The essential nutrient is needed to make the oxygen-carrying proteins hemoglobin, found in red blood cells, and myoglobin, found in muscles, according to the National Institutes of Health (NIH).
Lack of iron is the most common known form of nutritional deficiency. Its prevalence is highest among young children and women of childbearing age and pregnant women, the Centers for Disease Control and Prevention (CDC) says.
The recommended daily dietary allowance for iron for 19-to-50-year-old women is 18 milligrams and 8 mg for men. It doesn’t sound like much, but between 10 and 15 percent of adults in the U.S. don’t have enough and thousands are hospitalized every year.