Читать книгу Textbook of Lifestyle Medicine - Labros S. Sidossis - Страница 88

Diseases caused by specific nutrient deficiencies usually manifest soon after initiating the nutrient‐deficient diet and can be reversed within days or weeks after replacing the specific nutrient(s). However, the degenerative chronic diseases are not just a matter of nutrient deficiencies; their development is contingent on a constellation of risk factors, and they are characterized by heterogeneity and complexity. The interplay between human metabolism and all of the compounds found in foods of plant or animal origin create an intricate nexus of interactions, rendering the isolation of a single effect difficult and possibly misleading.

This notion triggered scientists to speculate that food components interact with the food matrix in which they are found, developing additive or even antagonistic effects on human metabolism and, by extension, on human health. This combined effect is defined as food synergy and food antagonism, respectively. Therefore, provided that the individual components of a food interact with each other and have a paired influence on health, questions began to emerge as to which is the best way to assess the overall impact of food consumption on health and disease. As a consequence, a new approach developed, that of the impact of whole foods and food groups on specific pathologies. For example, the increased consumption of whole‐grain products has been shown to lower the risk for developing CVDs, T2DM, and some types of cancer. Whole‐grain products are rich in several bioactive micronutrients and macronutrients with various health benefits; many of these beneficial micro‐ and macronutrients are lost during refining of the whole‐grain product. Other food groups with high concentrations of nutrients and non‐nutrients with advantageous influence on health are fruits, vegetables, and legumes.

Another important point to consider is that the health effects of foods depend on the biological properties that their nutrients maintain after digestion and not on the properties that they had before they were ingested. For example, although phytochemicals have been attributed advantageous effects against CVD, a study conducted in Welsh men, a population known for increased consumption of tea rich in flavonols, failed to detect such an effect. The researchers speculated that by adding milk to the tea, the flavonols could not be absorbed sufficiently, and therefore, this cohort of Welsh men did not benefit from the favorable effects of the tea flavanols. Another example of food antagonism is that of the inhibition of zinc absorption when iron is present. On the other hand, vitamin C enhances the absorption of plant‐derived iron, i.e., nonheme iron.

Moreover, for many years, eggs were thought to increase the risk for the development of CVD, due to their high cholesterol content. However, the available evidence so far does not support the notion that dietary cholesterol increases the risk of heart disease in healthy individuals. Indeed, the effect of egg consumption, up to seven a week, on blood cholesterol is minimal, especially when compared with the effect of saturated fatty acids on blood cholesterol. Dietary cholesterol is common in foods that are high in saturated fatty acids, and this might have contributed to the notion that dietary cholesterol is atherogenic. Focusing only on the cholesterol content of eggs, without taking into consideration the fact that eggs are also a rich source of amino acids, vitamins, minerals, and other nutrients, may negatively influence the quality of our diet. It is obvious that our knowledge of the relationship between dietary cholesterol and cardiovascular disease in patients with diabetes is still incomplete. Therefore, further research is needed.