Long-chain n?3 PUFA: plant v. marine sources

摘要

Increasing recognition of the importance of the long-chain na?’3 PUFA, EPA and DHA, to cardiovascular health, and in the case of DHA to normal neurological development in the fetus and the newborn, has focused greater attention on the dietary supply of these fatty acids. The reason for low intakes of EPA and DHA in most developed countries (0?·1a€“0?·5 g/d) is the low consumption of oily fish, the richest dietary source of these fatty acids. An important question is whether dietary intake of the precursor na?’3 fatty acid, ?±-linolenic acid (?±LNA), can provide sufficient amounts of tissue EPA and DHA by conversion through the na?’3 PUFA elongationa€“desaturation pathway. ?±LNA is present in marked amounts in plant sources, including green leafy vegetables and commonly-consumed oils such as rape-seed and soyabean oils, so that increased intake of this fatty acid would be easier to achieve than via increased fish consumption. However, ?±LNA-feeding studies and stable-isotope studies using ?±LNA, which have addressed the question of bioconversion of ?±LNA to EPA and DHA, have concluded that in adult men conversion to EPA is limited (approximately 8%) and conversion to DHA is extremely low (