Study debunks hypothesis that calcium causes dementia in older women

New research has found no evidence that calcium increases the long-term risk of dementia in older women. This debunks previous theories that the mineral supplements could impact cognitive health.

The publication in The Lancet Regional Health Western Pacific included 1,460 women aged 70 and above who received a daily calcium supplement (1,200 mg of calcium) or a placebo for five years. They were observed for an additional 9.5 years afterwards. 

Researchers from Edith Cowan University, Curtin University, and the University of Western Australia analyzed the data.  

Dementia events were noted for 269 women, or 18%, but this was not significant when compared to placebo, the study finds. 

Edith Cowan University’s senior research fellow, Dr. Marc Sim, notes that the results did not change even when the analysis was adjusted for supplement compliance and lifestyle factors, such as dietary calcium intake and genetic risk.

“Some 730 older women were given calcium supplements over five years, and a further 730 were given a placebo. This study design offers more accurate data on dosage and duration, and we had a long follow-up period of 14.5 years, which strengthens our results.”

Role of calcium 

The study notes that ~20% of women over 70 suffer from osteoporosis, and that calcium supplements are widely recommended for its management or prevention. Calcium supplementation was previously hypothesized to increase dementia risk through vascular calcification or neuronal damage.

“Previous research has raised concerns around the impacts that calcium supplements could have on cognitive health, particularly dementia. Results from our study provide reassurance to patients and clinicians regarding the safety of calcium supplements in the context of dementia risk for older women,” says Ph.D. student Negar Ghasemifard at Edith Cowan University.

In support of calcium supplementation, a previous study from the Center for Translational Medicine at Temple University, Japan, suggested that an imbalance of calcium ions in the mitochondria may contribute to cell death and, specifically, neurodegeneration in brain cells during Alzheimer's and dementia.

Separate dietary research supported dietary calcium’s significant protective benefits while linking alcohol and red or processed meat to increased colorectal cancer risk.

Further research required

Although the findings negate concerns linking calcium supplements to higher all-cause dementia risk in older women, Edith Cowan University’s Centre for Precision Health director, professor Simon Laws, suggests that further research is needed.

“Whether this extrapolates to other demographics, such as men or women commencing supplementation earlier in life, remains unknown,” he notes. 

“To confirm the current findings, particularly regarding brain health, and to address these population gaps, future clinical trials of calcium supplements, with or without vitamin D, would need to be undertaken. These should include specific and robust assessments of brain health as the primary outcome measures.”

Curtin University’s professor Blossom Stephan, director of the Dementia Centre of Excellence and a Dementia Australia honorary medical advisor, assures: “Given calcium’s critical role in multiple physiological functions, including bone health, these results provide reassurance that long-term calcium supplementation did not increase dementia risk in older women.”

Dementia and nutrition 

Among other dietary studies on dementia prevention, researchers have suggested that any amount of alcohol consumption raises dementia risk, challenging the previously held beliefs on the benefits of light drinking.

Scientists have also warned that eating processed red meat increases dementia risk and cognitive decline compared with people who eat very little meat.

Meanwhile, Chinese herb Zizyphi spinosi semen, dried seeds of a jujube, was praised for its potential to prevent neurodegenerative diseases.