Get ready to uncover the secrets of your stomach's mysterious language! Have you ever wondered what those grumbling sounds really mean? Join us as we discuss the science behind stomach growls. It's time to satisfy your curiosity and transform your mealtime soundtrack.

M: I’m Professor Megan 

S: and I’m Professor Susan, and we’re

Both: Your Nutrition Profs!

M: We are registered dietitians and college professors who have taught more than 10,000 students about health and nutrition. We have answered a LOT of questions about nutrition over the years – 

S: Some questions we get asked every year and some are rarely asked but very interesting.

M: We’re here to share our answers to these common (and uncommon) nutrition questions with you.

S: So bring your curiosity and let’s get started. 

Both: Welcome to our class!

S: Hey everyone. Listen to this….. (Baxter’s bowel sounds). Have you ever heard strange sounds like that coming from your abdomen? Were you hungry at the time? Or were you really full? or maybe stressed out? What in the heck are those sounds anyway? 

M: Today we’re going to answer the question, “Why does my stomach growl”?

S:  Or gurgle or grumble… This question is from a listener in South Dakota and we do love listener questions. 

M: Yes, keep them coming! 

S: Ok, so these strange noises like the ones we just heard come from our abdomens and they happen to everyone. These actually came from my dog Baxter who has some digestive issues once in a while and I actually mentioned him in our IBS episode a few weeks ago. Poor Baxter.

M: Poor Baxter! Well our bodies make all sorts of noises. Body noises are normal and natural, but they can be embarrassing!

S: For sure.

M: Joints can pop or creak, we sigh, we cough, we belch, hiccups, farts- all of it. 

S: Yeah, but today we’re going to focus on the sounds our digestive system makes and these are usually called stomach growling or stomach grumbling, but the sciencey word for this is borborygmi and that’s the Greek word for “rumbling”.

M: I like that.

S: Borborygmi.

M: Some people say it sounds like “water moving through pipes”.

 S: Well, the GI tract is hollow so…

M: Yeah, it’s…

S: …I can see that!

M: kind of what’s happening.

S: Yeah, it really is.

M: Medical professionals often call them “bowel sounds”. Bowel is just another word for intestine. And as we said, these noises are absolutely normal. 

S: The sounds, the rumblings are caused by rhythmic muscle contractions of your digestive organs and these muscle contractions are called peristalsis.

M: These muscle contractions begin in the esophagus and continue throughout the gastrointestinal tract to the anus and are often described as coming in waves. The function of these contractions is to push food through the tract from organ to organ during digestion, kind of like pushing toothpaste out of the tube.

S: Yeah, that’s a good analogy. The contractions occur fairly regularly, sort of like your heartbeat only slower. And they occur about 3 times per minute in the stomach, and about 12 times per minute in the small intestine. 

M: And just like your heartbeat, the number of contractions can be influenced by several things. They increase when food is present in the GI tract after eating which makes total sense.

S: Mmm hmm.

M: You’re trying to digest your meal.  

S: Right. But they also increase after your stomach and small intestine have been empty for about 2 hours. And scientists think there are receptors in the wall of the stomach that sense the absence of food and this absence of food causes waves of electrical activity and that causes what they call “migrating myoelectric complexes” or MMCs. 

M: MMCs cause muscle contraction of the stomach and intestinal walls, probably to sweep out all of the leftover stomach contents including mucus, any food residue, and bacteria so that they don’t accumulate in the stomach or in the intestinal folds. 

S: And these contractions produce vibrations and rumbling noises associated with being hungry. They usually continue for 10 to 20 minutes, and then stop. But the process repeats every 1-2 hours until you eat something. 

M: These muscle contractions that create the noises are not the same as “hunger pangs” or “hunger pains” which are a sensation of discomfort, gnawing, or pain in your stomach or abdomen. 

S: So what's the difference? Let’s explain the difference.

M: Well, hunger pangs are caused by the stomach’s release of a hormone called ghrelin when the stomach is empty. The hormone travels to the brain telling it to “seek out food”. The pangs usually begin when you’ve gone 12 to 24 hours without eating and can be very uncomfortable. 

S: So that’s hunger pangs.

M: Correct.

S: Not the same as stomach growling, ok. But back to our borborygmi…we often notice these sounds when our stomachs are empty, but our digestive system makes sounds all the time. The sounds might just be a little bit more noticeable when we’re hungry because there is less in the digestive tract to muffle them or you might be paying more attention. 

M: Yeah. These sounds are so important to overall health that there is actually a push by some to classify them as “vital signs” like heart rate, blood pressure, and body temperature. These sounds can be indications of the health of our digestive system and healthcare professionals will often listen to these “bowel” sounds using a stethoscope. The sciencey word for this is called auscultation of the abdomen.  

S: More sciencey words… Yay! 

M: You gotta love ‘em!

