By now, we know that a healthy diet is important for physical well-being. Researchers are studying whether probiotics — live bacteria that are safe to eat — can improve gastrointestinal health and your mood.
“Probiotics are what we believe to be good organisms that are beneficial to our health,” says Linda Lee, M.D.
But do they work?
Possible Benefits of Probiotics
Probiotics are beneficial bacteria that exist naturally in foods like yogurt and kimchi. They’re also available in pill or powder form. Probiotics are thought to improve digestive health, and they’re often used to treat diarrhea or bloating.
Probiotics can have many positive effects on the body, including:
- Shaping the body’s immune system
- Producing antimicrobial substances
- Fermenting fiber in the diet to generate nutrients for the cells that line our intestines
Now researchers are finding evidence that the effects of bacteria in the gastrointestinal (GI) system send signals to the central nervous system, linking the gut with the brain. This could account for some known connections between GI illness and mental illness. For example, a higher-than-average number of people with irritable bowel syndrome also develop depression and anxiety.
Could better GI health via probiotics boost emotional health too? The link between probiotics and mood isn’t clear, says Lee.
She points out that certain foods can seem to boost mood — just think of the comfort foods we reach for when we’re low, whether it’s macaroni and cheese or a bowl of ice cream. However, this might simply be a behavioral association rather than something triggered by bacterial responses to nutrients in food.
“It's not to say that the food itself has nutrients that are affecting our mood, but it's that our brains associate eating that food with comfort,” she says.
Although it’s tempting to link probiotic use with mood, more research is needed, says Lee. “Right now, we don't have a lot of proof that taking probiotics is going to change depression or anxiety. It's an attractive theory, but we need a lot more research to guide us.”
Pick Your Probiotics Carefully
One problem with probiotics is a lack of consistency. Lee warns that consumers can’t always be sure of what they’re getting.
“Probiotics are considered food supplements, not drugs, by the FDA. Therefore, we don't have a lot of regulation over how they're made or whether they even contain what they say they contain,” says Lee.
In the United States, Lactobacillus and Bifidobacterium are the probiotic strains most commonly used to treat GI issues, but there are many probiotic products on the market. They contain different types of bacteria and in different amounts. Lee cautions that the lack of regulation means that one batch might be different from another.
“By the time you buy a probiotic off the shelf, there’s no way to know if the bacteria in it are as active as they were as when the product was made,” Lee says. In addition, each person may have different types and numbers of bacteria in their gut. This means the probiotic that works for one person might not work for another.
How to Take a Probiotic
The good news is that it appears most probiotic strains are probably harmless. But use caution. “There have been many studies that have shown that often what's on the label is not what's in the bottle. People really have to be careful,” Lee says.
Will taking one a day improve your mood? The jury is still out, says Lee, and she cautions against using them as a replacement for any prescribed mood-managing medication. But if taking one a day for a month at least helps ease your gut issues, that alone might make you feel a little bit more “up.”
But if the probiotic you’ve tried doesn’t have any effect at all? “It probably isn’t the right one for you,” concludes Lee.