Vitamin B3 (Niacin) is essential for the following body functions:
| Food / 100g | Amount (mg) |
| Yeast extract | 73 |
| Grapenuts | 20 |
| Peanuts, plain | 19 |
| Corn flakes | 17 |
| Shiitake mushroom, dried | 15 |
| Life Stage Group | RDA/AI* mg / day |
Upper Limit mg / day |
| Infants 0-6 months 7-12 months |
2* 4* |
Not determinable Not determinable |
| Children 1-3 years 4-8 years |
6 8 |
10 15 |
| Males 9-13 years 14-18 years 19 - >70 years |
12 16 16 |
20 30 35 |
| Females 9-13 years 14-18 years 19 - >70 years |
12 14 14 |
20 30 35 |
| Pregnancy <19 years 19 - >50 years |
18 18 |
30 35 |
| Lactation <19 years 19 - >50 years |
17 17 |
30 35 |
RDA = Recommended Dietary Allowances
AI* = Adequate Intakes
UL = Upper Limit
A deficiency of vitamin B3 can cause:
An excess of vitamin B3 (over 3g a day) can cause: