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Diet
& Lifestyle
Vegetarianism Research
Vegetarianism
& Colon cancer
Vegetarians
have lower rates of colon cancer than non-vegetarians (Phillips, 1980).
Incidence of colon cancer has been strongly linked to the consumption of
meat (Armstrong, 1975). Willett (1990) carried out a study of over 88 000
women aged 34 to 59 years. Women eating red meat daily ran over twice the
risk of developing colon cancer than women eating red meat less than once
a month.
Reduced incidence of colon cancer in
vegetarians may be attributed to dietary differences which include
increased fibre intake, increased consumption of fruit and vegetables, and
decreased intake of total fat and saturated fat. The mechanism by which a
vegetarian diet is protective against colon cancer is unclear and a great
deal of research is being carried out in this area.
It has been suggested that secondary
bile acids are carcinogens which may play an important role in colon
cancer. These are derived by bacterial metabolism from primary bile acids
made in the liver and secreted into the intestine. Vegetarians have lower
levels of secondary bile acids than non-vegetarians (Turjiman, 1984). The
differences in bacterial populations between the intestines of vegetarians
and non-vegetarians may also be important. Bacterial flora in vegetarians
has been shown to possess reduced ability to transform bile acids into
potential carcinogens (Johansson, 1990).
The role of dietary fibre in
prevention of colon cancer may also be important. This was first noted in
1971 when it was suggested the high incidence of colon cancer in Western
countries was linked to low fibre diets. Other dietary components
associated with high fibre foods have also been implicated as having
protective effects.
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Vegetarianism &
Diverticula disease
Diverticular disease affects the
colon and symptoms include lower abdominal pain and disturbed bowel habit.
It occurs frequently in western countries where intake of dietary fibre is
low. Gear (1979) found diverticular disease to be less frequent in
vegetarians, 12% of vegetarians studied having diverticular disease
compared with 33% of non-vegetarians. This is thought to be due to the
increased fibre of vegetarian diets.
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Vegetarianism &
Gall
stones
Gall stones are composed of
cholesterol, bile pigments and calcium salts. They form in the gall
bladder and can cause severe pain. A study of over 750 women found the
incidence of gall stones to be less frequent in vegetarians. 25% of
non-vegetarians compared with 12% of vegetarians had gall stones. After
controlling for age and body weight, non-vegetarians were found to have a
relative risk of gall stones almost twice that of the vegetarians (Pixley,
1985).
Vegetarians are leaner, and consume more dietary fibre and less dietary
cholesterol, all of which is believed to protect against gall stone
formation.
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Vegetarianism &
Kidney
stones
Kidney stones form in the
kidney and can cause considerable pain when passing down the urinary
tract. Prevalence of kidney stones is lower in vegetarians (Peacock,
1969).
A high intake of animal protein increases the urinary loss of calcium
and oxalate, known risk factors in kidney stone formation. Meat is also
high in purines which leads to increased uric acid in the urine. Urinary
uric acid is also a risk factor for kidney stones.
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Vegetarianism & Other diseases
A vegetarian diet has been claimed
to reduce the risk of gout, hiatus hernia, constipation, haemorrhoids, and
varicose veins. These diseases are linked to diets low in fibre and high
in saturated fat.
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Vegetarianism & Food poisoning
Over 58 000 cases of food poisoning
were reported in 1990 and the actual incidence of food poisoning is
estimated to be ten times this figure. Meat, eggs and dairy products are
the primary sources of food poisoning. Professor Richard Lacey of the
University of Leeds has stated that "More than 95% of food poisoning
is derived from meat and poultry products".
Pesticide residues in foods include PCBs and dioxins. These are found
in highest concentrations in meat, fish and dairy products. Studies have
shown these toxic chemicals can be passed on from pregnant women to
infants during both pregnancy and lactation and may damage the developing
nervous systems. Hall (1992) has stated a vegetarian diet minimises the
risk of contamination.
