This week I had a patient come in to the office who was recently diagnosed with multiple sclerosis. I remembered reading something about diet affecting the symptoms and course of multiple sclerosis, so off I went to the research literature. What does it have to say about diet and multiple sclerosis?
I found a great review article just published this year that summarizes a lot of the current understanding of the link between diet and multiple sclerosis.
Multiple sclerosis is an inflammatory illness in which the immune system attacks the insulating myelin protecting the nerve cells of the brain and spinal cord. Without myelin the nerve cells don’t function properly, leading to numbness, weakness, vision loss and the inability to function normally. Speech, swallowing and movement may all be affected.
Since inflammation is key, how do we influence inflammation in the body? Multiple sclerosis therapies are heavily targeted to stopping the immune system’s attack on the nervous system. Unfortunately these therapies are very expensive and produce a lot of side effects.
If we can identify lifestyle factors that are contributing to the inflammation and immune dysfunction in the body, it stands to reason that changing those lifestyle factors to ones that relieve inflammation and support proper immune function may be helpful.
There is a lot of evidence that the risk of multiple sclerosis is dependent on lifestyle. For instance, a study published in 2011 reported that people who migrated from the UK and Ireland (where MS risk is high) to Australia (where MS risk is low) had the same risk as their birth country if they migrated after age 15. However, if they migrated before age 15, their MS risk was low. Since lifestyle habits are learned early, and those who migrated after age 15 likely brought their lifestyle with them, this argues that lifestyle habits may be great contributors.
What is the lifestyle of places where MS risk is high? Multiple sclerosis tends to occur in countries that are affluent and have a sedentary habit and western-style diet. It also tends to occur in higher-latitude areas where sun exposure is limited and vitamin D deficiency is prevalent. There is a documented correlation between vitamin D deficiency and MS risk.
How does lifestyle affect inflammation and the immune system? There are two main factors that have been identified so far. Lifestyle affects the cells of the body themselves, and it also affects the population of bacteria in the intestine. Believe it or not, the organisms that live in the intestine (which outnumber the cells in your body 10-to-1, by the way) have a huge impact on your body’s well-being.
Typical western diets are high in calories, saturated fat, animal-based foods, trans-fatty acids, sugar and salt and low in dietary fiber. These factors increase inflammation and upregulate pro-inflammatory signaling molecules in the body. Inflammatory molecules such as NF-kB and AP-1 are increased in multiple sclerosis.
What type of lifestyle downregulates these molecules? Pretty much the opposite of the western diet. Low in calories, saturated fat, animal foods, sugar and salt and high in fruits, vegetables, fish, nuts and dietary fiber, with plenty of physical exercise.
How do the bacteria in the intestine affect our well-being? First of all it’s important to understand that everyone’s bacterial passengers are unique. The specific composition of the intestinal microbiota is determined by diet, age, physical activity, stress, medications, and many other factors.
As an illustration, there was a study published in 2010 comparing the intestinal bacteria of children living in Italy (who consumed a western-style diet) to those living in Africa. The African children got plenty of exercise and consumed a diet composed of mostly plant foods high in fiber.
The Italian children’s intestinal bacteria contained species that generally thrive on simple sugars and are considered more harmful. The African children’s intestinal bacteria contained species that thrive on complex carbohydrates, are more beneficial, and produce butyrate as part of their metabolism. Butyrate is known to downregulate the production of NF-kB, a pro-inflammatory molecule increased in multiple sclerosis.
The intestinal bacteria are so powerful that one group was able to use them to trigger an MS-like autoimmune demyelinating disease in transgenic mice.
What you eat not only affects your own body’s cells, it also impacts the bacterial species that live in your intestine. These bacteria aren’t just passengers. They can cause illness or they can promote health. They make vitamins and cofactors that influence how your body functions.
What type of diet is best if your goal is to reduce inflammation in the body? Pretty much the opposite of the typical western diet, of course. Avoid animal foods, especially red meat and saturated fat (including milk fat), trans fats (in partially hydrogenated vegetable oils), added sugar, added salt, and excess calories.
Now that I’ve told you what NOT to eat, what SHOULD you eat? The shorthand is the Mediterranean diet. This diet includes lots of fresh colorful vegetables and fruits, beans, nuts and seeds, whole grains, fish and olive oil. Resist the temptation to include lots of pasta; a true Mediterranean diet has limited amounts of pasta which are often combined with beans, potatoes and vegetables to round out the starches.
I want to say a few words about supplements. There are a lot of anti-inflammatory supplements out there, such as fish oil, turmeric/curcumin, vitamin D, selenium and polyphenols. These are fine as an addition, but you should never forget that the main dietary intervention in inflammatory conditions is just that, the DIET. You cannot eat a pro-inflammatory diet and expect a fish oil supplement to undo the damage.
If you or someone you love has been diagnosed with multiple sclerosis or another inflammatory condition such as Crohn’s disease, ulcerative colitis, rheumatoid arthritis or coronary artery disease, there is a lot you can do with diet to impact it.