Taking calcium supplements with the hope of keeping osteoporosis at bay may raise an older women’s risk of dementia, a new study suggests.
And that seems particularly true if a woman has already sustained an event causing poor blood flow to the brain (cerebrovascular disease), such as from a stroke, the researchers said.
The study can’t prove cause-and effect. However, dementia risk was seven times higher in female stroke survivors who took calcium supplements, compared to women with a history of stroke who didn’t use the supplements, the findings showed.
Lead researcher Dr. Silke Kern stressed that the findings apply only to calcium supplements. Calcium from food appears to affect the brain differently than calcium from supplements, she explained. Food calcium appears to be safe or even protective said the neuropsychiatric researcher at the University of Gothenburg in Sweden.
Kern isn’t sure why calcium supplements might have this effect. Calcium plays a crucial role in cell death, she said, and high levels of calcium in the blood might prompt the early death of neurons. Excess calcium also might somehow affect the blood vessels within the brain.
But Dr. Neelum Aggarwal cautioned against blaming calcium supplements alone for any person’s dementia risk. “We need to consider that the combination of nutrients will be more predictive than one nutrient,” said the associate professor of neurological science and director of research for the Rush Heart Center for Women at Rush University Medical Center in Chicago. “For example, calcium, phosphorus and magnesium all are typically looked at for their effects on multiple organs, and cognitive [mental] functioning will be affected most likely by a combination of these nutrients. To say that only one nutrient increases the risk of dementia is premature, and more studies need to look at a combination of nutrients.”
Osteoporosis is a major problem for seniors, and it’s worth looking further into the tradeoffs that come with calcium supplements, Aggarwal said.
The findings were published online Aug. 17 in the journal Neurology.
Duffy MacKay, a spokesperson for the Council for Responsible Nutrition, raised several questions about this study. “The authors mined data from a decade-old observational study, which was not originally designed to assess calcium intake,” MacKay noted.
The study was limited to only 98 women who took calcium supplements and did not include any information on their supplemental calcium dose or duration, or dietary intake of calcium.
Further, the study did not look at the source of calcium supplementation. Calcium supplements contain elemental calcium bound to a weak acid. So calcium lactate is calcium bound to lactic acid. Calcium carbonate is calcium bound to carbonic acid. Calcium oratate – you guessed it, oratic acid. On and on the list goes. However, the various forms of calcium are absorbed at various rates and also have differing rates of bio-availability.
None of the subjects had their blood levels of calcium measured but I can guarantee none of them had elevated blood calcium as Dr. Kern suggests. Calcium blood levels are independent of calcium intake, from any source.
The Bottom Line:
I still believe that all women and many men are in need of calcium supplementation as our diets are lacking in this essential mineral. However, supplementation should vary in the source of calcium and also include magnesium, possibly some potassium and a little vitamin C as well. Avoid dolomite and coral calcium supplementation because of lead contamination. Calcium carbonate is the cheapest but also very poorly absorbed.
Source: August 18, 2016 National Institutes of Health