Men who have a high intake of calcium supplements appear to have a greater risk of CVD (cardiovascular disease) death, researchers from the National Cancer Institute, Bethesda, Md., reported in JAMA Internal Medicine. The authors noted that women do not appear to be affected in the same way.
Elderly Americans are taking calcium supplements in progressively higher numbers, the authors explained as background information. They do so because of the health benefits for their bones. However, apart from the benefits in the prevention and treatment of osteoporosis, experts are not sure what non-skeletal health effects they might have. In fact, the subject has become “increasingly contentious”.
Qian Xiao, Ph.D. and team set out to determine whether the consumption of dietary and supplemental calcium might be linked to mortality from total cardiovascular, heart, and cerebrovascular diseases. There were a total of 388,229 participants in the study, men and women aged from 50 to 71 years from the NIH-AARP Diet and Health Study, across six states and two major cities from 1995 to the end of 1996.
They found that supplemental, but not dietary calcium intake, was linked to greater CVD mortality in men but not in women.
The participants were followed-up for an average of 12 years. During that period 3,874 CVD deaths in women and 7,904 in men were identified. 51% of the men and 70% of the women regularly took calcium supplements.
The men on over 1,000 mg/day calcium supplementation had a 20% greater risk of total CVD death (including 19% higher heart disease and 14% higher cerebrovascular disease risk of death).
Taking calcium supplements was not linked to CVD death, heart disease or cerebrovascular disease death among the women.
The researchers concluded:
“Whether there is a sex difference in the cardiovascular effect of calcium supplement warrants further investigation. Given the extensive use of calcium supplement in the population, it is of great importance to assess the effect of supplemental calcium use beyond bone health,” the authors conclude.
Susanna C. Larsson, Ph.D., of the Karolinska Institutet, Stockholm, Sweden, in a Commentary in the same journal, wrote:
“More large studies are needed to further assess the potential health risks or benefits of calcium supplement use on CVD morbidity and mortality.
Meanwhile, a safe alternative to calcium supplements is to consume calcium-rich foods, such as low-fat dairy foods, beans and green leafy vegetables, which contain not only calcium but also a cocktail of essential minerals and vitamins.
These non-dairy food sources of calcium have the added health benefits and have recently been reported to improve glycemic control in persons with diabetes. The paradigm ‘the more the better’ is invalid for calcium supplementation.”
Some studies over the years have pointed to a higher risk of heart and/or cardiovascular diseases associated with taking calcium supplements. Two studies are listed below:
- After analyzing data on almost 24,000 people over a ten-year period, researchers reported in the journal Heart that calcium supplements increase the risk of heart attack.
The scientists said that people should take calcium supplements with caution. They add that until further research can corroborate their findings, patients who are concerned should discuss their calcium requirements with their doctor.
Previous research had indicated that a higher calcium intake was associated with a lower risk of developing several conditions and illnesses that predispose patients to heart disease and stroke, such as obesity, type 2 diabetes and hypertension.
- Researchers from New Zealand reported in the BMJ (British Medical Journal) (April 2011 issue) that older females who take calcium supplements have a higher risk of cardiovascular events.
Written by Christian Nordqvist