The optimum intake of vitamin B3 (niacin) for health promotion and chronic disease prevention is not yet known.
In 1993, the European Scientific Committee for Food set population reference intakes (PRI) for vitamin B3 (niacin) in milligrams (mg) per day (21):
| Age | Males: mg/day | Females: mg/day |
| 6–12 months | 5 | 5 |
| 1–3 years | 9 | 9 |
| 4–6 years | 11 | 11 |
| 7–10 years | 13 | 13 |
| 11–14 years | 15 | 14 |
| 15–17 years | 18 | 14 |
| 18 years and older | 18 | 14 |
| Pregnant | - | 14 |
| Breast-feeding | - | 16 |
The actual daily requirement of vitamin B3 (niacin) depends on the quantity of the amino acid ‘tryptophan’ in the diet and the efficiency of tryptophan to niacin conversion. The conversion factor is 60 mg tryptophan to 1 mg niacin, which is referred to as 1 niacin equivalent (NE). This conversion factor is used for calculating both dietary contributions from tryptophan and recommended allowances of niacin.
In 1998, the U.S. Food and Nutrition Board set recommended dietary allowance (RDA) values for vitamin B3 (niacin) in milligrams niacin equivalent (mg NE) per day that should prevent deficiency in most people (22):
| Life Stage | Age | Males: (mg NE*/day) | Females: (mg NE/day) |
| Infants | 0–6 months | 2 (AI) | 2 (AI) |
| Infants | 7–12 months | 4 (AI) | 4 (AI) |
| Children | 1–3 years | 6 | 6 |
| Children | 4–8 years | 8 | 8 |
| Children | 9–13 years | 12 | 12 |
| Adolescents | 14–18 years | 16 | 14 |
| Adults | 19 years and older | 16 | 14 |
| Pregnancy | all ages | - | 18 |
| Breast-feeding | all ages | - | 17 |
*NE, niacin equivalent: 1 mg NE = 60 mg of tryptophan = 1 mg niacin
For a detailed overview of recommended daily intakes (PRIs/RDAs) of vitamins and minerals for adults derived from different countries and organizations see PDF.
Authored by Dr Peter Engel in 2010, reviewed by Giorgio La Fata on 06.06.2017
