Our joints grow stiff and painful as birthdays mount up —no surprise there.
But arthritis, while common, is not just one disease. Because it can be confusing, a brief primer may help, beginning with the type of arthritis that can strike at any age.
Rheumatoid arthritis (RA)
This equal opportunity version of arthritis is autoimmune in nature. It inflames joints and other musculoskeletal areas; disability and organ damage is not uncommon. Oftentimes, sufferers have gut problems including nausea, diarrhea, and constipation.
A growing body of evidence links the microbiome with the disease path of rheumatoid arthritis (RA). Studies show that both the gut and oral microbiomes may trigger rheumatoid arthritis by inciting local inflammatory responses in the host. In turn, inflammation results in a cascade of harmful cellular changes that stress and damage the microbial community.
Indeed, microbes are critical to the development and activation of the immune system, especially with regards to cell types intimately associated with autoimmunity such as Th17 T helper cells.
Osteoarthritis (OA) is the most common form of arthritis which affects millions of people worldwide. Age is a big driver.
Protective cartilage on bones in joints erodes, causing disability in joints, most commonly hands, knees, hips and spine. OA is not autoimmune in origin but is associated with a host of risk factors: age, gender (female), obesity, injuries, occupation, genetics, bone deformities and other diseases such as diabetes.
In one study, fecal analyses in patients diagnosed with OA showed elevated counts of species from the genera Enterococcus, Streptococcus, Staphylococcus, Eubacterium, Lactobacillus, Bifidobacterium and Clostridium.
And interestingly, Prevotella were seen in 5% of the patients tested. By sequencing 114 stool samples from rheumatoid arthritis patients and controls, researchers in 2013 identified the presence of Prevotella copri as strongly correlated with disease in new-onset untreated rheumatoid arthritis. Increases in Prevotella abundance correlated with a reduction in Bacteroides and a loss of reportedly beneficial microbes associated with an anti-inflammatory state.
Possible fix? Modulation of the microbiota may alter bacterial by-products that lead to synovial inflammation and arthritis.
According to a recent review of OA animal studies, a rat model suggests that probiotic Lactobacillus casei could relieve pain and inflammation as well as cartilage degradation. Further research may clarify if strain-specific probiotics are beneficial adjunct therapies in OA.
Probiotic supplementation and arthritis
Lactic acid-producing bacteria demonstrate immune and anti-inflammatory effects and the ability to lessen the symptoms of arthritis:
- Lactobacillus acidophilus protected organs in rats with experimental arthritis by regulating the pro-inflammatory cytokines in a 2013 study. Lactobacillus acidophilus managed organ damage associated with arthritis.
- In a 2014 study from Iran, supplementation with Lactobacillus casei improved symptoms and inflammatory cytokines in female patients with established RA for more than 1 year as compared to a group receiving placebo.
A study from China also looked at Lactobacillus casei Shirota (LcS) in osteoarthritis.
537 patients with knee OA were enrolled in this double-blind, placebo-controlled trial, and randomized to receive skimmed milk containing either LcS or placebo daily for 6 months.
- Both WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and VAS (visual analog scale) scores were significantly improved in the LcS groups of patients compared to the placebo group.
- Serum levels of high sensitivity C-reactive protein hs-CRP were also significantly lower in patients receiving LcS than placebo.
- Strong linear correlations were observed between serum hs-CRP levels and WOMAC and VAS scores.
But positive change is diverse even within the same species. Identification of functional probiotics with specific immune regulatory properties is key. And worth noting is that Western diets with fewer prebiotic and fermented foods may also act as drivers in the dysbiosis leading to the increases in inflammatory diseases.