According to the American Academy of Family Physicians, the incidence of iron deficiency anemia in the U.S is 2% of adult men, 9-12% in non-Hispanic white women, and nearly 20% in black and Mexican-American women. Toddlers, adolescents and adult females (age 12-49) are amongst the highest risk.
Iron is absorbed in the intestinal tract. In most people, iron absorption is higher in the presence of iron-deficiency than when body iron stores are normal or excessive. Those with hereditary hemochromatosis are unable to down-regulate iron absorption when iron stores are normal or high, so they develop iron overload.
Heme iron, found in meats, poultry and fish, is well absorbed. Whereas nonheme iron found in other foods and supplements is much lower. Depending on the individual, 15-35% of heme iron, and 2-20% of nonheme is absorbed. Fish, poultry and meat have a high content of cysteine which is what increases iron absorption in these foods. Most studies have found that the absorption of nonheme iron is inhibited by a variety of foods including coffee, tea and soy products. Wheat, oat products, nuts, casein, egg white and whey protein also inhibits some absorption, while Vitamin C enhances the absorption. Organically grown crops have been found to contain significantly moe iron than conventionally grown crops.
We know that supplementing with iron (besides consuming heme iron foods) is the best treatment for iron deficiency anemia. But I have found that even when the recommended dose of iron is given, it doesn’t always lead to the optimal outcome. Besides trying different types, is there a better way to absorb the iron thats given?
One important peptide that inhibits intestinal iron absorption is “hepcidin”. researchers studied 54 non anemic young women who received ferrous sulfate in daily or twice a day doses. The investigators found that the higher dose of iron supplement was associated with a decrease in fractional iron absorption. Hepcidin levels were significantly higher after the twice-daily iron dosing (as soon as 24 hours after the dose was taken) than after daily dosing. Perhaps this is a protective mechanism of our bodies to prevent iron overload (except those with hereditary hemochromatosis as described above).
Ferrous sulfate is the most common iron prescribed for patients with iron deficiency anemia in doses of 60 mg of elemental iron (which is the amount in 300 mg of ferrous sulfate). It is usually dosed three times daily. Researchers have now concluded that oral elemental iron doses equal or greater than 60 mg will result in higher fractional iron absorption when spaced by 48 hours, in other words given less frequently. Less frequent dosing may be more acceptable to patients and produce fewer side effects.
Absorption is clearly different for each individual. Diet (meat eaters vs vegetarians), the use of antacids and gastric infections can effect absorption in each individual. Those with low stomach acids will have a markedly decreased iron absorption as stomach acids are necessary for absorption of minerals and proteins. Therefore, the use of antacids and proton pump inhibitors (Prevacid, Nexium, etc) will alter stomach acid content and put people at risk for iron deficiency anemia, osteoporosis and malabsorption. Patients with H. Pylori-associated gastritis were found to have anemia, which was completely reversed once this infection was treated.
If is very easy and inexpensive to check for iron-deficiency anemia. Get it checked if you have symptoms of fatigue, pale skin, shortness of breath, dizziness, tingling or crawling feeling in the legs, poor concentration, and hair loss.
Moretti D et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. Blood 2015 Oct 22; 126:1981.
Gaby, A. Iron. Nutritional Medicine. Fritz Perlberg Publishing 2011. pp.145-149
Therapeutic Research Faculty. Natural Medicines Comprehensive Database 2013. Iron. pp. 905-912.