Function: Prevents neural tube defects (must be taken by the mother in early pregnancy). Methyl donor that is required for many processes in the body (reduces homocysteine levels). Cardiovascular health. Red blood cell production. Skin and nail health.

Sources: Dark green vegetables-spinach, kale, broccoli, asparagus-as well as organ meats, kidney beans, beets, yeast, orange juice, whole grains

Optimal Intake: 400 to 800 micrograms (mcg)

Deficiency Signs: Macrocytic anemia, fatigue, irritability, weakness, weight loss, anorexia, dyspnea, sore tongue, palpitations, forgetfulness, digestive upset,­ diarrhea

Interesting Fact: Even though folic acid is added to many foods, folic acid deficiency is the most common vitamin deficiency in the world.

Toxicity: None