How dietary prebiotics may help to reduce stress when we sleep

When we become stressed, it can become increasingly hard to reap the benefits of a good night's sleep. New research is indicating that dietary probiotics might be able to flip that situation on its head.   According to The National Sleep Foundation, adults should aim to get between 7-9 hours of sleep each night for optimal health and well-being. However, around 1 in 3 of us fail to meet these recommendations, particularly during times of stress.  Approximately 47 percent of adults in the United States report a lack of sleep due to stress, and 21 percent report that having poor sleep only worsens their stress, according to the American Psychological Association. First study author Robert Thompson (of the Department of Integrative Physiology at the University of Colorado, Boulder) and his colleagues noted that previous studies have suggested that stress can alter gut bacteria in a way that interferes with the sleep-wake cycle. Until now, it was unclear whether prebiotics might have any effect on improving sleep in the face of stress.   What exactly are prebiotics? They are non-digestible food components, found in chicory, artichokes, onions, leeks, and other vegetables that fuel the growth of “good” gut bacteria. Research shows that when these good bacteria digest prebiotic fiber, they release byproducts that can affect brain function.   In their study, Thompson and colleagues placed male rats on one of two diets for 4 weeks: one was supplemented with prebiotics, the other a standard chow diet (the control diet). On analyzing fecal samples from the rodents after 4 weeks, the team found that the rats fed the prebiotic diet showed an increase in beneficial gut bacteria, including Lactobacillus rhamnosus, known to aid immune system function, compared with rats who were fed the control diet. Using electroencephalography to measure the rats’ sleep-wake cycles, the researchers observed that the rats fed the prebiotic diet also had more non-rapid eye movement (NREM) sleep, also known as the restorative sleep stage, compared to the rodents fed the control diet. “Given that sufficient NREM sleep and proper nutrition can impact brain development and function and that sleep problems are common in early life, it is possible that a diet rich in prebiotics started in early life could help improve sleep, support the gut microbiota and promote optimal brain/psychological health,” the authors note.   When the two groups of rats were exposed to acute stress (induced by tail shocks), the researchers found that the group fed the prebiotic diet had more rapid eye movement (REM) sleep than the group that was fed the control diet. The team noted that REM is the sleep stage associated with better recovery from stress. In addition to this, the researchers found that the rats fed the prebiotic diet were less likely to experience abnormalities in body temperature that can arise due to stress-induced alterations to gut bacteria.   As with any new research, further studies are required to better determine how prebiotics affect sleep quality. Nevertheless, the researchers believe that their findings suggest that dietary prebiotics might offer benefits towards dealing and combatting stress. The team concludes: “These data are the first to show that a diet rich in prebiotics can modulate the sleep-wake cycle both before and after stress and induce stress-protective effects in diurnal physiology and the gut microbiota. Our results, however, cannot address how increases in Lactobacillus rhamnosus or other changes in microbial community structure contribute to the observed effects of a diet rich in prebiotics and more work is necessary to further elucidate the potential mechanisms. Nonetheless, our work is the first to demonstrate that consumption of a prebiotic diet can provide stress-protective effects on sleep-wake behavior.”