Coronary
Dear
heart
disease
and
dietary
fiber
Sir:
Klevay (I) has written that dietary fiber may be a protective factor in coronary heart disease. The British Department of Health and Social Security has already stated that “populations who eat a diet rich in fibre (particularly fibre from cereals and legumes) usually have a lower serum cholesterol concentration and a lower mortality from I.H.D. than those who eat a western type diet relatively low in this kind of fibre” (2). Epidemiological studies also lend support to this hypothesis (3). Prospective animal experiments have now demonstrated that fiber, even cellulose, affects the metabolism of cholesterol and/or bile salts (4-8). Many investigators emphasize that dietary fiber, defined as various celluloses, hemicelluloses, lignins and related substances (9), is an extremely complex group of substances. Fresh light is thrown on the fiber hypothesis by a consideration of the experiment MG of Grande, Anderson and Keys to determine the effect of isocaloric quantities of different carbohydrate foods on serum lipids in man (10). Twelve healthy young men were evenly divided into four groups and each group ate one of four diets, which averaged nearly 3,000 kcal/day, in consecutive 2-week periods. Each diet was composed of a large amount, about 2,500 kcal/day, of a Western-type lowfiber basic diet supplemented by a small amount, 500 kcal/day, of different carbohydrate foods, fiber-free sucrose in diet S, very low-fiber white wheat flour in diet W, moderate-fiber mixed fruit in diet F, and highfiber mixed vegetables in diet V. The crude fiber (CF) content of the four resultant supplemented diets, recorded as CF g/ 100 kcal, was of diets S and W 0.1, of diet F 0.2 and of diet V 0.6. The mean serum cholesterol and serum phospholipid levels of all groups of men remained stationary during the 2-week periods during which men ate low-fiber diets 798
to the editor
The American
Journal
of Clinical
Nutrition
S. W and F, but both lipid levels fell significantly in each group of men while high-fiber diet V was eaten. Starchy sweet potato contributed much energy in the so-called mixed vegetable supplement of diet V. British nutritionalists tend to restrict the term vegetable to low-energy leafy and root vegetables; they place in a separate group high-energy staple starchy foods, roots and tubers (II). This category includes all varieties of potato and plantain and should include even bananas. The socalled mixed vegetable diet V contained starchy staple carbohydrate foods, wherein the full complement of fiber surrounds the starch. It is not fiber-depleted; it remains “packaged” starch. This, in my opinion, is crucial. It is suggested that these four experimental diets illustrate the fundamental difficulty of Western man. He cannot safely supplement his present day basic diet, composed of very low-fiber high-energy foods, such as white wheat flour, sugar, fats, flesh and fish, with small supplements of high-fiber low-energy nonstarchy fruits or nonstarchy leafy and root vegetables. The only adequate supplement is high-fiber high-energy starchy staple foods, such as any variety of potato, also whole cereals and mature leguminous seeds. Further he will not eat these large supplements unless motivated to do so. These foods must be served in an appetizing manner, arid he must be hungry because he voluntarily decreases considerably his traditional highenergy low-fiber foods, especially fat, even also sucrose. Another example of the protective action of starchy staple foods, undepleted of dietary fiber, is now cited. Irish men who grew up in Ireland and subsequently emigrated to Massachusetts had nearly 90% more abnormal coronary disease-type electrocardiograms 28:
AUGUST
1975,
pp.
798-805.
