Large Doses of Calcium and Iron Supplements May Increase Glaucoma Risk, Says Study

Iron and calcium supplementation above a certain level may increase your risk of developing glaucoma, says recent research.

In a cross-sectional study of participants in the 2007-2008 National Health and Nutrition Examination Survey, 3,833 people aged 40 or older were interviewed about their use of dietary supplements and antacids (which usually contain calcium) during the previous 30 days.

Those who took at least 800 mg per day of supplementary calcium or at least 18 mg per day of supplementary iron (both are oxidants) had a greater chance of glaucomatous disease than those not taking these supplements. In fact, taking both iron and calcium above these levels increased the odds of developing glaucoma even more.

For perspective, here are the amounts of iron and calcium found in some popular supplements:

  • A two-tablet dose of Tums Ultra Strength 1000 contains 800 mg of calcium, while two tablets of Tums Extra Strength 750 contain 600 mg.
  • A one-tablet daily dose of Centrum Silver Women 50+ contains 500 mg of calcium and 8 mg of iron, while the same dose of Centrum Women Under 50 contains the same amount of calcium but 18 mg of ironĀ· A two-tablet daily dose of Nature Made Calcium 500 mg with Vitamin D contains 1,000 mg of calcium. Incidentally, this is the recommended daily amount of calcium, according to the label.
  • A one-tablet daily dose of Nature Made Iron contains 65 mg of iron.

The researchers noted that further study is needed to decide whether oxidant intake is a definite risk factor for the eye disease.

Worcestershire Glaucoma Support Group