The gut microbiome is a unique collection of trillions of microbes that heavily influences human health. Roseburia is a genus of beneficial bacteria that plays a vital role in butyrate production and downstream systemic health benefits within the intestines. This article will discuss how Roseburia spp., or the lack thereof, influences health and how functional medicine can help ensure normal levels within the microbiome to support health and longevity.  

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What Is Roseburia spp.?

Roseburia is a genus within the Firmicutes phylum. Roseburia spp. are Gram-positive, slightly curved, rod-shaped bacteria motile within the body by employing their flagella, which are thread-like appendages. Roseburia inhabits the human colon and provides various health benefits to the host when present at sufficient levels. (1)

In a healthy gut, Roseburia makes up between 3-15% of the total bacterial count (1). But unlike some of its commensal counterparts, studies have shown that Roseburia is not present in the gut microbiomes of newborns. Instead, Roseburia appears to colonize the gut after birth, likely through breast milk consumption. (2)

What Are the Main Roseburia spp?

This genus of bacteria includes five species: R. intestinalis, R. hominis, R. inulinivorans, R. faecis, and R. cecicola. The distinct Roseburia species act together as predominant producers of short-chain fatty acids (SCFAs) acetate, propionate, and butyrate. Roseburia is known to preferentially produce butyrate over the other SCFAs, and does so in part through the conversion of acetate. Butyrate has many known physiologic effects in the intestines, including being the preferred energy source for colonocytes and improving barrier function, maintaining colonic pH, modulating the immune system and reducing inflammation, and regulating gastrointestinal absorption. (1)

What Is Roseburia's Role in the Gut Microbiome?

Healthy levels of Roseburia spp. fill intestinal niches that pathogenic microorganisms could otherwise colonize to maintain healthy homeostasis within the intestinal microbiome and play a significant role in gut health. It is through their production of SCFAs that Roseburia spp. can influence colonic motility, support immunity, and suppress inflammation.

Aside from digestive function, a healthy gut plays an important role in immunological, metabolic, and neurological health. R. intestinalis and hominis strengthen gut barrier function and modulate anti-inflammatory immune responses (4). Butyrate produced by Roseburia increases energy expenditure, lipid metabolism, and glucose homeostasis. Roseburia also influences the gut-brain axis, the bidirectional connection between the gut and the intestines via immune cells, neural connections, and neurotransmitter synthesis. (1, 3)

What Are The Health Consequences of Unbalanced Roseburia in the Gut Microbiome?

Research has helped us understand critical differences between the microbial composition of those with certain health conditions and those without. When interpreting this research, it is important to remember that these dysbiotic patterns do not diagnose disease but correlate with increased risk of certain disease states. In other words, findings of unbalanced Roseburia spp. in the gut microbiome must be taken in context with a patient's complete health history, lifestyle, and presenting symptoms to determine health risk. That being said, low levels of Roseburia spp. have been associated with digestive, metabolic, and neurologic diseases.

Gut Health

Many studies have found a link between Roseburia and digestive conditions, including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and colon cancer. Reductions in Roseburia spp. and fecal butyrate have been measured in patients with IBD, both ulcerative colitis and Crohn's disease. Slowed intestinal motility and reductions in intestinal-derived melatonin resulting from dysbiotic Roseburia patterns may contribute to constipation and other symptoms of IBS. Even more, the severity of IBS symptoms is directly associated with the degree to which Roseburia levels are reduced. (1)

Cardiometabolic Disease

Reduced levels of Roseburia have been noted in overweight and type 2 diabetic patients compared to healthy controls. Increased inflammation, inefficient energy metabolism, and intestinal permeability associated with dysbiotic Roseburia patterns also increase the risk of nonalcoholic fatty liver disease, atherosclerosis, and chronic kidney disease. (1)

Neurological Disease

Because of its anti-inflammatory properties, Roseburia is assumed to play a protective role within the nervous system. In animal models, propionate and butyrate produced by R. hominis have been shown to reduce neuroinflammation. This seems consistent in humans, as a higher abundance of fecal Roseburia is associated with a lower incidence of Parkinson's disease (5).

What Causes Low Levels of Roseburia spp.?

Lower abundance of Roseburia spp. appears to be a part of the normal aging process, but other factors can contribute to Roseburia dysbiosis (6). Colonic alkalinity, measured by a higher intestinal pH, attributed to insufficient butyrate production, inhibits beneficial microorganisms' growth and allows harmful species to overgrow. Influenza infection and antibiotic use also result in reductions in Roseburia spp. (1)

Certain dietary patterns have also been correlated with reductions in Roseburia. A high intake of animal protein and compliance with a gluten-free diet, even in the short term, have been shown to reduce Roseburia levels in the gut microbiome. (7)

What Causes High Levels of Roseburia spp.?

In contrast to a higher pH reducing Roseburia levels, an acidic (lower pH) intestinal environment will foster Roseburia growth. Intestinal fermentation of dietary carbohydrates and butyrate production are beneficial to maintaining an acidic gut environment. This is likely why the Mediterranean diet is associated with higher levels of Roseburia spp. in the gut (7, 8).

How to Test Roseburia spp. Levels

Interested in the levels of Roseburia growing in your gut and how that may influence your health? Comprehensive stool tests using PCR technology can quantify the growth of Roseburia spp. within the intestinal microbiome. GI-MAP by Diagnostic Solutions and GI Effects by Genova Diagnostics are two popular stool testing options that also measure fecal SCFAs to indicate the functionality of Roseburia within the intestines. GI360 by Doctor's Data measures all the above information, with the addition of intestinal pH.

Foods That Help Increase Roseburia spp. Levels

As stated above, a Mediterranean diet is associated with increased Roseburia growth. This diet emphasizes primarily plant-based foods: whole fruits and vegetables, whole grains, legumes, nuts and seeds, olive oil, and fatty fish. The high fiber and resistant starch content of these foods fuels Roseburia and the other beneficial flora of the human microbiome. (7)

Supplements That Increase Roseburia spp. Levels

As of now, probiotic supplements containing Roseburia spp. are unavailable; however, this may change in the future as the current research shows that Roseburia spp. make for a safe and effective dietary probiotic supplement. In the meantime, consider taking an oral probiotic that contains Lactobacillus and Bifidobacterium probiotic species; research shows that these two probiotics encourage the growth of Roseburia within the intestines. (1, 8)

Prebiotics, selectively fermentable carbohydrates by the gut microbiota, fuel healthy bacteria and can be used alone or with probiotics to support the beneficial organisms of the microbiome. Inulin, fructooligosaccharides (FOS), and galactooligosaccharides (GOS) are well-established prebiotics.

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Summary

Five species of Roseburia bacteria are known to be a normal and healthy part of the intestinal microbiome. Reductions in the growth of this bacteria are associated with reduced butyrate production and downstream effects related to increased inflammation, slowed metabolism, and poor immune function. Diseases of the digestive tract, metabolic health, and nervous system correlate with a lack of Roseburia colonies within the gut microbiome.

Comprehensive stool tests are available to qualify and quantify the health of the gut microbiome. Dietary modifications that emphasize high-fiber and prebiotic foods and dietary supplements can support the healthy growth of Roseburia to combat and prevent inflammation and systemic disease.

The gut microbiome is a unique collection of trillions of microbes that heavily influences human health. Roseburia is a genus of beneficial bacteria that plays a vital role in butyrate production and downstream systemic health benefits within the intestines. This article will discuss how Roseburia spp., or the lack thereof, influences health and how functional medicine can help ensure normal levels within the microbiome to support health and longevity.