Niacin can be obtained
from food or made in our bodies from the amino acid, tryptophan. Tryptophan
is a constituent of protein, although not all proteins are good sources
of tryptophan. To obtain 1 milligram of niacin, we need 60 milligrams
of tryptophan. Thus, if both niacin and tryptophan in food are taken
into account, the niacin equivalent (in milligrams) in a food can be
worked out. However, not all niacin in food may be equally available
to the body, because some is rather tightly bound to other food constituents
and not easily released.
Since niacin is
water soluble, losses can occur by discarding water containing the dissolved
vitamin.
Those at particular
risk of niacin deficiency are the socio-economically deprived, those
with a high consumption of corn, which is low in both tryptophan and
niacin, and alcohol abusers (see
the 'Alcohol' Food Chart). Pellagra is a condition resulting
from niacin deficiency, in which there are symptoms of dermatitis in
skin exposed to the sun, diarrhoea and dementia. With lesser degrees
of deficiency, general weakness, loss of appetite and indigestion can
occur, but these symptoms can also occur in many other circumstances.
NIACIN
INTAKE
Recommended
daily dietary intake of niacin (Australia): |
Infants:
Children:
Adult men:
Adult women:
Pregnancy:
Lactation:
|
4-7 milligrams niacin equivalents
9-22 milligrams niacin equivalents
14-20 milligrams niacin equivalents
(related to energy intake, which declines with advancing years)
10-14 milligrams niacin equivalents
(related to energy intake, as above)
14-16 milligrams niacin equivalents
17-19 milligrams niacin equivalents
|