Natufood Nutritional Yeast Flakes Rich in vitamins B1, B2, B3 and B6, contains folic acid and zinc:Vitamin B1 contributes to a normal energy-yielding metabolism. Vitamin B2 and B3 contribute to the normal function of the nervous system. Also, they contribute, together with B6, to the reduction of fatigue. Zinc contributes to the maintenance of normal hair, normal fingernails and skin. Nutriti..