MedicalResearch.com Interview with: Lee Hooper PhD, RD Reader in Research Synthesis, Nutrition & Hydration Norwich Medical School University of East Anglia England, UK MedicalResearch.com: What is the background for this study? Response: The World Health Organization asked us to carry out a set of studies (systematic reviews of randomised controlled trials) assessing health effects of omega-3 and omega-6, which are polyunsaturated fats. This is because the WHO are planning to update their dietary guidance on fats in the near future. Worries about effects of long chain omega-3 on control of diabetes have long existed, and some experimental studies have suggested that omega-3 supplementation and diets high in PUFA and omega-3 raise fasting glucose. Pollutants such as methylmercury and polychlorinated biphenyl levels exceeding recommended thresholds are rarer now, but have been reported in seafoods and fish oil supplements; elevated mercury levels interrupt insulin signalling, raising fasting glucose, in mouse models. Body concentrations of organic pollutants are correlated with prevalence of diabetes in the US, but other cross sectional studies have suggested either no association with or benefits of eating fish on glycaemic control. Systematic reviews of observational studies have suggested both positive and negative associations with glucose metabolism, but strong evidence shows that omega-3 supplements reduce raised triglycerides and have little or no effect on body weight. Theories suggest that omega-3 and omega-6 fats compete in some metabolic pathways so that the omega-3/omega-6 ratio is more important than absolute intakes of either.  (more…)