Lachnospiraceae represent a family of bacteria within the human gut microbiome. These microorganisms are commonly present and play a role in maintaining the gastrointestinal tract’s complex ecosystem. Their involvement in human health continues to be an active area of scientific investigation.
Understanding Lachnospiraceae
Lachnospiraceae constitute a diverse family of bacteria classified within the phylum Firmicutes. They are obligately anaerobic, thriving in oxygen-free environments characteristic of the human gastrointestinal tract, particularly the colon. These bacteria are among the most abundant taxa in a healthy human gut, accounting for an estimated 10% to 45% of the total bacteria found in the feces of healthy adults.
This family includes numerous genera such as Lachnospira, Blautia, and Roseburia, frequently observed in the human gut. Lachnospiraceae colonize the intestinal lumen from birth, with their abundances generally increasing throughout an individual’s life. This long-term association highlights their role in human health.
Key Functions in the Gut
A primary role of Lachnospiraceae in the gut involves the fermentation of complex carbohydrates, such as dietary fibers and resistant starches, that human enzymes cannot digest. This fermentation yields short-chain fatty acids (SCFAs), with butyrate being an important product. Butyrate serves as the preferred energy source for colonocytes, the cells lining the colon, and supports the integrity of the gut barrier.
Beyond butyrate, Lachnospiraceae also produce other SCFAs, including acetate and propionate. Acetate can reduce fat accumulation and improve glucose tolerance, while propionate may help regulate cholesterol and reduce visceral and liver fat. Some Lachnospiraceae species can also produce butyrate from alternative nutritional sources like lysine, glutarate, and 4-aminobutyrate.
Influence on Health and Disease
A balanced population of Lachnospiraceae, through their production of SCFAs like butyrate, contributes to overall gut health by supporting the intestinal barrier and modulating the immune system. Butyrate strengthens the mucus layer and increases tight junction proteins, which maintain gut barrier integrity. This can help prevent the entry of harmful substances into the bloodstream, reducing systemic inflammation.
Conversely, an imbalance or dysbiosis involving Lachnospiraceae has been linked to various health conditions. Reduced levels of certain Lachnospiraceae genera, such as Roseburia and Blautia, have been associated with inflammatory bowel disease (IBD) and metabolic disorders. Studies indicate a correlation between high abundances of Lachnospiraceae within Firmicutes and disturbances in glucose and lipid metabolism, seen in conditions like obesity and type 2 diabetes. Research also suggests that an altered gut microbiota, including shifts in Lachnospiraceae, may play a role in some neurological disorders. The precise mechanisms and direct causal relationships are still subjects of ongoing research.
Modulating Lachnospiraceae Through Lifestyle
Supporting a healthy population of Lachnospiraceae in the gut can be achieved primarily through dietary interventions. Consuming a diet rich in dietary fiber from fruits, vegetables, whole grains, and legumes provides the necessary substrates for these bacteria to ferment. Specific prebiotics, such as fructo-oligosaccharides (FOS) and inulin, found in foods like onions, garlic, and chicory root, can selectively stimulate the growth and activity of beneficial gut bacteria, including some Lachnospiraceae species.
Resistant starches, found in foods like unripe bananas, cooked and cooled potatoes, and certain legumes, also serve as fermentable substrates that can increase butyrate-producing Lachnospiraceae. Incorporating fermented foods, such as sauerkraut, kefir, or kimchi, may also introduce beneficial microbes and provide substrates that support a diverse gut microbiome. Beyond diet, lifestyle factors such as regular physical exercise can promote the growth of butyrate-producing groups like Lachnospiraceae, and managing stress may indirectly influence gut microbiota composition.