Why Some Treats Are Trickier for Your Gut Microbiome

Rachel Feltman: Happy Halloween, listeners! For Scientific AmericanIt is Science quickly, My name is Rachel Feltman.

Halloween is pretty much my favorite holiday. It’s mostly because of the cool fall weather and spooky vibe, but I certainly don’t mind having an excuse to eat a lot more candy than usual. But what does this annual sugar madness mean for the microbes that live in our guts? The answer isn’t as scary as you might think: the trick is to choose your treats wisely.

Today’s guest is Chris Damman, clinical associate professor of gastroenterology and medicine at the University of Washington. He’s here to tell us how our candy consumption can help treat – or trick – the creatures that haunt our guts.

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Thank you very much for coming to chat with us today.

Chris Damman: Yeah, no, it’s great to be here, and thanks for the invitation.

Feltman: So, as a gastroenterologist, when you think about Halloween, what are the big concerns that come to mind?

Damn: Well, that’s a good question. When I think of Halloween, first of all, it’s one of my favorite holidays…

Feltman: Same here.

Damn: It’s always been, you know, going back to high school and Halloween window paintings. And, you know, of course, candy comes to mind when we think of Halloween, along with fun costumes and pumpkin kids.

In terms of concerns, I’m pragmatic, realistic when it comes to nutrition, and my kids remind me too, that it’s okay to cheat from time to time. And I think the holidays are one of those times where it’s probably okay to relax a little bit when it comes to nutrition. Candy is a treat and should be treated as such. Halloween is a holiday full of candy and treats, so [laughs]so there you go.

But, you know, moderation, ultimately, is a common thread, and moderation can happen on any given day, but can also happen over the course of weeks and months.

Feltman: Well, and you wrote an article for the Conversation last Halloween about the gut microbiome in particular that I thought was really interesting. Like you said, the holidays are great cheat days, and someone who watches their sugar intake year-round definitely won’t have a problem enjoying candy on Halloween. But how true is this for our gut microbes? What do we know about the effects of a sugar overload on them?

Damn: So our microbes, when they see sugar, certain bacteria in our microbiome thrive on sugar, and they happen to be, unfortunately, the ones that tend to be a little more inflammatory. And so they can cause intestinal inflammation; they can cause inflammation throughout the body.

So when we treat ourselves to Halloween candy, we also treat these less tasty microbes to a Happy Meal, who often end up not feeling so happy in the end. [laughs]. We pay the consequences.

But not everyone reacts the same way to nutrition, and some will have more of these microbes; some might increase their blood sugar levels further due to underlying health conditions. So at the end of the day, a lot of nutrition is actually about listening to your body and how you feel.

Feltman: Well, and you talked in your article about, you know, how some candies might be kinder to your good gut microbes than others. Could you tell us a little about it?

Damn: It’s something I’m really passionate about. I don’t think, you know, all processed foods are equally bad. Sure, it would be best if you always had a whole food, but I think some processed foods are better than others, and that is also true for Halloween candy.

Now, if you go for lollipops and Starbursts and Skittles, you know, which are really just pure sugar and there are, you know, colorings also present in those foods, that’s going to be less healthy than if you go for something that has whole nuts in it, like a Snickers or a Payday. Or, you know, God forbid, have a candy apple with a solid apple in the center. A candy with whole food elements will be better for you than a candy made almost entirely of processed sugar.

And then intermediate to something like a Payday and something like a Starburst would be a peanut butter cup. You know, there’s still good, healthy peanut butter mixed with lots of sugar, but this peanut butter still retains a lot of the original elements of the peanuts that were used to make it.

Feltman: And could you tell us a little bit about what happens in our guts when we digest these whole foods that make them better for our gut microbes?

Damn: You know, I feel like our conversation about nutrition in general has been mostly about the things that are bad for us and we’ve focused on sugar, salt, and fat. And that’s certainly a piece of the puzzle, and I wouldn’t call them bad; these elements of food are extremely important, and it’s really a matter of lack of balance.

And with balance, even though there are things that we consume too much of, there are also things that we consume too little of, and we’re starting to hear more about them, things like fiber and phytonutrients, polyphenols. These are the kinds of things that are often processed directly from food and are missing from ultra-processed foods.

So when we talk about rebalancing our diet, it’s really about reintroducing some of these things. And what’s fascinating is that these elements are often as good for our microbiomes as they are for us, and our microbiomes transform them into things like modified polyphenols and things called short-chain fatty acids that are extremely important to the health of our body in regulating our immune system, our metabolism, and even our brain.

Feltman: So obviously, there are a lot of things about a big sugar spike that might make you feel worse, but if we’re talking specifically about the gut microbiome, what can people do after a day full of treats like Halloween to really support their gut flora?

Damn: [Laughs.] Absolutely, you know, so after a day of indulgence, it’s best to get back on the health bandwagon, so to speak. And there are certainly, you know, some things that are healthier to eat than others: of course, whole foods. And these are all the things you usually hear about as being healthy: fruits and vegetables, but also whole grains and legumes like beans, nuts and seeds – these are things that are often forgotten but are actually extremely important. Refocusing your diet on these types of foods can help your body move backwards [laughs] of the indulgence of Halloween candy.

Feltman: Well, thank you very much for coming to chat. I hope you have a happy Halloween and enjoy some treats.

Damn: Yeah, wonderful, and likewise, similar wishes to you and your listeners. Happy Halloween.

Feltman: That’s all for today’s episode. We’ll be back on Monday with our weekly roundup of science news.

Science quickly is produced by me, Rachel Feltman, with Fonda Mwangi and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more recent and in-depth scientific news.

For Scientific American, This is Rachel Feltman. Have a great weekend!