Printed
in U.S.A.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
letters
LETTERS
TO
Pastoral African tribes, like the Masai, adapted from being hunters to that of wandering herdsmen probably 10,000 years ago; they never, like Western man, cultivated crops. Masai have consumed animal fat 300 g/day but rarely manifested signs of coronary disease either on their electrocardiograms or at autopsy (13). Other African tribes, like the Venda, were agriculturists and had only a few cattle. Venda males, who lived as an urban group in the stress of industrialized South Africa, ate fat 126 g/daily, of which 106 g was animal fat (14). They were typical of those Bantu urban groups who very rarely develop coronary heart disease (15, 16). These urban Venda men ate much lightly processed corn meal 494 g/daily. This contributed most of the crude fiber intake of 5.7 g/daily for it was noted that they ate few vegetables and little fruit (14). The British daily diet in 1970 contained on average crude fiber 0.5 g derived from all starchy cereals, 0.9 g derived from potatoes, and 2.7 g from
799
EDITOR
vegetables and fruit (17). British men had very much coronary heart disease. After 26 years continuous medical practice in East Africa, a colleague and I recorded the first case of coronary heart disease in the 15 million inhabitants of those countries; the patient was an obese East African judge consuming a partially Westernized diet (18). It is also suggested that dietary fiber associated with starchy foods is protective against diabetes mellitus (12, 19, 20) and obesity (19, 21). It is suggested that man, subject to evolution, has adapted poorly to fiber-depleted staple foods that contain starch, fats, sucrose and other nutrients. Hugh Trowel!, M.D.
Woodgreen, Hants SP6
Fordingbridge, 2AZ, England
References 1.
L. M. Coronary heart disease and dietary fiber. Am. J: Clin. Nutr. 27: 1202, 1974. 2. Diet and Coronary Heart Disease. Report of the Advisory Panel of the Committee on Medical Aspects of Food Policy (Nutrition) on Diet in Relation to Cardiovascular and Cerebrovascular Disease. Department of Health and Social Security, London; H. M. Stationery Office, 1974, p. 18. 3. TROWELL, H., N. PAINTER AND D. BURKITT. Aspects of the epidemiology of diverticular disease and ischemic heart disease. Am. J. Digest. Diseases 19: 864, 1974. 4. KRITCHEVSKY, D., AND J. A. STORY. Binding of bile salts in vitro by nonnutritive fiber. J. Nutr. 104: 458, 1974. 5. BALM ER, J., AND D. B. ZILVERSMIT. Effect of dietary roughage in cholesterol absorption, cholesterol turnover and steroid excretion in the rat. J. Nutr. 104: 1319, 1974. 6. RANHOTRA, G. S. Effect of cellulose and wheat mill fractions on plasma and liver cholesterol levels in cholesterol-fed rats. Cereal Chem. 50: 358, 1973. 7. MORGAN, B., M. HEALD, S. D. ATKIN, J. GREEN AND E. B. CHAIN. Dietary fibre and sterol metabolism in the rat. Brit. J. Nutr. 32: 447, 1974. 8.
KLEVAY,
MENGE, H., L. H. LITTLEFIELD, L. T. FROBISI-I AND B. T. WEINLAND. Effect of cellulose and cholesterol on blood and yolk lipids and reproductive efficiency of the hen. J. Nutr. 104: 1554, 1974. 9. SPILLER, G. A., AND R. J. AMEN. Research on dietary fibre. Lancet 2: 1259, 1974. 10. GRANDE, F., J. T. ANDERSON AND A. KEYS. Sucrose and various carbohydrate-containing foods and serum lipids. Am J. Clin. Nutr. 27: 1043, 1974. I I. PLATT, B. S. Tables of Representative Values of Foods Commonly Used in Tropical Countries. London: H. M. Stationery Office, 1962.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
than their own brothers who had remained in Ireland. The latter ate approximately 80% more crude fiber, derived largely from a very high consumption of Irish potatoes (12). There need be little disagreement between those who have clearly demonstrated that many Western men have adapted poorly to modern diets which contain much fat, especially animal fat, and those who have suggested, only recently, that fiber, especially that associated with the high-energy starchy staple foods, such as cereals and potatoes, is a protective factor with respect to coronary heart disease. The coin of ischemic heart disease has two sides, risk factors and protective factors, both acting on the mixed amalgam of inheritance. In voluntary diets if fat increases 1 g then staple starchy carbohydrate foods usually decrease 2 g for sugar intakes usually remain stationary. Only thus can the daily voluntary energy intake remain unaltered. If the starchy carbohydrate foods decrease, or increase, then their fiber may decrease, or increase, but on/v if this food is undep/eted offiber. Western man cannot find salvation in supplementing his basic low-fiber high-energy diet with high-fiber low-energy leafy vegetables and fruit; he must change the basic diet to contain much more high-fiber high-energy starchy staple foods.
THE
800 12.
14.
15.
16.
TROWELL, H. Dietary fibre, ischaemic heart disease and diabetes mellitus. Proc. Nutr. Soc. 32: 151, 1973. MANN, G. V., A. SPOERRY, M. GRAY AND D. JARASHOW. Atherosclerosis in the Masai. Am. J. Epidemiol. 95: 26, 1972. LUBBE, A. M. Dietary evaluation. In: A comparative study of rural and urban Venda males, edited by A. Le R. Van Der Merwe and S. A. Fellingham. S. African Med. J. 45: 1289, 1971. WALKER, A. R. P. Studies bearing on coronary heart disease in South African populations. S. African Med. J. 47: 85, 1973. SEFTEL, H. C., I. M. G. SPITz, I. BERSOHN, A. R. GOLDIN, B. I. JOFFE, A. H. RUBENSTEIN AND B. E.
Behavior
Dear
TO
of body
weight
under
a low
THE
EDITOR METZGER.
Metabolic
features
of
Johannesburg
Bantu with myocardial infarction. S. African Med. J. 47: 1571, 1973. 17. ROBERTSON, J. Changes in the fibre content of the British diet. Nature 238: 290, 1972. 18. TROWELL, H. C., AND S. A. SINGH. A case of coronary heart disease in an African. E. African Med. J. 33: 391, 1956. 19. TROWELL, I-I. Diabetes mellitus death-rates in England and Wales 1920-70 and food supplies. Lancet 2: 998, 1974. 20. TROWELL, H. Incidence of diabetes in children. Lancet 2: 1510, 1974. 21. TROWELL, H. Obesity in the Western World. Plant Foods for Man. 2: 20, 1974.
carbohydrate,
high
fat
diet
Sir:
Criticism has been leveled by Hirsch and van Itallie (1) at our findings reported in this journal (2) with respect to the body weight behavior in obese and healthy individuals on a high fat, low carbohydrate diet. However, this criticism did not include any findings of the authors to disprove our results. The question of an increase in metabolism due to an altered carbohydrate-fat relation in favor of fat, and of putting to practical use this effect in the dietotherapy of obesity has been discussed over the years, and varying concepts have been proposed in the literature. Recently, some further insight in support of our findings has been provided by Yoshimura et al. (3). After animal experimentat ion these investigators presented evidence that the oxygen consumption was raised under a regimen high in dietary fats as compared to a carbohydrate-rich diet. Under a fat-rich diet these authors observed an activation of thyroid function (increased iodine uptake by the thyroid gland and increase in labeled protein bound iodine (PBI) after doses of “I) as the possible cause of the observed increase in metabolism. Based on these observations and the findings reported by us (2) on the behavior of the body weight under a high fat, low carbohydrate diet, Sch#{246}nborn et al. (4) studied the metabolization of l-’4C-palmitic acid and the oxygen consumption in normal weight healthy subjects receiving diets high in fat and low in
carbohydrates and low in fat and high in carbohydrates, respectively, but with a constant protein content. These studies revealed that the FFA concentration and metabolism was increased under the high fat, ketogenic diet. The suggestion that the enhanced metabolism detectable under a ketogenic diet might be used to advantage in the dietetic management of obesity could be validated by Rabast et aI. (5) in a group of 45 hospitalized patients with a mean overweight of 58 ± 35%. When comparing the results of a high fat, 1,000-calorie diet to an isocaloric diet high in carbohydrates, the mean daily weight loss throughout the 35-day treatment period was higher under the ketogenic diet with a statistical probability of 90%, the water balance in the two groups not differing significantly. The problem of body-weight regulation involving the supply of dietary energy in excess of nutrient requirements is intimately linked with the question of an increased metabolic activity and of weight reduction under diets with different proportions of carbohydrates and fat. Some decades ago, the concept of “luxus consumption” was formulated by Neumann (6) and Grafe and Graham (7) who pointed out that both in humans and experimental animals a supply of dietary energy in excess of the calculated requirements does not produce the increase in body weight that would be expected to occur on the basis of calculations. These authors, and also some other
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
13.
