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Whether you’re looking to help your immune function, decrease disease risk or simply improve your overall health, probiotics can make a worthy addition to your daily routine.

Not only that, but some people — including billionaire philanthropist Bill Gates — even believe that probiotics could hold the key to ending malnutrition across the globe someday.

What are probiotics? Probiotics are a type of organism that can help boost the amount of beneficial bacteria in your gut. Nestled inside your gut are trillions of these live microorganisms that make up the microbiome.

They are also found in supplements, fermented foods (such as tempeh, natto and miso) and probiotic drinks, such as kombucha.

Different microbes living in your gastrointestinal tract play a role in either promoting health or disease. For example, many of these bacterial cells are considered “good bacteria” and help support immune function, enhance nutrient absorption, and aid in the synthesis of key neurotransmitters and other compounds.

What Are Probiotics?

Probiotics are defined as live bacteria that line your digestive tract that support your body’s ability to absorb nutrients and fight infection.

Did you know that your body contains about the same number of gut bacteria molecules as it does cells for the rest of your body? It’s no wonder then that your gut is so important to your health. Your skin and digestive system alone host about 2,000 different types of bacteria.

The National Center for Complementary and Integrative Health (NCCIH) calls probiotics “live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut.” The NCCIH makes the point that we often think of bacteria as harmful “germs” — however, probiotic bacteria actually helps the body function properly.

What happens when you start taking probiotics? Probiotics benefits have been proven effective in supporting immune function, reducing inflammation, promoting healthy digestion, managing inflammatory bowel disease, as well as maintaining beautiful skin, especially when combined with prebiotics.

Your “good gut bacteria” is also responsible for:

  • Producing vitamin B12, butyrate and vitamin K2
  • Crowding out bad microbes
  • Enhancing gut mucosal barrier function and preventing the invasion of pathogens in the intestinal epithelium
  • Helping regulate the central nervous system
  • Creating enzymes that destroy harmful microbes
  • Stimulating secretion of IgA and regulatory T cells, which support immune function

Probiotics are in your system from the moment you are born. When a newborn is in the birth canal of the mother during delivery, the baby is exposed to the live bacteria of his or her mother for the first time.

This event starts a chain of events inside the baby’s gastrointestinal tract, and the infant’s GI tract starts to produce good bacteria.

Historically, people had plenty of probiotics in their diets from eating fresh foods from good soil and by fermenting foods to keep them from spoiling.

Today, however, because of refrigeration and agricultural practices, like soaking our foods with chlorine, much of our food contains little to no probiotics in the name of sanitation. Actually, many foods contain dangerous antibiotics that kill off the good bacteria in our bodies.

Health Benefits

1. Improve Digestive Health

The first major benefit of probiotics is as a promoter of good digestive health. A 2019 review explains that probiotic consumption has been shown to improve the immune, gastrointestinal and reproductive health systems in healthy adults.

In fact, according to a meta-analysis of clinical trials:

Probiotics are generally beneficial in treatment and prevention of gastrointestinal diseases… When choosing to use probiotics in the treatment or prevention of gastrointestinal disease, the type of disease and probiotic species (strain) are the most important factors to take into consideration.

Eating foods rich in good bacteria and using probiotic supplements may help provide protection from inflammatory bowel diseases, including ulcerative colitis and Crohn’s disease. The evidence is stronger, however, for an improvement in ulcerative colitis, while Crohn’s disease may not benefit as greatly.

In addition, there is ongoing research studying the role of probiotics in gluten issues, including celiac disease.

Large bodies of evidence suggest that probiotics are also effective against several forms of diarrhea, including antibiotic-associated diarrheaacute diarrheatraveler’s diarrheainfectious diarrhea and other associated diarrhea symptoms. They also help with constipation relief.

Additionally, probiotics have been found in meta-analyses to reduce the pain and severity of irritable bowel syndrome (IBS) symptoms, aid in the eradication of H. pylori and treat pouchitis, a condition that occurs after the surgical removal of the large intestine and rectum. For the most benefits in managing IBS, studies suggest that it’s best to take multi-strain probiotics capsules over a period of at least eight weeks.

2. Help Decrease in Antibiotic Resistance

The World Health Organization considers antibiotic resistance “one of the biggest threats to global health, food security and development today.” Bacteria become resistant to antibiotics due to the overuse of prescription antibiotics, lack of diversity in these medications and improper use of antibiotics.

By using probiotics, it’s possible to help rebuild a poor variety of gut bacteria often seen after a course of taking antibiotics and prevent antibiotic-associated gut issues. In addition, probiotic from supplements and foods may increase the effectiveness of antibiotics and help prevent the bacteria in your body from becoming resistant.

