n–3 fatty acids induce oxidative modifications in human erythrocytes depending on dose and duration of dietary supplementation

• Published in: The American journal of clinical nutrition 1996-09, Vol.64 (3), p.297-304
• Main Authors: Palozza, P, Sgarlata, E, Luberto, C, Piccioni, E, Anti, M, Marra, G, Armelao, F, Franceschelli, P, Bartoli, GM
• Format: Article
• Language: English
• Subjects: Adult; Amidines - pharmacology; Biological and medical sciences; Blood; Diet; Dietary Fats - pharmacology; Docosahexaenoic Acids - pharmacology; Dose-Response Relationship, Drug; Eicosapentaenoic Acid - pharmacology; Erythrocyte Membrane - drug effects; Erythrocyte Membrane - metabolism; Fatty Acids, Omega-3 - blood; Fatty Acids, Omega-3 - pharmacology; Feeding. Feeding behavior; Female; Food, Fortified; Fundamental and applied biological sciences. Psychology; Humans; Lipid Peroxides - metabolism; Male; Middle Aged; Nutrition; Oils & fats; Oxidation; Oxidation-Reduction; Time Factors; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vitamin E; Vitamin E - blood
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/64.3.297

The present work was performed to study an optimal dose and duration of dietary n-3 polyunsaturated fatty acid (PUFA) supplementation that would not result in harmful modifications of oxidative cell metabolism. Forty healthy subjects were divided into four groups that received 2.5 g/d eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA), 5.1 g EPA + DHA/d, 7.7 g EPA + DHA/d, or placebo. Fatty acid composition, tocopherol status, and susceptibility to lipid peroxidation induced in vitro by 2,2′-azobis-(2-amidinopropane) (AAPH) were evaluated in human red blood cell (RBC) membranes on days 30 and 180. n-3 PUFA treatment increased EPA and DHA concentrations in RBC membranes in a time-dependent manner in all of the n-3 PUFA groups. These modifications occurred with concomitant dose- and time-dependent increases in the membrane unsaturation index. After 30 d of treatment with n-3 PUFAs, alpha-to-copherol significantly increased in RBC membranes of the intermediate- and high-dose groups. Because of the higher concentration of this antioxidant in these groups, the susceptibility of RBC membranes to peroxidation was decreased. However, after 180 d of treatment, alpha-tocopherol decreased to baseline values and AAPH-induced lipid peroxidation increased in a dose-dependent manner. These results show that high doses of dietary n-3 PUFAs, as well as long-time treatments, affect human RBC susceptibility to lipid peroxidation by changes in fatty acid composition and tocopherol content.