In the early 1800s Michel-Eugène Chevreul, a French organic chemist, first discovered butyric acid in its impure form while acidifying animal fat soaps. (Source)
Butyric acid, also known as butanoic acid, is a four-carbon short-chain fatty acid that is found in a number of foods and is also produced in our bodies. Its name comes from the ancient Greek word for butter.
Known as the “stinky fat,” butyric acid boasts an aromatic odor (to put it kindly) that has been described as both rancid butter and stale cheddar. It’s also responsible for the familiar lactic acid flavor that we often associate with fresh, homemade bread, butter, and yogurt.
Although butyric acid is naturally occurring in different types of dairy products, it's found in even greater amounts in the digestive tracts of humans and other mammals. The organic compound is produced when complex sugars are broken down during the process of fermentation. Its main function is to provide energy to cells of the colon, but it also supports the immune system with its powerful anti-inflammatory and antimicrobial properties.
In today's edition, we're exploring butyric acid, AKA the pungent, rancid odor that you might recognize from that time your butter went bad — and also a powerful healing nutrient in our bodies.
What Is Butyric Acid and Why Should I Care?
Butyric acid is an important short-chain fatty acid produced in the gut
Butyric acid, also known as butanoic acid, is a short-chain, saturated fatty acid (SCFA) that is found in plant oils and animal fats, especially products such as butter, ghee, and raw milk. It’s also produced when carbohydrates like fiber are fermented by bacteria in the colon.
Butyric acid is the preferred fuel of your enterocytes, the cells that line the intestines. In other words, it's what your gut cells prefer to burn for energy. Estimates suggest that the compound provides your colon cells with about 70% of their energy needs. (Source)
Note: Although the terms “butyric acid” and “butyrate” are commonly used interchangeably even in the literature, scientifically speaking, the two compounds have slightly different structures (butyrate has one less proton than butyric acid). However, research appears to show that they have identical health benefits.
Butyric acid is a powerful healing nutrient
Butyric acid can also help support your immune function and keep your gut barrier healthy. It's known to have anti-inflammatory and anti-carcinogenic properties and to play a role in gut barrier function, immune system regulation, and metabolic regulation. (Source) That's why the compound has gained attention for its potential role in treating inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and colorectal cancer. On the flip side, decreased butyrate concentrations and numbers of butyrate-producing bacteria have been linked with disorders, ranging from dysbiosis to strokes and even metabolic conditions. (Source, Source, Source, Source)
It may explain the tremendous health benefits of high-fiber diets
A diet high in fiber has long been considered a cornerstone of gut health, and now science is backing that up. Fiber promotes healthy intestinal flora and helps maintain healthy gut barrier function. It can also help reduce inflammation and insulin resistance, and may help reduce your risk of developing certain diseases, such as diabetes and heart disease.
As dietary fiber is fermented by bacteria in the gut, butyric acid is formed. Research suggests butyric acid in the gut helps kill colon cancer cells, making a high-fiber diet an important cancer prevention tool. (Source) Beyond that, butyrate can affect our brains by acting via the gut–brain axis. Through its ability to cross the blood–brain barrier, butyrate can activate the vagus nerve and hypothalamus, indirectly affecting appetite. (Source)
What Does the Research Show About Butyric Acid?
Butyric acid has powerful effects on the immune system
Thanks to its anti-inflammatory properties, butyrate can help control inflammation and modulate the immune response. In addition, butyric acid helps regulate the production and development of regulatory T cells in the colon, which are responsible for helping your body distinguish between itself and foreign invaders. Without the ability to tell self from nonself, the immune system may begin to attack your own tissues and organs, resulting in an autoimmune condition. (Source)
Butyric acid helps promote gut barrier integrity
Related to immune function, butyrate also helps maintain healthy gut barrier function and prevent the incidence of leaky gut. (Source) Emerging evidence suggests there may be a link between butyrate and autoimmunity in humans as well. For example, people with type 1 diabetes — an autoimmune condition that affects the ability of the pancreas to produce insulin — have been found to have lower levels of butyrate-producing bacteria in their gut than those without diabetes. (Source)
Butyric acid may improve your brain function
Studies have revealed that butyric acid has a profound effect on the brain, ranging from memory and cognition issues to neurodegenerative diseases. In rat studies, butyrate stimulated the release of brain-derived neurotrophic factor (BDNF), a molecule that supports the growth and differentiation of healthy neurons in the brain. (Source) And in studies looking at animal models of Huntington’s disease and Parkinson’s disease, butyric acid has been shown to protect brain neurons from cell death and to extend the lifespan of mice with Huntington’s. (Source, Source)
Butyric acid may help treat IBD
Numerous studies have reported that butyrate metabolism is impaired in patients with IBD. (Source) Butyric acid has been shown to decrease colitis-associated intestinal inflammation and colon cancer in both animal and human models. In a small 2005 study looking at the effects of butyrate on Crohn’s disease, 69% of patients saw clinical improvements after treatment, with 53% of participants achieving remission. (Source)
Butyric acid is a promising therapy for IBS
Emerging evidence suggests that butyric acid may be a potential treatment option for IBS as well. (Source)
In one double-blind, randomized, placebo-controlled study, 66 adult patients with IBS took either a placebo or 300 milligrams of sodium butyrate (the sodium salt of butyric acid) per day, in addition to receiving standard therapy. Just four weeks into the 3-month study, researchers found that subjects who took the butyric acid had a statistically significant decrease in the frequency of abdominal pain during bowel movements. (Source)
Butyric acid may improve insulin sensitivity
One of the more controversial potential applications of butyric acid is its ability to impact insulin sensitivity and obesity. In many studies, butyrate has been shown to significantly improve insulin sensitivity and reduce insulin resistance in people with metabolic syndrome. (Source) Researchers believe that this may be a result of the compound's ability to increase GLP-1 (glucagon-like peptide-1) and PYY (peptide YY), hormones that help your body to control food intake and increase fat burning (Source, Source, Source).
However, although a large body of evidence has suggested that butyrate may attenuate obesity and insulin resistance, a few studies have shown the opposite effect. Therefore, more research is needed to understand the effects of butyrate on obesity.