You may have heard these words thrown around and you may even have a vague idea about them, but in this article, we are going to deep dive into three important (and deeply connected) parts of gut health: prebiotics, probiotics, and postbiotics.
Summary
- Prebiotics are any type of fiber that feeds and stimulates beneficial bacteria in the gut but can also feed some pathogenic (disease-causing) organisms.
- Probiotics are live beneficial organisms (usually yeast or bacteria) that provide health benefits during their passage through the gut, even if they do not permanently colonize it.
- Postbiotics are beneficial compounds produced by gut bacteria, contributing to gut health, immune function, and overall well-being.
Prebiotics
Prebiotics are non-digestible food ingredients, typically fibers, that feed and stimulate the growth and/or activity of beneficial bacteria in the colon. They resist digestion in the small intestine so they reach the large intestine intact, where they are fermented by microbiota (the living organisms) of the gut.
Examples of Prebiotics:
- Inulin and Fructooligosaccharides (FOS): Found in chicory root, Jerusalem artichoke, garlic, onions, leeks, asparagus, bananas, and wheat.
- Galactooligosaccharides (GOS): Present in legumes, lentils, chickpeas, and beans.
- Resistant Starch are carbohydrates that humans can’t digest but bacteria in the colon can. They are found in unripe bananas, cooked and cooled potatoes and rice, and whole grains.
- Pectins: Present in apples, citrus fruits, and carrots.
- Beta-glucans: Found in oats, mushrooms and barley.
Effects on Gut Health:
Prebiotics serve as food for beneficial bacteria such as Bifidobacteria and Lactobacilli that live in your large intestines, promoting their growth and activity. For instance, eating foods high in inulin and FOS stimulates the growth of beneficial Bifidobacteria family of bacteria in the human colon. Bifidobacteria help with digestion and increase a person’s immune system. Another example is eating resistant starch which feeds the beneficial bacteria Eubacterium rectale, which is one of the primary butyrate-producing bacteria in the human colon (see the section on Postbiotics below). The more prebiotics you eat, the more of these beneficial bacteria you will have.
While prebiotics generally promote beneficial bacteria, they may also be used as food by pathogenic bacteria under certain conditions. This highlights the importance of maintaining a balanced gut microbiota by utilizing specific diets (such as low-sugar) or anti-microbial herbal protocols as needed.
Special Note:
If you get a lot of bloating immediately after consuming foods high in prebiotics, please see our article Bloating After Eating as this is a very unique condition that needs to be addressed.
Probiotics
Probiotics are live microorganisms (very, very small living things) that, when consumed in adequate amounts, bring health benefits. These are often strains of bacteria that naturally occur in the human gut.
Examples of Probiotics:
- Lactobacillus bacteria species: L. acidophilus, L. rhamnosus, L. casei
- Bifidobacterium bacteria species: B. bifidum, B. longum, B. breve
- Bacillus bacteria species: B. coagulans, B. subtilis, B. licheniformis
- Saccharomyces boulardii (a beneficial yeast)
Foods Rich in Probiotics:
When probiotics are added to a food, they eat the prebiotics in that food, making the food easier for humans to digest and adding other health benefits. These are called “cultured” or “fermented” foods. There are many cultured dairy products on the market today that specifically include live and active cultures. These will have the specific probiotics (cultures) listed in the ingredients. Cultured dairy includes yogurt, kefir, cottage cheese, sour cream, and even cream cheese. There are two brands we personally use, Nancy’s and Good Culture, but there any many, many great choices for yogurt and kefir!
There are traditionally fermented vegetables and beans, such as sauerkraut (cabbage), kimchi (cabbage), miso (soybean), and tempeh (soybean). Make sure “vinegar” is not listed in the ingredients, as these are pickled vegetables, not fermented vegetables.
