Is it safe to take 100mcg of vit b12 and 400 mcg of folic acid daily? my doc said i'm deficient. what would cause a deficiency in these?

Several causes: Vegans are vulnerable to deficiencies in these vitamins because they eat no animal source foods. These deficiencies may show up in alcoholism too. Also, elderly people and those with genetic polymorphisms can absorb these vitamins poorly. Eating foods rich in B12 & folate (folic acid) (such as legumes & leafy greens) can help. Taking vit B12 and Folic Acid as your doctor suggests, is safe.