How does an imbalanced gut impact rheumatoid arthritis?

• A recent review of studies on gut dysbiosis (imbalanced gut) and rheumatoid arthritis examined how the gut microbiome impacts the disease.
• The studies show that too little or too much of certain organisms in the gut can increase inflammation, a characteristic of rheumatoid arthritis.
• While an imbalanced gut may contribute to rheumatoid arthritis, there are some steps people can take towards balancing their gut that may alleviate symptoms.

Rheumatoid arthritis is an autoimmune disorder that can cause joint pain and bone deformities. It is a progressive disease, and while there is no cure for it, researchers are looking more into treatments and preventative options.

Many researchers are interested in how the gut microbiome can affect autoimmune disorders, including rheumatoid arthritis.

Since the presence of certain bacteria in the gut can cause inflammation, researchers want to learn more about the role they play in this condition.

A review that appears in the journal Nutrients took a closer look at some recent rheumatoid arthritis studies that examine the link.

Around 1.3 million people in the United States have rheumatoid arthritis, which can affect multiple body systems. In addition to affecting joints throughout the body, rheumatoid arthritis can also impact the eyes, lungs, and heart.

• pain in the joints
• fatigue
• inflammation in the gums
• sensitivity to light
• stiffness in the morning.

While experts are not sure exactly what causes rheumatoid arthritis, genetics and environmental factors may play a role in developing the disease. Additionally, some scientists believe the gut may factor into developing rheumatoid arthritis or worsening symptoms.

According to a 2015 review, experts define the gut microbiome as “all the bacteria, viruses, fungi, archaea, and eukaryotes that inhabit the human body.“

There are trillions of microbes in the gut, and they affect many bodily processes, including metabolizing food, protecting the body against infection, and harvesting energy.

The gut microbiome has both good and bad bacteria, and too much or too little of certain bacteria can negatively impact the body and even disrupt the regulation of the immune system — a phenomenon termed “dysbiosis.”

According to a 2020 review, “the presence of certain bacteria is associated with inflammatory molecules that may bring about inflammation in various body tissues.”

With this in mind, researchers want to learn more about how bacteria that cause inflammation may contribute to a disease like rheumatoid arthritis. The authors of the current review included multiple studies, including a large meta-analysis, to provide a closer look at the diet, gut microbiome, and rheumatoid arthritis.

Prevotella copri is a gut bacterium associated with rheumatoid arthritis — multiple studies in the review connected P. copri to the pathogenesis of the disease.

These bacteria increase in the gut in early-stage rheumatoid arthritis patients, so detecting an abundance of these bacteria early on could point to developing the disease.

Elevated P. copri contributes to rheumatoid arthritis by causing immune system dysfunction and can lead to joint damage. The review shows that diets high in fiber that are also high in carbohydrates and simple sugars can lead to increased levels of P. copri.

One study said that the Collinsella bacterium is a crucial bacterium to look out for in terms of possibly developing rheumatoid arthritis. Many early-stage rheumatoid arthritis patients had high levels of Collinsella, which can contribute to systemic inflammation.

While too much of some bacteria can worsen rheumatoid arthritis symptoms or increase the risk of developing this condition, an abundance of other bacteria, such as Lactobacillus casei, can have benefits.

According to the review, L. casei leads to “lower C-reactive protein (CRP) levels and the number of tender and swollen joints and induces anti-inflammatory responses.”

The foods and drinks a person consumes influence the gut microbiome, inflammation, and the body’s immune response. As a result, a person’s diet can have an “indirect” impact on rheumatoid arthritis progression.

According to the review, fiber is a key component in adjusting the gut microbiome and possibly improving health outcomes for people with rheumatoid arthritis.

Gut bacteria convert fiber into short-chain fatty acids (SCFAs), which can improve the functioning of the intestinal barrier, thus lowering inflammation.

Also, when fiber turns into SCFAs, it can help regulate the body’s immune response.

The review also shows that a low-fiber diet is associated with a 25% increased prevalence of rheumatoid arthritis and that high-fiber diets improve symptoms.

The authors note that 98% of people in one rheumatoid arthritis study consumed fewer than 30 grams (g) of fiber daily. The current dietary recommendations in the U.S. for fiber intake for adults is of 38 g of fiber per day for men, and 25 g of fiber per day for women.

According to the review, people who increased their fiber intake for 28 days using supplements such as fiber bars or cereals saw a reduction in their rheumatoid arthritis symptoms.

The review also indicates that people with rheumatoid arthritis symptoms can reduce the frequency and severity of those symptoms by eating less red meat, increasing their intake of vitamin E, and reducing consumption of saturated fats.

The Mediterranean diet can improve rheumatoid arthritis symptoms. This type of diet focuses on eating whole grains, healthy fats, fruits, fish, and vegetables.

The Mediterranean diet provides protective heart benefits and reduces joint pain. The diet also promotes beneficial bacteria in the gut that can reduce inflammation.

Raj Dasgupta, MD, an ABIM Quadruple board-certified physician specializing in internal medicine, pulmonology, critical care, and sleep medicine and Medical Reviewer for NCOA, spoke with Medical News Today about the review.

“There’s quite a bit of evidence suggesting that imbalances in the gut microbiome are linked to rheumatoid arthritis,” said Dasgupta, who was not involved in this review. “Studies show that people with rheumatoid arthritis often have less diversity in their gut bacteria, with certain harmful bacteria, like Prevotella copri, showing up more frequently.”

Dasgupta also cautioned that while such changes can contribute to chronic inflammation, more research is needed to confirm the relationship: “While the links are strong, it’s still a bit tricky to prove exactly how these microbiome changes cause [rheumatoid arthritis]. More studies are needed to figure out the exact relationships at play.”

He also addressed some steps people can take to help with gut problems and potentially reduce their risk of rheumatoid arthritis.

“Eating more fiber helps good bacteria grow, which can reduce inflammation,” he advised.

“Including omega-3 fatty acids from fish (like salmon), flaxseeds, and walnuts can also lower inflammation. Eating lots of fruits and vegetables provides antioxidants that fight inflammation, and probiotic foods like yogurt and sauerkraut can boost gut health.”

– Raj Dasgupta, MD

Roger Sen, MD, CCFP, a physician and co-founder and director of Eagles Landing Medical Centre in Ontario, also spoke with MNT about the review findings. Sen was also not involved in this review.

“While the research on gut dysbiosis and [rheumatoid arthritis] is promising, it’s important to note that this is a complex area with much still to learn,” he noted. “Individual responses to dietary interventions may vary, and it’s always recommended to consult with a healthcare professional before making significant changes to your diet or lifestyle.”

Sen also recommended that people attempting dietary interventions for gut dysbiosis should focus on a high-fiber diet, incorporate omega-3 fatty acids, take probiotic supplements, and focus on an anti-inflammatory diet.

“Limiting processed foods, red meat, and sugary drinks can help reduce inflammation,” Sen advised.