From the gut to the brain: how do microbes affect your cravings?
How can miniature microbes hijack our awesome human brains?
We know there are certain chemicals that are designed to give us a rush of pleasure. But, one of the most amazing things about being human is our capacity to override that pleasure. To either say, 'I don't need that pleasure right now. I'm going to ignore the craving.' Or to find something else that we find a deeper sense of reward from. – Charles Duhigg
Last week, we talked about the amazing notion that gut microbes affect our cravings, getting us to eat what they want, healthy or not. The fact is, we are being played. Gut microbes are not our "friends", they are associates that we share meals with but can turn on us at any moment. If the food runs out, they will be just as happy to digest us.
They each have their own appetites: some microbes crave sugar, others enjoy fat, carbs and fiber. They each have their own method of asking for their favorite meal, using variations on two basic techniques to influence our food choices.
Microbes can produce toxins that make us feel like crap if we don’t give them what they want. They know how to make us miserable.
Microbes increase our craving for food that they like by changing our taste buds, increasing opioid and cannabinoid receptors, and producing neurotransmitters such as dopamine and serotonin. So they also know how to make us happy.
Microbes use a stick and carrot-cake approach to mold our cravings. They are very good at it, but their benefit is not always ours.
Cravings and Mood
Cravings may seem like a frivolous thing to worry about, but your food preferences are tightly linked to your mental state. As we've seen, your microbiota can create many of the same neuroactive compounds that are behind antidepressants, anxiety drugs, and recreational drugs. These are the powerful levers your gut microbes can pull to modify your eating behavior.
That microbial muscle-flexing can lead to several outcomes, not all of them good. A well-fed and balanced microbiota presents a healthy bulwark against the nasty pathogens of the world. It can reduce anxiety and lift your mood. On the other hand, crappy diets that unbalance your microbiota can lead to obesity or anorexia, dangerous syndromes that are strongly comorbid with depression and anxiety. An unbalanced gut may make us avoid healthy foods and instead seek out the junk food adored by some of our more selfish bacteria.
We've been under the mistaken perception that we make our own food choices, but ignorance is no longer an excuse: We need to manage our microbes before they make us sick. It's important, not just for our gut, but for our mood.
What to Do
Your gut microbiota turns over every half-hour or so because bacteria have a short life cycle. What you eat changes the composition of your microbiota; certain species thrive and others wither, depending on dinner. So, if you can override your bad cravings, you can effectively rebuild your microbiota in just a few days. Of course, that goes both ways—the lure of Oreos should not be underestimated, and you can be right back to where you started in a flash, a victory of microbe over prudence.
Still, all is not lost. You can build a better, healthier microbiota in no time at all. Here are some tips to deal with your junk-food crazed microbes:
Increase the variety in your diet to increase the variety in your microbiota. Diversity prevents a bully microbe from dominating and pushing hard on your buttons.
Eat more fiber. You can change your microbiota overnight with just a few good fiber-filled veggies like broccoli and artichokes – although to really make it stick you’ll need to eat these foods daily. They will actually help you crave healthier foods after a while.
Substitute: when you are craving that donut, choose strawberries instead. We tend to forget how good fruit is when confronted with a glazed delicacy. You may complain for the first few days (OK, maybe weeks), but once you've established a healthier microbiota, it just gets easier and easier.
Exercise, not to lose weight, but to balance your microbes. Researchers aren't sure why, but it works. Just walking for 15 minutes a day does your gut a world of good.
Befriend some lean foodies and see if you can catch their cravings for healthy food. Don't laugh: if cravings come from microbes, then cravings may be contagious.
Dredge up some will power. We tend to identify with our cravings. We are chocolate lovers or meat-eaters. But knowing how much our microbes influence our cravings should make it easier to overcome them. After all, who do you want to be in charge of your diet: you or your selfish microbes?
References
Temko, Jamie E., Sofia Bouhlal, Mehdi Farokhnia, Mary R. Lee, John F. Cryan, and Lorenzo Leggio. “The Microbiota, the Gut and the Brain in Eating and Alcohol Use Disorders: A ‘Ménage à Trois’?” Alcohol and Alcoholism 52, no. 4 (July 1, 2017): 403–13.
Hill, Alison L., David G. Rand, Martin A. Nowak, and Nicholas A. Christakis. “Infectious Disease Modeling of Social Contagion in Networks.” PLOS Computational Biology 6, no. 11 (November 4, 2010): e1000968.