Niacin deficiency symptoms can be seen in diets with niacin intake below 7.5 mg. per day, but often this is not the only deficiency; vitamin B1, vitamin B2, and other B vitamins, as well as protein and iron may be low. To treat pellagra and niacin deficiency disorders, vitamin B3 supplements should be taken along with good protein intake to obtain adequate levels of the amino acid tryptophan. As described earlier, about 50 percent of daily niacin comes from the conversion in our livers of tryptophan to niacin with the help of pyridoxine (vitamin B6).
Requirements: Many food charts list only sources that actually contain niacin and do not
take into account tryptophan conversion into niacin. Approximately 60 mg. of tryptophan can generate 1 mg. of niacin. But tryptophan is available for conversion only when there are more than sufficient quantities in the diet to synthesize the necessary proteins as tryptophan is used in our body with the other essential amino acids to produce protein.
Niacin needs are based on caloric intake. We need about 6.6 mg. per 1,000 calories, and no less than 13 mg. per day. Women need at least 13 mg. and men at least 18 mg. per day. The RDA for children ranges from 9-16 mg.
Niacin needs are increased during pregnancy, lactation, and growth periods, as well as after physical exercise. Athletes require more B3 than less active people. Stress, illness, and tissue injury also increase the body's need for niacin. People who eat much sugar or refined, processed foods require more niacin as well.
Realistically, 25-50 mg. per day is adequate intake of niacin if minimum protein requirements are met. On the average, many supplements provide at least 50-100 mg. per day of niacin or niacinamide, which is a good insurance level. For treatment of the variety of conditions described previously, higher amounts of niacin may be needed to really be helpful, and levels up to 2-3 grams per day are not uncommon as a therapeutic dose. The other B vitamins should also be supplied so as to not create an imbalanced metabolic condition.