Do Probiotics Help Reduce Inflammation?

Check out this answer from Consensus:

The evidence suggests that probiotics can help reduce inflammation across various health conditions, including rheumatoid arthritis, mental health disorders, and metabolic diseases. However, the effectiveness of probiotics may vary depending on the specific strains used, the dosage, and the health condition being treated. Further research is needed to fully understand the mechanisms by which probiotics modulate inflammation and to identify the most effective probiotic formulations for different inflammatory conditions.

Inflammation is a critical component of the body’s immune response, but chronic inflammation can lead to various health issues, including autoimmune diseases, mental health disorders, and metabolic conditions. Probiotics, which are live microorganisms that confer health benefits to the host, have been studied for their potential to modulate inflammation. This article explores the evidence supporting the role of probiotics in reducing inflammation across different health conditions.

Probiotics and Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation. Several studies have investigated the impact of probiotics on inflammatory biomarkers in RA patients. A randomized, double-blind, placebo-controlled study demonstrated that a mixture of probiotics significantly reduced white blood cell count, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) plasma levels in RA patients1. Another study found that Lactobacillus casei supplementation decreased disease activity and levels of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-12, while increasing the anti-inflammatory cytokine IL-109.

Probiotics and Mental Health

Emerging evidence suggests a link between gut microbiota and mental health, particularly in conditions like major depressive disorder (MDD). A narrative review highlighted that probiotics might reduce systemic inflammation, which is often elevated in MDD patients2. A meta-analysis of randomized controlled trials (RCTs) found that probiotic supplementation significantly reduced C-reactive protein (CRP) and IL-10 levels, indicating an anti-inflammatory effect3.

Probiotics and General Inflammation

A comprehensive meta-analysis of 42 RCTs involving 2,258 participants revealed that probiotic supplementation significantly reduced serum levels of several pro-inflammatory cytokines, including high-sensitivity CRP (hs-CRP), TNF-α, IL-6, and IL-124. Another systematic review and meta-analysis confirmed these findings, showing that probiotics effectively reduced CRP and TNF-α in various health conditions, including metabolic disorders and inflammatory bowel disease (IBD)7.

Probiotics and HIV

The potential of probiotics to manage inflammation in people living with HIV (PLHIV) has also been explored. Although some studies reported improvements in certain inflammatory parameters, the overall evidence remains inconsistent, and no significant improvements in CD4 counts or other markers of inflammation were observed in randomized controlled trials5.

Probiotics and Maternal Health

Probiotic supplementation during pregnancy has been shown to influence inflammatory markers and improve health outcomes for both mothers and infants. Studies have indicated that probiotics can modulate the immune system and reduce inflammation, potentially lowering the risk of conditions like gestational diabetes and infant allergies6.

Probiotics and Elderly Population

In elderly individuals with chronic low-grade inflammation, a combination of probiotics and omega-3 supplements was investigated. While no significant difference in hs-CRP levels was observed, the supplementation did increase levels of the anti-inflammatory marker IL-10, suggesting a modest anti-inflammatory effect10.

Do probiotics help reduce inflammation?

Hannah Wardill has answered Uncertain

An expert from University of Adelaide in Gastroenterology, Microbiome

Evidence certainly supports the microbiota being a key modulator of innate immune activation, and therefore ‘inflammation’. In fact, the Functional Human Genomics Project identified the microbiota as the largest predictor of baseline circulating cytokine levels and stimulated responses in a large cohort of people. Naturally, we can assume that the beneficial microbes in the gut (sometimes considered “probiotics”) are driving this response (as described in the other answer). We know that some bacterial products target TLR2, which exerts anti-inflammatory responses. Similarly, the production of short chain fatty acids from gut microbes has been linked with reduced inflammation.

BUT, if the question is truly about whether taking commercially available probiotics influences inflammation … the evidence is much less clear. Certainly, in heathy people there is no strong evidence to support probiotic use. There is some evidence to support probiotics across various inflammatory diseases, e.g. IBS/IBD, radiation-induced gut toxicity, necrotising enterocolitis. But, the promising evidence gained in animal studies has not translated so well to humans, with many conflicting results in the literature.

I think this reflects 1) low microbial yield in commercial probiotic formulations, and 2) lack of diversity in probiotic formulations (usually one 1 or a few strains)… ie. these formulations aren’t typically enough to induce any detectable change in physiology.

Do probiotics help reduce inflammation?

Tom MacDonald has answered Unlikely

An expert from Queen Mary University of London in Immunology, Gastroenterology

There is a literature on this but it is pretty awful. The mouse models of intestinal inflammation where probiotics have been used ( DSS or TNBS) colitis are truly awful and the human data are either negative or barely positive. There was a study years ago that VSL3 was effective in patients with pouchitis, but there is a bit of a smell about it now.

There is literature showing that probiotics are pro-inflammatory in vitro ( as one would expect because they are bacteria and express PRR ligands) and in a paper in 2009 in PNAS where volunteers were given a probiotic and then a duodenal biopsy taken, the gene signature in the tissue was pro-inflammatory. Now folk say that it depends on the individual probiotic and it is true that different bacteria and even strains of the same bacteria differ in their ability to elicit pro- and anti-inflammatory cytokines but what this has to do with anything escapes me. They also increase NK and neutrophil function in man ( data I believe and which are reproducible) probably because they cause inflammatory cytokine production in the upper bowel which activates these cells in blood.

In one sense though they may be anti-inflammatory in that children taking probiotics are a little bit protected against small bowel virus infections and diarrhea is shorter in these taking the probiotics.