&noscript=1 />
Expert

Iron and Age-Related Macular Degeneration

Scheie Eye Institute, University of Pennsylvania
Woman with macular degeneration examining an iron supplement
Learn why iron may increase the risk of developing AMD, how you can decrease your risk, and how research may provide important answers.

“Everything in moderation” can be an important life principle. The saying also applies to the role of iron in health and disease. Iron is needed to avoid anemia and to make energy, but too much iron can cause free radical damage. Free radicals are very reactive molecules that can adversely interact with other molecules inside of our cells. The resulting inflammation can contribute to a number of age-related diseases, such as arthritis, heart disease, and age-related macular degeneration (AMD). Research over the past 15 years in my laboratory and others around the world has suggested that excess iron may increase the risk of age-related macular degeneration (AMD).

Evidence

Retinas from AMD patients generally have more iron than age-matched retinas from patients without AMD. People with rare genetic diseases causing retinal iron accumulation can develop AMD at an early age. People who get iron in the eye following an accident rapidly develop retinal disease. Mouse models genetically engineered to accumulate iron in the retina get a retinal disease that resembles AMD. These mice can be protected from retinal disease with a drug that binds to the iron, prevents the iron from exerting its damaging effects.

Dietary Risk

Iron in the diet may contribute to AMD risk. A large study in Australia showed that people who eat more red meat had a higher risk of AMD. While this risk may be caused by a number of components in red meat, it is very high in heme iron, the most readily absorbed form of iron. Most dietary iron is not absorbed. In fact, only about 10 percent of iron within vegetables (including spinach) is normally absorbed, whereas 50 percent of iron in red meat is taken up into the bloodstream from the intestines.

Iron Supplements

These findings beg the question whether iron supplementation may increase AMD risk. Many multivitamins and foods are supplemented, or “fortified” with iron, to prevent iron deficiency anemia. Those at greatest risk for iron deficiency anemia are menstruating women. Red blood cells are packed with iron. Post-menopausal women and men are a low risk of iron deficiency anemia, and should not be taking iron supplements unless they are diagnosed with iron deficiency.

Recently, a 40-year-old woman with iron deficiency anemia was given intravenous iron, as iron pills were causing her severe constipation, a common side effect. She had been examined by an ophthalmologist every year to check for glaucoma, which runs in her family. Within a year of getting the intravenous iron, she developed AMD. This may have been caused by the intravenous iron, as it is very unusual for a 42-year old to develop AMD. To further test this possibility, my laboratory administered intravenous iron to mice, and they developed retinal abnormalities with features of AMD. Additional studies of AMD risk in patients receiving intravenous iron are ongoing.

Decreasing Risk

For patients with AMD, it has been shown that a diet high in fruits and vegetables, with fatty fish (salmon, sardines, tuna, mackerel) twice a week, and low in red meat, decreases the risk of AMD. This type of diet is relatively low in iron.

The Future

If iron promotes AMD, then removing iron from the retina may be protective. Several drugs are capable of specifically removing iron from cells, and some can access the retina when taken orally. Clinical trials will be needed to test these drugs and determine whether they can safely decrease the risk of AMD.

Resources:

This content was first posted on: January 29, 2017

The information provided here is a public service of the BrightFocus Foundation and should not in any way substitute for personalized advice of a qualified healthcare professional; it is not intended to constitute medical advice. Please consult your physician for personalized medical advice. BrightFocus Foundation does not endorse any medical product, therapy, or resources mentioned or listed in this article. All medications and supplements should only be taken under medical supervision. Also, although we make every effort to keep the medical information on our website updated, we cannot guarantee that the posted information reflects the most up-to-date research.

These articles do not imply an endorsement of BrightFocus by the author or their institution, nor do they imply an endorsement of the institution or author by BrightFocus.

Some of the content may be adapted from other sources, which will be clearly identified within the article.

More Like This

  • Woman holding her right eye in discomfort
    Expert

    Common Causes of Eye Pain

    Learn about the nerve that is involved in many causes of eye pain and discomfort.

    December 18, 2020
  • Accessible Voting Machine
    Expert

    Making an Accessible Voting Plan

    As the 2020 election is quickly approaching on Tuesday, November 3rd, now is a great time to make your voting plan. In addition to reviewing the dates, deadlines, locations, and requirements for in-person or absentee voting in your state, for people with disabilities and impairments, it’s also important to know what your options are for accessible voting.

    October 14, 2020
Don't miss out.
Receive research updates, inspiring stories, and expert advice
Please enter your first name.
Please enter your last name.
Keep me informed about: *
Please select at least one.
You must select at least one disease category.