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Vegetarianism & Nephrotic syndrome
(Kidney disease)
Nephrotic syndrome is a kidney condition involving high levels of
protein in the urine which may lead to progressive kidney damage as well
as promoting atherosclerosis and heart disease. Studies have shown a low
protein vegan diet can be used to reduce the symptoms of nephrotic
syndrome (D’Amico, 1992).
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The
China Health Project
The China Project on Nutrition, Health & Environment is a massive
study involving researchers from China, Cornell University in Boston, and
the University of Oxford, into the relationships between diet, lifestyles
and disease-related mortality in 6500 Chinese subjects from 65 mostly
rural or semi-rural counties.
The rural Chinese diet is largely vegetarian or vegan, and involves
less total protein, less animal protein, less total fat and animal fat,
and more carbohydrate and fibre than the average Western diet. Blood
cholesterol levels are significantly lower. Heart disease, cancer,
obesity, diabetes, and osteoporosis are all uncommon. Areas in which they
are becoming more frequent are areas where the population has moved
towards a more Western diet with increasing consumption of animal
products.
The China Health Project has clearly demonstrated the health benefits
of a diet based on plant foods. One of the Project’s co-ordinators, Dr
Cohn Campbell of Cornell University, has stated that "We’re
basically a vegetarian species and should be eating a wide variety of
plant foods and minimising our intake of animal foods."
REFERENCES
- Abelow, B J et al. (1992) Cross-cultural association between dietary
animal protein and hip-fracture. Calcified Tissue International v.50
p.14-18.
- Appleby, P et al. (1995). Emercy appendicectomy and meat consumption in
the UK. BMJ v.49 p.594-596.
- Armstrong, B. (1977) Blood pressure in Seventh Day Adventist
vegetarians. Am Jnl Epidemiology v.105 p.444-9
- British Medical Association (1986). Diet, nutrition and health.
BMA,
London.
- Burr, M & Butland, B. (1988) Heart disease in British vegetarians.
Am Jnl Clinical Nutrition v.48 p.830-2.
- Claude-Chang, J et al. (1992) Mortality pattern of German vegetarians
after 11 years of follow-up. Epidemiology v.3 (5) p.395-401.
- D’Amico, Get al. (1992) Effect of vegetarian soy diet on
hyperlipidaemia in nephrotic syndrome. The Lancet v.339 p.1131-34.
- Dickerson, J & Davies, J. (1986) Consequences for health of a
vegetarian diet, Postdoctoral thesis, University of Surrey.
- Doll, R. (1990) Symposium on diet and cancer. Proc of the Nutrition
Society v.49 p.119-31.
- Dwyer, J T. (1988) Health aspects of vegetarian diets. Am .inI Clinical
Nutrition v.48 p.712-38.
- Fraser, G et aI (1991) Diet and lung cancer in Seventh Day Adventists.
Am Jnl Epidemiology v.133 p.683-93.
- Gear, J Set al. (1979) Symptomless diverticular disease and intake of
dietary fibre. The Lancetv.1 p.511-14.
- Hall, R H. (1992) A new threat to public health: organochlorines and
food. Nutrition & Health v.8 p.33-43.
- Johansson, Get aI. (1990) Shift from a mixed diet to a lactovegetarian
diet: influence on some cancer-associated intestinal bacterial enzyme
activities. Nutrition & Cancer v.14 p.239-46.
- Key, T J et al. (1998) Mortality in vegetarians and non-vegetarians: a
collaborative analysis of 8,300 deaths among 76,000 men and women in five
prospective studies. Public Health Nutrition
- Kjeldsen-Kragh, Jet aI. (1991) Controlled trial of fasting and one-year
vegetarian diet in rheumatoid arthritis. The Lancet v.338 p.899-902.
- Margetts, B M et al. (1986) Vegetarian diet in mild hypertension: a
randomised controlled trial. BMJ v.293 p.1468-71.
