The bacteria in your body are said to outnumber your body’s cells at a 10-to-1 ratio. However, a recent study says that the ratio is closer to 1-to-1.
According to these estimates, you have 39–300 trillion bacteria living inside you. Whichever estimate is most accurate, it’s certainly a large number.
Much of these bacteria reside in your gut, and the majority are quite harmless. Some are helpful, and a small number can cause disease.
Having the right gut bacteria has been linked to numerous health benefits, including the following:
- weight loss
- improved digestion
- enhanced immune function
- healthier skin
- reduced risk of some diseases
Probiotics, which are a certain type of friendly bacteria, provide health benefits when eaten.
They’re often taken as supplements that are supposed to help colonize your gut with good microorganisms.
What are probiotics?
Probiotics are living microorganisms that, when ingested, provide a health benefit .
However, the scientific community often disagrees on what the benefits are, as well as which strains of bacteria are responsible.
Probiotics are usually bacteria, but certain types of yeasts can also function as probiotics. There are also other microorganisms in the gut that are being studied, including viruses, fungi, archaea, and helminths.
You can get probiotics from supplements, as well as from foods prepared by bacterial fermentation.
Probiotic foods include yogurt, kefir, sauerkraut, tempeh, and kimchi. Probiotics should not be confused with prebiotics, which are carbs — often dietary fibers — that help feed the friendly bacteria already in your gut.
Products that contain both prebiotics and probiotics are referred to as synbiotics. Synbiotic products usually combine friendly bacteria along with some food for the bacteria to eat (the prebiotics), all in one supplement.
The most common probiotic bacteria are Lactobacillus and Bifidobacteria. Other common kinds are Saccharomyces, Streptococcus, Enterococcus, Escherichia, and Bacillus.
Each genus comprises different species, and each species has many strains. On labels, you’ll see probiotics identified by their specific strain (which includes the genus), the species, subspecies if there is one, and a letter-number strain code.
Different probiotics have been found to address different health conditions. Therefore, choosing the right type — or types — of probiotics is essential.
Some supplements, known as broad-spectrum probiotics or multi-probiotics, combine different species in the same product.
Although the evidence is promising, more research is needed on the health benefits of probiotics. Some researchers warn about possible negative effects from the “dark side” of probiotics and call for caution and strict regulation.
Importance of microorganisms for your gut
The complex community of microorganisms in your gut is called the gut flora, gut microbiota, or gut microbiome.
The gut microbiota includes bacteria, viruses, fungi, archaea, and helminths — with bacteria comprising the vast majority. Your gut is home to a complex eco-system of 300–500 bacterial species.
Most of the gut flora is found in your colon, or large intestine, which is the last part of your digestive tract.
Surprisingly, the metabolic activities of your gut flora resemble those of an organ. For this reason, some scientists refer to the gut flora as the “forgotten organ”.
Your gut flora performs many important health functions. It manufactures vitamins, including vitamin K and some of the B vitamins.
It also turns fibers into short-chain fats like butyrate, propionate, and acetate, which feed your gut wall and perform many metabolic functions.
These fats also stimulate your immune system and strengthen your gut wall. This can help prevent unwanted substances from entering your body and provoking an immune response.
Your gut flora is highly sensitive to your diet, and studies show that an unbalanced gut flora is linked to numerous diseases.
These diseases are thought to include obesity, type 2 diabetes, metabolic syndrome, heart disease, colorectal cancer, Alzheimer’s, and depression.
Probiotics and prebiotic fibers can help correct this balance, ensuring that your “forgotten organ” is functioning optimally.