Researchers looked at participants from the Rush Memory and Aging Project (MAP), an ongoing longitudinal study that aims to identify risk factors for Alzheimer’s disease and other disorders of cognitive decline, before and after death to see how their vitamin D levels affected cognitive function in later life. years.
With no known dementia at enrollment, all MAP participants agreed to participate in annual evaluations and organ donation upon death. In this study, the average age of the participants was 92 years at the time of death.
Total serum vitamin D levels [25(OH)D] and global cognitive function were assessed antemortem, while vitamin D3, 25(OH)D3, and 1,25(OH)D3 (the active form of vitamin D3) were measured in four brain regions (the mediotemporal cortex, the frontal half cortex, cerebellum and white matter of anterior basin) post-mortem.
The main form of vitamin D3 found in the brain (and therefore the form the researchers focused on in their analysis) was 25(OH)D3. It’s worth noting that there are two types of vitamin D, D2 and D3, and brain concentrations of vitamin D2 (the form found in most fortified food sources) were not measured in this study.
Mindbodygreen’s vice president of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN, explains this limitation: “Vitamin D3 is found in animal sources and key algae and lichens, while vitamin D2 comes from plant sources such as yeast and irradiated mushrooms. If your health care provider inadvertently measured serum 25(OH)D3, but you were taking irradiated mushrooms or a vitamin D2 supplement, your lab results would not reflect your intake.
While the results of this study remain relevant to dementia research, it is important to keep this discrepancy in mind when reading the results.
