It’s long been known that probiotics help with digestive troubles. But a new study shows that “good” bacteria offer a surprising bonus: They relieve depression.1 2
Researchers at McMaster University in Canada recruited 44 adults with irritable bowel syndrome (IBS) and mild to moderate anxiety or depression. IBS is the world’s most common digestive disorder. It causes stomach pain as well as constipation and/or diarrhea.
Since IBS is usually a chronic condition, it is strongly associated with adverse effects on mental health.
During the six-week study, half of the participants took a daily dose of the probiotic Bifidobacterium longum. The other half took a placebo.
After the participants stopped taking either the probiotic or a placebo, they underwent psychological evaluations and brain scans.
The probiotic group was twice as likely as the placebo group to report fewer symptoms of depression. A remarkable 14 of the 22 subjects in the probiotic group (64%) had improved depression scores. Just seven of the 22 subjects (32%) in the placebo group showed improvement.
The probiotic group also reported a significantly higher quality of life.
Even after they stopped taking probiotic, the benefits persisted for another four weeks.
When the participants underwent functional resonance magnetic imaging, the researchers found that improved depression scores were associated with changes in multiple brain areas involved in mood control, such as the amygdala and fronto-limbic regions. They concluded that the probiotic significantly reduced responses to negative emotional stimuli in these areas compared to placebo.
Probiotics: Better Than Drugs for Boosting Mood
The study provides further evidence that the microbiome directly communicates with the brain. In fact, the study shows that probiotics may be more effective at fighting depression than antidepressant drugs.
Previous studies show that antidepressants rarely work in cases of mild or moderate depression. And for severe depression, they are effective in only about half of patients.3
Dr. Premysl Bercik is lead author of the probiotic study. “This study shows that consumption of a specific probiotic can improve both gut symptoms and psychological issues in IBS,” he said. “This opens new avenues not only for the treatment of patients with functional bowel disorders but also for patients with primary psychiatric diseases.”
The study recently was published in the journal Gastroenterology.
In an earlier study, Dr. Bercik and his colleagues tested Bifidobacterium longum in mice. They found that the probiotic reduced anxiety-like behavior in mice caused by chronic gut inflammation.4
You can get the mood-boosting benefits of Bifidobacterium longum from fermented foods. They include yogurt, sauerkraut and fermented vegetables such as kimchi.5
When choosing probiotic foods, it’s important to read the label carefully to make sure you’re getting a product that is unpasteurized and contains live cultures. You’ll also want to make sure it has no sugar added. Organic brands are best.6
The most reliable way to get Bifidobacterium longum is to take a probiotic supplement containing it. Look for a brand that contains at least 10 billion CFUs per serving. This is a measure of potency.7