Are Calcium Supplements Bad for Women’s Brains?

Women appear more likely than men to suffer dementia as they age. Now scientists at the University of California San Diego think they can explain the difference in risk factors for men’s and women’s brains.

Are Women’s Brains More Vulnerable?

In an analysis of data from the Health and Retirement Study of 17,182 Americans past middle age, they identified a number of risk factors that are more common among women (Biology of Sex Differences, May 19, 2026). In addition, they estimate that women are more strongly affected by certain risk factors. Women are more likely to report depression and sleep problems, along with smoking and high cholesterol. They are also less likely to be physically active, which could put them at risk for osteoporosis. More on that in just a bit.

Men had higher rates of hearing loss and diabetes. They were also more likely to drink heavily. Hypertension and overweight affected both sexes, but women seem more likely to suffer cognitive consequences. In addition, women who have diabetes or hearing loss often perform poorly on cognitive tests. This suggests that women’s brains may be more sensitive to these risk factors.

What About Calcium Supplements?

For decades, women have been told to take calcium supplements to build strong bones. Many health professionals dismissed the value of multivitamins but were enthusiastic about supplemental calcium. The idea was that this would help build bone and prevent fractures, even though there is no evidence that this is effective. (You can read more about that here.)

A review of 69 randomized controlled trials assessed the benefits of vitamin D supplements with or without supplemental calcium to prevent falls and fractures in older people living on their own (BMJ, May 20, 2026). The analysis suggests these supplements are not helpful in preventing fracture.

In fact, the authors conclude:

“Based on absolute risk reductions and thresholds considered clinically meaningful, this review found little to no benefits from use of calcium, vitamin D, or combined supplementation on the prevention of fractures and falls.”

The Dangers of Too Much Calcium for Women’s Brains

Most people think of calcium supplements as safe. In fact, there are lots of foods and beverages that are fortified with extra calcium. Some experts worry, however, that supplemental calcium may not be as innocuous as it seems.

Several studies have suggested that calcium supplements might increase a person’s chance of suffering a heart attack or stroke. An enormous observational study of 400,000 adults, the NIH-AARP Diet and Health Study, found that high-dose calcium supplements were associated with an increased risk for cardiovascular complications in men (JAMA Internal Medicine, April 22, 2013). We wrote about that and other research suggesting risks of calcium supplementation here.

Although the NIH-AARP study did not find an increased risk in women, a Swedish study of more than 61,000 women followed up for 19 years found that those taking 1,400 mg or more of calcium daily were more likely to die from any cause or from heart attacks, though not from stroke (BMJ, online Feb. 13, 2013). You can read more about that research here.

Do Calcium Supplements Increase the Risk for Dementia?

Then a study of 700 Swedish women between the ages of 70 and 92 found that some of those taking calcium supplements to protect their bones might be inadvertently harming their brains (Neurology, Oct. 18, 2016).

More than half of the women who agreed to participate in the research had CT scans done of their brains at the beginning of the five-year study. Nearly three-fourths of these scans, 71 percent, showed lesions in the white matter of the brain. Such lesions indicate cerebrovascular disease. Just a few of the participants, 98, were taking calcium supplements at the time. 54 women had a history of stroke. All of the women took tests to assess their memory and cognitive function at the outset.

After five years of follow-up, some of the women had developed dementia. Specifically, 59 of the volunteers had scores on their cognitive function tests that had dropped dramatically into the range of dementia. Women who had had strokes were almost seven times more likely to be diagnosed with dementia if they took calcium supplements. Those with with white-matter lesions were three times more likely to land in the dementia category if they were taking calcium.

The authors conclude,

“Calcium supplementation may increase the risk of developing dementia in elderly women with cerebrovascular disease.”

They point out that these findings are preliminary and deserve further investigation. We agree that the numbers of women with strokes or dementia in this study are too small to support strong conclusions.On the other hand, if the benefits for bones are not there and there is a potential for harm to women’s brains, we think people should be very cautious about utilizing calcium supplements on a routine basis.

Bottom Line:

We would encourage people to take calcium supplements if the benefits were clear and there were no risks. Sadly, neither seems to be true at this point in time. The benefits have been controversial for years, especially with regard to osteoporosis prevention. Evidence has been accumulating that there may be significant risks.

Learn More

We urge women who have had strokes or TIAs to discuss calcium use with their doctors. We cannot judge whether calcium poses a risk of dementia for otherwise healthy women. People who would like to get their calcium from food rather than supplements may wish to consult the list in this article. You may also be interested in our Show #752 on Bone Vitality. It is an hour-long interview with Michael Castleman and Walter Willett, MD, DPH, Chair of the Department of Nutrition at the T. H. Chan School of Public Health at Harvard University.

We also interviewed Dr. Lisa Mosconi in Show 1231: How Can Women Reduce Their Risk for Dementia?  It is quite informative.