Noun
a B vitamin essential for the normal function of the nervous system and the gastrointestinal tract
Source: WordNetHowever, the roots are rich in calcium and vitamin C and contain a nutritionally significant quantity of thiamine, riboflavin and nicotinic acid. Source: Internet
These are hydrolysed in the intestine and the resulting nicotinamide is absorbed either as such, or following its hydrolysis to nicotinic acid. Source: Internet