LETTERS
Dear
heart
disease
and
dietary
fiber
Sir:
Klevay (I) has written that dietary fiber may be a protective factor in coronary heart disease. The British Department of Health and Social Security has already stated that “populations who eat a diet rich in fibre (particularly fibre from cereals and legumes) usually have a lower serum cholesterol concentration and a lower mortality from I.H.D. than those who eat a western type diet relatively low in this kind of fibre” (2). Epidemiological studies also lend support to this hypothesis (3). Prospective animal experiments have now demonstrated that fiber, even cellulose, affects the metabolism of cholesterol and/or bile salts (4-8). Many investigators emphasize that dietary fiber, defined as various celluloses, hemicelluloses, lignins and related substances (9), is an extremely complex group of substances. Fresh light is thrown on the fiber hypothesis by a consideration of the experiment MG of Grande, Anderson and Keys to determine the effect of isocaloric quantities of different carbohydrate foods on serum lipids in man (10). Twelve healthy young men were evenly divided into four groups and each group ate one of four diets, which averaged nearly 3,000 kcal/day, in consecutive 2-week periods. Each diet was composed of a large amount, about 2,500 kcal/day, of a Western-type lowfiber basic diet supplemented by a small amount, 500 kcal/day, of different carbohydrate foods, fiber-free sucrose in diet S, very low-fiber white wheat flour in diet W, moderate-fiber mixed fruit in diet F, and highfiber mixed vegetables in diet V. The crude fiber (CF) content of the four resultant supplemented diets, recorded as CF g/ 100 kcal, was of diets S and W 0.1, of diet F 0.2 and of diet V 0.6. The mean serum cholesterol and serum phospholipid levels of all groups of men remained stationary during the 2-week periods during which men ate low-fiber diets 798
to the editor
The American
Journal
of Clinical
Nutrition
S. W and F, but both lipid levels fell significantly in each group of men while high-fiber diet V was eaten. Starchy sweet potato contributed much energy in the so-called mixed vegetable supplement of diet V. British nutritionalists tend to restrict the term vegetable to low-energy leafy and root vegetables; they place in a separate group high-energy staple starchy foods, roots and tubers (II). This category includes all varieties of potato and plantain and should include even bananas. The socalled mixed vegetable diet V contained starchy staple carbohydrate foods, wherein the full complement of fiber surrounds the starch. It is not fiber-depleted; it remains “packaged” starch. This, in my opinion, is crucial. It is suggested that these four experimental diets illustrate the fundamental difficulty of Western man. He cannot safely supplement his present day basic diet, composed of very low-fiber high-energy foods, such as white wheat flour, sugar, fats, flesh and fish, with small supplements of high-fiber low-energy nonstarchy fruits or nonstarchy leafy and root vegetables. The only adequate supplement is high-fiber high-energy starchy staple foods, such as any variety of potato, also whole cereals and mature leguminous seeds. Further he will not eat these large supplements unless motivated to do so. These foods must be served in an appetizing manner, arid he must be hungry because he voluntarily decreases considerably his traditional highenergy low-fiber foods, especially fat, even also sucrose. Another example of the protective action of starchy staple foods, undepleted of dietary fiber, is now cited. Irish men who grew up in Ireland and subsequently emigrated to Massachusetts had nearly 90% more abnormal coronary disease-type electrocardiograms 28:
AUGUST
1975,
pp.
798-805.
Printed
in U.S.A.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
letters
LETTERS
TO
Pastoral African tribes, like the Masai, adapted from being hunters to that of wandering herdsmen probably 10,000 years ago; they never, like Western man, cultivated crops. Masai have consumed animal fat 300 g/day but rarely manifested signs of coronary disease either on their electrocardiograms or at autopsy (13). Other African tribes, like the Venda, were agriculturists and had only a few cattle. Venda males, who lived as an urban group in the stress of industrialized South Africa, ate fat 126 g/daily, of which 106 g was animal fat (14). They were typical of those Bantu urban groups who very rarely develop coronary heart disease (15, 16). These urban Venda men ate much lightly processed corn meal 494 g/daily. This contributed most of the crude fiber intake of 5.7 g/daily for it was noted that they ate few vegetables and little fruit (14). The British daily diet in 1970 contained on average crude fiber 0.5 g derived from all starchy cereals, 0.9 g derived from potatoes, and 2.7 g from
799
EDITOR
vegetables and fruit (17). British men had very much coronary heart disease. After 26 years continuous medical practice in East Africa, a colleague and I recorded the first case of coronary heart disease in the 15 million inhabitants of those countries; the patient was an obese East African judge consuming a partially Westernized diet (18). It is also suggested that dietary fiber associated with starchy foods is protective against diabetes mellitus (12, 19, 20) and obesity (19, 21). It is suggested that man, subject to evolution, has adapted poorly to fiber-depleted staple foods that contain starch, fats, sucrose and other nutrients. Hugh Trowel!, M.D.
