Every other year the International Society for the Study of Fatty Acids and Lipids (ISSFAL) convenes for the presentation of current research in the field. This year’s meeting in Maastricht, Netherlands, focused on lipids in metabolic health and
disease with a series of presentations on conditions such as the metabolic syndrome (aka Diabetes) and obesity, brain function and mental health, fatty acid metabolism and lipid signaling, maternal and infant health, neuro-inflammation and nutrigenomics (the study of the effects of foods on gene expression) among others.
Evidence is growing to link dietary omega-3 fatty acids with lower insulin resistance, less fat deposition and improved glucose tolerance in the metabolic syndrome. Other participants reported that animals fed less linoleic acid than is found in western diets and then switched to a western diet had 27% less fat, fewer fat cells and lower blood triglycerides than control animals. It was suggested that increased consumption of omega-3 fatty acids might prevent the metabolic abnormalities associated with the metabolic syndrome, but that once diabetes developed, the effect of omega-3 fatty acids was much less.
Several presentations argued that omega-3 fatty acids, especially the long-chain ones eicosapentaenoic and docosahexaenoic acids (EPA, DHA, respectively) might improve cognitive function in older adults. Evidence from one study observed that older adults with mildly impaired cognition had less EPA, but more omega-6 docosapentaenoic acid, in their red blood cells. The latter was correlated with poorer performance on two verbal tests and auditory learning. Higher levels of omega-6 docosapentaenoic acid usually occur only in omega-3 fatty acid insufficiency.
A provocative presentation raised the possibility that insufficient dietary DHA in the US military might be linked to higher soldier deaths from suicide than from combat. If established, such findings would support current evidence that low DHA status is a risk factor for suicide.
This current issue of the PUFA Newsletter returns to the question of whether omega-3 fatty acids are associated with lower total mortality and asks whether the question is relevant. Another article confirms reports of the low intakes of DHA in US toddlers, but reports significantly fewer cases of bronchiolitis among infants with the highest levels of DHA in their red blood cells. Two papers identify new clinical conditions associated with omega-3 fatty acids. One suggests that premenopausal women with higher intakes of omega-3 fatty acids have a significantly lower chance of developing endometriosis. Another links higher long-chain omega-3s with a lower risk of age-related hearing loss. In another article, authors from the University of Oklahoma describe mutation in a retinal protein that results in a rare type of macular degeneration. This abnormality results in a failure to make very-long-chain polyunsaturated fatty acids via chain-lengthening. The investigators showed that this mutation is not involved in the synthesis of DHA, which also requires chain elongation. What are these very-long-chain fatty acids doing in the retina?
By Joyce A. Nettleton, DSc
Editor, PUFA Newsletter and Fats of Life