Dietary Supplement S-Adenosyl-L-Methionine (AdoMet) Effects on Plasma Homocysteine Levels in Healthy Human Subjects: A Double-Blind, Placebo-Controlled, Randomized Clinical Trial

Objectives: To determine if exogenous S-adenosyl-L-methionine (AdoMet), a commonly used nutritional supplement, increases the level of plasma homocysteine (Hcy), a potential cardiovascular risk factor, in healthy human subjects. Design: Double-blind, placebo-controlled, randomized clinical trial. Setting: Mayo Clinic, Rochester, Minnesota. Subjects: Fifty-two (52) healthy human volunteers. Intervention: Subjects received placebo or AdoMet (800 mg per day) for 4 weeks. Hcy levels were measured before and after administration of AdoMet or placebo. Outcome Measures: The primary outcome measure was change in Hcy level. Secondary outcome measures included an interim Hcy determination (at 2 weeks) and changes in levels of high-sensitivity C-reactive protein (hsCRP), lipids, and alanine aminotransferase. Results: There was no statistically significant change in Hcy between groups. Similarly, no statistically significant differences in change in Hcy or hsCRP levels were observed at 2 or 4 weeks. There was a small but statistically significant increase (p < 0.04) in alanine aminotransferase at week 2 and a statistically significant decrease (p < 0.04) in total cholesterol in the AdoMet group compared with the placebo group. Conclusions: AdoMet at a daily dose of 800 mg for 4 weeks does not appear to significantly affect Hcy levels in the blood.