Probiotics are healthy bacteria that live in your digestive tract and help digest food, regulate your immune system, and even help synthesize neurotransmitters.
It should be no surprise that they play a huge role in digestive health and beyond, with research connecting gut bacteria health to everything from obesity to chronic digestive conditions like Crohn’s disease.
Taking a probiotic supplement is a powerful way to boost the population of healthy gut bacteria in your body. But not all probiotic supplements are equally effective: the best supplements deliver specific bacterial strains that have specific benefits.
Read on for more on how to pick the right probiotic supplement for your needs.
1. Probiotics can help you lose weight, bump up immune function, improve your digestion, and even cut your risk of chronic diseases
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 (1, 2).
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.
2. Probiotic bacteria can be found in fermented foods or in supplements
Probiotics can be taken in supplement form, and may also be ingested by eating probiotic 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 fibers that actually feed friendly gut bacteria. (4)
3. Probiotic bacteria work to maintain the integrity of gut wall
The gut wall is vital in preventing substances in the colon from leaking into other parts of the body and stimulating an immune response. (5, 6, 7)
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. (8, 9, 10)
4. Probiotic bacteria can counter the negative side effects of antibiotics
This is the area where the most research has been done on probiotics, especially in regard to diarrhea associated with taking antibiotics. (11)
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 (12, 13), as well as being effective in reducing bloating, gas, constipation, and other intestinal problems, including symptoms associated with irritable bowel syndrome (IBS). (14, 15)
5. Probiotics can assist in treating ulcerative colitis, Crohn’s disease, and helicobactor pylori infections
These infections are caused by the bacteria that leads to ulcers and raises the risk of stomach cancer (16,17).
Anyone who has digestive issues that have been difficult to resolve might consider taking a probiotic supplement.
6. Probiotic bacteria could help you lose weight
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 (18).
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 (19).
Human studies indicate that having the right gut flora can help with weight control (20, 21).
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 (22).
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 (23).
7. The health benefits from better gut bacteria could reduce your risk for heart disease
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.
The use of probiotics has been associated with improvements in a range of other health conditions, including dropping blood pressure for patients with hypertension, reducing inflammation (24), enhancing immune system function (25), lowering cholesterol and LDL cholesterol, improving skin conditions such as rosacea, acne and eczema (26) and reducing symptoms in patients suffering from depression and anxiety (treated with these strains: bifidobacterium longum and lactobacillus helveticus) .
Probiotics side effects
Probiotics might have mild, transient gastrointestinal side effects. 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 (27). Improved digestion usually follows these initial symptoms.
People with compromised immune systems should not take probiotics. 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 (28).
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.
Probiotic bacteria have been researched intensively in the last few years, and we now have much more detailed information on the appropriate dosage for a probiotic supplement (though there’s still plenty of work to be done on the scientific front).
Target five billion CFUs or more. For starters, virtually no clinical studies have demonstrated efficacy with probiotic doses of less than one billion CFUs, and most use at least five billion CFUs per day. Beyond this, the picture gets a little murky because the appropriate dose seems to depend on the exact health condition that is being treated.
For instance, one study on using probiotics to improve immune function in older adults found that five billion CFUs per day was equally effective compared to a dosage of 50 billion CFUs per day (29).
On the other hand, a review article highlighted a strong dose-response relationship in using probiotics to treat diarrhea that occurs after taking antibiotics (30). In these cases, doses of over 100 billion CFUs per day were decisively more effective than lower doses.
Some digestive conditions might call for higher doses. The takeaway from this research is that a baseline dosage of five billion CFUs per day is a good place to start, but for some conditions—particularly those linked to the digestive tract—much higher doses, in the range of 50-100 CFUs per day, might be a good idea.
Probiotics benefits FAQ
Q: Can a probiotic supplement work as a thermogenic for weight loss?
A: The relationship between gut bacteria and weight loss is complex, but clearly connected: obese people have substantially different gut bacteria profiles compared to healthy people, even after controlling for things like dietary intake.
On the other hand, the agricultural industry has long used specific bacterial strains to induce weight gain in cattle and other stock animals.
The weight loss or weight gain effects of a probiotic depends on the specific strain being used; some research suggests that certain strains of probiotics will consume some of the calories that you eat, which would (in theory) prevent weight gain.
However, if you are overweight or obese, certain probiotics do have other benefits, such as potentially being able to reduce your risk for type 2 diabetes, even independent of any weight loss that may occur.
Q: What do probiotics do?
A: Once inside your digestive tract, the bacterial spores in the colony forming units start multiplying. Of course, they don’t multiply forever, because they have to coexist in an ecosystem of other bacteria in your stomach and intestines which have access to a limited amount of food.
However, they do have a lasting effect on the composition of your gut bacteria. These changes can be especially helpful to jump-start the benefits of a healthy diet: scientific research suggests that, while your diet is by far the largest determinant of your gut biome, short-term dietary changes have little effect on gut bacteria composition (31).
To boost the beneficial changes in gut bacteria composition, a probiotic supplement could be just the trick.
Q: How long does it take for probiotics to work?
A: Clinical research suggests that you need at least eight to nine weeks, and perhaps up to 12 weeks, for probiotics to have a statistically detectable effect.
That being said, you may start to feel the benefits of probiotics much sooner, since these clinical studies have to detect the effect among large populations with a lot of inter-individual variability.
Still, probiotics do take time to have an effect—don’t expect amazing results overnight. At least eight weeks is necessary to assess whether your probiotic supplement is having a measurable effect on your gut bacteria.
Related: Our best probiotics picks
Probiotic supplements deliver live, healthy bacteria to your digestive tract, where they can shift the distribution of healthy bacteria to help with digestive problems, chronic gastrointestinal conditions, lingering side effects from antibiotics, and even weight loss.
Probiotics possibly the most exciting area of supplements today, with new research coming out all the time on their benefits. For optimal results, aim for a probiotic supplement that delivers five billion CFUs or more, and ideally with multiple different strains of proven probiotic bacterial strains.