Tuesday, July 14, 2015. An article published on May 3, 2015 in the European Journal of Nutrition reports an association between higher red blood cell omega 3 polyunsaturated fatty acid (PUFA) levels and a lower risk of metabolic syndrome—a group of risk factors for cardiovascular disease and type 2 diabetes that include abdominal obesity, hypertension, insulin resistance and abnormal blood lipid levels.
For their study, researchers at China's Sun Yat-sen University enrolled 4,343 men and women between the ages of 30 and 75 years beginning in December 2005. Fasting blood samples were analyzed for erythrocyte (red blood cell) membrane eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and alpha linolenic acid (ALA), as well as serum glucose, triglycerides, and low-density lipoprotein (LDL), high-density lipoprotein (HDL) and total cholesterol levels. Dietary questionnaire responses provided information concerning omega 3 fatty acid intake. Metabolic syndrome was determined by the presence of three or more components that included waist circumference of at least 90 centimeters (approximately 35 inches) in men and 80 centimeters (approximately 31 inches) in women, blood pressure of at least 130/85 mmHg or use of antihypertensive drugs, fasting glucose of at least 100 milligrams per deciliter (mg/dL) or use of antidiabetic drugs, HDL cholesterol of less than 40 mg/dL for men and 50 mg/dL for women, and triglyceride levels of 150 mg/dL or more.
Subjects who had higher total levels of omega 3 fatty acids had a significantly lower risk of metabolic syndrome compared with those whose levels were lowest. When individual omega 3s were analyzed, marine-derived omega-3 fatty acids EPA, DHA and DPA emerged as significantly protective. In comparison with men whose EPA levels were among the lowest 25% of participants, those whose levels were among the highest 25% had a 45% lower adjusted risk of metabolic syndrome, and for DHA and DPA, the risk was 55% and 46% lower. For women, being among the top 25% of EPA, DHA and DPA was associated with risk reductions of 26%, 25% and 27%.
Authors Xiao-wei Dai and colleagues note that the protective effect of omega 3 against metabolic syndrome observed in this study was primarily due to an association with more favorable lipid levels. "Omega-3 PUFAs and their metabolites are natural ligands for several nuclear receptors and transcription factors that regulate the expression of genes involved in obesity and lipid metabolism," they observe.
"Higher levels of total omega-3 PUFAs, EPA, DPA, and DHA, but not of ALA, in erythrocyte membranes are associated with a lower presence of metabolic syndrome in Chinese adults," they conclude.