Woodgreen, Hants SP6
Fordingbridge, 2AZ, England
References 1.
L. M. Coronary heart disease and dietary fiber. Am. J: Clin. Nutr. 27: 1202, 1974. 2. Diet and Coronary Heart Disease. Report of the Advisory Panel of the Committee on Medical Aspects of Food Policy (Nutrition) on Diet in Relation to Cardiovascular and Cerebrovascular Disease. Department of Health and Social Security, London; H. M. Stationery Office, 1974, p. 18. 3. TROWELL, H., N. PAINTER AND D. BURKITT. Aspects of the epidemiology of diverticular disease and ischemic heart disease. Am. J. Digest. Diseases 19: 864, 1974. 4. KRITCHEVSKY, D., AND J. A. STORY. Binding of bile salts in vitro by nonnutritive fiber. J. Nutr. 104: 458, 1974. 5. BALM ER, J., AND D. B. ZILVERSMIT. Effect of dietary roughage in cholesterol absorption, cholesterol turnover and steroid excretion in the rat. J. Nutr. 104: 1319, 1974. 6. RANHOTRA, G. S. Effect of cellulose and wheat mill fractions on plasma and liver cholesterol levels in cholesterol-fed rats. Cereal Chem. 50: 358, 1973. 7. MORGAN, B., M. HEALD, S. D. ATKIN, J. GREEN AND E. B. CHAIN. Dietary fibre and sterol metabolism in the rat. Brit. J. Nutr. 32: 447, 1974. 8.
KLEVAY,
MENGE, H., L. H. LITTLEFIELD, L. T. FROBISI-I AND B. T. WEINLAND. Effect of cellulose and cholesterol on blood and yolk lipids and reproductive efficiency of the hen. J. Nutr. 104: 1554, 1974. 9. SPILLER, G. A., AND R. J. AMEN. Research on dietary fibre. Lancet 2: 1259, 1974. 10. GRANDE, F., J. T. ANDERSON AND A. KEYS. Sucrose and various carbohydrate-containing foods and serum lipids. Am J. Clin. Nutr. 27: 1043, 1974. I I. PLATT, B. S. Tables of Representative Values of Foods Commonly Used in Tropical Countries. London: H. M. Stationery Office, 1962.
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
than their own brothers who had remained in Ireland. The latter ate approximately 80% more crude fiber, derived largely from a very high consumption of Irish potatoes (12). There need be little disagreement between those who have clearly demonstrated that many Western men have adapted poorly to modern diets which contain much fat, especially animal fat, and those who have suggested, only recently, that fiber, especially that associated with the high-energy starchy staple foods, such as cereals and potatoes, is a protective factor with respect to coronary heart disease. The coin of ischemic heart disease has two sides, risk factors and protective factors, both acting on the mixed amalgam of inheritance. In voluntary diets if fat increases 1 g then staple starchy carbohydrate foods usually decrease 2 g for sugar intakes usually remain stationary. Only thus can the daily voluntary energy intake remain unaltered. If the starchy carbohydrate foods decrease, or increase, then their fiber may decrease, or increase, but on/v if this food is undep/eted offiber. Western man cannot find salvation in supplementing his basic low-fiber high-energy diet with high-fiber low-energy leafy vegetables and fruit; he must change the basic diet to contain much more high-fiber high-energy starchy staple foods.
THE
800 12.
14.
15.
16.
