Study to evaluate effects of fasting on immune system and gut bacteria

July 12, 2018
Researchers at Washington University School of Medicine, in St. Louis, are launching a trial to evaluate whether drastically cutting calories twice a week can change the body's immune environment and the gut microbiome, and potentially change the course of the disease. The study is rooted in research that shows that fasting can reduce MS-like symptoms in mice.

The researchers are recruiting patients with relapsing-remitting MS for a 12-week study. Half will stay on their usual Western-style diet seven days a week, while the other half will maintain such a diet five days a week, but limit themselves to 500 calories of vegetables the remaining two days.

The trial is based on findings from a mouse study published earlier this month in the journal Cell Metabolism. The study showed that intermittent fasting reduces MS-like symptoms. In the study, mice were either allowed to eat freely or fed every other day for four weeks before receiving an immunization to trigger MS-like symptoms. Both groups of mice then continued on their same diets for another seven weeks.

The mice that fasted every other day were less likely to develop signs of neurological damage such as difficulty walking, limb weakness and paralysis. Some of the fasting mice did develop MS-like symptoms, but they appeared later and were less severe than in the mice that ate their fill every day. In addition, the fasting mice's immune systems seemed to be dialed down. As compared with mice that took daily meals, those that ate every other day had fewer proinflammatory immune cells and more of a kind of immune cell that keeps the immune response in check.

After four weeks, the mice that fasted sheltered a more diverse ecosystem in their guts than mice that ate every day. In particular, the fasting mice had more of the soothing probiotic bacteria Lactobacillus, which other studies in mice have linked to milder MS-like symptoms.

In addition, transferring gut bacteria from fasting mice to nonfasting mice made the recipients less susceptible to developing MS-like symptoms, suggesting that something in the microbial community was protecting the mice.

These results were encouraging enough to launch a human study of 40 to 60 people. Each participant will undergo a neurological assessment and provide blood and stool samples at the start, midpoint, and end of the study. Participants already taking injectable medications for MS will continue their prescribed drug regimens, and anyone who relapses during the study will receive appropriate treatment. Participants receive up to $265 for taking part in the study.

A pilot study with 16 people limiting their calories every other day for two weeks found immune and microbiome changes that echo the ones seen in mice. The current study is designed to more closely analyze those shifts – and perhaps set the stage for an even larger study to find out whether skipping meals can ease symptoms for people with MS.

To learn more about the study, call enrolling physician Dr. Valeria Tosti at 314-362-2394 or study coordinator Courtney Dula at 314-362-3402; or email picciol@wustl.edu, vtosti@wustl.edu or dulac@wustl.edu.

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