Is Your Gut Making You Depressed or Anxious?


Ellen Hendriksen, PhD
Episode #136
gut health

Connection #3: The gut may drive our food choices. If you’ve ever felt propelled to the fridge by a force other than your own, you may not be that far off. There’s a theory that your cravings may actually be caused by your gut bacteria. Apparently there’s a crowd of trillions in there that really likes chocolate cupcakes, bacon, cheese, or whatever it is your specific bacteria run on.

The theory goes like this: when we eat the foods our bacteria want, they produce particles that are small enough to cross the blood-brain barrier, like tyrosine or tryptophan, which, as luck would have it, get converted into dopamine and serotonin in the brain, both of which impact mood and reinforce those food choices.

If you’ve ever been besieged by cravings, not to mention grumpiness, after a few days on a diet, it may be because your gut bacteria are starving for their preferred sources of fuel. It makes sense: millions of years of evolving together have probably paired humans up with bacteria that can manipulate us. Feel like a giant robot controlled by tiny masterminds yet?

To make you feel even more like an automaton forced to do your gut’s bidding, gut bacteria are also thought to help control our feelings of satiety. In sum, bacteria may decide, at least in part, both what and how much we eat.

Keep in mind that this is a theory—a well-informed theory, but untested nonetheless. But it might explain why, when we change our diets, we have strong cravings for a while, but then all turns quiet on the gut front. Is this because sugar-loving bacteria starved and ended up in the toilet? We don’t know, but researchers are trying to find out.

What do we know about how we can influence the gut-mind connection?

That’s all fine—and a little freaky—you say, but what do we know about how we can influence the gut-mind connection?

Well, we do know that it’s difficult to change your gut microbiota cocktail. What you get from a vaginal birth process, breastfeeding, and the first few years of life pretty much sets your magical mix of gut bacteria by age three. But what can be changed is the metabolites of the bacteria—the products your gut bacteria produce. And to do that, you change what you’re feeding them.

How to do that? Dr. Emeran Mayer, co-director of the Digestive Disease Research Center at UCLA, recommends the following in his excellent book, The Mind-Gut Connection.

  1. Eat a diet high in plants and low in animal fats, the latter of which is a source of the molecules that cause chronic low-grade inflammation, which in turn raises the risk of cancer and heart disease
  2. Avoid processed food and food additives, like emulsifiers that disrupt your intestinal lining, and artificial sweeteners that alter your metabolism.
  3. Reduce stress, which impacts both the composition and activity of your gut bacteria.

Another recommendation for healthy guts include eating fermented foods like kimchi, miso, kombucha, kefir, and good old yogurt to maintain diversity in your gut bacteria. But with guts that are already sick with problems beyond the scope of this episode, like leaky gut, Small Intestine Bacterial Overgrowth (SIBO), or other disorders, fermented foods and probiotics can actually amplify the problems.

But there’s no doubt that the way we live and the way we eat are both impacting our guts, which in turn impacts not only our bodies, but our minds. So raise a glass (of kombucha or kefir, perhaps) to your trillions of guests and encourage them to help you make a healthy choice for dinner.

In addition to Dr. Mayer's book, another good one is Guilia Enders’s Gut: The Inside Story of Our Body’s Most Underrated Organ.


Image courtesy of Shutterstock.


About the Author

Ellen Hendriksen, PhD