The B vitamins are a group of water-soluble vitamins essential to energy metabolism and the working of many enzymes. The family includes B1 thiamine, B2 riboflavin, B3 niacin, B5 pantothenic acid, B6 pyridoxine, B7 biotin, B9 folate, and B12 cobalamin. They act as coenzymes in the breakdown of carbohydrates, fats, and proteins, and in DNA synthesis and red blood cell formation. Because they dissolve in water, they are not stored in large amounts and must be supplied regularly through foods such as whole grains, meat, eggs, dairy, legumes, and leafy greens. Deficiencies cause conditions from beriberi to megaloblastic anaemia.