ω-3 PUFAs, why are we speaking of them?

In spite of the fact that few dietary components are so widely recognized as able to improve human health such as ω-3 polyunsaturated fatty acids (PUFAs), so that their sector in the nutritional market has been increasingly growing worldwide, many unresolved questions still remain about them. In particular there is urgent need for better understanding their possible role as anti-neoplastic agents. First of all, the chemical structure, the intracellular metabolism and the dietary sources and bioavailability of these dietary fatty acids will be described in this introductive chapter to make easier the comprehension of the remaining parts of the book. Afterwards, a brief outline of ω-3 PUFA reported benefits in different fields of human health will be provided. In this introductive part we will tackle also the problem of the discrepancies occurring between the results of most experimental studies on animals and cultured cells, which, almost univocally, suggest the beneficial anti-neoplastic effects of these fatty acids, and the outcome of several of the epidemiological observational studies, which, conversely, show a scarce or null positive association between high intake of fish or fish oil at high content in ω-3 PUFAs and prevention of different kinds of cancer. Finally, a brief outline of the organization of the present book will be provided.