Probiotics are Tourists, Not Residents:
Probiotics don’t establish long-term residence in the gut. Rather, they move through like tourists visiting a favorite vacation spot, spending lots of money while they are there and propping up the local businesses. Probiotics can stay in the gut for as little as several hours, and as long as many days or even weeks. While the probiotics are making their way through, they can enhance immune function, inhibit pathogen growth, and improve intestinal barrier function. Because they are only temporary residents, you need to continually ingest probiotics to maintain their beneficial effects.
Not all probiotics make it to the large intestine alive. Certain bacteria, such as those in the Bacillus family, have the ability to form spores which can remain dormant through harsh conditions such as processing and the acidic digestive tract. This allows them to stay alive until they encounter favorable conditions in the gut, where they become active and start to grow.
Funny enough, probiotics can provide health benefits even when the probiotic organisms are dead at the time of consumption. This is because the cellular parts of the probiotics, and their metabolites (compounds produced by bacteria as they digest food), can interact with a person’s immune system and gastrointestinal environment, exerting beneficial effects similar to those of live probiotics. For example, multiple animal studies have demonstrated that several types of Lactobacillus improved resistance against influenza virus infection, even when heat-killed or inactivated prior to ingestion. In another animal study by Adams (2010), The probiotic paradox: live and dead cells are biological response modifiers, Adams found that multiple other types of non-viable (dead) probiotics produced various beneficial effects, summarizing as: “The probiotic paradox is that both live and dead cells in probiotic products can generate beneficial biological responses.”
A human study by Kawai et al. (2018), Health Benefits of Lactobacillus gasseri CP2305 Tablets in Young Adults Exposed to Chronic Stress, investigated the impact of a pasteurized (heated) Lactobacillus species on stress-related symptoms in medical students. The double-blind, placebo-controlled study found that consumption of the non-viable (dead) probiotic improved intestinal symptoms and sleep quality.
These studies support the concept that consuming probiotic supplements containing dead microorganisms can be beneficial, particularly in situations where live probiotics might pose risks, such as in immunocompromised individuals. Additionally, if you have to travel with probiotics, or if your bottles of probiotics accidentally get heated, you can feel confident to take them anyway.
While prebiotics feed and help probiotics, factors such as stress, high-sugar diets, lack of sleep, and antibiotic use can negatively affect the balance of probiotics in your gut.
Postbiotics
Postbiotics are chemicals produced by probiotics (when they eat) that have various health benefits. Postbiotics are one of the key benefits of probiotics! Examples of postbiotics are:
- Short-chain fatty acids such a butyrate, which reduce inflammation, strengthen the intestinal barrier, influence brain function, and improve mineral absorption.
- Certain enzymes which are anti-inflammatory and improve nutrient and mineral absorption.
- Certain proteins and acids which reduce inflammation, are antimicrobial, and strengthen the intestinal barrier.
Butyrate is a type of short-chain fatty acid and is one of the better-studied postbiotics. Butyrate provides approximately 70% of the energy used by the cells lining the colon for growth and repair. It strengthens the gut barrier which helps prevent harmful substances from entering the bloodstream. It’s also anti-inflammatory and may reduce the risk of autoimmune reactions. Butyrate has been shown to induce apoptosis (cell death) in cancerous colon cells and inhibit tumor growth, suggesting a protective effect against colorectal cancer. It also helps make the colon more acidic, which is a good thing, because it discourages the growth of pathogenic (disease-causing) bacteria.
There are even some studies that suggest that some postbiotics affect mood!
There is still a lot of research that needs to be done on postbiotics as it’s a relatively new field.
Frequently Asked Questions
Q: Should probiotics be taken all the time?
Generally, no. Most people who are eating a healthful diet don’t need to supplement with probiotics all the time, though things like cultured and fermented foods don’t tend to be problematic if eaten daily — though even with fermented/cultured foods, it’s best to have a variety. We usually recommend specific short-term probiotic supplements for specific situations. If you think you may need probiotics, talk to us and we’ll give our best advice for your unique situation.
Q: Can you take prebiotics and probiotics together, and should they be taken at the same time?
