Bread and cereals are usually fortified with niacin. In addition, foods that contain tryptophan, an amino acid the body coverts into niacin, include poultry, red meat, eggs, and dairy products.
-Vitamin B3 is available in several different supplement forms:
Niacinamide
Niacin
Inositol hexaniacinate.
Niacin is available as a tablet or capsule in both regular and timed-release forms. The timed-release tablets and capsules may have fewer side effects than regular niacin. However, the timed-release versions are more likely to cause liver damage. Regardless of which form of niacin you are using, doctors recommend periodic liver function tests when using high doses (above 100 mg per day) of niacin.
How to Take It
Generally, high doses of niacin are used to control specific diseases. Such high doses must be prescribed by a doctor who will increase the amount of niacin slowly, over the course of 4 to 6 weeks. Take niacin with meals to avoid stomach irritation.
Daily recommendations for niacin in the diet of healthy individuals are:
Pediatric
Infants, birth to 6 months: 2 mg (adequate intake)
Infants, 7 months to 1 year: 4 mg (adequate intake)
Children, 1 to 3 years: 6 mg (RDA)
Children, 4 to 8 years: 8 mg (RDA)
Children, 9 to 13 years: 12 mg (RDA)
Boys, 14 to 18 years: 16 mg (RDA)
Girls, 14 to 18 years: 14 mg (RDA)
Adult
Men, 19 years and older: 16 mg (RDA)
Women, 19 years and older: 14 mg (RDA)
Pregnant women: 18 mg (RDA)
Breastfeeding women: 17 mg (RDA)
Precautions
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider. Side effects may include diarrhea, headache, stomach discomfort, and bloating.
High doses (50 mg or more) of niacin can cause side effects. The most common side effect is called "niacin flush," which is a burning, tingling sensation in the face and chest, and red or flushed skin. Taking an aspirin 30 minutes prior to the niacin may help reduce this symptom.
At very high doses, used to lower cholesterol and treat other conditions, liver damage and stomach ulcers can occur. Your doctor will regularly check your liver function through a blood test.
People with a history of liver dise