Vitamin B-rich foods include poultry, fish, whole grains and mushrooms, which are rich in niacin; other such foods include dairy products, which are rich in vitamin B12, choline and vitamin B3. Many foods, including tomatoes, broccoli and avocados, are rich in vitamin B5.
Tofu, other soy foods and legumes are rich in vitamin B6, while organ meats such as liver and kidneys are high in biotin. Acorn squash and watermelons have lots of vitamin B1, while enriched cereals and grains have vitamin B2, or riboflavin. Folic acid exists in vegetables and legumes as well as fortified cereals and grains.
Vitamin B-9, or folate, is best known for its role in preventing spinal birth defects. It also plays roles in red blood cell function and in synthesizing the essential amino acid methionine, along with vitamin B-6, or pyridoxine, and B-12, or cobalamin. Vitamin B-6 also helps with the immune system and babies' brain development. The body uses vitamins B-1 (thiamine), B-3 (niacin) and B-5 (pantothenic acid) to help turn carbohydrates from food into glucose, the body's primary energy source. Vitamin B-2, or riboflavin, helps support red blood cell functioning, and vitamin B-7, or biotin, plays a role in synthesizing fats and proteins.
The B vitamins help the body use energy by breaking down carbohydrates into simple sugars and breaking down proteins and fats. Breaking down proteins and fats is particularly important for the health of the nervous system, and folic acid is important in the prevention of birth defects. Though B vitamins can be obtained from foods, some are synthesized in the gastrointestinal tract.
B vitamins are water soluble, which means the body uses as much of these vitamins as it needs and excretes the rest in the urine. However, some B vitamins are toxic if too much is taken at one time. The body stores some B vitamins in the liver.