Decreased Levels of Marine-Based Omega-3 in Modern Greenlandic Foods and Diet
Deutch B. et al., Science of the Total Environment 384: 106-119 (2007).
Centre for Arctic Environmental Medicine, Aarhus University, Aarhus, Denmark.
The authors conducted a study of current (2004-2006) daily intakes of long-chain omega-3 fatty acids (marine-based) along with other nutrients in the modern Greenlandic food/diet and compared these intakes with traditional consumptions (based on analysis conducted 30-50 years ago). As well, the corresponding blood levels of omega-3 fatty acids and omega-6 fatty acids were compared from these different time periods. The results indicated that the percentage of local food as consumed on a regular basis (seal and whale meat, blubber, organs, local fish including cod, halibut, capelin had decreased considerably resulting in a considerable reduction in the daily intake of omega-3 fatty acids. It was estimated that the mean daily consumption of omega-3 fatty acids based on 1976 data was 8.5g with a n-3:n-6 fatty acid ratio of 3.3 in the diet and the corresponding n-3:n-6 ratio in blood plasma lipid (a biomarker for omega-3 and omega-6 status) was 1.7. For the current (2004 group), the mean daily intake of n-3 fatty acids was estimated to be approximately 3-5 grams per day with dietary ratio of n-3: n-6 being 0.87 (26% of the 1976 value) with a corresponding ratio in human plasma lipid (n-3: n-6) of 0.60.
Dr. Holub's Comments:
The present findings on the traditional and current Greenland diet with respect to omega-3 fatty acid intakes (primarily as DHA/EPA + some DPA (docosapentaenoic acid) combined) raises a question as to whether any associated health outcomes may be associated with these changes in omega-3 fatty acid intakes. This subject was not addressed in the present study. However, the authors did indicate that the lower intake of omega-3 fatty acid and lower circulating blood ratios of n-3:n-6 may be implicated in the higher levels of circulating levels of triglyceride as compared to those observed many years previously. It is known that elevated levels of circulating triglyceride are significant risk factors for cardiovascular disease-related events (including atherosclerotic development) and that intakes of DHA/EPA (combined) of 3g/day can often result in a reduction in fasting triglyceride levels of approximately 25-30% within a few weeks. (Holub BJ. Can. Medical Assoc. J. 177(6): 604, (2007)).