Nutrition: Niacin is a member of the water-soluble B-vitamins and is also known as vitamin B3, nicotinamide and niacinamide. Unlike other B-vitamins, niacin can be produced in the body from tryptophan. This is a rather inefficient process because 60 mg of tryptophan are required to produce 1 mg of niacin. Niacin actually refers to two chemically related molecules, nicotinamide (which is also known as niacinamide) and nicotinic acid. Nicotinic acid can be easily converted to nicotinamide which is the form that the body utilizes. Niacin forms an essential part of nicotinamide adenine dinucleotide (NAD) and the phosphorylated form NADP. NAD and NADP play important roles in energy transfer reactions during the metabolism of carbohydrates, fats and alcohol.
Nicotinic acid also has been shown to reduce bad cholesterol levels while raising good cholesterol levels. Niacin is an essential nutrient that must be obtained from the diet or deficiency symptoms can occur. Deficiency results in a condition known as pellagra. Symptoms swollen tongue, diarrhea, dermatitis and dementia. Animal sources contribute about half of the daily need for niacin in the form of tryptophan. Plant sources such as mushrooms, asparagus and brewer’s yeast are sources high in niacin.
Unlike many water soluble vitamins, niacin can be toxic when taken in higher doses. One of the most common side effects is known as “niacin flush” that causes redness and tingling of the skin. Nicotinic acid has this effect while nicotinamide does not. High doses of niacin have been used by women trying to treat premenstrual syndrome and to lower cholesterol. High doses of niacin can cause liver dysfunction, ulcer, blood sugar alterations, dizziness and very high doses can cause eye troubles and even death. Recommended intake is 19 mg of niacin per day or an equivalent mixture of niacin and tryptophan.