Probiotics are living microorganisms that deliver a range of health benefits when included in the diet. (1) Traditional fermented food sources of these bacteria exist in nearly every culture, and can also be taken in supplement form.
This list of healthy fermented foods containing beneficial probiotics can help you round out your health plan and get the most out of your menu.
- Kefir and Traditional Buttermilk
These fermented milk products may be well-tolerated even by those who are lactose intolerant because friendly bacteria have already begun to digest the milk sugar (lactose) that causes problems for some people.
The name “kefir” is derived from the Turkish word “keyif,” referring to feeling good after eating it.
Kefir grains added to goat or cow’s milk are cultures consisting of yeast and lactic acid bacteria; the potent bacterial action of the several strains contained in kefir have been valued as a healthy food for centuries. (6)
Buttermilk can refer to any one of several fermented dairy products, but the only kind containing live cultures is the traditional type, which is the liquid remaining after butter is made.
Commonly used in Pakistan, India and Nepal, traditional buttermilk is skinny on calories and rich in several important nutrients, including calcium, phosphorus, riboflavin and vitamin B12. (9)
Keep in mind that cultured buttermilk found on supermarket shelves does not contain live probiotics.
Perhaps the best-known probiotic food in Western cultures, yogurt is made from milk fermented with several bacterial cultures, including bifidobacteria and lactic acid bacteria. (10)
Like kefir, yogurt is better than milk for people who are lactose intolerant since the fermenting process has already begun.
Studies indicate that children eating yogurt after taking a course of antibiotics have fewer problems with diarrhea, and patients with irritable bowel syndrome often experience improvements when they include yogurt in their diets. (13, 14)
This highly nutritious food should be chosen with care, since many yogurt products available don’t contain live cultures. Look for products labeled with the words “live” or “active.”
- Some Cheeses
While cheese is a fermented product, only certain types contain live probiotics. Bacterial cultures don’t always survive aging processes, so read labels carefully.
Fermented cabbage is made using the same lactic acid bacteria found in the dairy products mentioned above. It’s been around forever, and is popular in Europe and other parts of the world.
Often served with sausage, sauerkraut is both salty and sour, and will keep well for months in an airtight container.
Sauerkraut is an excellent source of fiber, as well as providing vitamins B, C and K; minerals you’ll get from sauerkraut include iron and manganese, and the antioxidants in this fermented food support eye health. (20, 21)
The pasteurization process kills friendly bacteria, so read labels to make certain you choose an unpasteurized product.
This fermented soybean product is a Japanese kitchen staple, usually served with rice at breakfast. The bacterial strain it contains is called Bacillus subtilis.
A high-protein food, the texture of natto is slimy and the flavor is strong. It also packs a distinct aroma, but studies show older Japanese men who consumed natto regularly were more likely to have dense, healthy bones, perhaps because of its high vitamin K2 content. (22)
Also made from fermented soybeans, tempeh originates in Indonesia and has become popular worldwide as a high-protein substitute for meat.
The flavor has been described as earthy and nutty, and it’s made in the form of a patty that holds together well and can be fried in slices, cubed, or crumbled.
While soybeans are known for their high phytic acid content, the fermentation process significantly decreases the amount of this substance that can inhibit mineral absorption. (25)
Another fermentation bonus is the vitamin B12 produced by bacteria, which isn’t available in soybeans; this can help vegetarians get an important nutrient present mostly in animal foods. (26)
Considered a seasoning, this soybean product is cultured with salt and koji fungus, and is traditionally used to flavor Japanese dishes.
Another version of miso can be made by combining soybeans with grains like rye, barley or rice. Miso soup is a popular breakfast food in Japan, and the salty seasoning comes in various colors, each with a slightly different taste.
Rich in protein and fiber, miso delivers a range of phytonutrients, vitamins and minerals. (27) Japanese women who eat generous quantities of miso have a lower risk of breast cancer and stroke. (28, 29)
A spicy side dish originating in Korea, kimchi is usually made with cabbage, but other vegetables can also be used.
Fermented with its own strain of bacteria called Lactobacillus kimchii along with lactic acid bacteria, this popular food is seasoned with garlic, scallions, chili flakes, ginger and salt, and is believed to improve digestive health. (30, 31)
This fermented drink is made with either green or black tea, and is popular worldwide, especially in Asian countries.
Made with bacteria and yeast, kombucha has a reputation for imparting a range of health benefits, but studies have been done only in the lab, so clear evidence to back up the claims aren’t available yet. (32)
Since it’s a fermented drink, it’s reasonable to believe it may have benefits similar to other foods we’ve covered here, and the probiotic content could make valuable contributions to overall health.
There are many other types of fermented foods besides the ones on this list, and if you aren’t already enjoying this beneficial class of foods, you may want to experiment and see which ones might tickle your taste buds.
Summary: Probiotic microorganisms found in fermented foods like these may improve digestive health, sharpen mental processes, protect the cardiovascular system, and help promote good bone density while providing a wide range of vital nutrients.
Part 2: the importance of probiotics
Cultivating friendly bacteria in the gut through eating foods and taking supplements that provide probiotics can help you lose weight, bump up immune function, improve your digestion, and even cut your risk of developing chronic diseases. (1, 2)
The importance of having a healthy gut doesn’t always get the attention it deserves, but research indicates it is just as vital as food choices, good sleep and exercise.
