Normal niacin requirements
The United States Institute of Medicine (IOM) of
the National Academy of Sciences has developed val-
ues calledDietary Reference Intakes(DRIs) for vita-
mins andminerals. The DRIs consist of three sets of
numbers. The Recommended Dietary Allowance
(RDA) defines the average daily amount of the
nutrient needed to meet the health needs of 97–98%
of the population. The Adequate Intake (AI) is an
estimate set when there is not enough information to
determine an RDA. The Tolerable Upper Intake Level
(UL) is the average maximum amount that can be
taken daily without risking negative side effects. The
DRIs are calculated for children, adult men, adult
women, pregnant women, andbreastfeedingwomen.
The IOM has not set RDAs or ULs for niacin in
children under one year old because of incomplete
scientific information. Instead, it has set AI levels for
this age group. RDAs and ULs for niacin are meas-
ured in micrograms (mg) of niacin equivalent (NE).
One mg NE equals 1 mg niacin or 60 mg tryptophan,
an amino acid that the liver can convert into niacin.
Unlike the UL for many vitamins, the UL for niacin
acid refers only to niacin that comes from fortified
food or that is in dietary supplements such as multi-
vitamins. There is no UL for niacin found in natural
plant and animal foods. The UL for niacin also does
not apply to individuals who are taking large doses of
niacin under the supervision of a medical professional
for the treatment of cardiovascular disease.
The following are the daily RDAs and IAs and
ULs for niacin for healthy individuals:
children birth–6 months: AI 2 mg; UL not estab-
lished. All niacin should come from breast milk,
fortified formula, or food.
children 7–12 months: AI 4 mg; UL not established.
All niacin should come from breast milk, fortified
formula, or food.
children 1–3 years: RDA 6 mg; UL 10 mg
children 4–8 years: RDA 8 mg; UL 15 mg
children 9–13 years: RDA 12 mg; UL 20 mg
boys 14–18 years: 16 RDA mg; UL 30 mg
girls 14–18 years: 14 RDA mg; UL 30 mg
men age 19 and older: RDA 16 mg; UL 35 mg
women age 19 and older: RDA 14 mg; UL 35 mg
pregnant women: RDA 18 mg; UL 35 mg
breastfeeding women: RDA 17 mg; 35 mgSources of niacin
Good sources of niacin include red meat, poultry,
fish, and fortified cereals. A niacin fortification pro-
gram began in the United States in 1938 when supple-
mental niacin was added to bread. Today niacin is
routinely added to flour, cereals, bread, and pasta.
These products can be labeled ‘‘fortified’’ or
‘‘enriched.’’ Because of niacin fortification, most
healthy Americans get enough niacin from their diet
without taking a dietary supplement. Niacin is also
found in multivitamins, B-complex vitamins, and as a
single-ingredient supplement.KEY TERMS
Alzheimer’s disease—An incurable disease of
older individuals that results in the destruction of
nerve cells in the brain and causes gradual loss of
mental and physical functions.
Amino acid—Molecules that are the basic building
blocks of proteins.
B-complex vitamins—A group of water-soluble
vitamins that often work together in the body.
These include thiamine (B 1 ), riboflavin (B 2 ), niacin
(B 3 ), pantothenic acid (B 5 ), pyridoxine (B 6 ), biotin
(B 7 or vitamin H), niacin/folic acid (B 9 ), and coba-
lamin (B 12 ).
Dietary supplement—A product, such as a vitamin,
mineral, herb, amino acid, or enzyme, that is
intended to be consumed in addition to an individ-
ual’s diet with the expectation that it will improve
health.
Enzyme—A protein that change the rate of a chem-
ical reaction within the body without themselves
being used up in the reaction.
Osteoporosis—A condition found in older individ-
uals in which bones decrease in density and become
fragile and more likely to break. It can be caused by
lack of vitamin D and/or calcium in the diet.
Steroid—A family of compounds that share a sim-
ilar chemical structure. This family includes the
estrogen and testosterone, vitamin D, cholesterol,
and the drugs cortisone and prendisone.
Vitamin—A nutrient that the body needs in small
amounts to remain healthy but that the body cannot
manufacture for itself and must acquire through
diet.
Water-soluble vitamin—A vitamin that dissolves in
water and can be removed from the body in urine.Niacin