Effects of B vitamins and omega 3 fatty acids on cardiovascular diseases: a randomised placebo controlled trial

Randomized placebo-controlled trial conducted in France among adults aged 45 to 80 years with prior ischemic cardiovascular disease, including myocardial infarction, acute coronary syndrome, or ischemic stroke within the previous year. Active intervention arms included B vitamins alone (n=622), omega-3 fatty acids alone (n=633), and B vitamins plus omega-3 fatty acids (n=620).

Three oral active regimens were tested: B vitamins alone (5-methyltetrahydrofolate 560 μg, vitamin B-6 3 mg, and vitamin B-12 20 μg; two capsules daily), omega-3 fatty acids alone (600 mg total EPA and DHA in a 2:1 ratio; two capsules daily), or the combination of both regimens at the same doses. Treatment was given daily in addition to standard cardiovascular care, with placebo-controlled comparison.

Daily B vitamin or omega-3 supplementation did not reduce major cardiovascular events in this secondary prevention population, so routine use for cardiovascular prevention was not supported. In the combined B vitamins plus omega-3 arm, major cardiovascular events were 75 vs 82 (hazard ratio 0.90, 95% CI 0.66 to 1.23; P=0.50), stroke was lower (21 vs 36; hazard ratio 0.57, 0.33 to 0.97; P=0.04), but all-cause mortality was higher (72 vs 45; hazard ratio 1.55, 1.07 to 2.25; P=0.02). Non-fatal myocardial infarction was not reduced (28 vs 32; hazard ratio 0.88, 0.53 to 1.46; P=0.61).

The trial was limited to a French secondary-prevention population with prior ischemic events, which may reduce generalizability to other settings or to earlier post-event treatment. The packet also shows mixed outcome signals, including no benefit on the primary endpoint and a higher all-cause mortality signal in the combined supplement arm.