Iron deficiency is the most common nutritional deficiency in the world, affecting 20 to 50% of the world’s population; however, it occurs less frequently in the United States.

One study showed that as many as 20% of women between the ages of 18 and 55 years old suffer from iron deficiency.

The most common cause of iron deficiency is insufficient intake, but malabsorption or excessive bleeding may be contributing factors. Some medications, such as aspirin, ibuprofen (Advil®), ranitidine (Zantac®), cimetidine (Tagamet®) and sodium bicarbonate (Alka-Seltzer®) also deplete the body of iron and may lead to iron deficiency.

The most common complaint with iron deficiency is fatigue, but may also include hair loss, brittle nails, poor memory and concentration, mood swings, anxiety, insomnia and depression.

Severe iron deficiency can lead to anemia (low red blood cell count), but in most women with iron deficiency, the deficiency is not severe enough to cause anemia.

Children paying attention in school

Iron deficiency in children can be observed as behavior or attention problems (such as ADHD) and can even lead to eating dirt (a condition called pica) if the deficiency is severe enough.

One study found that 136 non-anemic women with unexplained fatigue who took 80 mg of iron per day for one month had a 30% increase in their energy, compared with women who took a placebo.

Another study showed that 16 women with marginal iron deficiency, but not anemia, had better endurance during exercise while taking 16 mg of iron per day for 6 weeks. In children with ADHD and iron deficiency, supplementation with iron helped improve both behavior and performance in school. Even some children with ADHD who were not iron-deficient had some benefit from iron supplementation, though the benefits seem to be less pronounced in those children.

Diagnosing iron deficiency is not difficult, but nonetheless often goes undetected.

The reason is that most physicians screen for iron deficiency by testing for anemia. Unfortunately, these screening tests fail to identify people with mild to moderate iron deficiency, since iron stores will become almost completely depleted before blood counts drop.

Studies show that measuring blood levels of ferritin, a storage protein for iron in the body is the most sensitive test for iron deficiency and that normal ferritin levels should be greater than 40 mcg/L.

Blood test tubs in centrifuge

Despite the new guidelines, many laboratories continue to report ferritin levels below 40 mcg/L as normal, which suggests many iron deficient people are under diagnosed and fail to get proper treatment.

The symptoms of iron deficiency are not specific, so other causes of illness should be considered before starting iron supplementation. Taking supplemental iron can be harmful to people with a genetic condition called hemochromatosis, which causes an excessive accumulation of iron in the body.

People with hemochromatosis could develop diabetes or liver disease if they take supplemental iron. Too much iron can also lead to nausea, constipation or abdominal pain. Iron supplements should only be taken once it has been determined to be safe.

Some physicians recommend 50-100 mg per day of elemental iron and then decreasing the amount as the iron deficiency is corrected.

Taking 100 mg of vitamin C at the same time can help increase the absorption of iron. Iron should not be taken at the same time as coffee, tea, soy or calcium (including dairy products), since these substances interfere with the absorption of iron.

Iron supplements can also interfere with certain medications, such as tetracyclines, levofloxacin (Levaquin®), carbidopa/levodopa (Sinemet®) and warfarin (Coumadin®), and should therefore not be taken simultaneously.

Slices of medium rare steak

Increasing iron-rich foods in the diet is another way to boost iron levels if necessary. Foods high in iron include red meat, dark, green leafy vegetables (kale, Swiss chard, mustard greens), beans, nuts, Brewer’s yeast, eggs and black strap molasses.

It is important for anyone with iron deficiency to see a physician to determine the cause.