From foods to human consumption: bioavailability, metabolic conversion and blood levels in populations

Abstract

The massive and rapidly growing interest in the effects of Omega 3 Fatty Acids (FA) on human health requires awareness of: a) the biological and nutritional “peculiarities” of these compounds, and b) the very relevant and yet not adequately appreciated issues concerning the design, development and the evaluation of results of epidemiological and controlled intervention studies. In fact: a) Omega 3 FA are present in very limited amounts in conventional diets, especially when compared to the Omega 6 FA, being present exclusively in organisms that in the course of evolution have adapted to the aquatic environment; in certain, not yet adequately explored, “niche” foods, and, in organisms at higher levels in the evolutionary scale, only in functionally specialized biological structures (e.g.. synapses, contractile cells, ecc.), where they play essential roles. b) The assessment of the basal and the final Omega 3 FA “status” (information that cannot be adequately derived from the use of food questionnaires) is required in any population or group in planning epidemiological or intervention studies. These data can be obtained exclusively with the analysis of the FA composition of circulating lipids (plasma, whole blood), and in turn can be correlated with dietary intakes of Omega 3 FA, and with physiopathological parameters. In addition this type of information is useful in the assessment of the bioavailability of Omega 3 FA in relation to the sources and types of formulations. An innovative analytical strategy developped in our lab for the collection of blood drops from a fingertip and the direct preparation of FA derivatives for gas chromatographic analysis, allows to assess the Omega 3 FA “status” in large populations, including groups that cannot be easily handled, such as neonates, pregnant women, population groups in remote countries (e.g.. Cambodia and Tibet), and to address all the issues that have been raised (from foods to humans).