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How To Build The Ultimate Gut-Friendly Smoothie, According To A GI Doctor

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July 31, 2019

Anyone can make a smoothie—throw some frozen fruit and water or your fave dairy-free milk in a blender, and buzz until creamy. Better yet, you probably even know how to whip up a "gut-friendly" smoothie by adding in some fibrous plants or even inflammation-reducing ginger. You do, after all, pride yourself on staying in the know about these things.

But what about whipping up the ultimate gut-friendly smoothie? Sounds like a challenge you want to take, right? But here's the thing: To do that, you'll need to have something going on in that blender that is so next-level your microbes start doing the "Single Ladies" dance in chorus. 

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The good news: As a board-certified gastroenterologist and gut health expert, I'm more than happy to play the Beyoncé to your bacterial song and dance by sharing a few of my absolute favorite smoothie ingredients.

First, what does a healthy gut even look like?

To get this process underway, it's important to first define the building blocks of a healthy gut.

When things are working the way they're supposed to, we have a diverse, abundant community of microbes living in harmony in our colon. The colon itself is healthy and strong with an intact barrier of cells to keep everything in its rightful place. In this setting, our microbes reward us with a long list of benefits, including:

  • healthy digestion and absorption of nutrients
  • blissful bowel movement
  • balanced hormones and metabolism
  • an optimized immune system
  • reduced anxiety and depression
  • increased energy and optimism
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Yeah, so that basically sounds like nirvana, doesn't it?

Why doesn't everyone have a healthy gut?

If you read all of that and thought, "What the heck, man? Why is it not like that for me?" you're not alone. 

That's because you're one of many people who have noticed the increasing epidemic of digestive distress, fatigue, anxiety and depression, weight gain and hormonal imbalance, and metabolic and autoimmune diseases that has struck the United States.

These are often signs of a damaged gut microbiota. Some call it "leaky gut," but I prefer to call it dysbiosis, or damage to the gut that is caused by a microbial disruption. As a result, you lose a diversity of species and in the process see a higher proportion of inflammatory microbes emerge. In other words, the good stuff falls to the wayside, making more room for the not-so-good stuff to flood your gut.

This is problematic because now the colon wall is no longer protected by a healthy community of anti-inflammatory bugs, and the result is damage to the tight junctions holding the colon wall together and an increase in intestinal permeability that leads to the spillage of something called bacterial endotoxin into the bloodstream. This bacterial endotoxin jumps on the vascular superhighway throughout the body, and wherever it goes, it sets a fire (better known as inflammation). It's bad news!

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5 elements of a gut-healing smoothie.

I know, it's a lot of info, but in order to create this ultimate gut health smoothie, we need to understand what could be causing problems in the first place, as well as how to restore balance to the microbes, shore up the tight junctions, reduce intestinal permeability, and squash bacterial endotoxin release. Sounds tough, but it doesn't have to be. I promise, all you need is the power of plants. Here are the ones that will help you create the gut-healing smoothie of your dreams:


Green bananas

If we're going to talk about feeding our gut microbiota, we have to start with the single most important nutrient—fiber! Green bananas are a unique source because, in addition to soluble fiber, they contain resistant starch. Resistant starch is a type of prebiotic that can trigger the release short-chain fatty acids1 (SCFAs), beneficial compounds that alter the bacterial balance to increase the good guys and decrease the bad ones while also strengthening the colon cells, repairing tight junctions to shore up leaky gut, and reducing bacterial endotoxin release. As the banana ripens, the resistant starch breaks down into sugar, so for optimal gut health, let's use the green ones.

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OK, you're going to hear me talk about SCFAs again. Berries are also a rich source of fiber to promote SCFA release, but fiber isn't the only prebiotic. Berries also contain polyphenols, which are plant-based chemicals that give berries their color and have numerous health benefits. From a gut health perspective, they've been shown2 to swing the microbiome pendulum in our favor by selectively inhibiting the bad bacteria while augmenting the good ones. No need to hold back on the berries in your gut-friendly smoothie!



When you take an excellent source of fiber and add in healthy plant-based omega-3 fatty acids, you get a unique source of prebiotics that, once again, boost the gut microbes that help you achieve that healthy gut list we talked about up top.

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Ground flaxseeds

Yes, ground. That's because flaxseeds need to be ground to release their health-promoting benefits. Once you do, you get the fiber and plant-based omega-3 fatty acids that you find in walnuts—and then some. Ground flax is also a source of mucilage, a somewhat slimy, gelatinous substance produced by plants that promotes healthy bowel movements and supports the microbiota.


Broccoli sprouts

So, at this point we have a great smoothie, but now it's time to pull out the big guns—no more games, microbiome! Broccoli sprouts are a personal favorite of mine. If you take broccoli seeds and sprout them, which requires a few days and some water but no soil, you get broccoli sprouts.

But why do you want to throw 'em in your smoothie? Broccoli—and, therefore, broccoli sprouts—contains sulforaphane, a phytochemical that has been shown to increase healthy gut microbes, repair tight junctions, and reduce intestinal permeability and bacterial endotoxin release. And here's the magic: When you eat broccoli sprouts, you get up to 100 times more sulforaphane than you would get from fully mature broccoli. As you might have guessed, broccoli sprouts are bitter, so ease into using them.

Remember, diversity is key.

While these five ingredients make for a great jumping-off point to create the ultimate gut-friendly smoothie, you are by no means required to stop there. Plant-based diversity is the key to gut health, so when you add more plants, you are rewarded with a healthier gut. Feel free to toss in a handful of greens, some chia seeds, or whatever suits your fancy.

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Will Bulsiewicz, M.D., MSCI
Will Bulsiewicz, M.D., MSCI

Dr. Will Bulsiewicz, M.D., MSCI is a gastroenterologist and internationally recognized gut health expert who wants to help you tap into the incredible healing power that lives inside you—your gut microbiota. His medical training involved 16 years at America's elite institutions. He completed a bachelor’s degree from Vanderbilt University, a medical degree from Georgetown University, and a master's in clinical investigation from Northwestern University. Bulsiewicz was also the chief medical resident at Northwestern and the chief gastroenterology fellow at UNC, and received the highest award given by both his residency and fellowship. He also completed an epidemiology fellowship at UNC's prestigious Gillings School of Global Public Health.