Your gut microbiome is made up of microorganisms (microbes), like bacteria, viruses, and fungi, that live in your digestive tract. Your microbiome can affect bodily functions like digestion, metabolism, and immune system regulation. However, the microbes in your gut aren't always good. If your microbiome is unbalanced between healthy and unhealthy microbes, probiotics can help introduce healthy microbes back into your body.
Probiotics are live microorganisms that you can consume through food or supplements. Some research has shown that probiotics can have an antioxidant-like effect that helps reduce inflammation in your body and can increase the bacterial diversity of your gut microbiome.
Most probiotic foods are fermented because live microorganisms are introduced during fermentation. However, not all fermented foods have probiotics. If the food gets heated after it’s fermented (e.g., for sourdough bread and often tempeh or miso), the beneficial microorganisms are cooked off. Yogurt, on the other hand, maintains the live microorganisms added during fermentation.
More research is emerging on probiotics as a functional food, and more types of probiotic foods are being invented, such as new pre- and probiotic sodas. Researchers are also exploring different methods of preserving probiotics better in foods that otherwise wouldn’t have them and making probiotics resistant to heat.
Kefir: Is a fermented milk beverage that contains many probiotics. It’s made by mixing milk with fermented kefir grains, which is a culture of yeast and lactic acid bacteria. A culture is a laboratory method that gives microorganisms the time, space, and food they need to multiply. The fermentation process introduces a mix of bacteria and yeast that serve as probiotics.
Kefir has a tangy taste and can be described as a type of drinkable yogurt. It can be on its own or added to smoothies. It’s also a good source of protein and calcium and is often fortified with vitamin D.7 Because of how it’s processed, it’s usually quite low in lactose and so most people with lactose intolerance can tolerate kefir.
Kimchi: One of Korea's most popular foods, kimchi has more recently gained ground in the United States as people have become more interested in probiotics. It’s a condiment made by fermenting vegetables. Often, it includes cabbage, radishes, cucumbers, and onions. It’s especially high in lactic acid bacteria, one type of probiotic. Kimchi can range from mild to spicy.
Studies have found that fermented kimchi helps decrease the concentration of potentially harmful gut bacteria and promotes healthy blood glucose, blood pressure, and cholesterol levels. Not only is kimchi a good source of probiotics, but it’s also rich in fiber—another key nutrient for gut health. Fiber also supports healthy cholesterol levels and blood sugars, complementing the health benefits of kimchi even more.
Kombucha: is a carbonated, fermented beverage made from tea, sugar, yeast, and bacteria. It is often fermented with fruit to add flavor. Active yeast transforms the sugar during the fermentation process, so there is a very small amount of alcohol in it.
Many health benefits of kombucha have been demonstrated in research, but more research is needed. One study highlighted that certain kinds of kombucha can be good for your health thanks to its probiotics, vitamins, and antioxidants, but they aren’t well-regulated. Pregnant people and those who are immunocompromised should take caution and talk to their healthcare provider before consuming it.
Sauerkraut: Sauerkraut is a traditional Chinese food that is also popular in many areas of Europe and the United States. It's somewhat similar to kimchi, except the only vegetable included is cabbage. The cabbage is fermented in lactic acid bacteria, which serves as a probiotic. One study found that sauerkraut maintains most of its beneficial bacteria throughout the fermentation process and packaging, making it a great probiotic food. Even though you may only think of sauerkraut as a hot dog topping, it also goes great on burgers, sandwiches, and salads. You can even add it to a charcuterie board or topping for mashed potatoes.
Yogurt: One of the most common food sources of probiotics is yogurt. It’s a fermented milk product, similar to kefir. It’s made by heating milk, adding bacteria, and letting it ferment for a few hours. Note how the heating happens before the bacteria is added, so the probiotics don’t get cooked off.
Most yogurt containers list the probiotics they contain so you can see the specific strains they’ve added during the fermentation process. Lactobacillus and Bifidobacterium are the most common species. Yogurt, especially Greek or Icelandic Skyr yogurt, is also a good source of protein. It also contains calcium and vitamin D.
Yogurt can be enjoyed on its own, added to smoothies, or made into a parfait with fruit and granola.
Tips for Consuming More Probiotics
If you want to prioritize consuming more probiotics, check the label of a probiotic food to ensure it contains live active cultures. The label should list the cultures it contains so you can be sure they weren’t cooked off or otherwise destroyed during processing.
Store probiotic foods as recommended by the manufacturer. That often means refrigerating them to ensure the microorganisms stay alive and the product doesn’t spoil. Heating probiotics to a high temperature typically causes them to die off.
Here are some tips for consuming more probiotics: Add yogurt or kefir to your smoothies, Use kombucha or another probiotic beverage to make a mocktail, Add kimchi or sauerkraut to sandwiches and burgers, Use Greek yogurt to make salad dressings and marinades, Top oatmeal or pancakes with yogurt and berries
Side Effects of Probiotics
Our current research shows that probiotics, especially the most common Lactobacillus and Bifidobacterium species, are generally safe for most people to consume.
Researchers have found that minor gastrointestinal (GI) symptoms like gas are the main side effects. Introducing probiotics slowly can give your body time to adjust and reduce the risk of unpleasant digestive symptoms.
Probiotics may cause serious infections, but this is rare. Some products may contain strains other than the ones listed, which could have harmful effects. Preterm infants and people with severe illnesses or who are immunocompromised are at the highest risk for side effects from probiotics.
In Summary: Probiotics can help increase the diversity of your gut microbiome, supporting your digestive, immune, and mental health. They’re present in fermented foods like kimchi, kombucha, kefir, yogurt, and sauerkraut, thanks to the introduction of bacteria in the fermentation process.
To get more probiotics, you can try adding kefir or yogurt to your morning smoothie and topping your lunchtime sandwich with kimchi or sauerkraut.
As always be Safe, Stay Healthy and be Careful out there
James A Vito, D.M.D.