A large-scale study conducted by U.S. scientists indicates that vitamin D supplementation improved memory in women, while having minimal impact on cognitive functions in men. A Russian expert acknowledges the importance of vitamin D for brain function but emphasizes that «systematic and convincing» evidence regarding differences in its effects on men and women is not yet available.
Researchers from the Institute of Neuroscience and Human Behavior at the University of California investigated the relationship between vitamin D levels and cognitive function in adults. The findings, presented at the American Psychiatric Association`s APA-2025 annual meeting, were reported by Medscape and highlighted in Russia by the publication «Medvestnik».
According to reports, a five-year trial involved 25,871 participants (both women and men) who received vitamin D3 (2000 IU/day) and marine-derived omega-3 fatty acids. Another group was given a placebo. From this larger group, scientists selected 1132 participants (57% women, 43% men, average age 62) for detailed analysis. These individuals underwent neuropsychological testing to assess short-term memory and fluid intelligence (the ability to think logically, analyze, and solve novel problems). They also provided blood samples and underwent MRI scans to evaluate various biomarkers potentially linked to the aging process.
Among other analyses, the scientists measured the telomere length of the study participants. Telomeres are specialized structures found at the ends of chromosomes, composed of repetitive DNA sequences. They play a crucial role in cellular aging, particularly by protecting genetic material from damage and shortening.
The study revealed that taking vitamin D3 significantly reduced telomere attrition. Omega-3 supplementation did not have a significant effect on this process.
Furthermore, the researchers observed a correlation in women between high plasma vitamin D levels, better memory performance, and larger subcortical brain structures. There was also a trend towards increased volume of the thalamus, a key brain region that processes sensory information and relays it to cortical areas. In contrast, higher vitamin D levels in men were associated with smaller volumes of the thalamus and other brain structures. However, one of the study`s authors, Megan Reddy, stressed that these observed gender differences in the link between vitamin D, cognitive function, and brain volume require further investigation.
Galina Chudinskaya, a neurologist at JSC «Meditsina,» confirms that vitamin D is much more than just a calcium regulator; it actively participates in numerous bodily processes. It is known to influence the immune system, vascular and neuronal function, and modulate cell growth. Mortality rates from cancer, cardiovascular diseases, and diabetes are higher in regions with low sun exposure, while cancer survival rates are better in the summer – processes also linked to vitamin D levels. «However, most of this data is observational or experimental, including animal studies. At the population level, there isn`t yet sufficient evidence,» states Ms. Chudinskaya. «This is particularly true concerning the hypothesized differences in vitamin D`s effects on men and women: although some individual studies exist, systematic and convincing evidence has not yet been obtained. It`s possible this will become clearer as more research accumulates in the future.»
