Fasting, a tradition in many cultures for thousands of years, now gets buzz about its potential health benefits. In particular, researchers are looking at intermittent fasting, where you switch between periods of normal eating and extreme calorie cutting.
Some early studies suggest intermittent fasting might improve MS symptoms by calming the overactive immune response that damages nerves. It sounds promising, but more research is needed. Meanwhile, fasting isn’t a mainstream treatment, which includes disease-modifying drugs and steroids.
If you have MS and are thinking of trying fasting, you should know these things and talk with your doctor about them first.
Types of Intermittent Fasts
There are different ways people try intermittent fasting, including these plans:
Time-restricted eating. You only eat within a set number of hours each day. For instance, you might eat all your meals and snacks over 12, 10, or 8 hours a day and fast the rest of the time.
5:2. You eat normally five days a week and cut down to about 500 calories on the other two days.
Fasting-mimicking diet. You eat a very low-calorie diet for a few days, followed by your normal diet.
Alternate-day fasting. You eat nothing one day and go back to your usual schedule the next. This is the most extreme method.
Modified alternate-day fasting. You vary between a normal calorie count one day, and about 500 calories the next day.
How It Might Work for MS
In MS, your immune system attacks your brain and spinal cord. That attack causes inflammation, which damages myelin, the protective coating around nerve fibers. Nerve damage leads to MS symptoms like numbness, weakness, tingling, and vision problems.
Experts don't know exactly what causes MS. Some researchers note that a Western-style diet is linked to inflammation. Their theory is that intermittent fasting might bring down inflammation and prevent the immune system from releasing chemicals that harm myelin.
What the Research Shows
Scientists have mainly studied intermittent fasting in lab animals. A few studies have compared intermittent fasting to a Western-style diet in mice with MS. But findings in mice don’t always apply to people.
In one study, researchers compared two groups of mice. Mice in the fasting group ate a very low-calorie and low-protein diet 3 days a week for 3 weeks. The mice in the other group ate a normal diet. The fasting mice had lower levels of cytokines, which are immune system chemicals that promote inflammation. The fasting mice also had less myelin damage and their MS symptoms were less severe than the mice on a normal diet. In mice with progressive MS, symptoms improved in 20% of the fasting mice.
The same researchers did another small study comparing intermittent fasting to a normal diet in humans. Eighteen people went on a fasting-mimicking diet for a week and then switched to a traditional Mediterranean diet. After 6 months, they said they felt better. Their immune response had calmed, like what happened in the mice. But it wasn't clear how much each of the two plans -- fasting or Mediterranean -- had helped them.
In a more recent mouse study, an intermittent fasting plan scaled back the immune response. Mice that ate every other day had fewer inflammatory immune cells, and more cells that help control the immune response, than mice fed daily. They also had fewer MS symptoms, such as weakness and trouble walking.
In both of the mouse studies, mice that fasted had higher levels of the anti-inflammatory hormone corticosterone. And in one study, fasting mice also had more lactobacillus bacteria in their intestines. Other research shows that people with MS tend to have fewer of these “good” bacteria in their gut. Having more lactobacillus might help lower inflammation. But that isn’t certain.
A new study funded by the National MS Society will compare intermittent fasting to a Western-style diet in 40 people with MS for 12 weeks.
More Work Ahead
Researchers hope to do much bigger studies on intermittent fasting for MS. If it does work, researchers will also need to figure out which type of fast works best for MS, and how long or how often you’d need to do it.
Until doctors know more, don’t try it on your own. Intermittent fasting is considered safe, but it's not right for everyone. Skipping meals can cause blood sugar swings and side effects like constipation, low energy, and bad breath. You also need to make sure you get all the nutrients you need. And if you have diabetes or have ever had an eating disorder, fasting isn’t for you.