Operating through what is known as the gut-brain axis, the gut has been shown to play a crucial role in the regulation of mood—and vice versa. Leveraging this established link, a recent study has explored whether a combination of specific probiotics and L-theanine may be able to work together to help alleviate mood shifts through a key player in the gut-brain axis: brain-derived neurotrophic factor (BDNF).
As a crucial protein involved in cognition and mood regulation, low BNDF levels in the brain have been linked to mood disorders. Studies also suggest that BDNF supports proper mucosal function in the gut and that gut flora can have a significant impact on BDNF levels in the brain. As well, the presence of certain strains of probiotics, like Bifidobacterium and Lactobacillus, can work to increase BDNF in the brain. L-theanine, a commonly used supplement for mood support, has also been shown in animal studies to boost BDNF in the brain.
New research findings
The mouse study, published in Nutrients in May 2023, found that the probiotics Lactobacillus casei and Bifidobacterium lactis used in combination with supplemental L-theanine could alleviate stress-induced anxiety and depression by regulating BDNF more effectively than supplementation of probiotic or L-theanine alone.
Specifically, the research found that the combination not only increased BDNF but helped to reduce neuroinflammation, gut inflammation, and gut imbalance, reducing behaviors associated with anxiety and depression in the process.
While L-theanine and the probiotics featured in the study, Lactobacillus casei and Bifidobacterium lactis, can be found as dietary supplements, you can also get them naturally from food sources. Lactobacillus casei and Bifidobacterium lactis are available in varying amounts in many fermented foods, such as yogurt, kefir, pickles, and kimchi, while L-theanine can be found naturally in tea and some mushrooms.
This article was originally published in the December 2023 issue of delicious living magazine.