Effect on red blood cell membrane fatty acids of diets enriched with different sources of n‐3 fatty acids in healthy adults

Abstract

BackgroundConsumption of n‐3 fatty acids from algal‐oil supplements and plant sources produce health benefits, which may be dependent on the incorporation of eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA) into cell membranes.Aim and MethodsTo determine if plant sources (flaxseed oil and walnuts) of á‐linolenic acid (ALA) produce similar change in red blood cell (RBC) membrane fatty acids as algal‐oil (EPA/DHA) supplements, we performed a randomized cross‐over study (3 8‐week study periods) in 24 healthy adults (15 women, 9 men; mean±SE age 42±2.7 years; BMI 25.4±0.9 kg/m2). Under controlled feeding conditions, subjects consumed eucaloric lacto‐ovo vegetarian diets [Control, ALA (6‐7g/2400 kcal/d), EPA/DHA (0.20/0.72g EPA/DHA per 2400 kcal/d), and Combination (ALA + EPA/DHA)]. Fasting EPA and DHA levels were measured at baseline and at week 8 for the 3 study periods. Mixed model analyses were performed.ResultsIncreased EPA levels were observed in the RBC membrane with consumption of the EPA/DHA (41%, p<0.0001), ALA (54%, p=0.0064) and Combination (101%, p<0.0001) diets. DHA levels increased with consumption of the EPA/DHA (49%, p<0.0001) and Combination (36%, p=0.0025) diets.ConclusionN‐3 fatty acids from algal‐oil and plant sources produce similar increases in RBC membrane EPA levels; however DHA levels increased only in the algal‐oil containing diets.