative diseases than do non-vegetarians...Vegetarian diets offer disease protection benefits because of their lower saturated fat, cholesterol and animal protein content and often higher concentration of folate, antioxidants such as vitamins C and E, carotinoids and phytochemicals... vegetarian diets have also been successful in arresting coronary artery disease.” American Dietetic Association Position Paper on Vegetarian Diets, 1997 (182).
National Diet and Nutrition Survey: Young People Aged 4 to 18 Years June 2000 saw the publication of a national diet and nutrition survey. This survey looked into the eating habits of a representative sample of over 2000 young people aged 4 to 18 years. For most parents what this report reveals will come as no surprise and makes for grim reading. Roughly 80% of kids are guzzling away on white bread, savoury snacks, biscuits, chips and chocolate confectionery. Roughly 60-75% had not eaten any citrus fruits (oranges, kiwi fruits, berry fruits – all very rich in fibre and vitamin C) or leafy green vegetables (eg broccoli and greens rich in fibre and many minerals). Whilst girls were more likely to eat some salad vegetables, boys more often consumed convenience foods such as sausages, bacon, ham and pizza. When interviewed 1% of boys and 5% of girls reported to be vegetarian or vegan increasing to 10% of girls aged 15-18 years. Protein intakes for all ages considerably exceeded the government recommended intakes (known as Reference Nutrient Intakes or RNI for short). Carbohydrates (sugar and starch) are our primary energy source but should be predominantly starchy foods like bread, cereals, pasta and rice rather than sugar-laden processed foods. Sugars in the form of table sugar, honey and in baked goods contributed 17% of energy intakes with the RNI set at only 11%. Fibre intake (the indigestible part of plant foods that helps keep the body regular or NSP (Non-Starch Polysaccharides)) was some 10-11g per day – the RNI being 18g for adults with children slightly less so relative to their body size. Not surprising then that a third of children recorded not having a daily bowel movement. Dietary saturated fats (mainly from animal products) accounted for some 14% of daily fat intakes with the RNI set at some 20% less than this at just 10-11%. Dairy products contributed some 30% of this type of fat and meat products contributed 17%. Saturated fat intakes are a major contributor to cholesterol levels so with 20% higher intakes of this type of fat then recommended it is of no surprise that approximately 10% of boys and girls had cholesterol levels at or above the recognised safe levels. Looking at some specific vitamins, vitamin A intakes for 10-20% of boys and girls were lower than recommended. Beta-carotene intakes (the antioxidant or disease-busting form of vitamin A only found in plant foods) were found to be actually zero for 2% of boys and girls! Of particular importance here was the observation that since girls aged 15-18 were most likely to be vegetarian it was no surprise to find that this group had a diet richer in total carotene than other younger girls. Folate (a B-group vitamin rich in plant foods) was below the RNI for 1-4% of all sex/age groups. Over half the vitamin C intake was from fruit juice and soft drinks with 15% from potatoes and only 10-13% from fruits and nuts. Whilst fruit juices are rich in vitamin C they are devoid of any fibre and thus a far better source of this vitamin is from whole fruits and vegetables. A number of mineral intakes were also a cause for concern. The intake of iron for girls above seven years was below the RNI with the oldest age group having an intake of only 58% of the RNI. Calcium intakes were likewise below the RNI for 11-18 year olds and zinc intakes were below the RNI for all ages. Magnesium intakes were some 20-50% below the RNI for various different age groups – a mineral found principally in foods of plant origin. Not surprisingly, given the sort of highly salted, processed foods eaten by children, sodium (salt) intakes were twice the RNI. As far as physical activity was concerned – a key determinant along with diet for maintaining a suitable and stable body weight – 40% of boys and 60% of girls had less than the recommended one hour per day of moderate activity. About a quarter of all children reported to be unwell on at least one day during the seven-day dietary recording period. Approximately 5% of children had been diagnosed as having food allergies by their GP with double this percentage as reporting undiagnosed unpleasant reactions to food. What this survey reveals is that young children are eating a diet low in many of the vital health-promoting vitamins and minerals needed to help combat disease and high in disease-promoting foods such as high fat, high salt and high sugar convenience foods. Much of their daily nutrient intakes are gained not from the basic foods that provide them but from processed cereal, meat and dairy products that are themselves laden with harmful fats, sugar and salt. Fresh fruit and vegetable intakes are woefully lacking in the diet. The consumption of energy-giving starchy foods like unrefined cereals, breads, pasta, rice – the very foods that our diets should be primarily composed of – take a very poor secondary place in the diet. Meat and dairy products still take centre stage at every meal and children will undoubtedly suffer the consequences of this type of diet sooner rather than later in terms of their health and quality of life. A recent report from the Cancer Research Campaign paints a similarly worrying picture of children's diets. One in 20 of the 2,635 children (aged 11-16) questioned by MORI claimed not to have eaten any vegetables in the previous week, with one in 17 not eating any fruit. Compared with the recommended intake of 35 portions of fruit and vegetables per week, most of the children had eaten fewer than 13 portions (273). Vegetarian children nearly always have higher fruit and vegetable intakes. A very recent study found that vegetarian preschool children had in several ways a more desirable nutritional profile than those consuming meat products. The research revealed that, compared to omnivore children, vegetarian children had lower intakes of total and saturated fat, cholesterol and sodium and higher intakes of beneficial nutrients like potassium and vitamins beta-carotene (the precursor to vitamin A), C and E. No surprises that these findings reflected a higher consumption of fruits and vegetables than their meat-eating counterparts (274). How Animal Products Affect Children An allergy is the term used to describe an adverse reaction to a substance from the body's immune system – the body's defence against foreign substances. Asthma (breathlessness with wheezing episodes), eczema (areas of red, itchy, flaky skin), rhinitis (constant runny or congested nose), hay-fever and urticaria (skin rashes) are said to be classical allergies. Food allergy is also included here where there is an immediate violent reaction to a food – eg to peanuts. Food allergy is distinct from food intolerance which is the term used to describe an adverse reaction to a food where the involvement of the immune system is unproven and reactions are usually slower. The most common food intolerance's are to foods that are eaten very regularly – two of the most common being cow's milk and wheat. A recent paper in the European Journal of Clinical Nutrition found that a maternal diet rich in saturated fat during breastfeeding may be a risk factor underlying the later development of allergies (atopic sensitisation) of the infant. This was regardless of whether the mother herself was atopic or not. The effect of such a diet ends in infants whose sole source of energy and nutrients is breast milk during the period of rapid growth and development when the immune response is developing (1). Along with certain processed foods, saturated fats are predominantly found in foods based on animal products such as meat and cow's milk. One in seven children (aged two to 15) now suffer from asthma – that's over 1.5 million sufferers and over 1500 people die each year in the UK as a result (7). There are many possible triggers for an asthma attack, from animal hair, environmental pollution to dust. Whilst food and drink are not considered common triggers for people with asthma, the British Allergy Foundation estimate that food and food additive allergy may be involved in 5-10% of asthmatics (8). The National Asthma Campaign is also aware that an allergy to dairy products can be a trigger for this debilitating disease (2). According to Dr