Cary G Dean.
www.Cholesterol-and-Health.org.uk
The Bran Wagon
The belief that regular bowel movement is important for health is very ancient.
But the present theory is based on Dr. Dennis Burkitt's discovery that relatively few rural black Africans suffer from cancer of the colon.
He attributed this to their relatively crude diet.
The Bran Wagon
The belief that regular bowel movement is important for health is very ancient.
But the present theory is based on Dr. Dennis Burkitt's discovery that relatively few rural black Africans suffer from cancer of the colon.
He attributed this to their relatively crude diet.
The theory was that, as fibre made food travel through the gut faster, it allowed less time for cancer-inducing agents to form.
This, of course, presupposed that food became carcinogenic in the gut and there was no evidence that it did.
Neither was there any evidence that moving food through the intestine at a faster rate decreased the risk of colon cancer.
Moreover, the rural Africans' lifestyle was far from that of the Western city dweller: their diet is different, but also they were not exposed to so many pollutants, toxins or mental stresses.
Indeed, there were many factors that could have been responsible for a difference in disease patterns.
Other communities - the Mormons of Utah, for example - also enjoyed a low incidence of colon cancer yet they ate a low-fibre diet.
This, of course, presupposed that food became carcinogenic in the gut and there was no evidence that it did.
Neither was there any evidence that moving food through the intestine at a faster rate decreased the risk of colon cancer.
Moreover, the rural Africans' lifestyle was far from that of the Western city dweller: their diet is different, but also they were not exposed to so many pollutants, toxins or mental stresses.
Indeed, there were many factors that could have been responsible for a difference in disease patterns.
Other communities - the Mormons of Utah, for example - also enjoyed a low incidence of colon cancer yet they ate a low-fibre diet.
So the theory was unsubstantiated at the time and it was to be disproved in practice later as the rural Africans moved into towns and adopted a Western style low fibre diet.
Their incidence of colon cancer has remained low and this has continued with the second generation.
Nevertheless, these later findings were not publicised.
Burkitt's theories caught the attention of the media.
Always ready to exploit a good story, they expanded what was at best a very weak hypothesis into a treatment dogma that teaches that fibre is a panacea for all manner of illnesses.
Their incidence of colon cancer has remained low and this has continued with the second generation.
Nevertheless, these later findings were not publicised.
Burkitt's theories caught the attention of the media.
Always ready to exploit a good story, they expanded what was at best a very weak hypothesis into a treatment dogma that teaches that fibre is a panacea for all manner of illnesses.
Commercial interests were quick to see the potential in the recommendation and jump on the
"BRAN WAGON"?.
Burkitt's recommendation was based on vegetable fibre, but bran (cereal fibre) has a far higher fibre content and bran was a practically worthless by-product of the milling process that, until then, had been thrown away.
Almost overnight, it became a highly priced profit maker.
( As Alway's Folk's Just Follow the Money )
Although totally inedible, backed by Burkitt's fibre hypothesis, bran could now be promoted as a valuable food.
But Dr. Hugh Trowell, Burkitt's partner and another strong advocate of dietary fibre, stated in 1974 that:
"BRAN WAGON"?.
Burkitt's recommendation was based on vegetable fibre, but bran (cereal fibre) has a far higher fibre content and bran was a practically worthless by-product of the milling process that, until then, had been thrown away.
Almost overnight, it became a highly priced profit maker.
( As Alway's Folk's Just Follow the Money )
Although totally inedible, backed by Burkitt's fibre hypothesis, bran could now be promoted as a valuable food.
But Dr. Hugh Trowell, Burkitt's partner and another strong advocate of dietary fibre, stated in 1974 that:
"A serious confusion of thought is produced by referring to the dietary fibre hypothesis as the bran hypothesis, for many Africans do not consume cereal or bran"
Fibre and coronary heart disease.
The idea that fibre could protect against heart attacks was hypothesised by Trowell in 1972, again based on research on rural Africans.
The dietary intervention trials mentioned earlier, however, concluded that increasing dietary fibre had no beneficial effect on heart disease.
The dietary intervention trials mentioned earlier, however, concluded that increasing dietary fibre had no beneficial effect on heart disease.
Fibre and other diseases.
It may be useful at this stage to consider the claims for fibre in curing or preventing other diseases.
For example, bran has been a popular way to manage irritable bowel syndrome (IBS) for about thirty years, despite the fact that no placebo-controlled study of bran in IBS has yet shown any convincing beneficial effect.
A study, published in 1994, found that while fruit fibre was effective, bran only made the situation worse.
Far from being a cure for IBS, they found that it was the bran that was causing it!
Bran also caused bowel disturbances, abdominal distension and pain.
