The following list gives the daily RDAs and IAs
and ULs for vitamin C for healthy individuals as
established by the IOM.
children birth–6 months: RDA 0.27 mg; UL not
established
children 7–12 months: RDA 11 mg; UL not
established
children 1–3 years: RDA 7 mg; UL 40 mg
children 4–8 years: RDA 10 mg; UL 40 mg
children 9–13 years: RDA 9 mg; UL 40 mg
boys 14–18 years: RDA 11 mg; UL 45 mg
girls 14–18 years: RDA 55 mg; UL 45 mg
men age 19–50: RDA 8 mg; UL 45 mg
women age 19–50: RDA 18 mg; UL 45 mg
men who smoke: RDA 125 mg; UL 45 mg
pregnant women: RDA 27 mg; UL 45 mg
breastfeeding women 18 years and younger: RDA 10
mg; UL 45 mg
breastfeeding women 19 years and older: RDA 9 mg;
45 mg
PrecautionsPregnant women should consult their healthcare
provider before the fifteenth week of pregnancy about
the need for iron supplementation. They should not
start taking an iron supplement on their own.
Men and women over age 55 are not at risk for
iron deficiency and should take a multivitamin con-
taining iron only on instructions from their healthcare
provider.
People with kidney disease, liver damage, alcohol-
ism, orulcersshould consult a healthcare professional
before taking a supplement containing iron.
InteractionsIron interacts with many drugs and nutritional
supplements. General categories of substances that
may increase or decrease the amount of iron that is
absorbed include medications that decrease stomach
acidity (e.g. antacids, Tagamet, Zantac), pancreatic
enzyme supplements,calciumsupplements and dairy
products, vitamin C, citric, malic, tartaric, and lactic
acids, and copper.
The presence of iron also increases or decreases
the effectiveness of many prescription drugs. Individ-
uals should review their medications with a doctor or
pharmacist when they begin taking an iron supple-
ment to see if their other medications need adjustment.
Complications
Iron deficiency
The World Health Organization (WHO) consid-
ers iron deficiency to be the most widespread dietary
disorder in the world. WHO estimates that up to 80%
of the world’s population is iron deficient and up to
30% have iron deficiency anemia. The two main
causes of iron deficiency are low dietary intake and
excessive blood loss. In the United States, women of
childbearing age, young children, people with diseases
that interfere with the absorption of iron (e.g. Crohn’s
disease,celiac disease), and people receiving kidney
dialysis are most likely to seriously be iron deficient.
American men rarely have low levels of iron because
the tend to eat more meat than women and do not lose
blood through menstruation.
At first, the body is able to use stored iron to make
up for an iron deficit, but over time, the amount of
hemoglobin decreases and a condition called iron defi-
ciency anemia develops. (This is only one type of
anemia; other anemias have other causes.) Iron defi-
ciency anemia decreases the amount of oxygen reach-
ing cells in the body. Symptoms of iron deficiency
anemia include:
lack of energy
feelings of weakness
frequently feeling cold
increased infections
irritability
decreased work or school performance
sore swollen tongue
drive to eat dirt, clay or other non-food substances
(pica)
The preferred way to treat mild iron deficiency is
through changes in diet. If these changes are ineffec-
tive, iron supplements may be used. Dietary supple-
ments contain different formulations such as ferrous
fumarate, ferrous sulfate, and ferrous gluconate. Iron
in these different formulations is absorbed at differing
rates. Because too much iron can cause serious health
problems, iron supplements should be taken under the
supervision of a healthcare professional.Iron excess
Iron overload caused by an inherited disorder is
called hereditary hemochromatosis. This disorder
affects as many as one of every 200 people of north-
ern European descent. These people have a genetic
mutation that causes them to absorb iron from theIron