Here’s What Your Farts May Be Telling You About Your Gut Health

Photo: Stocksy/Gillian Vann
It can be a little embarrassing to rip one in, say, a crowded elevator, but you know what? It’s natural. We’re human, and we all fart. Some people, however, may pass gas more often—and with a little more aroma—than others. Knowing what causes particularly fragrant flatulence, including the best and worst foods for digestion, can help you manage your farts and gut health.

What causes farts?

Essentially, farts are gas expelled by your body. The cause is a combination of swallowing air or food, breathing, and how the liver and gut (and the bacteria in the gut) interact. “What ends up in the large and small intestines as a result of these interactions ultimately leads to the production of feces—and, of course, farts,” says functional medicine expert Aaron Hartman, MD, who practices in Midlothian, Virginia.


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“Most of the gas you pass from your rectum is from swallowed air," he says. "The rest is produced by bacteria that live in your gastrointestinal tract and the interaction between the foods you eat, the liquids you drink, and those bacteria,” he says. This makes for an interesting (and sometimes stinky) milieu of gases.

Most of us don't think about passing gas—it just happens. This is the way it should be.

How are farts and gut health connected?

It's no secret that good health starts in the gut. The bacteria in your gut work to create postbiotics, or metabolically active chemicals, vitamins, nutrients, and fatty acids that affect our entire body's metabolism. Those things can boost our well-being, digestion, and immune system—as well as keep our farting less smelly and under control.

“If your gut is in good health, you will pass gas seamlessly, and you should not really notice you're doing it," says Dr. Hartman. "But if you do notice your gas, then you are passing more gas than usual and you need to think about what you're eating and drinking."

Most of us don't think about passing gas—it just happens. This is the way it should be. If you are gas passing noticeably more or experiencing an out-of-the-ordinary amount of bloating after eating, then you might want to have a chat with your doctor.

Watch this video for a dietitian's guide to gut health:

How does food impact your farts?

Foods that are rich in undigested non-absorbable fibers, aka prebiotics, are great to feed the healthy bacteria in the gut. But foods like sugar, processed food, and processed wheat can feed unhealthy bacteria and yeast—and thus battle with the healthy bacteria in your gut for the same terrain within the gastrointestinal tract. “This battle can result in bloating and the formation of foul-smelling gas,” says Dr. Hartman.

Interestingly, his training taught him to notice odors associated with certain types of infections. “You learn what scents signify what type of bacteria are predominant in the gut,” he says. “When you have seen people with infections, colitis, C. diff, and so forth, after a while you learn to tell by the gas what kind of strange brew is going on in the bowels."

That said, it's unlikely that an untrained nose would really be able to sniff out specific bacteria in the gut based on a pungent fart, so it's best to leave that to the professionals.

What are the best foods to eat?

The best foods to eat for gut health are brightly colored and fiber-dense. “One of the newer leading edges of research is looking at plant chemicals like polyphenols and phytosterols,” says Dr. Hartman. These are all fancy words for the colors of vegetables and fruits that feed the bacteria in your gut. “Carotenoids are yellow or orange, polyphenols are purple, naringins are orange, and the like all feed the bacteria in your GI tract,” he says. Eating the rainbow feeds your gut and promotes better digestion with a healthy amount of farts.

The next thing to include is fiber. “Some of the best forms are root vegetables, artichokes, Jerusalem artichokes, resistant starches, such as from cold cooked potatoes, yams, broccoli, brussels sprouts, and cauliflower,” he says. All of these are great sources of the right kind of fiber and the right kind of nutrition for your gut. So, enjoy these in side dishes, stir-fried meals, salads, and more.

You might also try eating foods with probiotics, such as Greek yogurt or kefir. You can enjoy Greek yogurt in a number of creative ways, including smoothies, as a bowl for breakfast, as a gut-healthy ingredient in desserts and dips, and more.

What are the worst foods to eat?

The worst foods to eat for your gut are processed foods. Period. “Processed corn turns into corn syrup, and processed wheat removes the fiber and the protein, leaving the carbs,” Dr. Hartman says. “The homogenization and pasteurization of processed milk and dairy [remove] the good bacteria and enzymes." These are examples of how processing can remove the good gut health benefits from the original foods.

“Processing all of these foods affects how our body interacts with the food,” he says. “For example, oil and water should not mix, but homogenized milk is just that,” he says. It is the process of making milk fats and water mix. “This does not bode well for the bowels that are exposed to this processed unnatural product,” he says.

The best way to maintain good gut health is to eat real, whole, and unprocessed food.

In general, the best way to maintain good gut health is to eat real, whole, and unprocessed food. “Organic is a starting point, but the ideal is to know where your food is coming from and to educate yourself about sourcing your food,” he says. (You can look at the Clean Fifteen, Dirty Dozen from the Environmental Working Group for a crash course.)

Put simply, choose fresh, natural foods when possible and avoid foods that are made with nitrates and other additives (like processed meat, for example.) It's a great starting point for gut health and for keeping your gas levels—and your farts' stink potential—in check.

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