For example, bran has been a popular way to manage irritable bowel syndrome (IBS) for about thirty years, despite the fact that no placebo-controlled study of bran in IBS has yet shown any convincing beneficial effect.
A study, published in 1994, found that while fruit fibre was effective, bran only made the situation worse.
Far from being a cure for IBS, they found that it was the bran that was causing it!
Bran also caused bowel disturbances, abdominal distension and pain.
Moreover, there is no direct evidence that an increase of fibre by itself will prevent or cure the other diseases.
With respect to colon cancer, Burkitt's theory was questioned with the suggestion that the low cancer rates in rural Africans may be due to their high early death rates from other causes.
With respect to colon cancer, Burkitt's theory was questioned with the suggestion that the low cancer rates in rural Africans may be due to their high early death rates from other causes.
There is also a growing scepticism in the USA that lack of fibre causes cancer;
Some studies even suggesting that a fibre-enhanced diet increases!!! the risk of colon cancer.
Some studies even suggesting that a fibre-enhanced diet increases!!! the risk of colon cancer.
Other adverse effects.
Tests into the supposed benefits of dietary fibre soon showed that there could be other harmful side effects.
All the nutrients in food are absorbed through the gut wall and this takes time.
Fibre, by speeding food through the gut faster so that less nutrients are absorbed, inhibits the absorption of iron, calcium, phosphorus, magnesium, energy, proteins, fats and vitamins A, D, E and K.
This happens with all types of fibre although with a normal Western-style, nutrient-rich diet, the loss caused by vegetable fibre intake is unimportant.
More importantly, phytate found in cereal fibre (bran) also binds with calcium, iron and zinc making them indigestible, which in turn causes malabsorption.
One study, for example, showed that subjects absorbed more iron from white bread than from wholemeal bread even though their intakes of iron were fifty percent higher with the wholemeal bread.
Bran has also been shown to cause faecal losses of calcium, iron, zinc, phosphorus, nitrogen, fats, fatty acids and sterols, thus depleting the body of these materials.
All the nutrients in food are absorbed through the gut wall and this takes time.
Fibre, by speeding food through the gut faster so that less nutrients are absorbed, inhibits the absorption of iron, calcium, phosphorus, magnesium, energy, proteins, fats and vitamins A, D, E and K.
This happens with all types of fibre although with a normal Western-style, nutrient-rich diet, the loss caused by vegetable fibre intake is unimportant.
More importantly, phytate found in cereal fibre (bran) also binds with calcium, iron and zinc making them indigestible, which in turn causes malabsorption.
One study, for example, showed that subjects absorbed more iron from white bread than from wholemeal bread even though their intakes of iron were fifty percent higher with the wholemeal bread.
Bran has also been shown to cause faecal losses of calcium, iron, zinc, phosphorus, nitrogen, fats, fatty acids and sterols, thus depleting the body of these materials.
These findings are a cause for concern in several sections of the population who are at considerable risk from eating too much fibre - and bran fibre in particular:
The incidence of osteoporosis (brittle bone disease) is increasing and now affects one in two post-menopausal women, one in five of whom will die as a direct result.
Osteoporosis is also increasingly affecting men.
Osteoporosis is caused by several factors, but lack of calcium is the basic problem.
Bran both inhibits the absorption of calcium from food and depletes the body of the calcium it has.
Moreover, zinc, which bones need to heal, is another mineral whose absorption is adversely affected by bran.
Osteoporosis is also increasingly affecting men.
Osteoporosis is caused by several factors, but lack of calcium is the basic problem.
Bran both inhibits the absorption of calcium from food and depletes the body of the calcium it has.
Moreover, zinc, which bones need to heal, is another mineral whose absorption is adversely affected by bran.
Sufferers from Alzheimer's Disease (senile dementia) are found to have abnormal amounts of aluminium in their brains.
Tests on the people of Guam and parts of New Guinea and Japan, who get Alzheimer's disease at a much younger age, suggest that it is lack of calcium, causing a hormonal imbalance that permits the aluminium to penetrate the brain.
Tests on the people of Guam and parts of New Guinea and Japan, who get Alzheimer's disease at a much younger age, suggest that it is lack of calcium, causing a hormonal imbalance that permits the aluminium to penetrate the brain.
Infants may suffer similar brain damage if fed soy-based baby milk as this too has a high phytate content, inhibiting the absorption of zinc, which is essential for proper brain development.
Vitamin deficiency diseases such as rickets that were common in Britain until a diet high in dairy products and meat was advocated are on the increase again.
The situation is getting so bad here that doctors suggest that vegetarian-based fad diets should be classified a form of child abuse.
