Probiotics have received a lot of attention recently.
These living organisms have been credited with providing all
kinds of health benefits related to gut function and beyond
If you’re looking to use them to boost your own health, it’s
important to make sure you take the right probiotic supplements
to get the results you’re after.
This article takes a detailed look at the effects of probiotics
and provides recommendations for supplements that address
specific health issues.
What Are Probiotics?
Your gut contains bacteria acquired at birth and onward in a
process called colonization.
Many of these bacteria are considered beneficial or “friendly.”
Their functions include converting fiber into short-chain fatty
acids, synthesizing certain vitamins and supporting your immune
may help boost the numbers of these healthy bacteria.
The formal definition of probiotics is, “live microorganisms
which when administered in adequate amounts confer a health
beneﬁt on the host” (1).
Basically, probiotics are microorganisms that
provide beneficial effects when you consume them in the
Probiotics can be consumed in supplement form or in
fermented foods like sauerkraut, kefir and yogurt.
Summary: Probiotics are health-promoting
bacteria found in supplement form and some foods. Taking
probiotics can help increase the number of beneficial
bacteria that reside in your gut.
Certain Probiotics May Have Specific Benefits
Your gut microbiome, or gut flora, consists of a wide variety
Its exact composition is unique to you.
Your colon contains billions of bacteria with types from over
500 different species (4).
Probiotics that have been found to provide health benefits
include various strains of Bifidobacterium,
Lactobacillus and Saccharomyces. Many
probiotic supplements contain a combination of different
strains in the same supplement.
Research has shown that some strains seem to be more effective
than others for treating certain conditions.
Therefore, you’re more likely to get good results by taking
probiotics that have been shown to achieve specific effects,
such as controlling diarrhea.
In addition, it’s important to consume probiotics in sufficient
Probiotics are typically measured in colony-forming units
(CFU). Generally, higher doses have been found to produce the
best results in most studies (5).
However, some probiotics may be effective at dosages of 1–2
billion CFU per day, while others may require at least 20
billion CFU to achieve the desired effects.
Taking extremely high doses hasn’t been found to cause harm.
One study gave participants up to 1.8 trillion CFU per day.
However, it’s expensive and doesn’t appear to provide any
additional benefits (5).
Importantly, scientists still don’t know everything about
probiotics. Although research has rapidly expanded within the
past several years, there is much left to explore.
Summary: Different types of probiotic
bacteria may provide health benefits. Taking a sufficient
amount of the right probiotic is important for achieving the
Probiotics That May Help Relieve Constipation
Constipation is characterized by bowel movements that are
hard, difficult to pass and infrequent. Everyone experiences
constipation once in a while, but in some people it becomes a
Chronic constipation is most common among the elderly and
adults who are bedridden, although it can also occur in
In addition, some people with irritable bowel syndrome (IBS)
experience persistent constipation as their main symptom. This
is known as constipation-predominant IBS.
Conventional treatments include laxatives and stool softeners.
However, in recent years, dietary changes and probiotic
supplements have become increasingly popular alternative
In a study comparing probiotics and prebiotics in children with
IBS, B. lactis was shown to provide significant
Recommended Probiotics for Constipation
Summary: Several probiotic strains have been
shown to provide relief from constipation in children and
adults when taken alone or together.
Probiotics That Are Effective Against Diarrhea
Diarrhea is defined as loose-to-liquid bowel movements that
occur more frequently than normal.
It is typically short-lived, but can become chronic in some
Probiotics have been found to reduce stool frequency in the
infection-related diarrhea that occurs with food poisoning and
gastroenteritis, commonly known as “stomach flu” (13).
A large review of 34 studies found that probiotics reduced the
risk of diarrhea from various causes by 34%.
