The Family Health pillar is a key part of the Overcoming MS Program. There is a genetic element to MS, which means that children, siblings and other relatives of people with MS are at a greater risk of developing it too.

The general population only has about a 1 in 330 chance of developing MS, although this figure varies significantly from region to region. 

Risk of developing MS for family members

  • If you have an identical twin with MS, you have a 25% chance of developing it too.
  • If you have a sibling, parent or are the child of someone with MS, your chance of developing it is about 1 in 10.

Lifestyle changes for preventing MS

The following moderate lifestyle adjustments are likely to help protect relatives of people with MS who do not show signs of MS:

  1. Take vitamin D supplements during pregnancy
  2. Get regular exposure to sunlight
  3. Take daily vitamin D supplements (adjusted for weight of child)
  4. Stop smoking
  5. Eat a low-saturated fat diet
  6. Take omega-3 fatty acid supplements
  7. Learn how to handle stress better, through meditation and mindfulness

Please share with anyone you think is at risk of developing MS.

Sun exposure and vitamin D

In the US Nurses Health Study, those that took even a low dose of vitamin D had around half the risk of MS, and there are similar data for quitting smoking.

Overcoming MS believes doctors must advise people with MS of these important avenues to protect children and other relatives.


We recommend that close adult relatives of people with MS take 5,000 IU of vitamin D3 a day in winter (and in summer when sun exposure is limited), suitably reduced for children.

During pregnancy

Vitamin D supplementation should be routine in pregnancy, as folic acid is. Children are never too young to begin vitamin D supplements; ideally, they should start in the womb.

Should family members also change their diet to prevent MS?

The evidence on whether dietary changes help is not so clear-cut. We strongly advise people with MS to follow a plant-based wholefood diet that is very low in saturated fat, but it is not clear that putting family members on the same diet will reduce their risk.

In The Multiple Sclerosis Diet Book, Professor Roy Swank writes that he placed all family members of people with MS on the same diet, regardless of their own MS status.

He tracked more than 3,500 people with MS, and not one of their relatives on the diet developed the disease, to his knowledge.

So should you change your diet?

While the evidence around whether dietary changes reduce the risk of family members developing MS is limited, it may make sense for you to strongly consider a healthier diet anyway.

It is known that following a healthier diet with more fruits, vegetables and whole foods and less animal products, processed foods and saturated fat is important in preventing many other chronic health issues such as heart disease and type 2 diabetes. 

Research has demonstrated many beneficial effects for partners of people with MS who adopt lifestyle modification including their health and well-being. 

Also, if you are living with a family member who has MS, they need to be following a plant-based diet that is low in saturated fat. It is easier to cook one meal for the family than cook several meals each day.

For more information on the Overcoming MS Diet, please click here.

We are here for everyone with MS who wants to live a full and healthy life. If you or someone you care about has MS, sign up to our monthly updates for tips, recipes and resources helping you to live well with MS.