Calcium Ok, Does Not Cause Macular Degeneration

Calcium Ok, Does Not Cause Macular Degeneration

Calcium supplements are considered by some to be a risk for increasing the possibility of developing age-related macular degeneration (AMD). Several studies claimed that it was highly possible for your body to have a compromised reaction when trying to simply strengthen your bones. Studies reported that high levels of calcium supplementation and self-reported glaucoma as well as possible early AMD development were linked. About 43% of the US population, which includes 70% of older women, take calcium supplements. However, past studies that theorized the possibility of developing AMD due to over-calcification consisted of small groups and high age demographics which were already at risk. 

Recently, new research from the National Institutes of Health (NIH) has emerged with analysis that challenges past reports of calcium intake being linked to macular degeneration development. 

Ongoing Data

It can become somewhat disconcerting when studies theorize or even confirm various conclusions and then, decades or a short time after, new studies reverse such findings. Yet, that is science, and without continued re-examination, progress would remain in the dark. The recent research looked at the original data from the revered, Age-Related Eye Disease Study also known as AREDS which looked at the effects vitamin and mineral supplementation had on vision, primarily age-related macular degeneration. This study took place from 1992-2001 incorporating a large subject pool consisting of 4751 patients from academic and community retinal practices in the US. The current study is not the first time AREDS had a secondary analysis as it was re-adjusted six years after publishing and re-titled AREDS II. 

The first AREDS formula was:

  • 500 milligrams (mg) of vitamin C
  • 400 international units of vitamin E
  • 15 mg beta-carotene
  • 80 mg zinc as zinc oxide
  • 2 mg copper as cupric oxide

The AREDS II formula added:

  • 10 mg lutein and 2 mg zeaxanthin
  • 1000 mg of omega-3 fatty acids (350 mg DHA and 650 mg EPA)
  • No beta-carotene
  • 25 mg zinc

You will notice that there is no calcium in any of the AREDS formulas however, age-related macular degeneration has the word “age” in it for a reason. AMD mostly affects those over 65 years old and a huge proportion of this demographic take calcium supplements to combat osteoporosis. Therefore, researchers looked at how calcium affected the eyes. 

A Threshold 

Most researchers suggested not putting this mineral into the AREDS formula, although many researchers debated this choice. There was speculation from the beginning, even in a study published in JAMA (Journal of the American Medical Association) Ophthalmology, which concluded, 

“Self-reported supplementary calcium consumption is associated with increased prevalence of AMD, with the findings suggesting a threshold rather than a dose-response relationship. The stronger association in older individuals may be due to relatively longer duration of calcium supplementation in older individuals.”

Co-Researcher of the JAMA study, Caitlin L. M. Kakigi from University of California, San Francisco, wavered, 

“The findings in this study suggest that there is a threshold of calcium supplementation above which there is an increased odds of AMD,..However, due to the various limitations of our study, and the cross-sectional nature of our data, we cannot make claims of causation regarding calcium supplementation intake and AMD.”

Therefore, on a secondary analysis, it is determined that calcium should be taken up to a certain point or “threshold”. Always check with your medical or naturopathic doctor to determine the best calcium protocol for you.

Safe Calcium 

The threshold theory offers a benchmark that consumers and medical professionals. It adheres to a safe calcium intake protocol that maintains bone health while potentially protecting from AMD at the same time.

MD Magazine reported on the JAMA study stating,

“The increased risk seemed to be confined to participants aged 68 years or older, where the odds of an AMD diagnosis was 2.63 times higher in those who consumed more than 800 mg/day of calcium than in those who reported no calcium consumption. The association was not significant among those aged 40 through 67 years.” 

However, one of the secondary study lead authors, Emily Chew, MD, of the National Eye Institute (NIH) in the US, commented,

“Given the fact that the data up to this point had been mixed on the question of calcium intake and AMD risk, physicians who had reservations about recommending a calcium-rich diet or supplements for osteoporosis prevention and treatment may be reassured by the fact that we found no evidence of risk associated with high calcium intake and AMD,” 

In another secondary study of AREDS and calcium by researchers at the Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland which was also published in JAMA, it was concluded that, 

“In this secondary analysis, higher levels of dietary and supplementary calcium intake were associated with lower incidence of progression to late AMD in AREDS participants.”

Benefits of Calcium 

The results of the NIH study by Dr. Emily Chew and her team were accumulated over a nine year period. Dr. Chew commented that, 

“These latest findings provide no evidence that there is a need to change the management of calcium intake for individuals who are already taking calcium for other medical indications,”

Some stats were reported by United Press International (UPI) which stated,

“About 50 percent of men and 65 percent of women in the United States regularly use calcium supplements for strong bones and teeth, and to prevent and treat osteoporosis. Recommended daily amounts of calcium are 1,000 milligrams for adults 50 and younger, and 1,200 milligrams for those over 50.”

Taking a daily calcium supplement in conjunction with a professional practitioner’s guidance could assist in increasing your body’s levels. However, if possible, the best calcium is obtained through real food high in the mineral. The obvious calcium rich foods such as cheese and milk could be hard on your digestive system. Non-dairy foods that should be easier to manage are readily available.

WebMD breaks down some of these foods and each calcium content,

  • Calcium-fortified orange juice, 6 ounces 375 mg
  • Canned sardines with bones, 3 ounces 325 mg
  • Firm tofu made with calcium sulfate, 1/2 cup 253 mg
  • Canned salmon with bone, 3 ounces 181 mg
  • Calcium-fortified breakfast cereal, 1 cup 100-1,000 mg

Other foods with good calcium content include: chia seeds, broccoli, spinach, kale, edamame, beans, lentils, figs, and almonds.  

Taking care of your vision is essential so keeping abreast of new research is just as essential. The NIH studies that corroborated on adhering to a calcium threshold show how new information, such as this, can be managed and navigated accordingly.