We have ten times as many bacteria in our bodies as we do cells, and most of them live in the gut.
When these microorganisms are happy, we enjoy health benefits; when bacterial colonies aren’t thriving, we may suffer a range of negative effects. (3)
Certain types of yeast can also act as probiotics, but most of the conditioning required for keeping the gut healthy is performed by colonies of bacteria.
Probiotics can be taken in supplement form, and may also be ingested by eating foods prepared through fermentation processes that encourage the growth of friendly bacteria.
Some popular fermented foods include kefir, kimchee, sauerkraut, tempeh and yogurt.
You may also be familiar with prebiotics, which are dietary fibers that actually feed friendly gut bacteria. (4)
Researchers have identified dozens of types of bacteria known to impart health benefits; two common groups include bifodobacterium and lactobacillus, which are further broken down into sub-species. Within these species, many more individual strains exist.
Each kind of probiotic appears to affect different aspects of overall health, so selecting the right type or combination of types is important.
Supplements that contain several types of probiotic are known as multi-probiotics, or broad-spectrum.
The study of how probiotics affect health is relatively new, so evidence regarding some of the potential benefits may not be conclusive at this time. (5)
How Microorganisms Work in the Gut
Communities of bacteria live mostly in the large intestine; this is the final stretch of the digestive tract we refer to as the colon.
These “gut flora” are made up of hundreds, or possibly thousands, of different types of bacteria, viruses and yeast, although there are more bacteria than other kinds of microorganisms. (6)
The way these communities work together metabolically is similar to an organ. For example, gut flora manufactures some of the B vitamins as well as vitamin K. (7)
It can also turn fiber into short-chain fatty acids that perform other functions, such as feeding the gut wall and activating the immune system. (8)
Bacterial communities work to maintain the integrity of gut wall, which is vital in preventing substances in the colon from leaking into other parts of the body and stimulating an immune response. (9, 10, 11)
Besides friendly bacteria, harmful gut flora also exist, and when the balance gets out of whack, it can lead to diseases like type 2 diabetes, metabolic syndrome, heart disease, depression, Alzheimer’s disease, colorectal cancer and many more. (12, 13, 14, 15)
Both prebiotics and probiotics can help correct imbalance and insure optimal function of gut flora. (16)
The Effect of Probiotics on Digestive Health
This is the area where the most research has been done on probiotics, especially in regard to diarrhea associated with taking antibiotics. (17)
Diarrhea often occurs after a course of antibiotics is taken to treat a medical condition, and can persist for long periods of time. Antibiotics eradicate many bacteria in the gut, and this can shift the balance so bad bacteria dominate and thrive.
Many studies indicate probiotics can cure this problem (18, 19), as well as being effective in reducing bloating, gas, constipation, and other intestinal problems, including symptoms associated with irritable bowel syndrome (IBS). (20, 21)
Probiotics can assist in treating ulcerative colitis and Crohn’s disease (22), and may also help fight helicobactor pylori infections, which are caused by the bacteria that leads to ulcers and raises the risk of stomach cancer. (23)
Anyone who has digestive issues that have been difficult to resolve might consider taking a probiotic supplement.
Other Health Benefits Associated with Probiotics
If you’re carrying around a significant amount of extra weight, chances are your gut flora are different than someone who is thin or of normal weight. (24)
Researchers playing with this concept transplanted gut flora from thin animals into obese animals, and the result was dramatic: fat animals began to lose weight. (25)
Data from a study conducted in 2013 with more than 200 people suffering from central obesity (large amounts of belly fat) offered encouraging results: over three months, participants taking the probiotic lactobacillus gasseri had an average decrease of 8.5% in belly fat mass. (28)
It took only a month for test subjects to gain back the belly fat they lost after they stopped taking the probiotic.
Another study indicated that Bifidobacterium and lactobacillus ramnosis may help in preventing obesity and supporting weight loss. (29)
The use of probiotics has been associated with improvements in a range of other health conditions, including:
- Drops in blood pressure for patients with hypertension (30)
- A reduction of systemic inflammation (31)
- Enhanced immune system function (32)
- Lower total cholesterol and LDL cholesterol measurements (33)
- Improvements in skin conditions such as rosacea, acne and eczema (34)
- Reduced symptoms in patients suffering from depression and anxiety (treated with these strains: bifidobacterium longum and lactobacillus helveticus) (35)
Potential health benefits resulting from these effects may include a decreased risk of developing chronic Western diseases like autoimmune diseases, mental disorders, arthritis and heart disease. Further research is likely to reveal even more health advantages associated with healthy gut flora.
Side Effects and Dosage
Taking probiotics is completely safe for most people, though some experience digestive side effects during the first few days; abdominal discomfort, bloating and gas are the most common problems. (36)
Improved digestion usually follows these initial symptoms.
Those with compromised immune systems, such as patients diagnosed with AIDS or HIV, have had issues with infection after taking probiotics, and anyone with a medical condition should talk with a doctor before making a decision about supplementing. (37)
If you’re looking to treat a specific health issue, it’s important to do your homework and find out which strains of probiotics have been successful in specific applications; always purchase probiotics from a trusted manufacturer.
Summary: Providing assistance to your body for cultivating friendly gut bacteria in the form of probiotics can be helpful in improving a range of health conditions, including immune system function, weight management, depression and systemic inflammation.