The situation is getting so bad here that doctors suggest that vegetarian-based fad diets should be classified a form of child abuse.
In the UK, USA, Canada and South Africa the intake of 'anti-nutrients' such as dietary fibre that impair the absorption of iron, accompanied by a low intake of meat (another result of the diet-heart recommendations), is producing a real risk of iron deficiency anaemia.
Depression, anorexia, low birth weight, slow growth, mental retardation , and amenorrhoea are associated with deficiencies of zinc and the first five of these are also associated with a deficiency of iron.
Lastly, excess fibre affects the onset of menstruation, retards uterine growth and, later, is associated with menstrual dysfunction .
Because of the phytate, Professor David Southgate, arguably the world's leading authority on the effects of fibre, concludes that infants, children, young adolescents and pregnant women whose mineral needs are greater should be protected from excessive consumption of fibre.
Writing of the colon cancer risk, Drs. H. S. Wasan and R. A. Goodlad of the Imperial Cancer Research Fund stated in 1996:
"Until individual constituents of fibre have been shown to have, at the very least, a non-detrimental effect in prospective human trials, we urge that restraint should be shown in adding fibre supplements to foods, and that unsubstantiated health claims be restricted."
"Specific dietary fibre supplements, embraced as nutriceuticals or functional foods, are an unknown and potentially damaging way to influence modern dietary habits of the general population."
"Specific dietary fibre supplements, embraced as nutriceuticals or functional foods, are an unknown and potentially damaging way to influence modern dietary habits of the general population."
Until fibre can be shown not to be detrimental they suggest that.
"Restraint should be shown in adding fibre supplements to foods, and that unsubstantiated health claims should be restricted".
January 1999 saw the publication of the largest trial into the effects on fibre on colon cancer ever conducted.
After studying 88,757 women for sixteen years, doctors at the Brigham and Women's Hospital and Harvard Medical School say that
After studying 88,757 women for sixteen years, doctors at the Brigham and Women's Hospital and Harvard Medical School say that
"No significant association between fiber intake and the risk of colorectal adenoma was found."
"Our data do not support the existence of an important protective effect of dietary fiber against colorectal cancer or adenoma."
"Our data do not support the existence of an important protective effect of dietary fiber against colorectal cancer or adenoma."
Summary.
Bran is bad news. While there is not too much harm from fruit fibre, the usual bran that is pushed at us - wheat bran - should be avoided like the plague it is.
The tragedy of science is the slaying of a beautiful hypothesis
by an ugly fact.
T H Huxley
References:
D P Burkitt, et al. Some geographical variations in disease patterns in East and Central Africa. E Afr Med J . 1963; 40: 1.
H C Trowell. Fibre and irritable bowels. BMJ. 1974; 3: 44.
- Dietary fibre, ischaemic heart disease and diabetes mellitus. Proc Nutr Soc. 1973; 32: 151.
C Y Francis, P J Whorwell. Bran and irritable bowel syndrome: time for reappraisal. Lancet 1994; 344: 39.
F Swain, et al. Comparison of the effects of oat bran and low-fiber wheat on serum lipoprotein levels and blood pressure. New Eng J Med. 1990; 322(3): 147.
W E Connor. Dietary fiber - nostrum or critical nutrient? New Eng J Med. 1990; 322 (3): 193.
E Marshall. Diet Advice, with a Grain of Salt and a Large Helping of Pepper. Science. 1986; 231: 537.
M J Lichtenstein, et al. Heart rate, employment status and prevalent ischaemic heart disease confound relationship between cereal fibre intake and blood pressure. J Epid Comm Hlth. 1986; 40(4): 330.
D Norman, et al. The impact of dietary fat and fibre on intestinal carcinogenesis. Prev Med. 1987; (4): 554.
I MacDonald. Nonsense and non-science in nutrition.. Proc Nutr Soc. 1983; 42: 513Anon. BMJ . 1986; 292: 494.
J L Kelsay. A review of research on effect of fibre intake on man. Am J of Clin Nutr. 1978; (31): 142.
K Kaneko, et al. Effect of fibre on protein, fat and calcium digestibilities and fecal cholesterol excretion. J Nutr Sci Vitaminol (Tokyo). 1986; 32(3): 317.
D Kritchevsky. Fibre and cancer. In Dietary Fibre: Basic and Clinical Aspects. (G V Vahouny and D Kritchevsky eds.) p427. Plenum, NY. 1986.
- Dietary studies of cancer of the large bowel in the animal model . Ibid p469.
H S Wasan, R A Goodlad. Fiber-supplemented foods may damage your health. Lancet 1996; 348: 319-20.
