Gut Healthy Foods Worth Trying — or Not

In English, sauerkraut translates to "sour cabbage," but it's yummier than it sounds. This finely sliced fermented cabbage makes a great side dish or condiment. It's rich in vitamins C and K1 and essential nutrients like copper and manganese.

Meyer-Jax points out that sauerkraut adds flavor, probiotic bacteria, and prebiotic fiber to basic or plain dishes. She advises against cooking it, as heat reduces the diversity of the gut-friendly bacteria that aid digestion.

There's no research showing sauerkraut is beneficial for gut health, according to Gail Cresci, PhD, RD, a microbiome researcher in the department of pediatric gastroenterology, hepatology, and nutrition at Cleveland Clinic Children's Hospital. “But eating it won't harm your gut microbiome," she notes, so if your tummy can handle fermented foods, give sauerkraut a try.

If you can't tolerate fermented foods, she recommends eating foods with fermentable soluble fiber, such as beans, oatmeal, avocado, and Brussels sprouts. They will serve as a food source for the microbiome and help support its composition and function.

Kombucha or kombucha tea is black tea fermented with white sugar and a symbiotic culture of bacteria and yeast (SCOBY). The SCOBY "looks like a cross between an alien and a blobfish, but it can make some delicious kombucha," says Meyer-Jax. A review published in September 2022 in the International Journal of Food Microbiology noted that the fermented tea contains antioxidants, minerals, organic acids, probiotics, and B vitamins, which may ease inflammation and promote a healthier gut.

"Raw or unpasteurized brewed kombucha can be a rich source of acetic and lactic acid bacteria and yeasts with probiotic potential," she says. But there’s limited in vivo (in live animals or humans) research on how it directly affects the microbiome's composition.

Mayo Clinic notes that while some people claim that kombucha improves gut health and prevents a slew of other health conditions because of its immune-boosting properties, these claims are not science-backed, and the lack of verified information may pose a health risk. Several kombucha tea drinkers have reported side effects such as allergic reactions, headaches, infections, and stomach upset.

Kombucha — especially homemade — contains alcohol and isn't recommended for people with a compromised immune system or women who are pregnant or breastfeeding.

You gain nourishment through your diet when your body converts complex food molecules into nutrients and absorbs them. But you can’t digest food without the help of microbes and enzymes in your body.

Digestive enzymes are proteins that the pancreas produces to help with digestion. But if a person lacks the right amount of digestive enzymes or their pancreas can’t synthesize the required enzymes for digestion, they may have digestive enzyme insufficiency, according to Johns Hopkins Medicine. Common symptoms include poor digestion, malnutrition, and gut issues, including oily stool, stomach cramps, gas, bloating, and diarrhea.

What causes digestive enzyme insufficiency? It can be genetic, congenital, or caused by conditions or disorders such as pancreatic cancer, cystic fibrosis, and gastrointestinal surgeries. Cresci notes that digestive enzyme supplements are a way to combat digestive enzyme insufficiency, but there's no data to support taking them for better gut health generally. If you choose to try a digestive enzyme supplement, she recommends taking it before or within 20 minutes of your meals so the enzymes are available to digest target foods.

Extra-virgin olive oil (EVOO) is the cornerstone of the Mediterranean diet and has been linked to better heart health. And article in the February 2021 issue of Nutrition Reviews states that olive oil may also be one of the better foods for gut health. The review notes that olive oil is a prebiotic, which promotes the growth of beneficial bacteria like Lactobacillus and Bifidobacterium while inhibiting the growth of harmful bacteria.

While olive oil shows promising gut health benefits, Cresci advises that, as with any fat, "you don't want to go overboard on how much olive oil you consume." She recommends limiting fat intake to less than 30 percent of your total calories.

Polyphenols — micronutrients found in olive oil — can also help reduce gastrointestinal inflammation and boost immunity, according to a study published in February 2022 in Nutrients. According to the study, EVOO biophenols have antioxidant and anti-inflammatory properties that have the potential to reduce intestinal inflammation and promote gut microbiome diversity. Olive oil also shows potential for lowering IBD symptoms, but more study is needed to understand its effect and safety.

If your favorite pastime is binge-watching wholesome K-dramas, you've probably heard of this traditional food. Kimchi is a savory Korean side dish or condiment made from salted fermented vegetables such as napa cabbage, green onion, and radishes. You could find it seasoned with ginger, spring onion, and garlic, among other herbs and spices.

While it may have a pungent smell, kimchi is chock-full of gut-healthy benefits. It’s rich in probiotics to promote the growth of beneficial bacteria in your gut microbiome. “Kimchi is one of my favorite fermented veggie condiments that often has a spicy flavor,” says Meyer-Jax. “Like sauerkraut, it can be a terrific source of fiber and good-for-you bacteria.”

According to Stanford researchers who published a study in the journal Cell in 2021, a diet rich in fermented foods may benefit digestive health by enhancing gut microbiota diversity while lowering the risk of inflammation. The study looked at the effect of fermented versus high-fiber foods on the gut microbiome during a 10-week diet and found that the inclusion of yogurt, cottage cheese, and kimchi led to an increase in overall microbial diversity in the gut.

Cresci says fermented foods like kimchi are a boon for gut health, but you’ll need to follow a healthy diet overall. "If your diet is unhealthy, fermented foods may not have any effect (positive or negative) on your gut health," and a poor diet may cancel out the benefits of fermented foods. If you can't handle the spice in kimchi, foods like cabbage, sauerkraut, and yogurt are good alternatives.

Although apple cider vinegar (ACV) has been around for centuries, used as a remedy for various health problems like weight gain, digestive issues, and skin problems, there is little research to support its use. What we do know is that apple cider vinegar contains probiotics, which according to Cleveland Clinic, could benefit the digestive system and gut microbiome. But ACV in its raw form is quite different from its gummy form.

"While ACV gummies are convenient and delicious, they don't contain nearly as much apple cider vinegar as their liquid counterpart,” says Meyer-Jax. “The amount of ACV in each gummy varies from brand to brand, so there is really not a lot of data that shows it's effective or not for gut health."

Instead of taking ACV gummies, she recommends drinking extra water before and after meals to improve digestion and feel fuller longer.

Ka'Chava, a gluten-free meal replacement shake made with over 70 plant-based ingredients, claims to contain gut-healthy nutrients such as fiber, probiotics, zinc, digestive enzymes, vitamin D, and magnesium.

Meyer-Jax says probably not. "While it has many ingredients that would support gut health, it also has ingredients that individuals could be sensitive to."

Tips to Promote a Healthier Gut

Cresci says your diet is the most critical aspect of your gut health. The best way to reap gut-health benefits is to consciously add gut-healthy foods into an overall healthy diet.

Meyer-Jax advises everyone to:

• Eat foods rich in fiber from natural plant sources that promote gut microbiome diversity.
• Exercise regularly.
• Drink plenty of water, as it nourishes cells and promotes a healthy gut.
• Eat probiotic-rich foods such as yogurt, tempeh, and pickles for better gut health.
• Consult with a registered dietitian to create a gut-healthy meal plan.