Could Vitamin D Protect Against Alzheimer’s?


Could Vitamin D protect against Alzheimer’s or other types of dementia? The media recently wrote about this after a new study:

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.


Better Blood Sugar, Better Memory

Vitamin D: No Miracle Cure

Higher Blood Pressure and Blood Sugar, Poorer Memory


  1. Tyrannocaster
    I would think that since you are in Sweden you would have to supplement, given the low solar exposure you get most of the year. I am closer to the equator than you are and I know that I have to, although you may get more outdoor time than I do. But Sweden is pretty cold a lot of the year so I don't imagine you are running around in a bathing suit all the time. :-)

    Vitamin D is one of those things that seems to be necessary for us but that many of us can't get via food unless we supplement...IF that does much good. I try to get as much sun as possible during the summer as I have read that 30 minutes at this time of year can cause your body to synthesize 10-20k units; I am fine with this because I am one of those people who never seems to burn and I don't overdo it anyway. Some Nordic types must have a lot of trouble with that kind of exposure, though.

  2. erdoke
    Based on animal studies it is much more likely that in most cases vitamin D deficiency is in fact calcium deficiency causing low levels of vitamin D, or more exactly low 25(OH)D.
    Following this logic, the list of positive impacts of higher vitamin D levels provided by Andreas is strongly correlating to calcium need in different organs/systems in the body.
    No wonder supplementing has moderate effect if it does not address the root cause. Eat dairy as it is a (the) highly bioavailable calcium resource and avoid those plant foods rich in metal binding substances such as phytate (or glyphosate for that matter...).
  3. Ktina
    I think Sweden has the highest rate if ostheophorosis in the world, at the same time we are among the countries that have the most lactostolerant people in the world. Yet we are D-vitamin efficient. I think it's lack of sun during nine months of the year. People from countries like Somalia who lives in Sweden have a lot harder than "real" swedes because they dress differently and get even less sun. It has become so common that it has it's own name.

Leave a reply

Reply to comment #0 by

Older posts