No effects of n-3 fatty acid supplementation on serum total testosterone levels in older men: the Alpha Omega Trial

Abstract

The intake of the n-3 fatty acids alpha-linolenic acid (ALA), acid (EPA) and docosahexaenoic acid (DHA) has been related to testosterone levels in epidemiological analyses. The aim of this study was to assess whether the n-3 fatty acids affects testosterone levels in post-myocardial infarction (MI) patients, who are at risk of testosterone deficiency. In a double-blind, placebo-controlled trial of low-dose supplementation of n-3 fatty acids, we included 1850 male post-MI patients aged 60-80 years who participated in the Alpha Omega Trial. Patients were randomly allocated to margarines that provided 400 mg/day of EPA-DHA (n = 453), 2 mg/day of ALA (n = 467), EPA-DHA plus ALA (n = 458), or placebo (n = 472). Serum testosterone levels were assessed at baseline and after 41 months using whole day blood samples obtained at the subjects' home or at the hospital. Subjects were on average age of 68.4 (SD 5.3) years old and had baseline mean serum total testosterone of 14.8 (SD 5.6) nmol/L. The four randomized groups did not differ for baseline characteristics. ALA, EPA-DHA, and EPA-DHA plus ALA supplementation did not affect serum total testosterone compared to placebo. Moreover, n-3 fatty acid supplementation did not affect the risk of incident testosterone deficiency (n = 76 with total testosterone <8.0 nmol/L). We conclude that n-3 fatty acids supplementation did not affect serum total testosterone in men who had had a MI.

Figure 1

Flow chart of the Alpha Omega Trial. Prostate cancer was defined as non-fatal prevalent or incident prostate cancer (or the use of antiandrogenic or other androgen-modulating medication).