The intestinal flora not only ensures that the nutrients that enter the body through food are absorbed, but also prevents pathogenic germs from settling in the intestines, produces important vitamins and stimulates the immune system . After all, around 80 percent of all immune cells in the body are located in the intestinal mucosa. So it's no wonder that intact intestinal flora is so important for our health.

Having the right gut bacteria is associated with numerous health benefits, including weight loss, improved digestion, improved immune function, healthier skin, and a reduced risk of many diseases ( 1 , 2 ).

Probiotics, which are a specific type of friendly bacteria , provide health benefits when eaten.

They are often taken as dietary supplements designed to populate your gut with health-promoting microorganisms.

This article explores the health benefits of probiotics.

Probiotics are live microorganisms that provide numerous health benefits when ingested ( 3 ).

They are usually bacteria, but certain types of yeast can also act as probiotics.

You can get probiotics from dietary supplements, as well as from foods made through bacterial fermentation.

Probiotic foods include yogurt, kefir, sauerkraut, tempeh and kimchi. Probiotics should not be confused with prebiotics. This is fiber that feeds the friendly bacteria already in your gut ( 4 ).

Dozens of different probiotic bacteria provide health benefits.

The most common groups are Lactobacillus and Bifidobacterium . Each group includes different species and each species has many phyla.

Interestingly, different probiotics treat different health conditions. Therefore, choosing the right type(s) of probiotics is crucial.

Some supplements - known as broad-spectrum probiotics or multi-probiotics - combine different types in one product.

Although the evidence is promising, more research is needed on the health benefits of probiotics ( 5 ).

The complex community of microorganisms in your gut is called gut flora or microbiota ( 6 ).

In fact, your gut contains hundreds of different types of microorganisms - up to 1,000 by some estimates.

These include bacteria, yeast and viruses, with bacteria making up the vast majority.

Most of your intestinal flora is found in your large intestine, the last part of your digestive tract.

Surprisingly, the metabolic activities of your intestinal flora are similar to those of an organ. For this reason, some scientists refer to the intestinal flora as a “forgotten organ” ( 7 ).

Your intestinal flora fulfills many functions that are important for health. It makes vitamins, including vitamin K and some of the B vitamins ( 8 ).

It also converts fiber into short-chain fats like butyrate, propionate, and acetate, which feed your intestinal wall and perform many metabolic functions ( 9 , 10 ).

These fats also stimulate your immune system and strengthen your intestinal wall. This can prevent unwanted substances from entering your body and triggering an immune response ( 11 , 12 , 13 , 14 ).

However, not all organisms in your gut are friendly.

Your gut flora is very sensitive to your diet, and studies show that imbalanced gut flora is linked to numerous diseases ( 15 , 16 ).

These diseases include obesity, type 2 diabetes, metabolic syndrome, heart disease, colon cancer, Alzheimer's disease, and depression ( 17 , 18 , 19 , 20 ).

Probiotics—and prebiotic fibers—can improve this balance and ensure that your “forgotten organ” functions optimally ( 21 ).

Probiotics are widely studied for their effects on digestive health ( 22 ).

Strong evidence suggests that probiotic supplements can help cure antibiotic-associated diarrhea ( 23 , 24 , 25 ).

When people take antibiotics, especially over a long period of time, they often experience diarrhea - even long after the infection has been cleared.

This is because the antibiotics kill many of the natural bacteria in your gut , shifting the gut balance and allowing harmful bacteria to thrive.

Probiotics also combat irritable bowel syndrome (IBS), a common digestive disorder, reducing the occurrence of bloating , constipation, diarrhea, and other symptoms ( 26 , 27 , 28 ).

Some studies have also found benefits against inflammatory bowel diseases such as Crohn's disease and ulcerative colitis ( 29 ).

In addition, probiotics can fight Helicobacter pylori infections, which are a leading cause of ulcers and stomach cancer ( 30 , 31 , 32 , 33 ).

If you are currently experiencing digestive issues that you can't seem to overcome, a probiotic supplement may be worth considering.

Overweight people have different gut bacteria than slim people ( 34 ).

Interestingly, animal studies show that fecal transplants from lean animals can cause obese animals to lose weight ( 35 , 36 ).

Therefore, many scientists believe that your gut bacteria are important in determining body weight ( 37 , 38 ).

Although more research is needed, some probiotic strains appear to support weight loss ( 39 ).

In a study of 210 people with central obesity, which is characterized by excessive abdominal fat, taking the probiotic Lactobacillus gasseri daily for 12 weeks resulted in an 8.5% loss of abdominal fat ( 40 ).

When the probiotic therapists stopped, they gained the belly fat back within four weeks.

There is also evidence that Lactobacillus rhamnosus and Bifidobacterium lactis may help reduce weight and prevent obesity. ( 41 ).

Conversely, some animal studies show that other probiotic strains may cause weight gain rather than weight loss ( 42 ).

There are many other benefits of probiotics. They influence:

• Inflammation: Probiotics alleviate systemic inflammation, which plays a major role in many diseases ( 43 ).
• Depression and anxiety: The probiotic strains Lactobacillus helveticus and Bifidobacterium longum have been shown to relieve symptoms of anxiety and depression in patients with clinical depression ( 44 , 45 ).
• Blood cholesterol: Several probiotics have been shown to lower total cholesterol levels and “bad” LDL cholesterol levels ( 46 , 47 ).
• Blood pressure: Probiotics can also lead to a slight reduction in blood pressure ( 48 , 49 ).
• Immune function: Several probiotic strains can improve immune function, potentially leading to a reduced risk of infections, including colds ( 50 , 51 ).
• Skin Health: There is some evidence that probiotics may be useful for acne, rosacea, eczema, and other skin conditions ( 52 ).

This is only a small part of the overall benefits of probiotics, as ongoing studies indicate a wide range of health effects.

Probiotics are generally well tolerated and considered safe for most people.

However, in the first few days, side effects related to digestion may occur, such as: B. Gas and mild abdominal discomfort ( 53 ).

After you adjust, your digestion should improve.

In people with weakened immune systems, including those with HIV, AIDS, and several other diseases, probiotics can lead to dangerous infections ( 54 ).

If you have a medical condition, consult your doctor before taking a probiotic supplement .

Maintaining a healthy gut is about more than taking a probiotic supplement.

Daily diet and exercise are also important, as many lifestyle factors affect your gut bacteria.

However, probiotic supplements offer a range of benefits with few side effects. So if you want to improve your gut health, they are definitely worth a try.