Yes, you can take prebiotics and probiotics together. In fact, combining them can be beneficial because prebiotics serve as food for probiotics, enhancing their effectiveness. Taking them at the same time is acceptable but not necessary; they can be consumed separately and still provide benefits.
Q: Can you take different types of probiotics together, and can they be taken at the same time?
Yes, you can take different types of probiotics together. In fact, taking probiotic yeasts (like Saccharomyces boulardii) along with probiotic bacteria can actually have complimentary effects as shown in this study: Proven Complementary Effect of Probiotic Yeast and Bacteria
Q: Are there any side effects or risks associated with taking prebiotics, probiotics, or postbiotics?
Generally, prebiotics, probiotics, and postbiotics are considered safe for most people. Some individuals may experience mild digestive discomforts like gas, bloating, or diarrhea. People with compromised immune systems or serious underlying health conditions may do better with a probiotic that is inactivated, and not live.
Prolonged use of the same probiotics have the potential of causing imbalance in the gut. We generally don’t recommend long-term use for most people. Instead, consuming a small amount of a variety of cultured/fermented foods, and maintaining a low-sugar, high-prebiotic diet is very beneficial and promotes diversity of lifeforms in the colon without risks other than a little gas. If you get a lot of bloating immediately after consuming foods high in prebiotics, please see our article Bloating After Eating as this is a very unique condition that needs to be addressed.
Q: How do antibiotics affect the gut microbiota?
Antibiotics kill both harmful and beneficial bacteria, not just in the gut, but all over the body. There are many areas of the body that are colonized by beneficial bacteria, including the skin, mouth, nose, etc. Often beneficial bacteria can prevent pathogenic fungus (i.e. yeasts like Candida) from overgrowing. When you take the antibiotics, you are killing off bacteria (good and bad), but not killing off any fungus. People who already have a high amount of fungus may then experience negative symptoms of fungus-overgrowth, yeast infections, oral thrush, etc.
Q: Should probiotics be taken during or after antibiotic treatment?
Diarrhea is a common side effect of antibiotics, occurring in 5% to 25% of patients, particularly older individuals. Many studies have focused on probiotics specifically for preventing Clostridioides difficile (C. difficile) infection, which is typically caused by exposure to broad-spectrum antibiotics and can be life-threatening.
Some studies have found Saccharomyces boulardii (a beneficial yeast) at a dose of 500 mg twice daily to be quite helpful in preventing antibiotic-induced diarrhea as well as other gastrointestinal symptoms. Because it is a yeast and not a bacteria, it doesn’t interact at all with the antibiotic, and it helps to protect your good gut bacteria.
There are also studies that have tested different species of bacterial probiotics. While most bacterial probiotics were statistically more effective against antibiotic-induced diarrhea than the placebo, Lactobacillus casei was the most effective.
Remember that probiotics can work synergistically, so taking Saccharomyces boulardii and Lactobacillus casei at the same time would theoretically work better than either alone, though we don’t know of any studies that have tested these two in combination specifically. Additionally, live probiotics do have a small risk of contamination so may have a small risk for those who are already immuno-compromised, though we did not see any indication of this result in the dozens of studies we have read.
According to the studies, high-doses starting at the very beginning of antibiotic use and continuing for one week afterward were the most effective. Also, probiotics should be taken at least 2 hours away from antibiotics so as not to reduce the effect of the antibiotic or probiotic.
It is important to note that other studies recommend not continuing probiotic use for more than 1 week following antibiotics, but instead to focus on lots of prebiotics. The reason for this is simply that you have many, many, many different types of probiotics in your system, and any probiotic supplement you buy will have high amounts of only a few, so can cause an imbalance in your system. This doesn’t appear to be a concern at any time other than after antibiotic use.
Q: What is the best time of day to take probiotics or prebiotics for maximum effectiveness?
There isn’t a definitive best time, but taking probiotics with meals or just before eating may enhance their survival through the stomach acid — though the importance of this is debatable. Prebiotics can be taken at any time since they’re not affected by stomach acidity.
