Known as niacin, vitamin B-3 helps with producing energy from food (sugars and fats); and keeps skin, nerves and digestive system healthy.

How Much: Recommended dietary allowance (RDA) = 16 milligrams (mg) for men; 14 mg for women.

Too Much: Tolerable upper intake level (UL) = 35 mg from supplements. Large doses – 500 to 2,000 mg – are often prescribed to help lower cholesterol levels, but should be taken only under a doctor’s supervision.

Too Little: Rare: symptoms include dermatitis, diarrhea and dementia.

Foods: Chicken, tuna, turkey, fish, beef, salmon, green vegetables, tomatoes, yeast, eggs, peanut butter, sweet potatoes and beans.

Interactions: Diabetes medications; cholesterol medications and gout medications.

Research Note: Preliminary studies suggest a type of vitamin B-3 called niacinamide may improve osteoarthritis (OA) symptoms and reduce the need for non steroidal anti-inflammatory drugs (NSAIDS) by suppressing inflammation.