Coronary heart disease: dietary links and pathogenesis.

For decades it has been postulated that the main environmental factor for coronary heart disease (CHD) was the intake of saturated fatty acids (SFA). Nevertheless, confirmation of the role of SFA in CHD through intervention trials has been disappointing. It was only when the diet was enriched in n-3 fatty acids that CHD was significantly prevented, especially cardiac death. In addition to n-3 fatty acids, many other foodstuffs or nutrients such as fibers, antioxidants, folic acid, calcium and even alcohol contribute to prevent CHD. Thus the relationship between diet and CHD morbidity and mortality appears to be much more complex than formerly suspected considering as key factors only SFA, linoleic acid, cholesterol and atherosclerosis. Some of the mechanisms are briefly described, but many additional nutrients (or non nutrients) may also play an important role in the pathogenesis of CHD. Finally, as a result of the most recent epidemiologic studies the ideal diet may comprise: 8% energy from SFA, 5% from polyunsaturated fatty acids with a ratio 5/1 of linoleic/alpha-linolenic acid+longer chains n-3, oleic acid as desired, large intake of cereals, vegetables, legumes and fruits, fish twice a week, cheese and yogurt as dairy products, rapeseed and olive oils as edible fat. Without side effects, such a diet can be highly palatable, easily enjoyed by many populations and may prevent effectively and rapidly (within a few weeks or months) CHD.

Alpha-linolenic acid and cardiovascular diseases.

The intake of saturated fat was postulated to be the main environmental factor for coronary heart disease. It was also postulated that the noxious effects of saturated fatty acids (FA) was primarily through the increase in serum cholesterol. Nevertheless intervention trials either in coronary patients or even in primary prevention did not observe significant reduction in cardiac mortality, especially sudden death, when the diet was markedly enriched in linoleic acid (LA), the most efficient FA to lower serum cholesterol. In intervention trials, It is only when the diet was enriched in n-3 FA, especially alphalinolenic acid (ALA) that cardiac death was reduced. Studies in animals as well as in vitro on myocytes in culture, have shown that ALA was preventing ventricular fibrillation, the chief mechanism of cardiac death. Furthermore, studies in rats have observed that among n-3 FA, ALA, the precursor of the n-3 family, may be more efficient to prevent ventricular fibrillation than eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In addition it was demonstrated that ALA was the main FA lowering platelet aggregation, an important step in thrombosis, i. e. non fatal myocardial infarction and stroke. Thus, without side effects, a higher intake of ALA (2g / day) with a ratio of 5/1 for LA/ALA, could possibly constitute a nutritional answer to the main cause of morbidity and mortality in industrialized countries.

The nutritional intake of a free-living healthy French population : a four-year follow-up.

OBJECTIVE: To contribute to a better definition of the nutritional requirements of the healthy elderly and to improved knowledge the effects of age on these requirements. METHODS: We studied the nutritional intake of 96 elderly persons who had met criteria of good health status in 1993 at a four-year interval. The nutritional intake of the elderly subjects who remained healthy during the four-year interval (18 men and 64 women), was considered to globally correspond to their nutritional needs. The nutritional intake was evaluated by a three-day food record. RESULTS: The mean baseline weight of the subjects who remained in good health during the four years was 72,6 +/- 9,5 kg for men and 60,1 +/- 9,3 kg for women. In four years, mean weight remained globally stable. But in cross-sectional analysis, weight tended to decrease with the age of the subjects. This decrease was significant for women in 1993. Mean baseline intake was nearly 29 kcal/kg. Longitudinal and cross-sectional analyses showed that it changed only slightly with age. Though global energy intake varied slighlty in four years, we have observed some changes in the composition of this caloric intake. For men and women, protein intake tended to decrease in four years (respectively -0,4% and -0,6%), carbohydrate intake to decrease (respectively -1,1% and -2,7%) and fat intake to increase (respectively +2,1% and +2,9%). These variations were not significant except for fat and carbohydrate intakes in women. In 1993, for a majority of subjects, the intakes of iron, and vitamins C and B12 were higher and the intakes of calcium, zinc, vitamins A, B1, B6 and B9 were lower than the French recommendations. In four years, mean intake did not change significantly, except for calcium intake in women (-8,8%). CONCLUSION: In this study, healthy aging was associated with a mean caloric intake close to 29 kcal/kg which is near the upper limits of recommendations (between 25 and 30 kcal/kg/d). These intakes, like those of macronutrients and micronutrients changed little with advancing age. These results suggest that the needs of the elderly remain quite stable with aging. Nevertheless a tendency to weight loss with aging is observed, especially in older subjects, suggesting that even if food intake contributes to the maintenance of healthy aging, aging processes are multidimensional and frailty that is often associated with weight loss is ineluctable for older subjects.

Intake of fatty acids in western Europe with emphasis on trans fatty acids: the TRANSFAIR Study.

OBJECTIVE: To assess the intake of trans fatty acids (TFA) and other fatty acids in 14 Western European countries. DESIGN AND SUBJECTS: A maximum of 100 foods per country were sampled and centrally analysed. Each country calculated the intake of individual trans and other fatty acids, clusters of fatty acids and total fat in adults and/or the total population using the best available national food consumption data set. RESULTS: A wide variation was observed in the intake of total fat and (clusters) of fatty acids in absolute amounts. The variation in proportion of energy derived from total fat and from clusters of fatty acids was less. Only in Finland, Italy, Norway and Portugal total fat did provide on average less than 35% of energy intake. Saturated fatty acids (SFA) provided on average between 10% and 19% of total energy intake, with the lowest contribution in most Mediterranean countries. TFA intake ranged from 0.5% (Greece, Italy) to 2.1% (Iceland) of energy intake among men and from 0.8% (Greece) to 1.9% among women (Iceland) (1.2-6.7 g/d and 1.7-4.1 g/d, respectively). The TFA intake was lowest in Mediterranean countries (0.5-0.8 en%) but was also below 1% of energy in Finland and Germany. Moderate intakes were seen in Belgium, The Netherlands, Norway and UK and highest intake in Iceland. Trans isomers of C18:1 were the most TFA in the diet. Monounsaturated fatty acids contributed 9-12% of mean daily energy intake (except for Greece, nearly 18%) and polyunsaturated fatty acids 3-7%. CONCLUSION: The current intake of TFA in most Western European countries does not appear to be a reason for major concern. In several countries a considerable proportion of energy was derived from SFA. It would therefore be prudent to reduce intake of all cholesterol-raising fatty acids, TFA included.

Caloric restriction and aging.

Caloric restriction in species with a short life span has shown it can increase median and maximum life expectancy and reduce or delay the onset of most age-related diseases. The remarkable reproducibility of the phenomenon irrefutably proves its validity and makes caloric restriction one of the most frequently studied paradigms in experimental research on aging.