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? Nestled inside your gut are trillions of live microorganisms that make up the microbiome.
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.
Probiotics are a type of organism that can help boost the amount of beneficial bacteria in your gut. They are found in supplements, foods (such as tempeh, natto and miso) and probiotic drinks, such as kombucha.
What Are Probiotics?
Probiotics are live bacteria that line your digestive tract and support your body’s ability to absorb nutrients and fight infection. Your body contains about the same number of gut bacteria molecules as it does cells for the rest of your body, so it’s no wonder your gut is so important to your health.
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.
Your skin and digestive system alone host about 2,000 different types of bacteria. Probiotics benefits have been proven effective in supporting immune function, reducing inflammation, promoting healthy digestion, 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
- Creating enzymes that destroy harmful bacteria
- Stimulating secretion of IgA and regulatory T cells, which support immune function
Probiotics are in our systems from the moments we 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.
1. Digestive Health
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 effective against several forms of diarrhea, including antibiotic-associated diarrhea, acute diarrhea, traveler’s diarrhea, infectious diarrhea and other associated diarrhea symptoms. They also help with constipation relief.
Probiotics have also 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.
2. 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 supplements and foods may increase the effectiveness of antibiotics and help prevent the bacteria in your body from becoming resistant.
3. May Improve 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 “pscyhobiotics” (probiotics that impact brain function) in handling the development of these conditions. This anti-inflammatory quality is what seems to interest researchers most.
While no studies have been conducted in humans, early research suggests that, in animals, probiotic supplements may help alleviate symptoms of anxiety by reducing inflammation along this gut-brain connection.
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 currently underway to determine if probiotic supplements 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. Immunity Boost and Decrease in Inflammation
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.
Currently, 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.
5. Healthy Skin
Many avenues of research have examined probiotics benefits for skin, especially in children. Meta-analyses have found that probiotic supplements are 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 seem also 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. 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. The … 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. Lowering 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. Diabetes Treatment
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 that: “Modulation of the gut microbiota represents a new treatment for NAFLD.”
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.
Typically, there are two main species of probiotics, including Bifidobacteria and Lactobacillus. In addition to being the most widely available in both probiotic foods and supplements, these two 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 sporogens
- 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:
- Brand quality — Look for reputable, established dietary supplement brands with readily available customer reviews.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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).
So 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 able to reach your digestive tract quickly without getting stuck in the stomach behind your morning meal.
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’re consuming 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.
And, as always, all new supplement regimens should be conducted under the supervision of a medical professional.
Probiotic side effects can sometimes include 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, most studies have found that probiotics are associated with very few probiotics side effects and a large number of benefits.
- 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 diseases.
- 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.
- 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 probiotic supplement in order to take advantage of probiotics benefits.
- Probiotic side effects are rare, but always use caution when starting any new supplements.
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