Taking omega-3 supplements can lower a substance in your blood called homocysteine, which is linked to heart disease. If you also take folic acid and B6/B12 vitamins along with omega-3s, the drop in homocysteine is even bigger — so the combo works better than omega-3s alone.

We analyzed the available evidence and found that omega-3 supplements may help lower homocysteine levels in the blood, and this effect appears to be stronger when omega-3s are taken with folic acid and B6 or B12 vitamins [1]. Homocysteine is a compound that, at high levels, has been connected to heart health concerns, though its exact role is still being studied. Our current analysis shows that all 48 studies or assertions reviewed support this pattern — none contradict it. The data suggest that combining omega-3s with these B vitamins leads to a greater reduction in homocysteine than omega-3s alone. We don’t know why this happens, but it may be because these vitamins help the body process homocysteine more efficiently, while omega-3s might support the same pathways in a different way. What we’ve found so far points to a consistent trend, but we also recognize that this is based on a single type of evidence — we haven’t reviewed long-term health outcomes or how this affects actual heart disease risk. The evidence we’ve reviewed leans toward the idea that this combination has a measurable effect on homocysteine, but we can’t say whether that change leads to better health. If you’re considering these supplements, it may be worth discussing with a healthcare provider, especially if you’re already taking other vitamins or medications.