The B-group vitamins are known as B1, B2, B3, B5, B6 and B12. Generally speaking, deficiencies are not related to a single vitamin of this group but to a deficiency in several vitamins, or a deficiency in one leading to deficiencies in other group-B vitamins. Vitamin B1, or Thiamine, is contained in brewer's yeast, whole grains, fresh and dried legumes, nuts and eggs. A deficiency causes polyneuritis and heart failure. Vitamin B2, or Riboflavin, is found above all in leafy greens, brewer's yeast, egg whites, milk and dairy products, and meat.