3. May Fight Mental Illness

The “second” brain of the gut has been a major point of research since scientists have discovered the importance of the gut-brain connection. A review in 2015 highlighted the complex interactions between the gut and brain, stating:

[Various gut-brain] interactions seem to influence the pathogenesis of a number of disorders in which inflammation is implicated, such as mood disorder, autism-spectrum disorders, attention-deficit hypersensitivity disorder, multiple sclerosis, and obesity.

The authors discuss the need for “psychobiotics” (probiotics that impact brain function) in handling the development of these conditions. This anti-inflammatory quality is what seems to interest researchers most.

While limited clinical trials focusing on this topic have been conducted in humans, early research suggests that, in animals, supplementing with probiotics may help alleviate symptoms of anxiety by reducing inflammation along this gut-brain connection.

Several rodent studies have shown that consumption of probiotics can prevent increases in certain stress hormones, including ACTH, corticosterone and epinephrine, via the hypothalamic-pituitary-adrenal axis.

Probiotics benefits seem to include a reduction in depression symptoms, according to a 2016 meta-analysis — the first review of its kind. Taking probiotics might also help reduce re-hospitalizations from manic episodes for those with manic depression.

A slightly more surprising result, however, seems to be the way that probiotics may impact some of the symptoms of autism. Autism and gut health have been discussed for some time, as patients with the disorder typically suffer from a large number of digestive issues.

However, based on animal studies, it seems possible that altering the quality of gut bacteria might benefit not only the digestive system, but the abnormal behaviors in autism, too.

In 2016, a case study of a boy with severe autism was reported. While being treated with probiotics for digestive problems, the patient spontaneously improved on the ADOS scale, a diagnostic rating system for people with autism.

The score dropped from 20 down three points to a stable 17, and according to the report, ADOS scores do not “fluctuate spontaneously along time” and are “absolutely stable.”

Because of results like those above, human studies are underway to determine if probiotic treatments may improve not only the GI symptoms seen in autism, but also on “the core deficits of the disorder, on cognitive and language development, and on brain function and connectivity.”

4. Boost Immunity

Both probiotics and prebiotics are continuing topics of research regarding immunity. When used in conjunction, scientists refer to them collectively as synbiotics.

One 2015 review on the subject stated, “We suggest that LAB and Bifidobacteria and novel strains [of probiotics] might be an additional or supplementary therapy and may have potential for preventing wide scope of immunity-related diseases due anti-inflammatory effect.”

Because chronic inflammation is at the root of many diseases and health conditions, the fact that probiotics exert this effect in the gut, where 80 percent of the immune system lies, is crucial. The immune-boosting benefits of probiotics seem to be particularly helpful for the quality of life of seniors.

Research is underway to test whether probiotics can “reduce inflammation and improve gut immune health in HIV-positive individuals” who haven’t yet undergone treatment.

A 2021 review even found the poor prognosis in COVID-19 infections was seen in adults with underlying co-morbidities who had increased gut permeability and reduced gut microbiome diversity. According to the researchers’s findings, “Dietary microbes, including probiotics or selected prebiotics of Chinese origin, had anti-viral effects against other forms of coronavirus, and could positively impact host immune functions during SARS-CoV-2 infection.”

5. Support Healthy Skin

Many avenues of research have examined probiotics benefits for skin, especially in children. Meta-analyses have found that probiotics may be effective in the prevention of pediatric atopic dermatitis and infant eczema.

The integrity of gut bacteria is also connected to the development of acne, although the way this happens is still unclear.

The skin benefits of probiotics also seem to be connected to the reduction of inflammation seen in healthy gut bacteria. L. casei, a particular strain of probiotic, “can reduce antigen-specific skin inflammation.”

Indeed, research suggests that having a balanced gut environment has benefits for both healthy and diseased human skin.

6. Provide Food Allergy Protection

Did you know that infants with poor gut bacteria are more likely to develop allergies over the first two years of life? The reason probiotics can help reduce food allergy symptoms, in particular, is most likely due to their abilities to reduce chronic inflammation in the gut and regulate immune responses — in adults as well as children.

7. May Treat Serious Diseases in Infants

Two dangerous diseases in newborns, necrotizing enterocolitis (NEC) and neonatal sepsis, may meet their match with well-designed probiotic supplements. Both of these conditions are common in premature babies and are most dangerous in low birth weight and very low birth weight infants.

Research has confirmed that when a pregnant mother takes high-quality probiotics during pregnancy, her baby is significantly less likely to develop either NEC or sepsis, particularly when the baby is breastfed after birth (and mom is still taking the supplements) and/or when probiotics are added to formula. A probiotic supplement with multiple bacterial strains seems to be the most effective in these cases.