Nand Kishore Sharma, “a milk drinker can never cure his asthma.” The mucous-forming quality of cow's milk seems to trigger asthmatic development (9). In Sweden, doctors prescribed a vegan diet to twenty-four asthmatic volunteers. With only a few lapses, the volunteers followed the diet for a year and their health assessed. After one year 92% of patients reported an improvement in their condition and there was a significant decrease in asthmatic symptoms. This means that the decrease in symptoms was not down to chance or it just happening anyway but attributed to the change in the diet itself. In almost all cases, medication was withdrawn or drastically reduced. Some of the volunteers that had also suffered from rheumatic diseases found a lessening of these symptoms too (11). Most cancers affect adults rather than children – and diet is a major contributory cause. However, there has been some research on childhood cancers looking at the different types of variables (a variable simply meaning any quality like age or type of food consumed that varies in each individual) associated with certain cancers. One study in particular found that brain tumours in young people to be significantly associated with (amongst other variables) maternal exposures during pregnancy to frequent consumption of cured meat. Cured meat products contain nitrosamines – the most potent nervous system cancer-causing agents known – and cooking such meats means that relatively high levels may be released in cooking fumes (12). In a separate study, a statistically significant (ie not due to chance) threefold increased risk of brain tumours in offspring was associated with low maternal intake of vitamin C during pregnancy. This means that there was an association for the offspring of women having low intakes of vitamin C of having a three times greater chance of brain tumour than women who had high intakes of vitamin C. This effect remained even after adjustment for other variables (13) – ie the association remained at this increased risk level even after taking into account other factors or variables that may have increased the risk for brain tumours. A vegetarian diet is naturally high in this antioxidant vitamin which can help to protect against cancer. Meat and dairy foods contain no vitamin C. Diet has an enormous bearing on cancer according to the latest research (14) and it is therefore crucial that children are encouraged in healthy eating habits right from a very early age and that includes the removal of meat and dairy products from the diet. Indeed cancer specialist, Dr Rosy Daniel states that the main foods to cut out of your diet to prevent cancer are red meat and animal fats along with preserved foods and food additives. Thus she states that: “The best move for those who feel inspired to 'go the whole way' is to become completely vegan and eliminate animal products from the diet altogether.” (10). (See also Cancer section on how animal products affect cancer rates in adults). There
is growing concern about the effects of chemical pollutants
on both adults and children. Many harmful substances like
PCBs and dioxins are principally found in fatty foods – meat,
dairy, eggs and oily fish. This is because fatty tissue has
a tendency to 'soak up' and store these chemicals. Exposure
to PCBs and dioxins are linked to immune system damage, some
cancers and can negatively affect the intelligence of infants.
Nursing infants especially may be exposed to an array of chemical
pollutants from the breastmilk of their mothers. Hergenrather
and colleagues analysed samples of breastmilk from vegan mothers.
They found that the highest level of a number of chemicals
in the breastmilk of vegan mothers was lower than the lowest
level in the general population. For three chemicals, the
mean levels found in the vegan mothers were only 1 to 2% as
high as the average levels found in the non-vegetarian reference
population (17). Chemical pollutants are now a major problem in the sea and the inclusion of fish in the diet is increasingly being seen as a risky business. Sea pollution means that farmed salmon and other oily fish like mackerel are now a reservoir of harmful toxins. Though now illegal, PCBs were once widely used and stay in the environment – including the seabed – for many years. These toxins bind to organic matter on the sea floor which is eaten and absorbed into the fatty tissue of small fish. These seabed feeders are in turn eaten by larger fish which accumulate the toxin load from these smaller fish. At each stage of the food chain toxins will be concentrated and increase. The problem
with chemical pollutants in the food chain is now extremely
worrying. European Commission (EU) guidelines on safety limits
for dioxins in foods means that a third of all Britons and
half of all under-five's could be exceeding these safety limits
(276, 277). According
to Dr Alan Gaby (President of the American Holistic Medical
Association) cow's milk is probably the most common cause
of infantile colic. So sensitive are some infants to cow's
milk that they develop colic, even when exclusively breast
fed, if their mother continues to consume any cow's milk in
her own diet. Gaby Crohn's disease often affects young people, causing pain after mealtimes and can also bring on a fever and mild diarrhoea. It is a chronic inflammatory bowel condition that affects 90,000 people in the UK and rates are rising rapidly. The condition is thought to be partly genetic but also partly dietary. Some researchers believe that the problem starts when infections or food sensitivities aggravate the digestive tract. Crohn's disease is rare in Africa and rural Asia where diets are low in fat and high in fibre, more common in parts of Asia that have a Westernised diet and most common in North America and Northern Europe. A 19-year study in Japan suggests the strongest independent dietary risk factor for Crohn's is an increased intake of animal protein (22). The high fat, low-fibre, meat-based diets are believed to play a big part. One study found that when placed on a milk-free diet, one third of patients with Crohn's disease noticed a beneficial effect (23). A report by Professor John Hermon-Taylor of St. George's Hospital Medical School, London, strongly supports the belief that bacteria responsible for Johne's disease (found in cattle) is the same bacteria that causes Crohn's disease – Mycobacterium avium subspecies paratuberculosis (MAP). Research is now suggesting that pasteurisation of milk – heating it to 72 degrees for 15 or 25 seconds – may not be enough to kill the bacteria (24). Coronary heart disease (CHD) results from narrowing of the arteries and stiffening of the artery walls by hard fatty deposits – principally cholesterol. Blood supply to the heart muscles is then reduced and eventually they become short of blood, leading to a heart attack. Dietary cholesterol is only found in foods of animal origin and saturated fats (from processed foods and animal products) cause the liver to produce more cholesterol. The National Forum for Coronary Heart Disease Prevention states that: “in order to reduce the overall risk of coronary heart disease, healthy eating patterns should be established in childhood.” The report continues: “Children continue to eat more than the recommended percentage of energy in their diets from fat and consume less than the recommended amount of fibre. Several studies indicate that there has been no improvement in children's eating habits over the last ten years, with fat consumption at up to 43% of energy. The typical diet of school children in the UK is high in fat and sugar, low in fibre, low in iron and calcium and possibly low in folate. This means that children should be eating a diet which contains more bread, cereals and other starchy foods; more fruit and vegetables; and less fat, sugar and salty foods; and which is richer in minerals and vitamins.” (135). A vegetarian diet is ideal for promoting a healthy start in life and the sooner this diet is adopted, the better. “The avoidance of meat is likely to reduce the risk of coronary artery disease, because meat is the major source of saturated fat”. “High consumption of red meat has adverse health consequences: thus vegetarian diets tend to impart health advantages.” Dr Walter C Willett, chairman of the Department of Nutrition at the Harvard School of Public Health and Professor of Medicine at the Harvard Medical School, one of the world's most distinguished experts on nutrition (251). A study in the New England Journal of Medicine found that in autopsy studies of 204 children and young adults, aged two to 39, essentially