Butyrate, also known as butyric acid, is a short-chain fatty acid (SCFA) that plays a significant role in human health. It is one of three primary SCFAs, alongside acetate and propionate. Butyrate is primarily produced within the large intestine, contributing to various bodily functions and overall well-being, particularly gut health.
The Gut’s Butyrate Factory
Butyrate is naturally generated in the human body through a specialized process involving gut microbiota. Beneficial bacteria residing in the large intestine are responsible for this production. These microorganisms ferment indigestible dietary fibers that pass through the digestive system without being broken down in the upper tract.
This fermentation, carried out by anaerobic bacteria in the colon, creates butyrate. Common butyrate-producing bacteria include species from the genera Clostridium, Eubacterium, and Faecalibacterium. The term “pro butyrate” refers to the body’s natural ability to generate this compound, influenced by dietary inputs that support these beneficial gut bacteria.
The availability of fermentable fibers acts as a fuel source for these gut bacteria. Specific prebiotics, such as resistant starch, particularly encourage butyrate production.
Butyrate’s Diverse Functions
Butyrate performs diverse functions within the body, impacting both gut health and broader systemic processes. It serves as the primary energy source for colonocytes, the cells lining the colon. Butyrate can meet approximately 60-70% of these cells’ energy requirements, supporting the gut barrier’s integrity and health. This function helps prevent “leaky gut syndrome,” a condition where toxins and bacteria might pass into the bloodstream.
Beyond providing energy, butyrate exhibits anti-inflammatory effects. It inhibits the activation of nuclear factor kappa B (NF-κB), a protein complex involved in inflammatory responses, and promotes anti-inflammatory cytokines like IL-10. This action reduces inflammation within the gut and throughout the body. Butyrate also strengthens the gut barrier by upregulating tight junction proteins such as claudin-1, zonula occludens-1 (ZO-1), and occludin, which form seals between epithelial cells to control molecular movement.
Butyrate also plays a role in modulating the immune system. It supports a balanced immune response by influencing the function of regulatory T cells (T-regs), which are immune cells that help suppress overactive immune responses and maintain immune tolerance. This molecule can also impact cellular energy metabolism by influencing mitochondria, promoting energy restoration and resilience.
Emerging research suggests systemic roles for butyrate beyond the gut. It may aid in regulating blood sugar levels and insulin sensitivity by activating pathways that increase energy expenditure and reduce fat accumulation. Butyrate has also been linked to influencing appetite by stimulating specific G-protein-coupled receptors on gut cells.
Dietary Strategies to Enhance Butyrate
Increasing butyrate levels in the body primarily involves dietary strategies that support the gut microbiota responsible for its production. The most effective approach is to consume foods rich in fermentable dietary fiber. This includes various types of fiber that gut bacteria can break down, such as resistant starch and soluble fiber.
Resistant starch, which passes undigested into the large intestine, is a particularly effective precursor for butyrate. Foods high in resistant starch include:
Raw potatoes
Cooked and then cooled potatoes and rice
Green bananas
Legumes (like beans, lentils, and chickpeas)
Cashews
Raw oats
The cooling process after cooking certain starches, like potatoes and rice, transforms some digestible starches into resistant starches.
Soluble fiber also contributes to butyrate production. Excellent sources include fruits, vegetables, and whole grains. Specific examples are:
Broccoli
Brussels sprouts
Avocados
Flax seeds
Black beans
A diverse intake of plant-based foods promotes a more diverse gut microbiome, which supports greater butyrate production.
While some foods like butter contain butyrate, the most impactful way to increase its levels is by providing the gut bacteria with the fibers they need to produce it naturally. A general recommendation for fiber intake is approximately 25 to 35 grams per day for adults. Focusing on a variety of high-fiber foods ensures a broad spectrum of prebiotics that can nourish diverse butyrate-producing bacteria.