有抽菸就別吃了
If you smoke, stop. If you are unable to stop, avoid supplementing with B vitamins for an extended period of time, especially if you are male. Long-term B vitamin supplementation seems to increase cancer risk in male smokers...


沒抽菸的不確定?
The effect of B vitamins on non-smokers is still uncertain. In this study, sample sizes for never-smokers were too small to evaluate associations accurately.

https://examine.com/nutrition/vitamin-b-cancer/