Q: Are prebiotics and probiotics safe for children, infants, and pregnant or breastfeeding women?
Prebiotics and probiotics are generally safe for these groups. There are usually specific probiotic formulations for these groups.
Q: Can you get enough prebiotics and probiotics from diet alone, or are supplements necessary?
Many people can obtain sufficient prebiotics and probiotics from a balanced diet rich in fiber, cultured dairy and fermented foods. Supplements are beneficial for individuals with specific health needs or dietary restrictions, or during/after certain protocols.
Q: What are synbiotics, and how do they differ from prebiotics, probiotics, and postbiotics?
Synbiotics are just products that combine both probiotics and prebiotics. The prebiotics serve as food for the probiotics, enhancing their survival during storage and may even provide greater health benefits as they may be higher in postbiotics by the time you consume them.
Q: Can you overdose on prebiotics or probiotics, and what happens if you consume too much?
While overdosing is uncommon, consuming excessive amounts of prebiotics can lead to digestive discomforts like gas, bloating, or diarrhea due to increased fermentation in the gut. High doses of probiotics may also cause similar symptoms. Additionally, some people tolerate certain probiotics better than others. This can sometime just require trial-and-error to find the right one for your body.
Q: Do prebiotics or probiotics have benefits for skin health, and can they be used in skincare products?
Yes, prebiotics and probiotics can benefit skin health by promoting a balanced skin microbiome, reducing inflammation, and strengthening the skin barrier. They are used in some skincare products to help manage conditions like acne, eczema, and rosacea. Topical applications can enhance skin health by supporting beneficial bacteria on the skin’s surface. Our current favorite is the Derma Colonizer which we carry.
Q: How long does it take for probiotics to start working and show health benefits?
The time frame varies depending on the individual, the probiotic strains used, and the health condition being addressed. Some people may notice improvements within a day, while others might take weeks or months. Consistent daily use is important for achieving and maintaining benefits.
Q: Can gut health affect sleep and mental health?
There is more and more evidence supporting the effects of certain probiotics on sleep, mood and mental health. The gut microbiota produces various proteins and hormones essential for mood regulation and sleep. For instance, about 90% of the body’s serotonin (the feel-good hormone that also helps regulate our wake/sleep cycle), is produced in the gut! There was even a 30-day French study that evaluated a combination of Bifidobacterium longum R0175 and Lactobacillus helveticus R0052 (3 billion organisms total — sold in the U.S. and Canada by Jamieson) taken with breakfast for 30 days. They found significant improvements in depression, anger, anxiety, as well as lower levels of the stress hormone cortisol in healthy individuals taking the probiotic compared to those taking placebo — although some improvement also occurred in the placebo group.
This is another area that requires more research!
Q: What is the role of prebiotics and probiotics in weight management and metabolic health?
They may aid weight management by influencing gut bacteria associated with metabolism, fat storage, and appetite regulation. Certain probiotic strains have been linked to reduced body weight and fat mass. Prebiotics can promote satiety by stimulating the production of appetite-suppressing hormones. However, results vary, and more research is needed. One of the many reasons we recommend the whole-food diet that we do is that it is a high prebiotic diet as well. Again, when you eat lots of prebiotics, it feeds (mostly) the good bacteria and allows them to flourish.
Q: Can individuals with lactose intolerance or dairy allergies take probiotic supplements or consume probiotic-rich foods?
Yes, but they should take lactose-free or dairy-free probiotics. Additionally, there are non-dairy fermented foods like sauerkraut, kimchi, kombucha, coconut kefir and water kefir which provide probiotics without lactose.
Q: What is the shelf life of probiotic supplements, and how should they be stored to maintain their potency?
Shelf life varies but is typically indicated by an expiration date on the packaging. Some probiotics require refrigeration; others are shelf-stable. This will be indicated on the label somewhere. In general, keep all live probiotics away from heat, moisture and light (keep the container tightly closed).
Again, even if your probiotic bottle accidentally gets too hot, there is likely benefit in taking them anyway, as mentioned above.