Are there any recent articles on conversion efficiency?
Dr. Graham Burdge has reviewed the published studies wherein the conversion efficiency of alpha-linolenic acid (LNA) to the long chain omega-3 fatty acids including DHA and EPA have been studied in humans using tagged (deuterated) LNA as the ingested precursor fatty acid (Current Opinion in Clin. Nutr. Metab. Care, 7: 137-144 (2004)). In their studies as published, Dr. Burdge and colleagues reported a non-detectable conversion of LNA to DHA in men over a 21 day period whereas a 9% apparent conversion was observed in women. The combined apparent conversion of LNA to EPA +DHA was estimated to be approximately 8% in males (as EPA with the DHA being non-detectable) and approximately 30% in females (21% in the form of EPA and 9% in the form of DHA). Interestingly, poultry (laying hens) appear to have a considerably greater potential for conversion of dietary LNA to DHA. For example, the inclusion of flax seed as a source of LNA in poultry rations (up to 10% of total feed weight) has been found to result in omega-3 eggs containing approximately 300 mg of LNA omega-3 along with approximately 80 mg of DHA omega-3. Thus, the inclusion of LNA in the ration of laying hens results in a substantial conversion to DHA and a considerable enrichment of the egg in DHA as well as LNA.