Do Probiotics Work? Evidence-Based Benefits & Precautions
If you suffer from digestive issues or other inflammation-related problems, you’ve probably heard that probiotics can help. We frequently hear from readers and home cooks wondering if their family could benefit from adding things like kombucha, sauerkraut, and sourdough bread into their routine for the probiotics.
Is investing in more fermented foods or probiotic supplements worth it for you? And do probiotics work? Here’s what the scientific evidence has to say about how and what these helpful bacteria can do.
If you suffer from digestive issues or other inflammation-related problems, you’ve probably heard that probiotics can help. We frequently hear from readers and home cooks wondering if their family could benefit from adding things like kombucha, sauerkraut, and sourdough bread into their routine for the probiotics.
Is investing in more fermented foods or probiotic supplements worth it for you? And do probiotics work? Here’s what the scientific evidence has to say about how and what these helpful bacteria can do.
What Are Probiotics?
Probiotics are the good bacteria that live in your gastrointestinal tract. They are part of the various bacteria, viruses, and other organisms that make up your gut microbiome. These living microorganisms are present in some foods and supplements, and they thrive inside the human microbiome.
Here are a few definitions of terms used to describe probiotics and their counterparts:
Commensal bacteria, also called nonpathogenic, or non-disease-causing bacteria, aren’t harmful and, most of the time, support a healthy body. Probiotics are commensal bacteria! This is what I mean each time I refer to “beneficial bacteria” or “good bacteria.”
Pathogenic bacteria, also known as disease-causing bacteria, are strains that challenge the body’s immune system and, if successful, cause illness and disease. That’s what I mean when I refer to “bad bacteria” or “harmful bacteria.”
Prebiotics aren’t bacteria at all, but rather are the food source for probiotics to feast on. These fibers are found in many plant-based foods.
A quick note: There are pathogenic bacteria in every healthy body. The presence of harmful bacteria doesn’t mean you are ill; the key is that a healthy microbiome has a balanced amount of commensal and pathogenic bacteria, which lets the good stuff crowd out the bad.
How Probiotics Work
In your intestinal tract, probiotics produce vitamins and short-chain fatty acids that feed and nurture commensal bacteria that aid digestion. These microbes also help counteract and outnumber any harmful bacteria.
What Probiotics Work For, According To Science
There are tons of health benefits from a thriving probiotic community living in your digestive tract. Probiotics help break down the foods you eat, ease digestion, lower your risk of infection, support your immune system, reduce chronic inflammation, and more.
Here are some of the most notable health benefits of probiotics, according to research.
1. Gut Health
Without a healthy gut microbiome full of probiotics, rapidly-reproducing pathogenic bacteria can wreak havoc on your digestive system. Probiotics help balance and eliminate pathogenic and foreign bacteria in the stomach, intestines, and colon of kids and adults.
Probiotics are healthy gut bacteria used for treatment and prevention of several digestive system problems, including:
Constipation
Diarrhea (especially antibiotic-associated diarrhea and traveler’s diarrhea)
Bloating
Irritable bowel syndrome (IBS)
Crohn’s disease
Ulcerative colitis
Helicobacter pylori infections
2. Increase Nutrient Absorption
Probiotics may improve how well your body absorbs micronutrients (such as calcium and iron) from ingested foods by breaking down anti-nutrients that occur naturally in some foods.
For example, one placebo-controlled study showed that the iron status in young children was improved significantly by intake of a milk fortified with the probiotic Bifidobacterium lactis for one year.
This may be especially beneficial for malnourished individuals, including children, the elderly, and pregnant people.
3. Immunity
Probiotics boost the strength of immune cells and help maintain the strength of the intestinal epithelium (gut lining). This helps prevent serious and minor health conditions (from colds and flus to viruses and some cancers) by strengthening your intestine’s protective barrier against pathogenic microbes and detrimental substances.
Skin Health
Some research shows that probiotics, applied topically and ingested through the gut-skin axis, may help prevent and treat certain skin issues like:
Acne
Eczema
Psoriasis
Atopic dermatitis (an allergic reaction on the skin)
Vaginal Infections & UTIs
Lactobacilli, a type of probiotic, are the predominant microorganisms of the healthy human vagina. Taking probiotics and eating probiotic foods have been found to be beneficial in the prevention and treatment of vaginal infections, including female urogenital tract infections (UGTI) and urinary tract infections (UTIs).
Oral Health
Did you know that your gut microbiome isn’t the only kind you have? Your mouth, skin, and vagina (if you’ve got one) have microbiomes, too.
Research shows that probiotics are beneficial for good oral maintenance in healthy people, due to their ability to decrease the growth of oral pathogens and contribute to a healthy oral microbiome.
Oral probiotics are most effective when delivered directly to the mouth through probiotic lozenges, chewable tablets, or probiotic drinks. The strains most helpful for your mouth are a little different than the ones you might take for your gut.
7. Weight Loss
While taking a probiotic doesn’t necessarily contribute to weight loss, it is recommended that people on a weight loss protocol take a probiotic in order to maintain health. Drastic alterations in energy balance, lipid metabolism, and endocrine disturbances put stress on the body, and maintaining a healthy gut microbiome can help prevent sickness during this time.
