Vitamin D & MS: An interview with Dr. Brenda Banwell

During last week’s webcast, Living Well with MS: Lifestyle, Diet and Complementary Therapies, we received a number of questions about vitamin D. We sat down with Dr. Brenda Banwell, MD, following the webcast to get answers to some of the most popular questions you submitted.

How much vitamin D should a person with MS be taking?

The graph below shows the current recommendations, for the general population, according to the Canadian Food Guide. If you are living with MS, I would recommend that you work with your healthcare provider to obtain your vitamin D blood levels (also called a 25-hydroxy vitamin D), which is a measurement of the circulating vitamin D in the body. vitamin D levels should be around 75 nanomals per liter (Canada) or between 40-80 nanograms per milliliter (United States). 

Many people with MS will require much higher doses than is recommended for the general population in order to bring their blood levels up, particularly in the winter. Under the care of a physician, it wouldn’t be unusual for a person with MS to take 3,000 to 5,000 IUs per day. But, if you are taking vitamin D in doses beyond what is recommended, you will want to make sure you are being monitored by a doctor, as vitamin D can potentially be toxic.

Age group Aim for an intake of international units (IU)/day
Infants 0-6 months old 400
Infants 7-12 months old 400
Children 1-3 years old 600
Children 4-8 years old 600
Children and Adults 9-70 years old 600
Adults over 71 years old 800
Pregnant and Breastfeeding Women 600
*This includes vitamin D from both food and supplements

Is it better to get Vitamin D through nutrition or sunlight?

The most effective way of obtaining vitamin D nutrition is through sunlight acting on the skin – particularly for people with lighter skin. People with darker skin absorb less vitamin D. If we weren’t worried about the negative effects of sunlight, then it would be a very good way (in the sunnier months) of obtaining vitamin D – but of course we have to balance the risks. We live in a world where there are harmful effects of ultraviolet (UV) radiation and skin cancer is a very real concern. Therefore, sunblock has become a major health initiative, and if you wear sunblock, you also block vitamin D production pretty dramatically. I advocate for the safer route of wearing sunscreen and taking oral supplements in order to obtain vitamin D.

Is it possible to get enough vitamin D from sunlight alone?

During certain times of the year, the amount of UV radiation from the sun is so low that no vitamin D is even made. One expert, Dr. Vieth, states that if you’re taller than your shadow, there’s not enough UV radiation to synthesize vitamin D through your skin. Typically in temperate climates, this would be from the end of September through the middle of April. So, during the winter months, we don’t make enough vitamin D on our own, and likely need supplements to keep normal blood levels.

Can vitamin D help prevent MS in family members of people with MS?

There haven’t been any primary prevention trials using vitamin D, so it would be very difficult to assume that vitamin D alone would be sufficient to prevent MS. However, the data at this point would suggest that there may be a connection between vitamin D levels and MS risk. One study looked at military recruits in the US who were sampled as part of routine blood screening when they entered the military. This study found a fairly strong relationship between levels of vitamin D and MS. Those who had higher levels of vitamin D at the time of the routine screening were much less likely to be diagnosed with MS in the 5 to 10 years following the screening than those with lower levels. What that suggests is that if you have robust vitamin D during childhood and teenage years, it could be one of the factors that reduces your MS risk.

Having healthy vitamin D levels and nutrition during childhood and teenage years is important not only for reduction in MS risk. It is important for bone health, and may also help reduce your risk for other autoimmune diseases. I would suggest anyone living in places where we get little sunlight during half of the year take steps to maintain their vitamin D nutrition. And, for family members who have an increased risk of MS, I think it would be a really wise investment to have your vitamin D levels tested and take vitamin D supplements if your levels are low.

Please tune in to the MS Connection blog tomorrow as Dr. Banwell discusses other supplements that are potentially helpful and harmful for people with MS  and throughout the coming week as we chat with Drs. Allen Bowling, Timothy Coetzee and Albert Lo about the roles of diet, exercise and other holistic approaches to living well with MS.

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Brenda Banwell, MD

Division Chief, Neurology, Professor of Pediatrics (Neurology), Children's Hospital of Philadelphia, University of Pennsylvania