- Marsh, A Get al. (1988) Vegetarian lifestyle and bone mineral density.
Am Jnl Clinical Nutrition v.48 (3) p.837- 41.
- Martin, M J et al. (1986) Serum cholesterol, blood pressure and
mortality: implications from a cohort study of 361 662 men. The Lancet
p.933-6.
- Millet, Petal. (1989) Nutrient intake and vitamin status of healthy
French vegetarians and non-vegetarians. Am .inI Clinical Nutrition v.50
p.718-27.
- Mills P K et al. (1988) Dietary habits and past medical history as
related to fatal pancreas cancer risk among Adventist men. Cancer v.61
(12). p.2578-85.
- Mills, P K et al. (1989) Cohort study of diet, lifestyle and prostate
cancer in Adventist men. Cancer v.64 (3) p.598-604.
- Ornish, D et al. (1990) Can lifestyle changes reverse coronary heart
disease ? The Lancet v.336 p.129-33.
- Peacock, Metal. (1969) Hypercalcuria of renal stone disease. Proc of
Renal Stone Research Symposium, Livingston, London.
- Phillips, R Let al. (1985) Role of lifestyle and dietary habits in risk
of cancer amongst Seventh Day Adventists. Cancer Research v.35
(Supplement) p.3513-22.
- Phillips, R Let al. (1980) Mortality among California Seventh Day
Adventists for selected cancer sites. .Jnl National Cancer Institute v.65
p.1097-107.
- Pixley, F et al. (1985) Effect of vegetarianism on development of gall
stones in women. BMJ v.291 p.11-12.
- Rao, P N et aI. (1989) Epidemiology of oesophageal cancer. Seminars in
Surgery & Oncology v.5 (5) p.35l-4. Resnicow, K et aI. (1991) Diet and
serum lipids in vegan vegetarians. .inI Am Dietetic Association v.91 (4)
p.447- 53.
- Sabate, J et al. (1992) Lower height of lacto-ovo vegetarian girls at
pre-adolescence: an indicator of physical maturation delay. .inI Am
Dietetic Association v.92 (10) p.1263-64.
- Sacks, FM et al. (1974) Blood pressure in vegetarians. Am .inI
Epidemiology v.100 p.390-8.
- Slattery, Met al. (1991) Meat consumption and its associations with
other diet and health factors in young adults: the CARDIA study. Am .inI
Clinical Nutrition v.54 p.930-35.
- Snowdon, D. (1985) Does a vegetarian diet reduce the occurrence of
diabetes Am .Jnl Public Health v.75 p.507-12.
- Snowdon, D. (1988) Animal product consumption and mortality because of
all causes combined, coronary heart disease, stroke, diabetes, and cancer
in Seventh Day Adventist. Am .inI Clinical Nutrition v.48 p.739-48.
- Taber, LA. & Cook, R A. (1980) Dietary and anthropometric
assessment of adult omnivores, fish-eaters and Iacto-ovo-vegetarians. .inI
Am Dietetic Association v.76 p.21-29.
- Thorogood, M et aI. (1994) Risk from death from cancer and ischaemic
heart disease in meat and non meat-eaters. BMJ v.308 p.1667-1671.
- Thorogood, Metal. (1990) Dietary intake and plasma lipid levels:
lessons from a study of the diet of health conscious groups. BMJ v.300
p.1297-1301.
- Turjiman, N et al. (1984) Diet, nutrition and metabolism in populations
at high and low risk for colon cancer: metabolism of bile acids. Am Jnl
Clinical Nutrition v.4 p.937-41.
- Willett, WC et al. (1990) Relation of meat, fat and fibre intake to the
risk of colon cancer in a prospective study among women. New England Jnl
of Medicine v.323 p.1 664-72.
- World Health Organisation (1990). Diet, nutrition and the prevention of
chronic diseases. WHO, Geneva.
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This page was last updated on 28 March 2001 11:27:48
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