all persons had fatty streaks in their aortas (the main artery from the heart to the body's tissues). The prevalence of fatty streaks in the coronary arteries (the arteries that carry blood to the heart) increased with age from approximately 50% at two to 15 years of age to 85% at 21 to 39 years. The study found that the same risk factors that encourage heart disease in older people – high cholesterol levels, overweight and high blood pressure – do the same in the young (136). A more recent study echoes this statement finding that early deposition of cholesterol in the walls of the arteries (atherosclerosis) is influenced by these risk factors for clinical Coronary Heart Disease (CHD) and that the long-term prevention of CHD must begin in adolescence or young adulthood (60). The WHO reaffirms the importance of introducing a healthy high-fibre, low-fat diet early in a child's life, one of the major reasons being that it is known that the atherosclerotic process leading to heart disease starts in childhood (15). But of course it is not only diet that influences the development of CHD. Exercise is also important. The National Forum for Coronary Heart Disease Prevention discovered that children's hearts are under a huge strain from a poor diet and lack of exercise. Only 4% of boys aged 11-16 and less than 1% of girls could sustain a heart rate of over 140 beats per minute for periods up to 20 minutes which is the recommended level for children (137). As every parent is more than aware, sugar in the diet is the most important dietary determinant in the development of dental caries (tooth decay). The properties of different foods, including their stickiness and nutrient content can affect the rate at which caries are formed. The foods that can help reduce dental decay are starchy foods like rice, bread and potatoes and the less refined the better. Thus when children are given carbohydrates such as beans, oats, rice, wholemeal bread and fruit, they will tend to develop fewer and smaller cavities than children fed a more refined diet. Fresh fruit, even though it contains fruit sugars (fructose) has a low cariogenic potential (138). A typical vegetarian diet provides all these types of foods for children in abundance. Diabetes
mellitus is a group of disorders that all lead to elevation
of glucose (sugar) in the blood due to inaction of insulin
– a hormone produced by the pancreas that helps to take glucose
out of the blood and into the body's cells. There are two
types – Insulin-Dependent Diabetes Mellitus (IDDM) where there
is an absolute deficiency of insulin and Non-Insulin Dependent
Diabetes (NIDDM) where insulin Although
it is not a killer disease in itself, it is still a factor
in the development of premature heart disease, kidney failure
and blindness (25). Insulin-dependent diabetes mellitus (IDDM)
is on There is increasing evidence from a number of studies to show that early exposure to cow's milk may be a trigger for IDDM. (139,222,227). In particular that cow's milk may destroy pancreatic beta cells (cells that secrete insulin) in genetically susceptible hosts, thus potentially increasing the risk for IDDM (223). In 1994, Diabetes Care published a critical review and statistical analysis of cow's milk and IDDM by Hertzel Gerstein MD. His review showed that early cow's milk exposure may be an important determinant of subsequent IDDM and may increase the risk by about one and a half times. Dr Hertzel concluded that: "74-94% of the variation in diabetes incidence across countries may be related to differences in cow's milk consumption." (27). Diseases of the middle ear are primarily a disease of childhood with as many as 1.5 million cases in Britain every year (30). They are often linked with a cold or other problems of the respiratory system. The avoidance of dairy produce is recommended by some nutritionists and may be particularly valuable (31). According
to the British Allergy Foundation: “...the food intolerance
patient is often mildly addicted (often without realising
it) to the food or foods causing the problem. The child with
catarrh, recurrent ear infection, insomnia and irritability
who craves regular milk, cheese and yoghurt is a good example.
Night-time waking, only An allergy to cow's milk protein is the most common food allergy in childhood, affecting between four and 75 babies in every 1000 (32). It can cause a whole host of symptoms including eczema in a child but can also play a part in the development of eczema in adult life. A number of studies have therefore concluded that whole cow's milk should not be given during the first year of a baby's life in order to help prevent the onset of a number of diseases and conditions in childhood and adulthood (33,34). In 1999 a government report stated that an astonishing 9.5 million people in the UK get food poisoning each year, at a cost of £750 million to the National Health Service. Amongst the groups most endangered by food poisoning are young children – especially under one's but anyone can suffer. Eating animal products causes 95% of all cases with meat being the main culprit as the bacterial micro-organisms responsible thrive on rotting flesh. Food poisoning can range from being quite mild to a cause of death from a heart attack or stroke. Abdominal pain is the first sign of poisoning with the pain becoming excruciating and may lead to explosive diarrhoea. Although the illness usually lasts for five to 10 days, most often it is a further one to two weeks before someone feels well again (35). A very recent report in the New Scientist detailed results of a study from the Royal London School of Medicine which found that a staggering one in 10 British children are carrying superbugs resistant to one or more antibiotics. The proportion of adult carriers could be even higher. The researchers found that 11% of seven and eight year olds in the study population contained bacteria such as E. coli that were resistant to antibiotics that the children themselves had never previously been given (156). Once resistant, bacteria can easily spread from person to person and they can be picked up from food and agricultural sources. There is already strong evidence that feeding farmed animals antibiotics can lead to resistant strains of bacteria in the gut which can then be passed on to people by eating infected animal products. Farm use of antibiotics have caused antibiotic resistance to medical drugs in 3 types of food poisoning (Salmonella, Campylobacter and Escherichia coli) (41). Now researchers from the University of Illinois have discovered that bacteria in the soil and water beneath pig farms seem to be acquiring tetracycline resistance genes from bacteria originating in the pigs' guts. Once transferred, these resistance genes can persist and could potentially be passed on to humans through drinking water (236). Escherichia
coli (E. coli) is a normal inhabitant of the gastrointestinal
tract of humans and animals. Whilst this bacteria colonises
infants within hours after birth and performs vital functions
throughout “A diet free of meat, fish, milk and eggs is by far the safest and one that I highly recommend.” Emanuel Goldman Professor of Microbiology & Genetics (35). Many children display intolerance to the proteins (casein) in cow's milk with symptoms initially restricted to diarrhoea and vomiting (37). Cow's have a four-stomach digestive system ensuring, amongst other things, that calves can deal with casein easily – but cow's milk is clearly not designed for humans. Because it cannot be readily absorbed by humans cow's milk remains undigested in the gut and begins to putrefy. This putrefaction in humans produces toxins and mucus and it clings as undigested matter to the lining of the intestines, preventing the absorption of vital nutrients in the body (29). Although chronic diarrhoea is usually the most common gastrointestinal symptom of intolerance to cow's milk among children, a recent study in the New England Journal of Medicine found other consequences of feeding children cow's milk. This study reported on 65 children between 11 months and six years of age with chronic constipation who had been treated unsuccessfully with laxatives. Taking them off cow's milk and switching to soya milk cured 44 of the children. The authors concluded that in young children, chronic constipation could be a manifestation of intolerance to cow's milk (38). A 1993 review study concluded that in some children whole cow's milk-induced gastrointestinal blood loss appears sufficiently great to be nutritionally significant and may contribute to the development of iron deficiency anaemia (40). “Ideally the infant should be exclusively fed human milk for the first year of life... After the first year of life the child requires no milk of any type. The child, like us adults, can thrive without cow milk ever crossing his lips.” Frank Oski MD (1932-1996). Internationally recognised specialist in paediatric nutrition and former Director, Department of Paediatrics, Johns Hopkins University School of Medicine and Physician-in-Chief, the Johns Hopkins Children's Centre (281). Along with Haemolytic Uraemic Syndrome (discussed above under Food Poisoning), Nephrotic Syndrome is another potentially serious kidney disease that may be related to the consumption of animal products. Nephrotic Syndrome is linked to cow's milk allergy. Children with the disease suffer from protein deficiency and severe fluid retention and may ultimately develop permanent kidney damage. In one study, allergy to cow's milk was found to be a cause of nephrotic syndrome in five out of the six children studied. Elimination of cow's milk from their diet resulted in a marked improvement (43). Migraine is a common condition characterised by recurring intense headaches and affects around 10% of the population (44). Usually accompanied by nausea, vomiting and visual disturbances, a migraine can be terrifying, especially for young children. Meat, dairy products and eggs can all trigger a migraine (as can citrus fruits, wheat, nuts, coffee, tomatoes and chocolate). The Elimination Diet recommends abstinence from these foods for two weeks and then reintroducing them one at a time in order to assess which food or foods trigger the migraine attack (45). The UK government has recognised that the prevalence of overweight and obesity in the population is increasing rather than declining (46). Body Mass Index (BMI) provides an estimation of an individual's level or risk of morbidity and mortality. BMI is calculated by dividing a person's weight (kg) by the square of his or her height (m). A BMI of 20-25 means that a person has a normal weight. A BMI of 25-30 indicates a person is overweight and a BMI of 30 and over indicates obesity. At least 10% of children in this country could be regarded as overweight (47). Two recent papers in the British Medical Journal make grim reading. The first study reported trends in overweight and obesity over 20 years in British children (four to 11 years) and found that in 1994 an average of 10% of boys and 14.5% of girls were overweight (39). A second study observed that one in five nine-year olds and one in three 11-year old girls are overweight (42). In 1998, the prevalence of obesity in England had trebled compared to 1980 to 21% of women and 17% of men. Currently, over half of women and about two thirds of men are overweight or obese (48). It is therefore vital for current as well as future health that weight problems are tackled early on. Psychological
damage can be inflicted early in childhood as a result of
being overweight and this damage can last a lifetime. Healthy
eating habits should be started early. The typical diet of
school children in the UK is high in fat and sugar, low in
fibre, low in iron The 1991 Bogalusa Heart Study showed that even mild obesity in childhood is related to higher levels of blood pressure, insulin and cholesterol and that to some extent these track into adulthood. There is evidence that fatty deposits and the development of atherosclerosis start in childhood and emphasise the need for preventative cardiology in early life (50). Research is clear on how diet affects obesity: energy (food) intake exceeds energy output. Meat and dairy products all contain saturated fat. A much healthier source of energy comes from complex, slow-releasing carbohydrates and the good news is that vegetarians are on average leaner than omnivores (51, 52, 53, 54). RHEUMATOID ARTHRITIS (Juvenile) Rheumatoid Arthritis affects more than 750,000 people in the UK and one child in every thousand has arthritis. Dairy products, meat and eggs can all be common triggers for rheumatoid arthritis (as can corn, nuts and citrus fruits) in children and adults alike. In 1985 the Journal of the Royal Society of Medicine reported on the case of a 14 year old girl who had first been admitted to hospital at the age of eight due to pain and swelling of the wrist. During the following years she had been hospitalised nine times as the swelling and pain spread and been diagnosed with juvenile rheumatoid arthritis (JRA). At 14 she again presented at hospital and after tests, doctors advised her to avoid dairy products and the swelling disappeared within a week. By the end of three weeks the pain had also gone. The arthritis was to return just three times in this girl's life, each time after she'd eaten dairy products. Even a small piece of milk chocolate was enough to cause the painful symptoms to recur (61). SUDDEN INFANT DEATH SYNDROME (SIDS) Researchers are currently investigating a link between cow's milk and SIDS, saying that some cot deaths may be as a result of an allergic reaction to cow's milk. Research at Southampton University has discovered certain proteins, released during an allergic reaction, in the blood of babies who have died with no apparent cause. Researcher Dr Andrew Walls said that cow's milk was “a promising line of research.” Although the number of babies dying from cot death has dropped in recent years, it still kills nearly 10 babies a week and is the leading cause of death among children aged under 12 months (62). How Animal Products Affect Adults Many diet-related diseases and conditions begin in childhood but don't show themselves until much later. The 1997 Scientific Conference on Preventative Nutrition: Paediatrics to Geriatrics reported that similar dietary guidelines are appropriate for children (aged over two years) as well as adults in order to reduce the risk of cancer, heart disease, diabetes and obesity. These include choosing a diet with plenty of wholegrain products, vegetables and fruits and a diet low in fat, saturated fat and cholesterol (64). When you consider that the main source of saturated fats in the diet are processed foods and animal products – both meat and dairy – the arguments in favour of a vegetarian diet get stronger and stronger. Experts worldwide now believe that over a third of cancer deaths – and possibly many more – may be linked to diet. The percentages
of cancer deaths attributable to various factors is shown
below (65): One quarter of a million people in the UK discover they have cancer every year and it kills one in four. If the two main risk factors (diet and smoking) were noted and acted upon, it is estimated that two thirds of cancers could be prevented. In 1981 Professor Sir Richard Doll estimated that 35% of fatal cancers are linked to diet. He currently estimates that 20-60% of cancers might be reducible by practicable dietary means (66). According to the WHO, evidence suggests a direct relationship between the risk of certain cancers and the level of total fat in the diet and that it may prove necessary to lower the upper limit for total fat [intake] from 30% to 25% or perhaps even 20% (67). The EPIC (European Prospective Investigation on Cancer) Project initiated in 1993 is a multi-centred prospective study designed to investigate the relation between diet, nutrition, various lifestyle factors and the risk of cancer. Prospective studies record the diets of subjects and track their health over the coming years. The EPIC study is set against the background that the most consistent result of epidemiological (population) studies on food choices and cancer is that a diet rich in vegetables, fruit and more generally, in plant foods is associated with a reduced risk of many cancers (59). The study has 480,000 subjects in nine European countries including 60,000 participants in the Oxford Study for the UK element of the project. Data is now being prepared for analysis and the results will be compiled over the next year (86). (See section under Colorectal Cancer below for interim results from EPIC studies.) Way back in 1892, Scientific American asserted that “cancer is most frequent among those branches of the human race where carnivorous habits prevail.” (68). More recently it has been found that the very process of cooking meat, particularly at high temperatures for long periods, produces carcinogens which are thought to increase certain cancers (69). As animal proteins are heated, they produce cancer-causing chemicals called heterocyclic amines. This phenomenon occurs in all meats and the level of heterocyclic amines is 15 times higher in chicken than beef (70), suggesting that