Over the years, scientists have found strong links between psychiatric disorders and an increased risk of constipation, particularly in older adults. The gut is considered as our second brain. It has more neurons than the spinal cord, and it operates with a similar suite of neurotransmitters as the brain. People with depression oftentimes have lower levels of serotonin, a neurotransmitter in their brain. Neurons in the gastrointestinal (GI) system use serotonin. Reducing serotonin in the gut had several effects; the scientists showed that it lowered the overall number of neurons, caused the gut lining to deteriorate, and reduced the speed of movement through the gut.
The bacteria in the gut play many crucial roles in the health of the digestive system. The gut bacteria produce substances, called lactate and short chain fatty acids, that change the pH (acid level) of the intestine. This can increase peristalsis (wave-like muscular contractions that move food through the intestines), reduce transit time and improve stool frequency. Dysbiosis, which is an imbalanced gut microbiota, contributes to constipation. Individuals with constipation often have significantly different gut bacteria composition than non-constipated healthy people, with higher levels of methane producing bacteria in their intestines, which slows intestinal transit time. A balanced microbiota can reduce methane production, alter gut function, improve stool consistency and frequency, and help with constipation symptoms, including bloating, abdominal discomfort and pain.
Do probiotics provide constipation relief? Researchers found that on average, probiotics slowed “gut transit time” by 12.4 hours, increased the number of weekly bowel movements by 1.3, and helped soften stools, making them easier to pass. Probiotics that contained Bifidobacterium appeared to be the most effective.
But there’s still not enough evidence to recommend a specific probiotic for constipation. Many of the studies are small and had different designs and widely variable results, making it difficult to make a specific recommendation. What is needed is a large, multicenter trial, with standardized outcomes to determine which probiotic species and strain is most effective, how much to take, and for how long.
Probiotics do not seem to have any side effects and are generally considered safe. However, it is also wise to remember that dietary supplements like probiotics are not tested by the FDA like medications are.
