Too Much Calcium May Raise Risk Of Cardiac Death For Older Women
Alan McStravick for redOrbit.com – Your Universe Online
A new study from Uppsala University in Sweden details the health benefits of maintaining a steady, moderate calcium level in older women. Prevailing medical wisdom typically recommends an increase in calcium intake for women as they age since the naturally occurring mineral plays a vital role in a variety of biological processes. Currently, more than 60 percent of middle-aged and older women in the US take calcium supplements.
According to this new study, however, high levels of calcium intake in women are associated with an increased risk of death from all causes, most notably cardiovascular disease. By contrast, women with lower – but not too low – levels of calcium had a lower overall risk of death. The results of the study were published this week in the online version of the British Medical Journal.
For the study, Uppsala University researchers observed 61,443 Swedish women, all born between 1914 and 1948. The average observation duration per subject was 19 years, and researchers believe that the length of the study improved the accuracy of their results.
While few studies have been undertaken to examine the association between calcium and increased risk of death, recent studies on the subject have indicated a link between an increased risk of ischemic heart disease and stroke, and the use of calcium supplements. However, another separate study of the same issue did not find the same connection.
The data for the study was obtained from the Swedish Cause of Death Registry, while more specific data related to diet was taken from the Swedish Mammography Cohort. The concept of total calcium intake included both naturally occurring and supplemental forms of the mineral. The lowest measured intake of calcium was 572 mg per day, which is the equivalent of about five slices of cheese. The highest topped out at 2,137 mg per day.
The researchers obtained a wide variety of additional information about the women including their menopausal status, use of postmenopausal estrogen therapy, parity information, weight, height, smoking habit, typical physical activity and educational level.
During the study some 17 percent of the women, or 11,944 individuals, died. Of these women, 3,862 died from cardiovascular disease, while another 1,932 succumbed to heart disease. The research team also found that the highest rates of all-cause, cardiovascular and heart disease were among those women who had an average daily dietary calcium intake of 1400 mg or more. However, the researchers also observed higher-than-average death rates among women whose daily intake of calcium was below 600 mg.
The researchers also observed that women who took calcium supplements in addition to having a dietary calcium intake of 1,400 mg or more per had a higher overall mortality rate than women who took no supplements. The apparent ‘sweet spot’ for calcium intake in middle-aged and older women was between 600 and 999 mg per day.
The team suggests that diets too low or too high in calcium can effectively override the body’s normal homeostatic control, causing undesirable changes in levels of calcium in the blood.
The importance of calcium, especially in middle-aged and older women, cannot be overstated. And while the researchers concluded that elevated calcium levels are associated with “higher all-cause and cardiovascular mortality rates,” they also believe that emphasis should be placed on monitoring the diets of patients prior to recommending supplementation.