Effective strains included Lactobacillus rhamnosus GG,
Lactobacillus acidophilus and Lactobacillus
Antibiotic use is another common cause of diarrhea. When
antibiotic therapy kills harmful bacteria that cause infection,
beneficial bacteria are destroyed as well. The shift in
bacterial balance can lead to inflammation
A large review of 82 controlled studies found that taking
probiotic supplements reduced the risk of developing
antibiotic-associated diarrhea by 42%. However, the most
effective probiotic strains weren’t discussed (16).
Although some people with IBS struggle with constipation,
others experience frequent episodes of diarrhea, which is known
as diarrhea-predominant IBS.
Research suggests that certain probiotics seem to be especially
effective for diarrhea-predominant IBS, including B.
coagulans, S. boulardii and a combination of
several Lactobacillus and Bifidobacterium
strains (17, 18, 19, 20).
However, one study did not find any significant improvement in
diarrhea among IBS patients who were treated with S.
Recommended Probiotics for Diarrhea
Summary: Probiotic therapy has been shown
help reduce the severity and frequency of diarrhea related to
infection, antibiotic use and IBS, among other causes.
Probiotics That May Improve IBS Symptoms
Sometimes the main symptoms of IBS aren’t related to stool
consistency or frequency. Instead, some people experience
bloating, gas, nausea and lower abdominal pain on a regular
A review of 19 studies found that while some people reported
improvement in IBS symptoms while taking probiotics, results
varied between individuals. Researchers couldn’t determine
which probiotics were most effective (22).
In addition, because the symptoms of IBS are so diverse,
sometimes one symptom improves while others do not.
For instance, one study of people with constipation-predominant
IBS found that although S. cerevisiae improved
constipation, it didn’t have much of an effect on abdominal
pain or discomfort (11).
In another study, participants with diarrhea-predominant IBS
were given a supplement known as VSL#3, which contains
Lactobacillus, Bifidobacterium and
Bowel movement frequency and consistency didn’t improve, but
bloating did (23).
Another study found significant reductions in pain and bloating
during treatment with VSL#3. Researchers believe the probiotics
led to an increase in melatonin, a hormone involved in
digestive function (24, 25).
Recommended Probiotics for IBS
Summary: Certain probiotics have been shown
to help relieve bloating, abdominal pain and other symptoms
of irritable bowel syndrome. However, taking probiotic
supplements may not improve all symptoms.
Probiotics That Might Help You Lose Weight
Some studies suggest that taking probiotic supplements may be
helpful for achieving weight loss and a healthier body
Animal and human studies have found that certain bacterial
strains may decrease the amount of fat and calories your gut
absorbs, promote a healthy balance of gut bacteria and reduce
weight and belly fat (27, 28, 29, 30, 31, 32).
According to a 2014 analysis of several studies, probiotics
that seem to be effective for fat loss include
Lactobacillus gasseri, Lactobacillus
rhamnosus and the combination of Lactobacillus
rhamnosus and Bifidobacterium lactis (33).
In one study, obese men who took L. gasseri for 12
weeks experienced significant reductions in body weight and
body fat, including up to an 8.5% decrease in belly fat. By
contrast, the placebo group had very little change in body
weight or body fat (31).
In another study, obese women who took L. rhamnosus
for three weeks lost twice as much weight as those who received
What’s more, they continued losing weight during the
maintenance phase of the study, whereas the placebo group
gained weight (32).
Taking probiotic supplements may also help limit weight gain
during times of high calorie intake.
In a four-week study, lean young men ate 1,000 excess calories
per day. Those who took the probiotic formulation VSL#3 gained
less weight than the control group (34).
However, because results from some studies haven’t been
impressive, researchers feel there isn’t enough evidence at
this time to draw firm conclusions about the benefits of
probiotics for weight loss (35).
Recommended Probiotics for Weight Loss
Summary: Results from several studies
suggest that certain probiotics may promote fat loss in obese
subjects. However, further research is needed.
Probiotics to Support Brain Health
There is a strong connection between gut and brain health.
A review of 38 studies on animals and humans found that various
probiotics helped improve symptoms of anxiety, depression,
autism, obsessive-compulsive disorder and poor memory (37).