In one clinical trial, obese patients who followed a low-carb, high-protein eating plan while taking a synbiotic (a prebiotic and probiotic together) showed no difference in body mass, BMI, waist circumstance, and body fat mass versus those taking a placebo at the end of 3 months. However, those taking the synbiotic displayed more beneficial microbial species and fewer disease biomarkers at the end of the study.
8. Chronic Inflammation
Probiotics play a role in maintaining the delicate balance between the body’s necessary defense mechanisms (acute inflammation) and overextended inflammatory responses (also known as chronic inflammation).
By interacting with intestinal epithelial cells and contributing to overall good health, probiotics can help the body’s defense cells tame and target their inflammation response.
9. Brain And Mental Health
Studies show that probiotics and a healthy microbiome may contribute to brain health through the gut-brain axis. Probiotic supplementation could improve cognitive function and mood and they may play a role in delaying disorders of the central nervous system, such as dementia and Alzheimer’s.
Which Probiotics Are Most Beneficial?
The most commonly identified and used probiotic species and strains are:
Lactobacillus — present in many probiotic supplements, fermented foods, and breast milk
Lactobacillus acidophilus — common in enriched milk, yogurt, miso, and tempeh
Bifidobacterium — used mostly in probiotic supplements
Escherichia
Escherichia coli Nissle 1917 (ECN) — one of the first probiotics identified
Saccharomyces
Saccharomyces boulardii — a probiotic yeast strain with the potential advantage of being resistant to antibiotics
Streptococcus
Enterococcus
Bacillus
How To Get More Probiotics In Your Diet
There are two ways to get more probiotics: by eating more probiotic foods and by taking a probiotic supplement (or both).
Probiotic foods are fermented foods including:
Yogurt
Kefir
Buttermilk
Cultured cottage cheese
Pickled fermented vegetables
Sauerkraut
Kimchi
Pickles
Sourdough bread (although the baked bread contains no live cultures)
Preserved lemons
Kombucha
Miso
Tempeh
Natto
There’s a wide variety of probiotic supplements available, as well as prebiotic and synbiotic options. In general, the best options are those with clinically studied probiotic strains, as well as enzymes that help the probiotics survive digestion.
One of the few dietary supplements we have used and recommend is Seed Probiotic, a synbiotic supplement that contains 24 strains of probiotics and prebiotics together.
Risks, Side Effects, And Precautions
Some people should avoid or limit their intake of probiotic supplements and fermented foods due to potential side effects and risks. Those include:
people with a histamine intolerance — people who lack an enzyme called diamine oxidase (DAO)
someone with a weakened or compromised immune system — such as someone with HIV/AIDS, cancer patients undergoing chemotherapy, and organ transplant recipients
people with digestive disorders — someone with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) should consult a registered dietitian or their health care provider. In many cases, taking a probiotic or eating or even increasing fermented foods is a positive strategy for someone with digestive health disorders, though some people with extremely sensitive digestive systems may experience excess gas and bloating
Premature infants — while taking a pediatric probiotic is often recommended for babies and toddlers, premature infants should not be given a probiotic supplement until cleared by their pediatrician due to their weaker immune systems
Frequently Asked Questions
Is it better to get probiotics from food or supplements?
Getting gut exposure to multiple strains and forms of probiotics can help ward off a variety of health problems. Probiotic-containing foods are believe to be most efficient at delivering probiotics to the gut microbiome and surviving digestion. However, if you don’t commonly eat probiotic foods, taking a multi-strain probiotic supplement is the next best option. While we always promote ‘food first’ sometimes a supplement is the best way to get adequate amounts of a micronutrient as is the case with creatine when taken to support muscle growth and maintenance.
What happens if you take a probiotic every day?
Most probiotic supplements are intended to be taken every day, and some even multiple times each day. Taking a probiotic supplement on a regular basis is the most effective way to reap its benefits and discover if the probiotics strains are improving and regulating your digestion.
How do you know if probiotics are working?
Most probiotic supplements, when taken regularly, begin working within 2 weeks. You’ll know the probiotic is working if your symptoms improve. For example, if you’re taking a probiotic to relieve chronic constipation, then constipation symptoms should improve within 2 weeks.
It can also be beneficial to take a probiotic as a preventative measure, too. By maintaining a healthy gut microbiome, you can ward off future sickness and reduce chronic inflammation that tends to increase with age.
Do probiotic supplements need to be refrigerated?
Not all probiotic supplements need to be refrigerated. They are available in both refrigerated and shelf-stable formats and certain probiotic strains are sensitive to heat while others can withstand more variable temperatures. Read supplement labels to learn if the manufacturer recommends refrigeration.
Most probiotic-containing fermented foods, such as yogurt, kefir, fermented pickles, and fresh sauerkraut are sold refrigerated and should remain chilled in order for the probiotics to live.
What is the difference between probiotics and prebiotics?
The difference between probiotics and prebiotics is that probiotics are live microorganisms, whereas prebiotics are not living organisms (they just provide food for probiotics). Prebiotics and probiotics are both components of your gut microbiome and they work together: The more prebiotic foods you eat, the more probiotics are able to thrive inside your gut microbiota.
