Iron Requirements and Dietary Sources

Mineral Guide

Spinach is high in iron.
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Iron is a trace mineral your body uses for transporting oxygen to cells throughout your body. Iron is also essential for cell growth and differentiation. Most of your body's iron is found in red blood cells with a small amount in muscle cells and some enzymes.

The Institute of Medicine of the National AcademyThe National Academies of Sciences, Engineering and Medicine, Health and Medicine Division has determined the dietary reference intakes (DRI) for iron.

It's based on the daily nutritional needs of an average healthy person and varies by age and sex. If you have any medical issues, you should speak with your health care provider about your iron requirements.

Dietary Reference Intakes

Males

1 to 3 years: 7 milligrams per day
4 to 8 years: 10 milligrams per day
9 to 13 years: 8 milligrams per day
14 to 18 years: 11 milligrams per day
19 to 50 years: 8 milligrams per day
51+ years: 8 milligrams per day

Females

1 to 3 years: 7 milligrams per day
4 to 8 years: 10 milligrams per day
9 to 13 years: 8 milligrams per day
14 to 18 years: 15 milligrams per day
19 to 50 years: 18 milligrams per day
51+ years: 8 milligrams per day
Women who are pregnant: 27 milligrams per day
Women who are breastfeeding: 9 milligrams per day

Iron-rich foods include meat, fish, poultry, oats, legumes and spinach. There are two forms: the form found in animal tissue is called heme iron (from hemoglobin), and non-heme iron is the form found in plants.

While both forms are acceptable, the heme iron is more easily absorbed. You can increase the availability of non-heme iron by combining the plant sources with foods rich in vitamin C.

Iron deficiency results in a reduced amount of oxygen being delivered to the cells and leads to fatigue and a condition called microcytic anemia.

Not getting enough iron can also negatively affect your immune system. Deficiency can occur from lack of iron in the diet, difficulty absorbing enough iron from the foods you eat, or from chronic blood loss during menstrual periods or some digestive system disorders.

What Happens If You Take Too Much Iron?

The Institute of Medicine sets the upper tolerance for iron supplements, which is the highest daily dose that appears to be safe, at 45 milligrams per day. Taking more than 45 milligrams per day can lead to digestive problems such as nausea, vomiting, and constipation.

Iron supplements should always be kept in childproof containers because a single large dose of iron (over 60 milligrams) can cause serious iron poisoning in children under the age of five years. Seek emergency care if you think a young child might have taken a large dose of iron.

Iron Overload Disease

Hemochromatosis is a condition that causes too much iron to be stored in the liver and other organs. It isn't caused by taking too much iron, but people who have it are unable to remove any extra iron that their bodies don't need.

It's more common in males than females and might lead to organ damage if left untreated. People who have hemochromatosis must watch their iron intake. They may also take medication or have blood occasionally removed to reduce iron build-up.

Sources:

Medline Plus. "Hemochromatosis." Accessed March 14, 2016. http://www.nlm.nih.gov/medlineplus/hemochromatosis.html.

National Academies of Sciences, Engineering and Medicine, Health and Medicine Division. "Dietary Reference Intakes Tables and Application." Accessed March 14, 2016. http://www.nationalacademies.org/hmd/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx.

National Institutes of Health, Office of Dietary Supplements. "Dietary Supplement Fact Sheet: Iron." Accessed March 14, 2016. http://ods.od.nih.gov/factsheets/iron/.

Office of Dietary Supplements, National Institutes of Health. "Dietary Supplement Fact Sheet: Iron." Accessed March 14, 2016. http://ods.od.nih.gov/factsheets/Iron-HealthProfessional.

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