chicken can no longer be viewed as a healthy food option. Heterocyclic amines are most strongly linked to colon cancer but have also been linked to cancer of the breast, ovary and uterus. A 24-year Finnish study of nearly 10,000 people found that fried meat consumption was linked to higher risk of these hormone-related cancers in women (71). In 1996, researchers at the American Institute for Cancer Research (AICR) presented new evidence on how fat affects cancer. Dr Laurence Kolonel from the University of Hawaii Cancer Research Centre and his team believe that fats (mainly of animal origin) in the diet produce bile acids in the intestinal tract that seem to promote colon cancer. Apparently eating high-fibre foods like fruits, cereals and vegetables can reduce the concentration of these bile acids and help prevent colon cancer (72). High-fat diets also increase the amount of oestrogens (female sex hormones) in the blood. It is known that many breast tumours are fuelled by an excess of oestrogen. When women begin a low-fat diet, their oestrogen levels drop sharply and vegetarians have significantly lower oestrogen levels than omnivores (63,73,74). Researchers in New York tested the effect of low-fat diets on immunity and found that people with a low-fat diet had more 'natural killer' cells than those on a high-fat diet. These cells seek out and destroy any abnormal cells that may turn cancerous. The authors of this paper state: “The enhanced natural cytotoxicity may be one of the factors contributing to the lower cancer risk shown by vegetarians.” (75). BREAST
CANCER Researchers in Buffalo, New York calculated what they believed to be the degree of risk posed by fat in the diet. For a woman with metastatic breast cancer where the disease has spread to other parts of the body, the risk of dying from the disease at any point in time increases 1.4-fold for each 1000g of fat consumed monthly (79). This means that the typical Western diet could lead to about a 40% higher risk of dying of breast cancer at any given point, compared to a low-fat vegetarian diet (80). The relationship between dietary habits and breast cancer was studied in 240 women aged 50-65. Results suggested that diets that are low in fat, high in fibre, carbohydrates and Vitamin A seem to help the prognosis while alcohol slightly worsens it (81). The World Cancer Research Fund echoes this view. The advice given in their information leaflets is that research has shown that cancers of the breast are more common in overweight women and a diet to lower cancer risk is low in fat, high in vegetables, fruits and wholegrains (82). Well-balanced vegetarian diets typically incorporate this way of eating as a matter of course. A diet rich in vegetable products, especially fibre, may lead to a later menarche (onset of menstruation) which is thought may lessen the risk of developing breast cancer later in life (83). The association of cooked meat and thus exposure to heterocyclic amines formed during high-temperature cooking may also play an important role in the risk of breast cancer. This was the conclusion of a paper by Zheng et al who conducted a case-control study among members of the Iowa Women's Health Study. This study looked at a group of 41,836 women who had been followed over the years from 1986 for mortality, cancer incidence and diet eaten. During 1995 to 1996 Zheng and colleagues looked at all members of the original group who had been diagnosed with breast cancer (the cases), compared them to a random sample of women from the original group who were free of cancer (the controls) and looked at the intake and preparation of meats consumed by both groups over the years. This analysis found that risk of breast cancer was elevated with increasing intake of well done to very well done meat (56). The role of cow's milk as a possible risk factor for breast cancer has also been investigated. There is increasing speculation that one particular hormone – Insulin-Like Growth Factor-1 (IGF-1) – may have a major role to play. IGF-1 is a naturally occurring compound that stimulates growth in children and declines as a child ages. IGF-1 also encourages breast cancer cells to multiply and cow's milk contains about 30 micrograms of IGF-1 in every litre (84). A recent paper published in 1997 in Medical Hypotheses put forward the view that regular cow's milk ingestion after the age of weaning may produce enough IGF-1 in mammary tissue to cause the cell cycle to supersede its boundaries of control, thus increasing the risk of breast cancer (18). A study published in The Lancet found that pre-menopausal women with even small increases in blood levels of IGF-1 have up to seven times the breast cancer risk of women with lower levels (85). Professor
Jane Plant was diagnosed as having breast cancer in 1987 and
had five recurrences. She began to research the disease and
came to the conclusion that cow's milk had a major part to
play. Seven years on, and after removing dairy products from
her diet, the cancer has never returned. Her book on the subject
presents the argument that cutting out cow's milk dramatically
reduces the body's exposure to antibiotics, biologically active
chemicals and a powerful cocktail of hormones thought likely
to promote breast – and prostate – cancer (19). Contrary to claims that white meat is somehow healthier than red meat a 1998 prospective study (whereby subjects diets are recorded and their health tracked over the coming years) identified both red meat and white meat (fish and poultry) intake as important dietary risk factors for colon cancer. Researchers at Loma Linda University examined eating habits of 32,000 men and women between 1976 and 1982 and monitored cancers over the six years. Among those who avoided red meat but ate white meat less than once a week, colon cancer risk was 55% higher than for those who avoided both kinds of meat. Those who had white meat at least once a week had more than a three-fold risk of suffering colon cancer. Conversely eating legumes such as beans, peas or lentils at least twice a week was associated with 50% lower risk compared to never eating these foods (21). A paper in the American Journal of Epidemiology in 1998 makes two very interesting points. Firstly that it is the overall dietary intake pattern that is important with greater emphasis on fruits and vegetables that is associated with lower risk for colon cancer. Secondly that 'substituters' (people who use low-fat dairy products instead of high-fat ones, margarine instead of butter, poultry instead of red meat and wholegrains instead of refined grains) were at reduced risk for colon cancer but the reduction was not significant. The authors conclude that this was because many adopting these 'substituter' so-called 'healthier' diets were not increasing their vegetable consumption and this aspect of the diet is important in significantly reducing colon cancer risk (55). Fibre or non-starch polysaccharides (NSP) are major constituents of a plant-based diet and it has been long thought that high-fibre diets offer a measure of protection against colon cancer. The reason for this centres around the digestion of dietary fat. Fat is broken down in the body by the secretion from the gallbladder of bile acids made in the liver. Bacteria in the intestines turn these bile acids into cancer-promoting substances (mutagens) called secondary bile acids. Meat – unlike plant foods – fosters the growth of bacteria that cause these disease-causing acids to form. Fibre actually changes the type of bacteria that are present in the intestine so the production of carcinogenic (cancer-causing) secondary bile acids is reduced (88). Fibre may also help both by diluting the presence of such harmful acids in the faeces and by greatly speeding up their passage through the colon. Jerome J DeCosse, a surgeon at Cornell Medical Centre in the US gave a high-fibre grain supplement to patients with recurring polyps of the colon. Polyps are small growths that may go on to become cancerous but within six months in this study, the polyps became smaller and fewer in number (90). Virtually every food that comes from a plant contains fibre while food from animal sources contains no fibre at all. However it may not be simply a matter of increasing fibre and still eating meat that will help reduce risks of colon cancer. A study by O'Keefe et al in 1999 found that the low prevalence of colon cancer in black Africans was not so much explained by dietary 'protective' factors including fibre but may be influenced by the absence of 'aggressive' factors such as excess animal protein and fat as well as differences in colonic bacterial fermentation (57). Preliminary results from the EPIC study on the link between meat consumption and colorectal cancer are showing that a high intake of red meat and particularly of processed meat, are associated with a moderate but significant increased risk of colonic cancer (89). Overall first results suggest that frequent consumption of beef, veal, pork and lamb is associated with a 20-40% increase in colorectal cancer risk (87). This contradicts a recent review paper by Key, Davey and Appleby which found no association between a vegetarian diet and a reduced risk of colonic cancer (225). ENDOMETRIAL
