Sources of Nicotinamide

Niacin, niacinamide, nicotinic acid and nicotinamide are terms used synonymously to refer to vitamin B-3. However, each has a slightly different chemical structure yet similar vitamin function in your body. Niacin converts to nicotinamide once digested. The biological requirement for vitamin B-3 is met by adequate intake of niacin or nicotinamide, which is found in natural food sources or by converting the amino acid tryptophan readily found in the body.

Conversion of Niacin

Nicotinamide is the active form of niacin; your body can supply itself with nicotinamide by synthesizing amino acids into niacin. Tryptophan, an amino acid essential for life long growth and development, is obtained from protein-containing foods like dairy or poultry. Once you eat foods with tryptophan, your body breaks the amino acid down into a protein that synthesizes niacin. The niacin then converts into nicotinamide for further use in metabolic functions. The conversion process cannot happen without adequate intake of niacin or tryptophan containing sources from food or supplements.

Food Sources

Niacin and tryptophan are prominent in animal-based foods. Chicken and turkey at 3 oz. servings supply 5.8 to 7.3 mg of niacin. Beef, salmon and tuna have 3.1 to 11.3 mg in a 3 oz. serving. Plant-based foods also supply niacin in small amounts. Pasta, cereal and nuts yield 2.3 to 7 mg of niacin per serving. Dairy foods including cheese, milk and yogurt have tryptophan, which converts to niacin.

Supplements

Over-the-counter supplemental forms of niacin are available as nicotinamide or nicotinic acid. According to the Council for Responsible Nutrition, supplements with nicotinamide are less likely to cause adverse side effects like flushing than nicotinic acid. However, you should discuss dosing with your physician. Hair, skin and cosmetic products may contain nicotinamide, which serves to keep your skin conditioned. Prescription-strength niacin is available if you have complications with high cholesterol, but you must get your physician's recommendation before using an increased dose.

Daily Intake

The recommended daily intake of niacin for adults is 14 to 16 mg. Dietary intake prevents niacin deficiency symptoms including stomach upset, nervous system disruptions, neurological disturbance, fatigue and depression. Food sources of niacin in doses exceeding the recommended intake are not associated with adverse effects. However, the tolerable upper intake is 35 mg per day and supplemental forms of vitamin B-3 exceeding this amount can cause gastrointestinal disturbance, skin flushing, liver cell damage or nausea and vomiting. Do not exceed the daily recommended intake of niacin without physician supervision.