C S Fuchs, et al. Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women. N Eng J Med 1999; 340: 169.
G Gerutti, et al. Phytic acid in bran and in 'natural' foods. Bolletino Chimico Farmaceutico, Milan.
J Stevens, et al. Effect of psyllium gum and wheat bran on spontaneous energy intake. Am J Clin Nutr. 1987; 46: 812.
Editorial. The Bran Wagon. Lancet. 1987; i: 782.
Y P Suri. The Bran Wagon. Lancet. 1987; ii: 42.
G S Bindra and R S Gibson. Iron status of predominantly lacto-ovo-vegetarian East Indian immigrants to Canada: a model approach. Am J Clin Nutr. 1986; 44: 643.
J R Turnlund, et al. A stable isotope study of zinc absorption in young men: effects of phytate and alpha-cellulose. Am J Clin Nutr. 1984; 40: 1071.
B Sandstrom, et al. The effects of vegetables and beet fibre on the absorption of zinc in humans from composite meals. Br J Nutr. 1987; 58 (1): 49.
L Hallberg, et al. Phytates and the inhibitory effect of bran on iron absorption in man. Am J Clin Nutr. 1987; 45(5): 988.
R Balasubraminian, et al. Effect of wheat bran on bowel function and fecal calcium in older adults. J Am Coll Nutr . 1987; 6(3): 199.
J Hallfisch, et al. Mineral balances of men and women consuming high fibre diets with complex or simple carbohydrate. J Nutr . 1987; 117(2): 403.
Fractured neck of femur: prevention and management. A report of the Royal College of Physicians, London. 1989.
Editorial:
Why so many fractured hips? Lancet. 1989; 1: 57.
A M Fehily. Dietary determinants of bone mass and fracture risk: a review. J Hum Nutr and Diet . 1989; 2: 299.
M J Wargovich, A R Baer. Basic and Clinical Investigations of Dietary Calcium in the Prevention of Colorectal Cancer. Prev Med. 1989; 18: 672.
BBC. Horizon: The Poison That Waits . BBC2 broadcast 16 Jan 1989.
N Bishop, M McGraw and N Ward. Aluminium in infant formulas. Lancet. 1989; i: 490.
B E Golden, M H N Golden. Plasma zinc, rate of weight gain and the energy cost of tissue deposition in children recovering from malnutrition on cows' milk or a soya protein based diet. Am J Clin Nutr . 1981; 34: 892.
A Prasad. The role of zinc in gastrointestinal and liver disease. Clin Gastroenterol. 1983; 12: 713.
P Aggett, N Davies. Some nutritional aspects of trace elements. J Inter Metab Dis. 1983; 6(2): 22.
M Hambidge. The role of zinc and other trace metals in paediatric nutrition and health. Paediat Clin N Am. 1977; 24: 95.
D Bryce-Smith, R Simpson. Anorexia, depression and zinc deficiency. Lancet. 1984; ii: 1162.
V Fonesca, C Harvard. Electrolyte disturbances and cardiac failure with hypomagnesaemia in anorexia nervosa. BMJ. 1985; 291: 1680
N Meadows, et al. Zinc and small babies. Lancet . 1981; ii: 1135.
D Bryce-Smith. Environmental chemical influences on behaviour and mentation. John Jeyes lecture. Chem Soc Rev. 1986; 15: 93.
A McMichael, et al. A prospective study of serial maternal zinc levels and pregnancy outcome. Early Human Development. 1982 (Elsevier); 7: 59.
D Addy. Happiness is: iron. BMJ. 1986; 292: 969
E M Luk'ianova. Diagnosis of vitamin D deficiency rickets. Pediatriia. 1988;(3):15.R Adelman. Nutritional rickets. Am J Dis Child. 1988; 142(4): 414.
M R Clements. The problem of rickets in UK Asians. J Hum Nutr Diet , 1989; 2: 105.R E Hughes. A new look at dietary fibre. Hum Nutr Clin Nutr. 1986; 40c: 81.
R E Hughes, E Johns. Apparent relation between dietary fibre and reproductive function in the female. Ann Hum Biol. 1985; 12: 325.
T Lloyd, et al. Inter-relationships of diet, athletic activity, menstrual status and bone density in collegiate women. Am J Clin Nutr. 1987; 46: 681.
D A T Southgate. Minerals, trace elements and potential hazards. Am J Clin Nutr. 1987; 45: 1256.
H S Wasan, R A Goodlad. Fiber-supplemented foods may damage your health. Lancet 1996; 348: 319-20.
C S Fuchs, et al. Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women. N Eng J Med 1999; 340: 169.
About the Author:
-------------------------------------------------------------
No comments:
Post a Comment