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 intestine, 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 an 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 colonize your gut with health-promoting microorganisms.

This article examines 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 produced by bacterial fermentation.

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

Dozens of different probiotic bacteria offer health benefits.

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

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

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

While 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 the gut flora or microbiota (6)

In fact, your gut contains hundreds of different types of microorganisms - it's been estimated up to 1,000.

This includes bacteria, yeast and viruses, with bacteria making up the vast majority.

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

Surprisingly, the metabolic activities of your gut flora are similar to those of an organ. For this reason, some scientists refer to the intestinal flora as "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 gut 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 an 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 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 may help cure antibiotic-associated diarrhea (23, 24, 25).

When people take antibiotics, especially over a long period of time, diarrhea is common - even long after the infection has 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 fight 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).

Furthermore, probiotics can fight Helicobacter pylori infection, which is a major cause of ulcers and gastric cancer (30, 31, 32 , 33).

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

Overweight people have different gut bacteria than lean 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 excess 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 regained the belly fat within four weeks.

There is also evidence that Lactobacillus rhamnosus and Bifidobacterium lactis can contribute to weight loss and the prevention of obesity. (41).

Conversely, some animal studies show that other probiotic strains can lead to weight gain and not weight loss (42).