Could Vitamin D protect against Alzheimer’s or other types of dementia? The media recently wrote about this after a new study:
- The Telegraph: Study: sunshine “could help to stave off dementia”
- Science Daily: Link between vitamin D, dementia risk confirmed
However, there are a few important points to keep in mind. The study is based solely on statistical associations (an observational study). The statistics show that people with dementia are more commonly Vitamin D deficient. But this doesn’t mean that we know what the cause is.
We know from similar previous studies that almost all diseases are more common in people with Vitamin D deficiency. However, it may just as well be that for some reason people with diseases are less often out in the sun than healthy people.
If you only look at the statistics, you might think that Vitamin D is the all-time magic bullet that with some luck, may cure any disease. The most incredible pill that ever existed. However, it isn’t that fantastic.
To know for sure you need to test Vitamin D supplements in large high-quality studies to see what the effect is. Existing studies investigating supplementing with Vitamin D show more modest results than the fantastic hopes.
Maintaining a good Vitamin D level through supplementation (or sun) seems to, on average, have small or moderately positive effects on the immune system (including in several autoimmune diseases like MS), muscle strength and coordination, bone density, mood as well as fat and lean mass. It might also, on average, slightly prolong life.
Large reviews of existing studies on supplementation don’t, however, show any significant protective effect on common diseases such as heart disease, cancer or stroke. When this is tested, it will probably also be shown to apply to Alzheimer’s. But we don’t know yet.
Personally, I continue to supplement with Vitamin D daily, especially during the winter months. This is the only supplement I take daily. I think it’s good for my health and well-being – but I don’t expect any miracles.