Evidence is mounting that vitamin D is needed to protect against Alzheimer’s and other neurodegenerative diseases. One study shows that people who supplement have less risk.
Getting the right amount of vitamin D each day could reduce the risk of developing dementia with age, according to researchers at the Hotchkiss Brain Institute at the University of Calgary and the University of Exeter. The study has been published in the journal Alzheimer’s & Dementia.
Studies that discover new properties of this vitamin do not stop appearing. which has traditionally been associated with the absorption of calcium and phosphorus. Recently, for example, supplementation has been found to reduce the risk of melanoma. It has now been found to be also important for keeping the brain in good shape and preventing neurological degeneration.
VITAMIN D DELAYS THE ONSET OF DEMENTIA SYMPTOMS
The study authors looked at the relationship between vitamin D supplementation and dementia among 12,388 people gathered in the U.S. National Alzheimer’s Coordination Center cohort.
The average age of these participants was 71 years and all were dementia-free at the time of enrollment. Within the group, 37 percent (4,637) reported taking vitamin D supplements.
The research team found that taking vitamin D was linked to a longer dementia-free period. In the group of people taking vitamin B supplements, the incidence of dementia diagnoses was 40% lower.
In the entire sample analyzed, a total of 2,696 participants developed dementia over the course of a decade. Among that group, 2,017 (75%) had no exposure to vitamin D at all visits prior to receiving a dementia diagnosis, while 679 (25%) had baseline exposure.
“We know that vitamin D has some effects on the brain that could have implications for reducing dementia, however, until now, research had yielded conflicting results. Our findings offer key insights into groups we could specifically target for vitamin D supplementation. Overall, we found evidence that supplementation before the onset of cognitive decline could be particularly beneficial,” explains the director of the research, Professor Zahinoor Ismail in a statement from the university.
CAN VITAMIN D BEAT THE ALZHEIMER’S GENE?
While vitamin D was shown to be effective in all groups, the researchers note that the effects were significantly greater in women. Similarly, the effects were greater in those with normal cognition, unlike those who reported signs of mild cognitive impairment (changes in cognition linked to an increased risk of dementia).
Interestingly, taking vitamin D also appears to have a greater impact on those who don’t carry the APOE (apolipoprotein E) gene, which studies show increases the risk of Alzheimer’s disease, the most common form of dementia.
Researchers speculate that this is because carriers absorb vitamin D more efficiently in their gut, possibly reducing the effect of vitamin D supplementation. However, the team did not analyze blood levels to test this hypothesis.
Previous studies show that low levels of vitamin D may increase the risk of dementia and vitamin D may play a role in removing beta-amyloid plaque in the brain. The accumulation of this protein is a hallmark of the onset of Alzheimer’s disease.
Other projects indicate that vitamin D may also help protect the brain against the buildup of “tau,” another protein with a strong link to the development of dementia.
MORE CLINICAL STUDIES NEEDED
“The link to vitamin D in this study suggests that taking vitamin D supplements may be beneficial in preventing or delaying dementia, but we now need clinical trials to confirm whether this is indeed the case. The ongoing Vitamin study, at the University of Exeter, is exploring this issue by randomly assigning participants to take vitamin D or placebo and examining changes in memory and thinking tests over time,” said Dr. Byron Creese, co-author of the study.
VITAMIN D: THE SUNSHINE VITAMIN
Active vitamin D3 (cholecalciferol) is obtained from a physiological process in the body that begins with exposure of the skin to radiation from the sun. It is estimated that 15 minutes of sun exposure can generate 10,000 to 20,000 IU of vitamin D. The exact production depends on the season, geographical location, skin type and amount of skin exposed.
In addition, small doses of vitamin D3 are ingested with foods of animal origin and vitamin D2 (which in the body is transformed into D3), which is found in mushrooms that have been dried in the sun, especially shiitakes.
Vitamin D deficiency is common, probably because we spend too much time indoors, especially during the winter. Supplementation can serve to correct the consequences of this behavior.
Before taking a supplement, you can assess if you suffer from a deficiency with a simple blood test. If the level of 25-hydroxy-vitamin D (calcidiol) is less than 40 ng/mL, it can be said that there is a deficiency. To correct it, a dose of 4,000 IU can be taken for two to three months.