The mix of bacteria in your digestive tract, commonly known as your gut microbiome, can play a key role in your overall health. It’s also linked to rheumatoid arthritis (RA), a painful inflammatory disorder that can lead to joint damage.
Some people who have RA may be tempted to try kombucha and other so-called probiotic products to ease their symptoms by boosting “good” bacteria. But experts advise caution.
Kombucha is made by fermenting sweetened black or green tea with a type of acid called acetic acid, according to Sonya Angelone, a registered dietitian nutritionist in Northern California and a spokeswoman for the Academy of Nutrition and Dietetics.
But because kombucha isn’t federally regulated, it’s hard to say exactly what each sweet fizzy drink contains, Angelone says.
“I do caution [people] that kombucha is basically a slurry of bacteria and yeast,” she says. “And you need to be careful of that.”
Proponents say it helps restore the balance of good and bad bacteria in your digestive tract, with health benefits that include better digestion.
No controlled studies in humans have shown that kombucha products help with any health condition. A review of 310 studies, published in 2019, found that nearly all involved animals.
But the review was done when kombucha was just starting to gain popularity, according to one of its co-authors, Julie Kapp, PhD, an associate professor in health management and informatics at the University of Missouri. More researchers -- including Kapp -- are now looking at the potential health effects of kombucha in humans.
Kombucha contains live bacteria and other microbes, such as yeast, that are found naturally in your body. These probiotics are also marketed in pill form, often called dietary supplements, or in foods, such as a fermented dairy drink called kefir.
Researchers have found signs that probiotics can lower signs of inflammation in the body, says Aaron Emmel, PharmD, a pharmacotherapy specialist in St. Augustine, FL. But rigorous studies have not shown that probiotics can actually ease symptoms of rheumatoid arthritis, he says.
Emmel also stresses that probiotics such as kombucha may actually pose problems when combined with the medications that treat RA.
Prescription drugs like biologics fight rheumatoid arthritis by keeping “your hyperactive immune system at bay and helping to quell the inflammation that drives up disease,” he says. But that also means that they may put you at higher risk of an infection. Some doctors have reported severe infections in people with weakened immune systems who took probiotic supplements.
It’s more risky to brew kombucha at home, where it’s not clear exactly what mix of microbes you’ll grow, Emmel says. Kombucha made in a ceramic pot has even led to cases of lead poisoning.
The National Capital Poison Center, a nonprofit organization, advises young children, pregnant women, and people with weakened immune systems to avoid kombucha, whether it’s home-brewed or bought at a store.
Kapp, the Missouri researcher, says kombucha sold in stores is generally very safe, given how it’s been processed. She recommends that anyone who has concerns about a health condition check with their doctor before trying it.
If you want to try kombucha, be sure to protect your teeth, Angelone says. Acetic acid can eat into tooth enamel, so it’s best to drink the beverages with a straw, she says. Or you can rinse out your mouth with water after finishing.
If your goal is to lower inflammation in your body, hopefully easing your RA symptoms in the process, Angelone recommends taking a broader look at your diet.
Start by drinking more water each day and boosting how often you eat fruits, vegetables, and other fiber-filled foods like whole-grain bread, she says. Avoid overly processed food, like ready-to-eat cereals.
Good bacteria thrive on fiber, Angelone explains. “Healthy bacteria basically need fiber, and it’s the fiber that our bodies don’t digest. And that is their five-star meal.”
Make changes slowly, such as adding produce to each meal. “There isn’t one magic food that’s going to fix rheumatoid arthritis,” Angelone says. But with slow dietary changes, she’s seen people feel better, including those with RA.
“A lot of health really depends upon the health of your gut,” she says. “If you want to change your gut ecology, just change what you eat. And in a matter of days, it’s already changing.”