In the last week, vitamin D has again hit the headlines, with researchers in South Australia publishing their study showing that there is not enough evidence to say that vitamin D can protect the brain in neurological disorders such as MS, dementia and Parkinson’s Disease.
The research was published in the journal Nutritional Neuroscience. The researchers conducted what is known as a ‘systematic review’ of the international research literature on vitamin D studies. They analysed the data across all the studies to determine what they collectively tell us about vitamin D and neurological diseases.
The researchers found 73 original research studies that investigated vitamin D levels or levels of vitamin D supplementation in neurodegenerative diseases. They also included studies that looked at past or present sun exposure in people with neurological diseases. The diseases included MS, Alzheimer’s Disease and Parkinson’s Disease, among others.
Their analysis of the data showed that there is not enough strong evidence to indicate that vitamin D can protect the brain (that it is ‘neuroprotective’) in these neurological conditions.
Their analysis did suggest that sun exposure, independent of vitamin D production, may be protective against MS, Parkinson’s Disease and Alzheimer’s Disease. This is something that is already under investigation in MS research, with studies looking at how UV light can directly influence the activity of the immune system, separately to its role in stimulating vitamin D production, and having an effect on the immune system via vitamin D.
The majority of the evidence to date on vitamin D in MS is based on the finding of an association between low vitamin D and the onset of MS. This has led to the strong belief by many that vitamin D supplements could help people with neurological diseases, particularly MS. However, an association is not the same as causation – we still don’t know for sure that low vitamin D is one of the causes of MS, and we do not know that supplementing with vitamin D can reverse MS or improve disease outcomes.
In fact, clinical trials that have looked at vitamin D supplementation in people with established MS have proved inconclusive in terms of reducing relapses, lesions or disease progression. Furthermore there is no accepted evidence on what the correct blood level of vitamin D or optimal dose should be to help improve disease outcomes in MS.
This is why MS Research Australia and a team of Australian and New Zealand MS clinicians and researchers set out to conduct the PrevANZ Vitamin D MS Prevention Trial. PrevANZ aims to definitively answer the question of whether vitamin D supplements, and at what dose, can prevent or delay a diagnosis of MS in people who are at very high risk of developing the condition. The study is running at 18 sites around Australia and New Zealand and is recruiting people who have experienced a single, first ‘attack’ or episode of MS-like symptoms, known as clinically isolated syndrome.
In the meantime, as Vitamin D is crucial for many aspects of health, particularly bone health, it remains important for everyone, but especially people with MS, to ensure that they have adequate levels of vitamin D.
If you are concerned about your vitamin D levels please speak to your healthcare providers about appropriate supplementation, and for more information on how much sun is enough, and safe, you can visit our earlier article here or visit the Cancer Council Victoria’s webpage on UV and vitamin D where you can access their helpful vitamin D calculator.