Get access to everything we publish when you sign up for Outside+.
Whether you’re about to experience a huge shift in your life like a change in your career or you’re living with day-to-day stress, all kinds of external stressors can cause feelings of anxiety. Anxiety disorders are the most common mental illness in America, and they affect 40 million adults. Yet only 36.9 percent of people who live with anxiety get any type of treatment.
But there’s good news: Focusing on your gut health may have a positive impact on your mental health. There may be promise and potential hiding in your gut microbiome—and prebiotic supplements may provide a simple source of relief from anxiety.
Your gut and your brain are closely connected
Though anxiety can affect you physically from head to toe, it’s a condition that scientists believe is centered in the brain. And there’s evidence of a crucial, intimate connection between what’s happening in your brain and what’s occurring in your gut.
Research has strongly suggested that gut microbiota—microorganisms such as bacteria—can wield important influence over your brain’s function and behavior. When your gut microbiota changes due to factors like shifts in your diet, lifestyle adjustments or even increased stress, it may affect how your brain is operating. A decrease in microbial diversity, for example, may lead to psychological changes that are linked to mental illnesses. An increase in pathogenic microbes (or disease-causing bacteria) in your gut may do the same.
In fact, in a 2010 research study chronic gastrointestinal inflammation caused anxiety-like behavior, and results in a 2014 research review led researchers to speculate that changes in the gut microbiome may play a role in anxiety and other mental health conditions like depression. These studies separately examined the impact on the brain of factors like changes to gut bacteria and gut inflammation on the brain, and both suggested discovered a link between the gut and anxiety.
With such a close link between gut and brain suspected, keeping tabs on your gut health could have a direct impact on your mental health.
Prebiotic supplements can increase mental well-being
New research is helping to solidify the connection between gut and brain—and a study published in Scientific Reports found that taking prebiotic supplements regularly seemed to reduce anxiety levels and benefit the overall mental well-being of the participants. While probiotics contain live organisms and strains of bacteria that add to the healthy microbes already present in your gut, prebiotics are more similar to fertilizers. Prebiotics work to stimulate the growth of healthy bacteria in your gut.
Researchers examined the effects of daily prebiotic supplements on women’s mental well-being. For the duration of the four-week study, 64 female participants between the ages of 18 and 25 were divided into two groups: one that received a daily dose of prebiotics and one that received a placebo. None of the participants had been clinically diagnosed with anxiety previously. During the study, they completed surveys about their mood, anxiety, sleep and more; participants also provided samples for gut microbiome analysis.
At the end of the 28-day period, women who took the prebiotic supplements described improved mental well-being. The prebiotics group reported reduced anxiety levels and a more positive outlook. And they also had better gut health than those who took a placebo. Those prebiotic supplements, called galacto-oligosaccharides (or GOS), which are made up of plant sugars, improved participants’ abundance of beneficial gut bacteria while also improving their anxious feelings.
How to use prebiotic supplements for your anxiety and mental health
If you’re hoping to lessen your anxiety and its symptoms, increasing the good bacteria in your gut may help. As the study discovered, taking a prebiotic supplement may be one way to accomplish exactly that. Adding one of these supplements into your daily routine may have an effect similar to what researchers saw. You can also turn to food, as some foods do contain an amount of prebiotics.
But prebiotics aren’t the only potential solution. Other research, including a 2020 research review, suggests that probiotics may also have positive effects on anxiety and other ailments like depression. While more thorough research is still needed, probiotics may be a great way to increase your gut bacteria diversity and the amount of beneficial bacteria. You can supplement with probiotics just like you would with prebiotics, or you can try probiotic-rich recipes to boost your good bacteria.
From Clean Eating