One review of probiotics benefits for necrotizing enterocolitis was bold enough to say:

The results confirm the significant benefits of probiotic supplements in reducing death and disease in preterm neonates… overall evidence indicate that additional placebo-controlled trials are unnecessary if a suitable probiotic product is available.

Regarding sepsis in developing countries (where it is overwhelmingly more common), a 2017 randomized, controlled trial says that a large number of these cases “could be effectively prevented” if mothers are given a synbiotic (probiotic and prebiotic together) that contains the probiotic strain L. plantarum.

8. Lower Blood Pressure

A large analysis reviewed available research and determined that probiotics help lower blood pressure by improving lipid profiles, reducing insulin resistance, regulating renin levels (a protein and enzyme secreted by the kidneys to lower blood pressure) and activating antioxidants.

Researchers consider them valuable prospects in the treatment of high blood pressure because their side effects are generally minimal or nonexistent.

These effects are most pronounced in people who already have hypertension and improve when the subject consumes multiple probiotic strains for at least eight weeks or more in supplements containing 100 billion or more colony-forming units (CFUs).

9. May Fight Diabetes

Several large-scale studies and two meta-analyses have confirmed that probiotics should be a major consideration in determining natural treatment for diabetes. In a massive study involving almost 200,000 subjects and a total of 15,156 cases of type 2 diabetes, researchers confirmed that a higher intake of probiotic-rich yogurt reduced the risk of developing diabetes.

According to a 2014 meta-analysis, probiotics benefit diabetics by improving insulin sensitivity and decreasing the autoimmune response found in diabetes. The authors suggest that the results were significant enough to conduct large, randomized, controlled trials (the “gold standard” of scientific studies) to find if probiotics may actually be used to prevent or manage diabetes symptoms.

Combining probiotics with prebiotics may also help manage blood sugar, particularly when blood sugar levels are already elevated.

10. May Improve Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) affects 80 million to 100 million people in the U.S. alone. Characterized by fatty buildup in the liver, NAFLD can eventually lead to cirrhosis, ending in liver failure or death for some patients.

A 2013 meta-analysis of studies on probiotics and NAFLD found that using probiotics can improve a number of important factors for patients with the disease, leading the study authors to state: “Modulation of the gut microbiota represents a new treatment for NAFLD.”

11. May Improve Vaginal Health

Probiotics for vaginal health? While there’s still more to learn about the impact that probiotics can have on vaginal health, some evidence indicates that supplementation can lower the risk for reoccurring vaginal infections and the irritating symptoms they cause.

One study demonstrated the potential of probiotic supplements improving vaginal health, such as for bacterial vaginosis (BV) and vaginal odor. Another study showed that supplementing with a probiotic for 30 days helped create healthy vaginal flora in up to 90 percent of patients.

Related: Oligosaccharides: The Prebiotics that Support the Heart & Gut


There are many different types of probiotics on the market, each of which varies based on numerous factors, such as stability, strain diversity and CFU count.

What are the top probiotics? Typically, there are two main species of probiotics, including Bifidobacteria and Lactobacillus. Saccharomyces is another type of strain that has a long history of safe and effective use as a probiotic.

In addition to being the most widely available in products and foods, these three species have also been extensively studied for their beneficial effects on immune function, digestive health, weight loss and more.

There are also many specific strains of probiotics, each of which has been shown to benefit specific health conditions. Some of the best probiotic strains include:

  • Bacillus coagulans
  • Bacillus subtilis
  • Bifidobacterium bifidum
  • Bacillus clausii
  • Lactobacillus plantarum
  • Lactobacillus fermentum
  • Lactobacillus reuteri
  • Lactobacillus acidophilus
  • Lactobacillus gasseri
  • Lactobacillus rhamnosus
  • Lactobacillus sporogenes
  • Saccharomyces boulardii

Some these strains are among the best probiotics for dogs as well.

How to Use

Note that the probiotics benefits of one probiotic strain may be completely different from the health benefits seen from another probiotic. If you want to use probiotics to address a specific health concern, it’s vital to select the right probiotic for the right condition — or you can consume a wide range of probiotics in your food to be covered.

When reading a probiotic label, it should reveal the genus, species and strain of the probiotic. The product (usually in capsules or probiotics pills) should also give you the colony forming units (CFUs) at the time of manufacturing.

Also, the majority of probiotics can die under heat, so knowing the company had proper storing and cooling of the facility is also important.

