BROOKLYN, N.Y.—Saturated fats per se may not be responsible for many of the adverse health effects with which they have been associated, and it is time to re-evaluate the dietary recommendations that focus on lowering serum cholesterol and to use a more holistic approach to dietary policy, according to a review published in last month in the journal Advances in Nutrition.
Review author Glen D. Lawrence, department of chemistry and biochemistry, Long Island University, wrote “the influence of dietary fats on serum cholesterol has been overstated, and a physiological mechanism for saturated fats causing heart disease is still missing.”
A number of studies published in the 1960s and 1970s, including the seminal Framingham Heart Study, linked dietary fats—particularly saturated fats—to heart disease. In recent years, however, analyses of these older studies, coupled with new findings, have begun to call the purported negative health consequences of dietary fats into question.
The review examined studies of several dietary factors, including saturated fat, polyunsaturated fat, a-linolenic acid, total fat, meat, eggs and milk. None of these studies provided sufficient evidence to support a positive (or negative) association between fat consumption and heart disease.
For example, the review points to a recent analysis of 20 individual studies with more than 1 million subjects collectively that found that red meat in general was not associated with heart disease. Processed meats, however, were associated with increased risk of heart disease. This suggests that saturated fat itself does not lead to heart disease, but rather other factors such as preservatives or processing methods may be the real culprits. Similarly, claims that tropical oils with high saturated fat content (e.g., palm and coconut oil) increase the risk of heart disease lack scientific evidence to support them. Moreover, countries with high consumption rates of tropical oils have some of the lowest rates of heart disease in the world.
Lawrence wrote if diets high in fats, particularly saturated fats, are unhealthy, then logically we should see the beneficial effects of low-fat diets. Studies, however, have failed to show a health benefit to low-fat diets. In fact, the substitution of carbohydrates for saturated fats in the diet has clearly had a deleterious effect on health. Food processors, for example, often add large amounts of fructose to fat-free or low-fat foods to make them more palatable to consumers. This practice, however, has been linked to several adverse health consequences, including metabolic syndrome, obesity, hypertension and cardiovascular disease. There is also evidence that children who are switched from whole milk to either low-fat milk or fruit juice are more susceptible to infection.
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