New diet studies for multiple sclerosis
Few scientific studies have examined the possible benefits of dietary changes in people with multiple sclerosis. But a few pieces of new research were presented at this year’s annual meeting of the American Academy of Neurology.
Based on the observation that MS is less common in seashore communities compared to inland, many people have speculated that a diet that is high in fish and lower in animal fats may help MS. In support of this idea, a new study in animals found that a diet high in saturated fats worsened inflammation in the brain (Linker and colleagues. AAN 2014; abstract P6.149).
How well does this observation translate to people? U.S. researchers have conducted a study in 61 people with MS who either kept to a low-fat diet or ate their usual foods for a year (Yadav and colleagues. AAN 2014; abstract P6.152). The goal was to see if different diets affected MS measures, such as relapses, inflammatory activity seen on MRI, and disability. The median age of the study participants was 41 years, and they had been living with MS for an average of 5 years.
After one year, the people on the low-fat diet lost an average of 16 pounds (7 kg), whereas those on their usual diet gained about 1.6 pounds (0.7 kg). Reductions in low-density lipoprotein (LDL) and total cholesterol levels were about 2-3 times better in people on the low-fat diet. However, there were no benefits specific to MS. A low-fat diet didn’t provide any improvements in MRI measures of disease activity, nor did it help relapse rates, disability or MS fatigue compared to a regular diet.
Studies in animals have suggested that a high-salt diet can promote inflammation in the brain, and these findings may also apply to humans. Researchers compared people with MS who had a high-salt versus low-salt diet (Farez and colleagues. AAN 2014; abstract P6.150). Over a two-year period, they found that people with a high or medium salt (sodium) intake had a much higher relapse rate than those with a low-salt intake. In looking at MRIs, there was a 3-fold higher risk of having a new inflammatory MS lesion in the brain and more lesions overall in people with a high-salt diet. So these preliminary findings suggest that dietary salt can promote inflammation and make things worse for people with MS.
In looking at factors that may increase the risk of developing MS, researchers have recently turned their attention to obesity during adolescence – which is somewhat controversial. A population-based study of women found that at age 18, women with a body-mass index (BMI) of 30 or more (e.g. being 5-foot 5 inches and weighing 180 pounds) had a two-fold higher risk of developing MS compared to those with a lower BMI (Munger and colleagues. Neurology 2009;73:1543-1550). However, obesity during childhood didn’t appear to affect the risk of developing MS, nor did obesity in later adulthood. The same researchers subsequently revised their view of childhood obesity, finding that young girls with the highest body weight had a greater risk of developing MS later in life (Munger and colleagues. Mult Scler 2013;19:1323-1329).
A recent suggestion is that obesity may promote low-grade inflammation (Hedstrom and colleagues. Neurology 2014;82:865-872), although how it does this isn’t very well understood. One culprit may be leptin, a hormone produced by fat cells to regulate hunger. A new study has reported that in adolescents with MS, BMI was related to the amount of leptin in the blood stream (Correale and colleagues. AAN 2014; abstract S24.004). A higher BMI was associated with higher leptin levels. In those people who were obese, there were more inflammatory cells and lower production of cells that regulate the immune response (called regulatory T cells). So the overall picture appeared to be that obesity may help to drive the autoimmune response that is found in MS.
For more on diet, see:
– How does your diet affect MS? – Part 1
– Diet and MS: should I avoid milk? – Part 2
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