Iron

Also indexed as:Ferrous Sulfate
Iron: Main Image

Interactions with Supplements, Foods, & Other Compounds

Many foods, beverages, and supplements have been shown to affect the absorption of iron.108

Foods, beverages and supplements that interfere with iron absorption include

  • Green tea (Camellia sinensis).109, 110, 111, 112 This effect may be desirable for people with iron overload diseases, such as hemochromatosis. The inhibitory effect of green tea on iron absorption was 26% in one study.113

  • Coffee (Coffea arabica, C. robusta).114, 115, 116

  • Red wine, particularly the polyphenol component (also found in tea).117, 118 Since wine is also a dietary source of iron, it is not clear whether drinking red wine would lead to a deficiency of iron.

  • Phytate (phytic acid), found in unleavened wheat products such as matzoh, pita, and some rye crackers; in wheat germ, oats, nuts, cacao powder, vanilla extract, beans, and many other foods, and in IP-6 supplements.119, 120, 121

  • Whole wheat bran, independent of its phytate content, has been shown to inhibit iron absorption.122

  • Calcium from food and supplements interferes with heme-iron absorption.123, 124

  • Soy protein.125, 126

  • Eggs.127, 128

Foods and supplements that increase iron absorption include

Although vitamin C increases iron absorption,134, 135, 136, 137 the effect is relatively minor.138

Taking vitamin A with iron helps treat iron deficiency, since vitamin A improves the absorption and/or utilization of iron.139, 140

Although soy protein has been shown to decrease iron absorption (see above), certain soy-containing foods (e.g. tofu, miso, tempeh) have significantly improved iron absorption.141 Some soy sauces may also enhance iron absorption.142

Alcohol, but not red wine, has been reported to increase the absorption of ferric, but not ferrous, iron.143, 144

Iron has been reported to potentially interfere with manganese absorption. In one trial, women with high iron status had relatively poor absorption of manganese.145 In another trial studying manganese/iron interactions in women, increased intake of “non-heme iron”—the kind of iron found in most supplements—decreased manganese status.146 These interactions suggest that taking multiminerals that include manganese may protect against manganese deficiencies that might otherwise be triggered by taking isolated iron supplements.

Interactions with Medicines

Certain medicines interact with this supplement.

Types of interactions:beneficial= Beneficialadverse= Adversecheck= Check
dnicon_BeneficialReplenish Depleted Nutrients
dnicon_BeneficialReduce Side Effects
dnicon_BeneficialSupport Medicine

none

dnicon_AvoidReduces Effectiveness
dnicon_AvoidPotential Negative Interaction
dnicon_CheckExplanation Required
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, click a medicine and click through to "More about" or refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.