Did you ever have “butterflies in your stomach”? Did you learn to “trust your gut” when making decisions? Your gut and your brain talk to each other through a bidirectional communication network, linking the enteric and central nervous systems, endocrine, metabolic and immune communications. Your gut influences mood, sleep, cognition and overall mental health) and it’s your gut bacteria that do the talking.
The playground of probiotics: the gut
The gastrointestinal tract is a long tube that starts in your mouth and ends at the anus. Its main function is to process and absorb food. Digestive health is closely linked to immune health, as 70-80% of your immune system is located in your digestive tract.
The gut is a nervous organ (“second brain”) with more than 100 million nerve cells that exert complex interactions with the skin, muscle and the brain. The large intestine is the most heavily colonized organ in the human body with up to 1,000 different bacterial species; however, 99% of the total bacteria are derived from just 30-40 species. Most of the bacteria in our body are located here (1,000,000,000,000,000 – 1015 or one quadrillion).
Numerous factors influence the composition of our gut bacteria, with our diet having the greatest impact. The way we were born (Caesarian birth vs vaginal birth with exposure to bacteria in the birth canal) affects early bacterial composition, as do how the infant is fed via the breast or bottle.
Mature human milk contains approximately 7% carbohydrates, but new research suggests that other carbohydrates fractions are important in determining infant health. These complex carbohydrates are not intended to feed the infant; rather, they are food for the bifidobacterial inside the infant’s gut, allowing the bacteria to colonize and thrive.
We see several changes in the bacterial composition throughout the different life stages, such as an age-related decline in bifidobacteria. Our lifestyle choices—alcohol consumption, smoking, stress, diet, exercise—has a major impact on our gut bacteria throughout life. A diet rich in fiber or prebiotics, supplementing with probiotics, synbiotics, postbiotics, immunobiotics, or consuming fermented foods can significantly improve the balance of good-to-bad bacteria in our gut.
Improve mood via the gut-brain axis
The gut microbiota composition of patients suffering from mental health issues are significantly different from healthy controls. Transferring the microbiota from anxious IBS patients or depressed patients to mice induces depressive and anxious behaviors, establishing a clear link between the gut bacteria and mental health.
Several human studies have shown that improving the gut bacteria composition through probiotic supplementation can improve mood, anxiety and cognition, with a reduction in neuroinflammation and influencing neurotransmitter synthesis and release being the likely mechanism-of-action.
A new study in 70 healthy men and women supplementing with a multi-strain probiotic, consisting of 1 billion CFU of each L. fermentum LF16, L. rhamnosus LR06, L. plantarum LP01, and B. longum BL04 for six week showed significant increases in state (temporary feeling of a perceived threat) and trait anxiety (daily feelings of stress, worry and discomfort), as well as significant improvements in mood and how optimistic or pessimistic people feel about the future.
These results will be presented in depth at SupplySide East on Tuesday, April 18 from 12:00-1:00pm during the educational session, "Synbiotics and the evolving market for microbiome ingredients."
This new study confirmed previous findings of significant improvements in mood with a reduction in depressive feelings, anger and fatigue using the same multi-strain probiotic blend.
The gut-sleep connection
We sleep to repair and restore our brain chemistry, solidify information from the day and to conserve energy. Not getting enough sleep impairs all aspects of daily life, including poor memory and irritable mood. Having healthy sleep habits like trying to avoid blue light exposure from cell phones at night, cutting back on caffeine, getting up at the same time and sleeping in cold and dark rooms can improve sleep quality and duration.
Sleep disorders have been linked to gut dysbiosis and an imbalance of gut bacteria. Thus, improving gut health is seen as a major factor influencing sleep. The gut is also the largest hormone-producing organ (>30 hormones), including the neurotransmitter serotonin. Serotonin is the body’s natural “feel good” molecule that contributes to mood, happiness, and sleep. While serotonin’s main function in the gut is to promote intestinal motility, or the contraction of the muscles that mix and move food through the digestive tract, serotonin also produces melatonin—the main sleep-regulating hormone. Melatonin is being synthesized in response to darkness, while serotonin is primarily produced during daylight. Low levels of serotonin, for example due to stress or gut dysbiosis, can result in decreased levels of melatonin that negatively influences the circadian rhythm—the internal process that regulates the sleep-wake cycle.
Supplementation with a multi-strain probiotic, consisting of 1 billion CFU of each L. fermentum LF16, L. rhamnosus LR06, L. plantarum LP01, and B. longum BL04, increased sleep quality after 6 weeks of supplementation in a gold standard trial in Italy. Amazingly, sleep quality remained elevated even after a 3-week washout period. Dietary probiotics are transient, meaning as long as you supplement with them, they are present in your GI tract. Once you stop supplementing, they wash out within 7-14 days.
That benefits on sleep seem to last even after the probiotics have been washed out indicate that changes in sleep quality can be long lasting. While probiotics are present in the GI tract, they produce metabolic products and “communicate” with other bacteria. After the probiotics moved out, their influence on the other bacteria is longer lasting. A follow-up gold standard trial in the US confirmed the benefits of this multi-strain probiotic on sleep quality, and also showed a compelling mechanism of action, further explaining the observed benefits. The probiotics significantly increased serotonin levels, which can support sleep through increasing melatonin levels.
The impact of pre-, pro-, and postbiotic ingredients on the landscape for complex, condition-specific formulations including cognition, bone and joint health, and immune response will be presented at SupplySide East on Tuesday, April 18) from 12:00-1:00pm.
Dr. Ralf Jäger, PhD, FISSN, CISSN, MBA has conducted numerous clinical studies and published peer-reviewed scientific papers, industry publications and mainstream media articles on probiotics and sports nutrition, brain, joint, heart and gut health. A postdoctoral scholar in bio-organic chemistry at the California Institute of Technology (Caltech) in Pasadena, Calif., Dr. Jäger co-founded Increnovo in 2007.