Probiotics are live bacteria in the digestive system. Some foods and supplements also contain probiotics. Probiotics may play a role in relieving some symptoms of diseases, including rheumatoid arthritis (RA).

The human digestive system maintains a balance of bacteria, known as the gut microbiota, which work to digest food and maintain health throughout the body.

Probiotics are living bacteria found in food, supplements, and topical products. They are often the same as bacteria naturally found in the human body.

RA is an inflammatory, autoimmune disease that causes the body’s immune system to induce joint swelling. It may be chronic or flare and recede.

Probiotics may regulate gut microbiota, which may help influence the body’s immune response, reducing the swelling and pain caused by RA.

In this article, we examine whether probiotics could benefit people with RA. We also look at the role of probiotics and probiotic foods and supplements.

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Probiotics are living organisms that exist in the human digestive system and some foods and supplements.

The most common are types that belong to the Lactobacillus and Bifidobacterium bacteria groups. People also use the yeast Saccharomyces boulardii as a probiotic.

People with RA often have more gastrointestinal inflammation than most people, which can cause bacteria to leak into the bloodstream.

Although scientists need to conduct more research, initial studies indicate that probiotics may decrease digestive permeability or gut leakage and affect the immune system.

The after-effects of probiotics may include:

  • balancing helpful and harmful bacteria in the gut and the body
  • reducing the number of harmful bacteria that could cause illness
  • replenishing the beneficial bacteria lost during illness or through the use of antibiotics

People with RA usually have intestinal inflammation, leading to gut permeability.

Gut permeability can cause the leakage of harmful bacteria from the digestive system into the rest of the body. Probiotics may help reduce the inflammation RA causes and restore balance to the digestive microbiota.

Research suggests that compared to a placebo, treatment with probiotics Bacillus coagulans or Lactobacillus casei (L. casei) may lead to improvements on:

  • self-assessed pain marker scales
  • disability scales
  • swollen joint counts
  • lab results

One small, older study over 12 weeks involved a total of 29 participants. A group of 15 of them had L. rhamnosus GR-1 and L. reuteri RC-14 and another group of 14 had a placebo.

Results showed significant improvement on a health assessment questionnaire in the probiotic group but no clinical improvement in RA.

Different types of probiotics have specific effects on the body. One type of probiotic in the Lactobacillus group will not necessarily have the same effect on an illness as another probiotic in the same group.

Probiotics have names that refer to their genus, species, and strain.

For example, Bifidobacterium lactis BB12 is from the genus Bifidobacterium, the species lactis, and the strain is BB12. The abbreviations for Bifidobacterium and Lactobacillus are usually B. and L.

If a person is interested in trying probiotic supplements, they should look for the number of colony-forming units (CFU). That number should be at least 1 billion or 1 x 109.

Individuals with a weakened immune system or an implanted port should speak with a healthcare professional before adding probiotics to their routine.

It is important to note that probiotics are not the same as prebiotics. Probiotics are beneficial bacteria in certain foods and supplements, while prebiotics are high fiber foods that feed the friendly bacteria in the digestive system.

There are also synbiotics on the market. These are combinations of prebiotics and probiotics.

Several fermented foods are sources of probiotics. Some require preparation, while others are available for easy consumption. Probiotic food sources include:

  • yogurt
  • miso, a fermented soybean-based paste
  • tempeh, a plant-based protein source made from fermented soybeans
  • kefir, a fermented milk
  • pickled vegetables
  • sauerkraut, a fermented cabbage
  • kimchi, fermented vegetables
  • buttermilk

For the first few days of taking probiotics, people may experience some abdominal discomfort as the digestive system regulates, such as:

  • stomach upset
  • diarrhea
  • gas
  • bloating

The following people should receive guidance from a healthcare professional before adding probiotics to their diet:

  • those with weakened immune systems
  • children
  • people undergoing chemotherapy
  • older individuals

Probiotics may interact with certain medications and increase the risk of infections for some people.

For people with RA, probiotics may help regulate the digestive microbiome and reduce inflammation in the digestive tract. They may also affect the immune response, which abnormally attacks the body during an RA flare.

Research is ongoing on whether probiotics significantly help RA, and doctors do not know how much of certain foods or the dosage of probiotic supplements may alleviate RA symptoms.

Probiotic use has grown in popularity as research has discovered the importance of regulating the digestive microbiome for overall health.

For people with RA, it is common to have digestive system inflammation, causing leakage of bacteria into the bloodstream and inflammatory response throughout the body. Research suggests that probiotics may reduce inflammation and prevent this process.

Probiotics may also impact the immune system, which attacks healthy cells in an autoimmune condition such as RA.

People should not confuse probiotics with prebiotics or synbiotics, which have different mechanisms of action.