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The realization that diet is an important determinant of human health is not new. This fact imposes on us, nutrition scientists and public health officials, an obligation to act. As a first step towards meeting this obligation, we have developed food-based guidelines (FBNG) and we have asked the conscientious citizens to adopt them toward a better nutrition for a better life. Several countries have formulated their own national FBNG. The Hellenic Supreme Scientific Health Council has developed a document summarizing FBNG for the Greek population, taking into account evidence from studies in this population.
Current scientific evidence is altering our perceptions on nutrition and health and tends to transform nutrition guidelines. In this context I will comment on some elements of several FBDG from the point of view of the Mediterranean diet.
What is meant by fat?
Dietary guidelines have been widely perceived as indicating that total fat should be reduced. "Total fat" however, is not a very useful term, because fats and oils are distinct categories in the broad group of lipids. For southern Europe "fat" means mainly olive oil, whereas for northern and central Europe the word fat is associated with animal fat. By recommending "fat" reduction, we may have had, as a result, the reduction of olive oil consumption in southern Europe and the concomitant reduction of vegetable intake, (vegetables are consumed as salads as well as main dishes cooked in olive oil). For this reason I have advocated that the term fat should be replaced by the term dietary lipids which comprise both fats and oils.
Another argument allegedly supporting "low fats" intake is that "fat" is conductive to obesity. It has been found instead, that the proportion of fat and carbohydrate in a fully-controlled energy-restricted diet does not materially affect weight loss.
The evidence for the adverse health effects of dietary "fat" does not apply to olive oil and perhaps other types of plant oils. In any case, special emphasis should be given to the specific properties of various types of fat and oils and on how these should affect the recommended quantities. For the prevention of coronary heart disease the guidelines should emphasize reduction of saturated fat, and for the prevention of obesity, reduction of total energy intake. In both instances, and in several others, a central recommendation is to increase physical activity.
Vegetable and "fat"
There is strong evidence that antioxidants, largely derived from vegetables and fruits, contribute to the protection against coronary heart disease and probably cancer and other diseases. Recent findings suggest that polyphenolic compounds in vegetables are endowed with several beneficial biologic activities.
The campaigns to increase fruit consumption have been relatively successful, but only a minority of people in developed countries consumes adequate quantities of vegetables. However, how can one consume considerable amounts of vegetables unless they are cooked or seasoned in oil?
Antonia Trichopoulou
University of Athens Medical School, Greece
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