TROWELL, H. Dietary fibre, ischaemic heart disease and diabetes mellitus. Proc. Nutr. Soc. 32: 151, 1973. MANN, G. V., A. SPOERRY, M. GRAY AND D. JARASHOW. Atherosclerosis in the Masai. Am. J. Epidemiol. 95: 26, 1972. LUBBE, A. M. Dietary evaluation. In: A comparative study of rural and urban Venda males, edited by A. Le R. Van Der Merwe and S. A. Fellingham. S. African Med. J. 45: 1289, 1971. WALKER, A. R. P. Studies bearing on coronary heart disease in South African populations. S. African Med. J. 47: 85, 1973. SEFTEL, H. C., I. M. G. SPITz, I. BERSOHN, A. R. GOLDIN, B. I. JOFFE, A. H. RUBENSTEIN AND B. E.
Behavior
Dear
TO
of body
weight
under
a low
THE
EDITOR METZGER.
Metabolic
features
of
Johannesburg
Bantu with myocardial infarction. S. African Med. J. 47: 1571, 1973. 17. ROBERTSON, J. Changes in the fibre content of the British diet. Nature 238: 290, 1972. 18. TROWELL, H. C., AND S. A. SINGH. A case of coronary heart disease in an African. E. African Med. J. 33: 391, 1956. 19. TROWELL, I-I. Diabetes mellitus death-rates in England and Wales 1920-70 and food supplies. Lancet 2: 998, 1974. 20. TROWELL, H. Incidence of diabetes in children. Lancet 2: 1510, 1974. 21. TROWELL, H. Obesity in the Western World. Plant Foods for Man. 2: 20, 1974.
carbohydrate,
high
fat
diet
Sir:
Criticism has been leveled by Hirsch and van Itallie (1) at our findings reported in this journal (2) with respect to the body weight behavior in obese and healthy individuals on a high fat, low carbohydrate diet. However, this criticism did not include any findings of the authors to disprove our results. The question of an increase in metabolism due to an altered carbohydrate-fat relation in favor of fat, and of putting to practical use this effect in the dietotherapy of obesity has been discussed over the years, and varying concepts have been proposed in the literature. Recently, some further insight in support of our findings has been provided by Yoshimura et al. (3). After animal experimentat ion these investigators presented evidence that the oxygen consumption was raised under a regimen high in dietary fats as compared to a carbohydrate-rich diet. Under a fat-rich diet these authors observed an activation of thyroid function (increased iodine uptake by the thyroid gland and increase in labeled protein bound iodine (PBI) after doses of “I) as the possible cause of the observed increase in metabolism. Based on these observations and the findings reported by us (2) on the behavior of the body weight under a high fat, low carbohydrate diet, Sch#{246}nborn et al. (4) studied the metabolization of l-’4C-palmitic acid and the oxygen consumption in normal weight healthy subjects receiving diets high in fat and low in
carbohydrates and low in fat and high in carbohydrates, respectively, but with a constant protein content. These studies revealed that the FFA concentration and metabolism was increased under the high fat, ketogenic diet. The suggestion that the enhanced metabolism detectable under a ketogenic diet might be used to advantage in the dietetic management of obesity could be validated by Rabast et aI. (5) in a group of 45 hospitalized patients with a mean overweight of 58 ± 35%. When comparing the results of a high fat, 1,000-calorie diet to an isocaloric diet high in carbohydrates, the mean daily weight loss throughout the 35-day treatment period was higher under the ketogenic diet with a statistical probability of 90%, the water balance in the two groups not differing significantly. The problem of body-weight regulation involving the supply of dietary energy in excess of nutrient requirements is intimately linked with the question of an increased metabolic activity and of weight reduction under diets with different proportions of carbohydrates and fat. Some decades ago, the concept of “luxus consumption” was formulated by Neumann (6) and Grafe and Graham (7) who pointed out that both in humans and experimental animals a supply of dietary energy in excess of the calculated requirements does not produce the increase in body weight that would be expected to occur on the basis of calculations. These authors, and also some other
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/8/798/4732934 by Washington University, Law School Library user on 03 March 2019
13.
LETTERS
