Calcium supplements may increase risk for AMD

A recent study revealed that supplementary calcium consumption is associated with the development of age-related macular degeneration (AMD).

"Optometrists should be fully engaged in identifying over-calcified patients."
The findings suggest that people who consume more than 800 mg per day of supplementary calcium are 85 percent more likely to be diagnosed with AMD than those who do not supplement with calcium. The association between supplementary calcium and AMD was found to be stronger in older individuals, which is due to the longer duration of calcium supplementation.

The research, which was published in JAMA Ophthalmology, studied 3,191 participants—all 40 years and older—who were evaluated for the presence or absence of AMD by fundus photography. The use of calcium supplements was self-reported.

Stuart Richer, O.D., Ph.D., current president of the Ocular Nutrition Society, is unsurprised by the findings.

"Degenerative disease such as macular degeneration—and the most common types of glaucoma—are in part oculo-vascular diseases. Iatrogenic calcification via overzealous calcium supplementation, particularly in the face of widespread U.S. magnesium deficiency, is a very bad practice. Calcium is in fact regulated by magnesium," says Dr. Richer.

"In AMD specifically, Bruch's membrane calcification may serve as a barometer for systemic calcification. Bruch's membrane regulates the reciprocal exchange of biomolecules, nutrients, oxygen, fluids and metabolic waste products between the retina and the general circulation (choroid)," adds Dr. Richer.

Recommendations regarding supplements may shift
Calcium is certainly necessary for good health, but overconsumption and lack of proper oversight are serious concerns.

Dr. Richer notes that, often, females over the age of 50 use calcium supplements to reduce the risk of bone fracture, when in fact, the real issue is estrogen loss. He added that there has been an upward trend in cardiovascular event rates in healthy postmenopausal women receiving calcium supplementation.

"In our growth years and during pregnancy we need calcium. It can be obtained from ample plant food combined with sufficient vitamin D exposure of the skin, as well as dairy," says Dr. Richer. "In modern societies there is insufficient plant food consumption, insufficient magnesium and vitamin D intake, and excessive phosphate soda consumption, protein consumption and acid-forming foods—all of which adversely impact calcium status."

The findings about the link between calcium supplements and AMD should have an effect on how physicians—especially optometrists—speak to their patients about supplements.

"As primary care providers, optometrists should be fully engaged in identifying over-calcified patients with retinal disease or glaucoma. Those taking two or three or even four calcium supplements, especially without co-administered magnesium, are at risk," says Dr. Richer.