Calcium supplements have a beneficial effect on bone health. But with decades of use, they increase the risk of cardiovascular disease and death, at least in men, according to a recent US study.
A recent Swedish study, which sets women's calcium intake in relation to their cardiovascular health, shows increased death rates even in women who consumed very high levels of calcium or were undersupplied with the mineral.
In both studies, people who consumed calcium exclusively from food - without supplementation in tablet form - had the best results: they did not show any adverse effects on survival.
Like Prof. Dr. med. Helmut Gohlke from Bad Krozingen, who is responsible for prevention at the German Heart Foundation, told Medscape Germany that comparable data from Germany are not available. Therefore, such studies are also important in this country.
According to US study no unfavorable effects in women
From the epidemiological study by Dr. med. Qian Xiao of Bethesda National Cancer Institute, Maryland, USA, and her colleagues point out that men who supplemented 1000 mg calcium or more per day had a 20% increased risk of death, mostly from cardiovascular disease. According to their publication in the February issue of the Journal of the American Medical Association (JAMA), no gender difference could be found. One explanation for this could be: women with comparatively high calcium supplementation, which did not occur in men of similar size, were excluded from the analysis.
Data were collected from the National Institutes of Health's AARP Diet and Health Study, which included 388,229 men and women aged 50 to 71 from 6 US states. Based on data on the frequency of food intake, serving size and intake of multivitamins, calcium-containing antacids or calcium. The data was collected as self-report by means of a questionnaire. During a mean follow-up of 12 years, there were 7904 CVD deaths in males and 3874 in females. Supplemented calcium intake (1000 mg per day vs. no calcium supplements) increased the risk of cardiovascular disease, death and cardiovascular death by 20% in men. In women, such an association could not be proved.
The Swedes also see dangers for women
However, this was found in the Swedish study: Karl Michaelsson of the University of Uppsala evaluated the data of 61,443 Swedish women born in 1914-1948 from the Swedish Mammography Cohort and compared them with the cause of death statistics, the British Medical Journal reports. The calcium intake was divided into quartiles. The study participants of the lowest quartile consumed an average of 572 mg / day. In the quartile with the highest calcium intake, the mean was 2137 mg / day. During the 19-year follow-up, 3862 (32%) of those observed died from cardiovascular disease, 1932 (16%) from heart attack and 1100 (8%) from stroke. The highest proportion of cardiovascular deaths was in the group of those taking more than 1400 mg of calcium daily. The rate was twice as high as in the group with a daily calcium intake between 600 and 999 mg / day.
However, mortality was also increased in the lowest quartile with calcium intake below 600 mg / day. The most plausible explanation according to Michaelsson: too high as well as too low calcium intake can affect the hemostatic balance.
As Michaelsson tells Medscape Germany, the data of the men under the same question has not yet been evaluated.