CANCER NON-HODGKIN'S
LYMPHOMA OVARIAN
CANCER PANCREATIC
CANCER International comparison studies have shown that as Japan's diet has Westernised, so the incidence of pancreatic cancer has increased. One particularly pertinent aspect of this Westernised diet is in terms of animal fat consumption that previously was very low. Consumption has steadily increased from a daily level of 6.5 grams of animal fat per person in 1955 to 27.6 grams in 1987 and animal protein consumption has doubled in these 30 years (98). PROSTATE
CANCER Research has shown that men who consume diets based on animal products tend to have more testosterone and oestrogens compared to men who eat plant-based foods. This increase may be due to over-production of these hormones in the body or, since fibre in the diet is essential for the normal excretion of sex hormones, a lesser ability to get rid of them. This hormonal boost can affect the prostate and, according to the Physicians Committee for Responsible Medicine, is probably the reason for increased cancer risk among those on a meat-based diet (101). IGF-1 (Insulin-Like Growth Factor-1) – found in cow's milk – is already known to encourage breast cancer cell growth and may also be a risk factor for prostate cancer. A very recent study reported in the British Journal of Cancer found that vegan men had a significant 9% lower IGF-1 concentration compared to meat eaters and that this might reduce their risk of prostate cancer (97). Other studies have likewise found that cow's milk consumption is also very strongly implicated as a risk factor for prostate cancer (256, 257, 258). An important study published in 2001 in the prestigious American Journal of Clinical Nutrition also gives weight to the theory that dairy products are risk factors for prostate cancer. A high calcium intake, mainly from dairy products, may increase risk by lowering concentrations of a form of vitamin D (actually a hormone) thought to protect against cancer of the prostate. Results here showed that men consuming two and a half or more servings of dairy products (a serving being 140 grams of cheese, 170 grams of yoghurt or 75 mls of cow's milk) a day appeared to be almost a third more likely to develop prostate cancer then those eating the lowest amounts (less than half a serving per day). The authors concluded that their results supported the hypothesis that dairy products and calcium are associated with a greater risk for this particular cancer (269). Earlier in 1999 Grant used an ecologic (multi-country analysis) approach. Here mortality data from a particular year for various age groups in a number of countries (41 in this example) were compared with national consumer macronutrient supply values for a range of foods. Grant found that the non-fat portion of cow's milk had the highest association with prostate cancer. For an association to be causal (ie in this instance that the non-fat portion in milk actually causes prostate cancer) a number of criteria need to be satisfied including strength of the association, consistency and most important of all a likely mechanism to link the suspected agent with the observed effect. Grant concluded that for cow's milk the most likely mechanism may be related to calcium with high intakes suppressing conversion of one form of vitamin D to another form which has an anti-tumour effect for prostate cancer (270). In 1993, American researchers analysed data from the prospective cohort Health Professionals Follow-up Study looking at diet and subsequent disease patterns. Of all the foods studied red meat represented the food group with the strongest positive association with advanced prostate cancer (99). A lower risk of prostate cancer is associated with diets higher in rice, soya bean products and green and yellow vegetables (100). Not surprising then that vegetarians have been found to have low rates of prostate cancer (102) and increasing consumption of beans, lentils, fruits and vegetables are all associated with significantly decreased prostate cancer risk (103). UTERINE
CANCER THE ROLE OF FIBRE IN CANCER PREVENTION Eating high fibre foods can reduce the concentration of destructive bile acids and help prevent cancer from developing by sweeping away toxins in the intestines before cancers can form. The link between higher fibre consumption and lower cancer risk is clear and has been reaffirmed in many studies. Fibre first received worldwide attention in the 1970s when international studies showed that in countries where diets included large amounts of fibre, there were fewer cases of colon cancer, diverticulitis and other intestinal diseases, haemorrhoids, hiatus hernia, appendicitis, varicose veins, gallstones and heart disease. Since then, many scientists have reached similar conclusions and have also found that diets high in soluble fibre (eg oats, soya beans, fruits and vegetables) appear to lower the risk of diabetes and may reduce levels of cholesterol in the blood. The World Cancer Research Fund recommends adults introduce children to fibre-rich foods at an early age to ensure they grow up enjoying and eating these foods (106). THE PROTECTIVE NATURE OF FRUITS AND VEGETABLES Fruits and vegetables contain antioxidants such as beta-carotene (the precursor to vitamin A), and vitamins C & E which protect body cells against damage. The evidence is overwhelming that an abundant intake of fruits and vegetables can play an important role in reducing cancer risk (108). Members of the cruciferous family – broccoli, Brussels sprouts, cabbage and cauliflower – are widely regarded as potentially cancer preventative foods. A number of papers have looked at the issue and found strong evidence to support these beliefs (92, 93). For these
reasons, it is recommended we all eat at least five portions
of different fruits and vegetables per day as well as more
starchy carbohydrates. One portion is equivalent to one medium
fruit like an apple, banana or orange, two smaller fruits
like kiwis or plums, a cupful of berry fruits, a large bowlful
of green salad or two The World Cancer Research Fund (WRCF) states: “The emphasis of our meals needs to be reversed; it is plant foods that should be the focal point of our dinner plate, not meat and dairy products.” (109).
“Beta-carotene is the pigment that gives dark green, yellow and orange fruit and vegetables their colour. In the body it is converted to Vitamin A, which may well lower our risk of developing cancer, especially lung cancer (167). Vitamin C is believed to protect against cancer of the oesophagus and stomach. It is found almost exclusively in fruits and vegetables (167). Vitamin E may help in the prevention of stomach and throat cancers as well as other serious illnesses. It is present in moderate levels in most fresh fruits and vegetables and at higher levels in cereals (167). Selenium is a mineral that can probably protect against colon, breast and possibly other cancers. Scientists say an adequate amount passes into fruit and vegetables from the soil in which they are grown” (167). There has been much publicity in the lay press – both negative and positive – surrounding soya products and their effects on the body – no less so than in the area of cancer. Some studies point to the chemo-preventative nature of soya whilst other studies seem to point to the opposite effect. On balance research seems to be suggesting that soya foods can be a very valuable part of a varied vegetarian diet. Soya beans contain all eight essential amino acids (building blocks of protein), have strong antioxidant properties, are very rich in soluble fibre, contain no cholesterol and are high in the essential fats which are often lacking in many people's diets. Studies have also demonstrated that soya lowers cholesterol levels and the large amount of evidence linking soya to good heart health has even led the FDA (the US Food and Drug Administration) to allow health claims on food products containing soya. Soya
beans are rich in a class of compounds called isoflavones.
