A study of over a thousand people across Europe has found that most dementia patients are low in Vitamin D. Scientists are now looking to see if the low levels are just symptoms or a possible cause for Alzheimer’s disease. Dr. David Llewellyn, a senior research fellow at the University of Exeter Medical School says the next study he’s conducting will focus on how vitamin D and dementia are related.
- Severely vitamin D deficient patients double risk of developing dementia
- Research trying to determine if low Vitamin D linked to cause or symptoms
- Vitamin D plays a role in blood supply to brain
Being Patient: A lot of patients who suffer from Alzheimer’s or dementia are low in vitamin D. So tell me what research is finding? Is there a link between low vitamin D and dementia?
Dr. David Llewellyn: Well there certainly is. We have been doing research in this area since 2008. We first suspected a link in older English adults. We found those low in vitamin D had more cognitive problems and we followed that up with a series of studies. And the last one we did was in the United States, looking into the cardiovascular health study. Those who were severely deficient had more than double the risk of developing Alzheimer’s disease, or other types of dementia, and (in) those who were mildly deficient the risk was somewhere in between. So about 60 percent have an increased risk. That is important because that is a very strong association. That is roughly twice as strong as the link that we see for obesity or diabetes.
Being Patient: How extensive was the study? (In how) many people did you find this link?
Dr. David Llewellyn: We followed thousands of people for an average of just over five-and-a-half years so we were able to take advantage of enormous existing infrastructure in these major government-funded studies. We are able to go back to these large cohorts and do these studies very quickly and cost effectively. Blood is taken at a baseline and stored and then you can go back to that, you can take samples out and you can measure different things, potentially things you didn’t ever intend to measure in the first place because it acts as a kind of bio-resource.
Being Patient: Can we say that there must be a link because we know that a lot of people suffering from Alzheimer’s, or dementia, have low vitamin D?
Dr. David Llewellyn: We need to be very careful at this point because what we’ve shown is a link, only exactly that. What we don’t know is whether the vitamin D is driving the onset of dementia or if it’s the dementia driving the onset of vitamin D deficiency. It could be a combination of the two. What we’re all hoping for is a disease-modifying treatment that will either delay or prevent dementia, on the one hand, for people who are currently dementia-free, or act as a disease-modifying treatment for those who’ve already developed dementia.
Being Patient: Then why not just take more vitamin D today?
Dr. David Llewellyn: I don’t think we have the evidence to suggest that we should be taking vitamin D to prevent dementia or to treat dementia. I think that would be premature. We’re not saying that at this point. What we’re saying is it’s a really exciting area for research and that it’s something that we’re going to be prioritizing and hope to provide answers in the short to medium term. We have to be careful because we don’t want to elevate people’s hopes and then it not turn out to be causal. That would be very harmful. What we need to do is take a measured approach.
Being Patient: Why is vitamin D so important for your brain?
Dr. David Llewellyn: It’s only relatively recently that we have started to get excited about vitamin D doing other things in the body other than just promoting bone health. That was the classical function of vitamin D, if you like. It was well understood. There are vitamin D receptors throughout the brain, which seems to be doing good things. It seems to protect the blood supply to the brain, and it also seems to break down the amyloid plaques, which are hallmarks of Alzheimer’s disease, which is obviously one of the most prominent types of dementia. What we don’t know is how important those mechanisms are clinically.
Being Patient: How far away are you from knowing that this is a possible cause?
Dr. David Llewellyn: Our next studies will give us a really good insight into that. Our preliminary results should be available within a year or two, but we’re very dependent on funding. That’s always the challenge we have in the scientific community because resources are so tight. In the UK, for example, the levels of funding sounds grand. We’ve doubled the amount of funding, but we’re starting from a very low base actually. We need far more investment because that will accelerate the pace of discovery.