The research, published in the Journal of Internal Medicine, found that fecal microbiota transplantation (FMT) helped adults with chronic insomnia sleep longer and wake up less frequently after falling asleep, and these improvements lasted for up to six months.
The findings “provide clinical evidence that the gut microbiota may be a modifiable component of the biological systems regulating human sleep,” according to study authors Zhe Wang and Yanping Bao, who responded to Everyday Health by email. Wang works with the Institute of Brain Science and Brain-Inspired Research at the Shandong First Medical University in Jinan, China. Bao works with the National Institute on Drug Dependence at Peking University in Beijing.
The findings “also support the gut-brain axis as a potentially important therapeutic target in chronic insomnia,” they say.
Fecal Transplants Improved Sleep Efficiency
For the trial, researchers recruited 80 adults in China with chronic insomnia. Participants were first given a short course of antibiotics to reduce existing gut bacteria. Then, half received an FMT capsule and the other half received a placebo. The trial was randomized and double-blind, meaning neither researchers nor participants knew who received the treatment or the dummy pill.
Healthy donors with no sleep disorders or psychiatric symptoms provided the material for the capsules.
A month after receiving the FMT or placebo, participants came to a sleep lab so researchers could record:
- How long participants slept
- How frequently they woke up
- Sleep efficiency, or the percentage of time someone spent asleep
For adults who received a fecal transplant capsule, sleep efficiency increased from about 79 percent before treatment to 93 percent after one month. The placebo group’s sleep efficiency showed little change, going from about 85 percent to 87 percent.
Compared with the placebo group, those who received FMT spent about 42 fewer minutes awake after falling asleep. The treatment group continued to show improvements for up to six months, according to self-reported questionnaires.
The study has some limitations: 80 participants is a modest sample size, and the results need to be replicated in larger and more diverse populations, Wang and Bao say. “We do not yet know which specific microorganisms or microbial functions produced the benefits, whether different donor preparations would have similar effects, or how long the improvements may persist.”
How Gut Health Affects Sleep
“We also know that other digestive-related processes and symptoms can impact sleep,” Jansen says. For instance, acid reflux or gastrointestinal issues near bedtime can make it hard to fall and stay asleep.
The current study was designed to evaluate the clinical efficacy of fecal transplant, not to establish the precise biological mechanism, Wang and Bao say. Further research is needed to identify the specific microorganisms and pathways that might be responsible for improved sleep.
What to Eat to Improve Sleep
- Fruits (especially berries, kiwifruit, and bananas)
- Vegetables,
- Oatmeal
- Fatty fish
- Dairy
These sleep-supporting foods provide melatonin, tryptophan, antioxidants, and other essential nutrients linked to better sleep, she explains.
Other sources of these nutrients include:
- Turkey
- Eggs
- Chicken
- Peanuts
- Tart cherries
- Spinach
- Sweet potatoes
“It’s better to aim for balance than to focus on any one particular food,” Jansen says.
She also recommends avoiding foods high in saturated fat, sugar, and refined carbohydrates, like desserts, as well as alcohol and caffeine.
When you eat matters, too. “Not eating heavy meals too close to bedtime and aiming for consistency in timing of eating from day-to-day is beneficial for sleep.”