Short-Chain Fatty Acids Relieve Stress
Many of us are keen to protect ourselves from the harmful effects of stress. A new study hints that short-chain fatty acid supplementation can be beneficial.
It may seem far-fetched, but our gut and brain are closely connected. The microorganisms living in our intestines can have profound effects on our mental wellbeing.
Likewise, stress can have a detrimental impact on our gut microbiomes. In fact, high levels of stress can be as damaging as a high-fat diet.
So, the road runs both ways. Stress can alter gut bacteria, and gut bacteria can influence stress levels.
Research shows that many of the benefits of a healthy gut microbiome come from the products bacteria make by breaking-down fiber; in particular, short-chain fatty acids (SCFAs).
Researchers at University College Cork and Teagasc Food Research Centre are particularly interested in the potential roles and benefits of short-chain fatty acids.
So, they asked whether SCFA supplementation could be used to counteract the effects of stress in mice.
The researchers took 40 male mice and gave some of them SCFA supplements in their drinking water. After one week receiving the SCFA supplement, the mice were exposed to a battery of tests designed to induce stress for three weeks.
The researchers then looked at levels of the hormone corticosterone in the blood (which is known to rise in response to stress in mice and people), the amount of SCFAs in their feces, and the number of healthy gut bacteria.
The researchers then looked to see if the amount of healthy gut microbes changed in response to stress and whether the mice that had taken the SCFA supplement were less likely to gain stress-induced weight.
The researchers found that when they supplemented the mice’s diets with SCFAs, stress and anxiety behaviors were significantly reduced.
After demonstrating that SCFAs reduce anxiety, the team wanted to know how these molecules affect stress-induced leaky gut. Over time, high levels of stress increase intestinal permeability (leaky gut), which means that small particles (such as food and bacteria) can get into the bloodstream and cause chronic inflammation.
The researchers found that by supplementing SCFAs, they reduced the gut leakiness caused by persistent stress and the mice also seemed to have a more healthy functioning gut.
Although this study was conducted in mice, the implication is that supplementing the gut microbiome with SCFAs and/or fiber to increase SCFA production boosts the gut's natural defenses against the damage caused by stress.
van de Wouw et al. (2018) Short‐chain fatty acids: microbial metabolites that alleviate stress-induced brain-gut axis alterations. The Journal of Physiology. DOI: 10.1113/JP276431