These act as weak oestrogens – hence the name also given to
isoflavones – phytoestrogens or 'plant hormones'. Phytoestrogens
appear to have both antioestrogenic and oestrogenic effects
in the body – thus they act as oestrogen modulators. The prevailing
thought is that these plant hormones exert antioestrogenic
effects in a high-oestrogen environment (such as that exists
in pre-menopausal women) and oestrogenic effects in a low-oestrogen
environment (such as that existing in post-menopausal women).
Thus phytoestrogens appear to normalise oestrogen in the body.
At the present time the data so far produced is insufficient
to conclude that soya is protective against cancer but the
data certainly warrants further investigation of this relationship.
Indeed one important researcher in the field of soya states
that: “given the nutrient profile and phytochemical contribution
of legumes, nutritionists should make a concerted effort to
encourage the public to consume more beans in general and
more soya foods in particular.” (110). THE VERY BEST ANTI-CANCER DIET A landmark study published in 1994 in the British Medical Journal found that vegetarians suffer 40% less cancer mortality than the population average, even with controls for smoking, body weight and socio-economic status (114). In the words of Professor Jane Plant a completely plant-only diet may confer even greater advantages: “Undoubtedly, the best anti-cancer diet would be completely vegan.” (58). Coronary Heart Disease (CHD) is the cause of nearly a quarter of all deaths in England and persists as the UK's number one health problem with one in three men and one in four women dying from it. Treating CHD costs the NHS £500 million each year (115). According to the WHO's report on diet, nutrition and disease published in 1991, dietary factors clearly play a role in CHD: “All the available evidence suggests that, for cardiovascular disease and cancer, diet has an influence throughout the life cycle, even though the end-points are manifested in the adult.” (116). World renowned heart surgeon Christiaan Barnard performed the world's first heart transplant in 1967. After 30 years of surgery he has come to the conclusion that most heart attacks are unnecessary – we have the power to prevent them. He states that our diet lacks sufficient fruits and vegetables, is not properly balanced and that we should live like the people of Crete. Here heart disease is almost unknown, and along with other dietary norms fruit and vegetables are the mainstay of the diet and their consumption of meat is 32% less than in northern Europe (121). This is of course the typical 'Mediterranean' diet that has many elements to it that support a far more healthier way of eating. Indeed two recently published articles in the British Medical Journal detailing the results of the WHO World Health Report 2000 clearly show that many of the countries performing best in terms of health of their populations are characterised by such diets (265, 266). A well-balanced vegetarian diet – by its very nature – is very much along the lines of a Mediterranean-type diet typified as it is by higher intakes of plant foods especially fruits and vegetables and of course zero meat consumption. A number of studies have demonstrated that a vegetarian diet can lead to a much reduced risk of heart disease. A key paper published in 1998 concluded from a collaborative analysis of 76,000 men and women in five prospective studies that vegetarians have a lower risk of dying from ischaemic heart disease (IHD) than non-vegetarians (122). A similar review study in 1999 actually put a figure to this decreased risk. Here, compared with non-vegetarians, Western vegetarians were found to have a lower BMI, a lower plasma cholesterol concentration and lower mortality from ischaemic heart disease by about 25%. These findings led the authors to state that the evidence available suggests that widespread adoption of a vegetarian diet could prevent approximately 40,000 deaths from IHD in Britain each year (123). Faced with such clear evidence as this and a cash-strapped NHS it is a surprise that a vegetarian diet is not available by prescription! Indeed a recent comprehensive review of the beneficial and adverse effects of vegetarian diets in various medical conditions makes this exact point. The authors conclude that: “The burden of modern lifestyle diseases is enormous when the costs of investigation, diagnosis, treatment and primary and secondary prevention are included. Thus, dietary intervention with a vegetarian diet seems to be a cheap, physiological and safe approach for the prevention, and possibly management of modern lifestyle diseases.” Dr M Segasothy, NT Clinical School of Medicine of Flinders University, Australia (239). A new piece of research published this year in the Journal of Clinical Pathology gives a clue as to one of the reasons why a vegetarian diet may lead to lower heart disease risk. Scottish researchers found that levels of salicylic acid in the blood of vegetarians were up to one and a half times significantly higher than in meat eaters. Some vegetarians had levels up to 12 times higher (253). Salicylic acid is the main component of aspirin – widely prescribed to reduce the risk of heart attacks – which helps fight the inflammation that causes most cardiovascular illness. Salicylic acid is also present in fruits and vegetables suggesting a high dietary intake may produce some of the same good effects as aspirin. Dr John Paterson who helped conduct the research states there is also evidence that aspirin can protect against bowel, breast and lung cancer as well as Alzheimer's disease. “It may be that salicylic acid in the diet can help prevent these diseases.” (252). Another reason why vegetarians have a reduced risk of heart disease is thought to be caused by factors in the diet having a beneficial effect on vascular dilatory responses. Impairment of the ability of blood vessels to dilate or relax is an important early event in the lead up to plaques forming in vessels. A recent study reported in Atherosclerosis found that the vascular dilatory responses of vegetarians are better than omnivores. Just as importantly these effects are dependent on diet alone, independent of other known risk factors for atherosclerosis (clogged up arteries) such as smoking, diabetes, hypertension and ageing (261). Whilst not the only factor in the causation of CHD cholesterol is still considered a prime indicator of risk for this disease. Dietary cholesterol is not an essential nutrient since the liver can make all that it needs. Cholesterol is transported in the bloodstream and supplied to different body tissues by five major classes of lipoprotein, (fat and protein complexes) the two most important being low-density lipoproteins (LDL-cholesterol) and high-density lipoproteins (HDL-cholesterol). LDL-cholesterol transports cholesterol to the arteries and plays a significant role in the metabolic processes leading to atherosclerosis. HDL-cholesterol – 'good cholesterol' – carries cholesterol to the liver so the body can get rid of it. Since LDL-cholesterol accounts for most of the total cholesterol in the blood, elevated total serum cholesterol is therefore regarded as a reliable indicator of the risk for developing atherosclerosis and CHD (120). The foremost dietary determinant of total serum cholesterol is the intake of saturated fat. This type of fat is found principally in foods of animal origin and is particularly rich in the fatty portion of meat, eggs and milk products. Studies have suggested that whereas saturated fats elevate serum cholesterol levels, polyunsaturated fats (and possibly monounsaturated fats) actually lower levels (124). This is echoed by research showing that replacement of saturated fatty acids with almonds or walnuts (typical vegetarian staples which are high in polyunsaturated fats) lowers both total cholesterol levels and LDL-cholesterol levels. Compared with a reference population this study found that there were significant reductions of 7% and 10% respectively with almonds and 5% and 9% reductions respectively when walnuts were used in place of saturated fat (267). Saturated fat encourages the body to make more cholesterol than it needs and seems to prevent it from getting rid of the excess, leading to the narrowing of the arteries (118). Approximately 15% of dietary energy (calories) in the UK diet comes from saturated fat. Experts recommend that this be reduced to just 11% (125). A very recent literature review makes the point that the advice to reduce consumption of eggs – a major source of dietary cholesterol – may still be important in the prevention of coronary heart disease. The paper's authors also state that other major sources of dietary cholesterol – dairy fats and meat – are already considered as increasing the risk of heart disease because of their saturated, cholesterol-rich profiles and should likewise be reduced (268). The WHO report in 1991 states: “Population data clearly associate a decrease in saturated fatty acid intake with a progressive fall in cardiovascular disease mortality... A value of 10% of energy has thus been fixed as the maximum upper limit for saturated fatty acids... Saturated fatty acids are not essential nutrients... The lower limit for saturated fatty acids is therefore zero.” (127). This statement is lent support when one considers that from a public health standpoint, 'lean' red meat diets and white meat diets are both largely ineffective in reducing serum cholesterol concentrations. Hardly suprising when one considers that unlike fat, cholesterol is located mainly in the lean portion of meat. Low-fat vegetarian diets that forgo all meats can achieve serum total and LDL-cholesterol concentration falls of 23% and 32% respectively. These stand in stark contrast to many cholesterol-lowering programs that see serum cholesterol concentrations fall by only 5 to 6% (126). A recent study by Ashton and colleagues also highlights the greater benefits of plant sources of protein compared to protein from lean meats. Replacement of lean meat with tofu (soya bean curd) in this study found significantly lower total cholesterol and triglyceride (fat) levels compared with the lean meat diet (237). There is increasing evidence to suggest that vegans may have an even greater advantage. Thorogood et al found that differences in total cholesterol concentration suggest that not only the incidence of coronary heart disease may be 24% lower in lifelong British vegetarians but 57% lower in lifelong vegans (131). There is increasing speculation that cow's milk products may be playing a role in the high rates of CHD in Western countries. Research by Sacks et al has found that dairy products were the major sources of dietary saturated fat and cholesterol and that ingestion of fatty dairy products raises the LDL-cholesterol levels in the subjects followed (128). Way back in 1982 Segall made the compelling point that in Switzerland a falling cardiovascular mortality rate has been associated selectively with a fall in milk consumption, amounting to 46%, between 1951 and 1976 (129). The theory that plasma homocysteine levels are directly associated with cardiac disease risk is one gaining considerable ground. This too may therefore be another factor why plant-based diets reduce CHD risk. Homocysteine is an amino acid found in high levels in foods of animal origin. A straightforward hypothesis would be that a vegetarian diet and more so vegan diet would have lower levels of this potentially damaging protein. Very recently DeRose and colleagues in Preventive Medicine published a study clinically demonstrating such an effect. In just one week on a vegan diet, as well as lifestyle interventions, subjects mean homocysteine levels fell 13% (130). A study by Grant into possible dietary associations with CHD in 1998 found that milk carbohydrate (lactose) had the highest statistical association for CHD for males aged 35+ and females aged 65+. Non-fat milk was found to have the highest association for CHD for males aged 45+ and females aged 75+, while for females 65-74, milk carbohydrates (and sugar) had the highest associations. A number of possible mechanisms have been put forward for this, the most prominent of which is the plasma homocysteine hypothesis. Animal proteins contribute to homocysteine (Hcy) production and cow's milk lacks adequate B vitamins (vitamin B6, B12 and folic acid) to convert Hcy to less harmful products. Lactose and calcium in conjunction with Hcy from consumption of non-fat milk may also contribute to calcification (hardening) of the arteries (132). A VEGETARIAN DIET CAN REVERSE CHD Not only can a vegetarian diet lower the risks of getting heart disease in the first place it can also halt and reverse even severe CHD. Dr Dean Ornish and colleagues have demonstrated that a near-vegan diet (no animal products allowed except egg white and one cup per day of non-fat milk or yoghurt) caused a significant overall regression of coronary atherosclerosis in patients with moderate to severe coronary heart disease (119, 211). “The Reversal Diet is a very low-fat vegetarian diet.. This is what the patients in our study consumed, whose coronary heart disease began to reverse. I am convinced that this is the world's healthiest diet for most adults, whether or not they have heart disease.” Dr Dean Ornish, Director of Preventive Medicine Research Institute, California, and the first clinician to offer proof that heart disease can be halted or even reversed on a vegetarian diet (282). The evidence for a protective effect of a vegetarian diet for heart health is very clearly documented in an on-going landmark study – The China Health Study. This is a comprehensive survey of diet and mortality characteristics in 65 counties in rural China overseen by Professor Colin Campbell. All the evidence points to the conclusion that even small intakes of foods of animal origin are associated with significant increases in plasma cholesterol concentrations, which are associated, in turn, with significant increases in chronic degenerative disease mortality rates (117). Fibre or NSP (Non-Starch Polysaccharides) is a collection of indigestible substances found in all plant cells. Hence virtually every food that comes from a plant will contain it and is why vegetarians have greater intakes than non-vegetarians do. Food from animal sources contains no fibre whatsoever. There are two types of fibre – soluble and insoluble. Soluble fibre is found in fruits and vegetables and the richest sources are vegetable protein foods like lentils, peas and beans. Oats are also rich in this type of fibre. Soluble fibre dissolves in the fluid of the gut and helps to maintain even blood sugar levels. It is also known to reduce cholesterol levels in the body. Insoluble fibre found in cereals, breads, rice, pasta as well as fruits and vegetable adds bulk to waste products ensuring easy passage of this waste through the digestive system. According to the National Food Survey the average intake of fibre in the UK diet is 11.9 grams per person per day (133). Nutritionists are in agreement that adult diets should contain an average for the population of 18 grams of fibre per day (134). Not surprisingly, vegetarian diets are found to be far richer in fibre than average meat-based diets (254). Non-Insulin Dependent Diabetes (NIDDM) is much more common than the childhood-onset variety (IDDM). It is estimated that 150 million worldwide people have NIDDM with 5% or 22.5 million adults in Europe affected, including two million in the UK. The WHO estimates that by 2025 there will be at least 300 million sufferer's worldwide. The cost implications are truly staggering. In Europe and the US 10-15% of total health care expenditure goes on NIDDM and associated complications. This amounts to £2bn a year in the UK (216). By maintaining an appropriate weight, the risk of developing the disease is greatly diminished. Once again vegetarians – who as a group are typically leaner than omnivores – have a particular advantage in this aspect of health. NIDDM, which usually starts in middle adulthood, is strongly associated with an increased risk of CHD as well as kidney, nerve and eye disorders. In pregnant diabetics the disease may have an adverse effect on the foetus. Approximately 80% of NIDDM sufferers are obese. The incidence rate is close to double in people who are only moderately overweight (226). Vegetarians and vegans are less at risk from diabetes than meat-eaters as a 21-year study in America found. Over 25,000 adult Americans were studied and the results showed that people on meat-free diets had a 45% reduced risk of developing diabetes compared to the population as a whole. Meat consumption was po |