A Diet with 3% of Energy from a Mixture of Omega-3 Fatty Acids Significantly Increases in Vivo Lipid Peroxidation in Postmenopausal Women

Dietary omega-3 (n - 3) polyunsaturated fatty acids (PUFA) are recommended by public health organizations to reduce the risk of cardiovascular disease, and several epidemiological studies have suggested there is an inverse association between n - 3 intake and human cancers. However, n - 3 are susceptible to an increase in lipid peroxidation in the human body. As part of a crossover dietary intervention study of a diet (20% of energy from fat) with or without an additional 3% of energy from a mixture of n - 3 (with 5.36 g α-linolenic acid and 1.45 g eicosapentaenoic acid and docosahexaenoic acid per 2000 kcal per day), we measured total in vivo lipid peroxidation in healthy postmenopausal women (n = 15). Our results indicated that the diet with 3% of energy from n - 3 significantly increased the urinary concentrations of total polar lipophilic aldehydes and related compounds produced via lipid peroxidation (p < 0.05) as well as the α, β-unsaturated hydroxy aldehydes 4-hydroxy-2-trans - hexenal (p < 0.05) and 4-hydroxy-2-trans -decenal (p < 0.05) compared to the diet with less than 1% of energy from n - 3. This is also the first study to document the presence of 4-hydroxy-2-trans -decenal in the urine of individuals consuming n - 3. These results demonstrate that an increase in 3% of energy from dietary n – 3 increases in vivo lipid peroxidation.