There are seven specific things you want to consider when buying a probiotic supplement:

  1. Brand quality — Look for reputable, established dietary supplement brands with readily available customer reviews.
  2. High CFU count — Probiotic dosage is measured in “colony forming units,” or CFUs. Ideally, you should aim for at least 5 billion–10 billion CFUs per day for children and 10 billion–20 billion CFUs each day for adults. However, the recommended dosage may vary based on individual health concerns, so discuss with your doctor for personalized guidance as needed.
  3. Survivability and strain diversity — Look for strains like Bacillus coagulans, Saccharomyces boulardii, Bacillus subtilis, Lactobacillus plantarum, Bacillus clausii, and other cultures or formulas that ensure probiotics make it to the gut and are able to colonize.
  4. Prebiotics and supplementary ingredients — For probiotic bacteria to grow, they also need prebiotics. High-quality probiotic supplements have both prebiotics and other ingredients designed to support digestion and immunity. Examples of these ingredients are (preferably fermented) flaxseed, chia seed, cañihua seed, astragalus, ashwagandha, hemp seed, pumpkin seed, milk thistle, peas, ginger, mung bean and turmeric.
  5. Stability and organism types — Some probiotic strains need to be kept cold in order to preserve their potency. This applies to their production, transport, storage and sales. Others are shelf-stable and don’t require refrigeration. Unfortunately, most refrigerated probiotics never make it past the stomach because they aren’t stable. Instead, look for a shelf-stable product that contains soil-based organisms.
  6. Sugar — Sugar is not a good food source for probiotics. Prebiotics are the food source meant to keep probiotics alive. A synbiotic is a dietary supplement that contains both prebiotics and probiotics. The best synbiotics contain healthy plant starches and fiber.
  7. Living vs. dead — “Live and active cultures” are a better bet than “made with active cultures.” After fermentation, the product may be heat-treated, which kills off both good and bad bacteria (extending shelf life).

Is it OK to take a probiotic every day?

Yes, most people can benefit from continually taking probiotics at a consistent time each day.

When is the best time to take a probiotic?

Most sources typically recommend taking your probiotic first thing in the morning, about 15–30 minutes before breakfast. This ensures that your probiotic supplement is better able to reach your digestive tract quickly without getting stuck in the stomach behind your morning meal.

Related: 7 Fulvic Acid Benefits & Uses: Improve Gut, Skin & Brain Health

Top Foods

In addition to probiotic supplements, you can also try adding more probiotic foods into your diet to help optimize your gut health. Fermented foods and foods with added probiotics are a great option to help get in your daily dose.

Some of the best probiotic foods include:

Keep in mind that these probiotic foods should be low in added sugar, preservatives and extra ingredients to really get the most bang for your buck. Even if you consume the best probiotic drink or best probiotic yogurt, it may not contain the same health benefits if it’s highly processed and pumped full of additives.

Need some inspiration to help get you going? Here are a few simple probiotic-rich recipes to start experimenting with:

Risks and Side Effects

All probiotics aren’t created equally. Not all strains have beneficial effects, and it’s important to do your research before starting a new supplement.

The U.S. Food and Drug Administration (FDA) regulates products with probiotics in different ways (as dietary supplements,  food ingredients or drugs), however not all products are guaranteed to be of high quality.

As always, if you have an existing medical condition, all new supplement regimens should be conducted under the supervision of a medical professional. This is especially important if you’re immunocompromised.

Probiotic side effects can sometimes include bloating, flatulence and diarrhea if you take too much too fast. You can start off with a smaller amount, like one tablespoon of kefir or one probiotic capsule a day, and work your way up if you’re just getting into eating probiotic foods or taking dietary supplements.

One very rare side effect of probiotics seen in cancer patients is sepsis. This is an extremely rare occurrence.

Overall, according to the FDA, studies have found that probiotics are associated with very few probiotics side effects and a large number of benefits.


  • Different microbes living in your gastrointestinal tract play a role in either promoting health or disease.
  • Because so much of your health begins in the complex microbiome of the gut, proper balance of your gut bacteria is crucial to overall health.
  • Natural probiotics are bacteria in your digestive tract that support the immune system and help reduce chronic inflammation, potentially impacting the development of a large number of conditions, such as inflammatory bowel disease, IBS and more.
  • You can incorporate probiotics into your routine by eating more sour and fermented foods, feeding your gut bacteria with insoluble fiber in high-fiber foods, and even by taking a high-quality supplement in order to take advantage of probiotics benefits.
  • What is the best probiotic to use? Look for capsules with a CFU count of at least 10 billion and a product that includes strains like Bacillus coagulans, Saccharomyces boulardii, Bacillus subtilis, Lactobacillus plantarum and Bacillus clausii.
  • Probiotic side effects are rare, but always follow directions and use caution when starting any new supplements.

~ Dr. X 


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