Iron helps prevent anemia by helping produce hemoglobin, the protein in red blood cells that carries oxygen throughout the body.

How Much: Recommended dietary allowance (RDA) = 8 milligrams (mg) daily for men; 18 mg daily for women until menopause; 8 mg for women after menopause.

Iron supplements can cause constipation, nausea and stomach upset. Take with vitamin C to aid iron absorption.

Too Much: Tolerable upper limit (UL) = 45 mg per day.

Too Little: Iron deficiency is the most common form of nutritional deficiency. Symptoms of mild deficiency include tiredness, shortness of breath, decreased mental performance, poor appetite, unstable body temperature and decreased immunity.

Foods: Liver, beef, turkey, fish; dried beans, peas and lentils; spinach, raisins. Iron from animal sources is better absorbed by the body than from vegetarian sources – but vegetarian sources are still good choices.

Interactions: Cholesterol medications, anti-ulcer medications and antibiotics.

Research Notes: Anemia – low red blood cell levels – is common in people with rheumatoid arthritis (RA) and may result from inflammation, which inhibits iron absorption, or from digestive tract bleeding caused by medications. Studies show that people who have both RA and anemia have more severe disease and joint damage than people who don’t have anemia.