The strains most commonly used in these studies were
Bifidobacterium longum, Bifidobacterium
breve, Bifidobacterium infantis,
Lactobacillus helveticus and Lactobacillus
One study found that when throat cancer patients took
probiotics for two weeks prior to surgery, they had lower
levels of stress hormones in their blood and their anxiety
decreased by 48% (40).
In an eight-week study of patients with major depression, those
who took L. acidophilus, L. casei and B.
bifidum had a significant decrease in depression.
What’s more, they experienced reductions in insulin levels and
inflammatory markers (45).
Recommended Probiotics for Brain Health
Summary: Brain and gut health are strongly
connected. Taking certain probiotics may promote better
mental health by reducing anxiety, sadness, depression and
Probiotics That May Improve Heart Health
Taking probiotics may help reduce the risk of heart disease.
Several studies have found that certain bacteria in yogurt or
probiotic supplements may lead to favorable changes in heart
Specific bacterial strains that seem to be effective at
lowering cholesterol levels include Lactobacillus
acidophilus, Bifidobacterium longum and
An analysis of 14 studies found that probiotics led to an
average reduction in LDL cholesterol, a slight increase in HDL
and a decrease in triglycerides (50).
There are probably several processes responsible for these
effects on LDL cholesterol, including changes in fat metabolism
and decreased absorption of cholesterol in the gut (51).
Probiotics may also help lower blood pressure.
One review of nine controlled studies found a modest reduction
in blood pressure among those who took probiotics. However,
only treatment longer than eight weeks at doses higher than 10
billion CFU per day had significant effects (52).
Recommended Probiotics for Heart Health
Summary: Taking certain probiotic
supplements may help lower LDL cholesterol, raise HDL
cholesterol and decrease blood pressure.
Probiotics to Boost Immunity
Studies suggest that taking probiotic supplements may shift the
balance of gut bacteria in a way that increases your body’s
defenses against allergies, infections and cancer (53).
Of particular note are the strains Lactobacillus GG,
Lactobacillus crispatus, Lactobacillus
gasseri, Bifidobacterium bifidum and
In addition, probiotics have been shown to reduce inflammation,
a known risk factor for many diseases.
In one study, older adults consumed a blend of
Lactobacillus gasseri, Bifidobacterium
bifidum and Bifidobacterium longum or a placebo
for three weeks each.
After taking probiotic supplements, their inflammatory markers
decreased, anti-inflammatory markers increased and gut bacteria
balances became more like the type seen in young, healthy
Certain probiotics may also help prevent gingivitis, or gum
A 14-day study looked at adults who refrained from brushing and
flossing while being treated with Lactobacillus brevis
or a placebo.
Gingivitis progressed more rapidly in the placebo group,
suggesting the probiotics helped protect against infection
Recommended Probiotics for Immune Health
Summary: Taking probiotics may help
strengthen your immune system and help reduce the risk of
infection and illness.
Probiotics for General Health
In addition to targeting specific diseases and conditions, you
can also take probiotics to promote overall health.
A recent study in healthy adults showed that taking
Bifidobacterium bifidum for four weeks helped boost
production of beneficial short-chain fatty acids (59).
Of course, it’s important to make sure you’re consuming a
healthy diet and practicing other health-promoting behaviors as
well. Otherwise, you can’t expect probiotics to provide much
In addition, although probiotics are safe for most people, they
may cause harm in people who are extremely ill or have
compromised immune systems, including those with HIV or AIDS
Recommended Probiotics for General Health
Summary: Probiotics may help support
wellness in healthy people. However, taking probiotic
supplements may be dangerous for people who are very ill or
have compromised immune systems.
The Bottom Line
Having a healthy gut microbiome is extremely important.
Although research is still emerging, probiotics appear to
provide beneficial effects for a number of different conditions
and may also support better general health.
Taking the right type of probiotics may help you target
specific health issues and improve your overall health and
quality of life.