S: The sounds are notoriously difficult to measure directly and assess. And current gut health diagnostic tools are expensive and they can usually only be found in places like hospitals. So there are research groups that are trying to use AI to generate tools that would help identify and analyze these sounds.

M: Like an electrocardiogram (or ECG or EKG) is used to assess heart health.

S: Yeah, right. These would probably be cell phone apps for both doctors and patients and might be especially useful for people who have GI disorders, like IBS. If you haven’t already listened, we just did an episode about IBS a couple of weeks ago, so check it out. 

M: You know, an app would be so cool to listen to those sounds. 

S: It would be cool.

M: As we stated earlier, these are usually assessed by abdominal auscultation via a stethoscope. And bowel sounds are identified as normal, hypoactive, or hyperactive. 

S: But just because you have hypo or hyperactive bowel sounds it doesn’t necessarily mean there is a problem with your digestive system. 

M: Well hypo means low, so hypoactive bowel sounds means you’re having fewer than normal. And this can occur if you’re taking certain medications, opioids for pain, like codeine, and even supplements like iron, can slow down digestion and elimination. Or if you have a bowel obstruction, if you’re coming out of general or spinal anesthesia. If you’ve had radiation treatments of the abdomen or even if you’ve had abdominal surgery.

 S: So all of that makes sense, right? You’re usually told not to consume any food or even water for 6 to 12 hours before you go under general anesthesia. And that’s because undigested food can cause complications like vomiting or aspiration. Aspiration is when food comes into the esophagus and the lungs.

M: Right, so no food in your system means less peristalsis which means less gurgling and fewer noises. 

S: So hypoactive!

M: Yep.

S: Now the opposite can also happen. Your digestive system may make more sounds than usual and that’s called being hyperactive. And this happens especially if you have issues like food allergies or intolerances, like lactose intolerance, fructose intolerance or sugar alcohol intolerance. You can also have hyperactive bowel sounds if you are experiencing diarrhea or constipation, if you have inflammatory bowel disorders like Crohn’s or ulcerative colitis. If you have celiac disease or you’re like my dog Baxter and you’re having an IBS day!

M: Noises can also increase with infection: stomach flu (the sciencey word is viral gastritis), food poisoning, inflammation of the small intestine (another sciencey word is infectious enteritis), or even GI bleeding. All of these can increase sound.

S: Wow this episode is so full of sciencey words! 

M: Yes, so pay attention it will be on the test… No I’m just kidding…

S: If you have not been diagnosed with any of the conditions that we just mentioned, but you have excessive noises along with other symptoms like fever, nausea or vomiting, frequent diarrhea or constipation, bloody stools, or unintentional or sudden weight loss, please see a healthcare provider. 

M: Definitely. Your doctor will usually do blood tests, CT scans, or an endoscopy or colonoscopy which is where they send a camera through your digestive system to see if there are issues.  

S: And you may also notice more gurgling and grumbling after consuming foods that are more difficult to digest. Foods high fiber foods: beans/lentils, cruciferous vegetables (like broccoli, cauliflower, or Brussels sprouts), and even some leafy greens, especially if you’re not used to eating them.

M: Or if you consume “gassy” foods like carbonated beverages or foods that contain certain alternative sweeteners, especially sugar alcohols like sorbitol, xylitol, and mannitol which can be difficult for some people to digest. 

S: Foods high in sugar, alcohol, and acidic foods (like citrus fruits and coffee) can also increase your bowel sounds. I definitely notice more stomach noises after drinking beer, but not so much after drinking coffee.

M: And slowing down can help! Chew food slowly and with your mouth closed to minimize swallowing air that can lead to increased bowel sounds. 

S: So many people eat so fast! I’ve really been trying to slow down my own eating.

M: Yeah, I eat really fast too.

S: You do!

M: I know, I know I do! But that’s a good idea. Eating quickly can lead to overeating as well as can take about 20 minutes for the gut to send messages to the brain that it’s being fed. And eating large portions can also contribute to hyperactive bowel sounds.

S: That’s happened to me before. I’ve eaten a super large meal really, really quickly, like within a few minutes. And then about 20 minutes later I feel miserable! If I just slowed down my eating, I would have felt full sooner and I probably wouldn’t have eaten as much. 

M: The Nutrition Profs always recommend slowing down and enjoying a meal. 

S: Enjoy your food.

M: Yes. A follow-up question that we’ve gotten on this topic is, “Why does my stomach growl more at night?” 

S: Well there are several reasons that scientists think you might hear these sounds more often at night. One reason is you may actually be hungry. It may have been several hours since you’ve eaten. Another reason could be you’ve eaten a large meal before bedtime, especially if the meal is high in fat or accompanied by alcohol and your environment may be quieter at night and so you’re less distracted and so that makes the sounds more noticeable. 

M: Some people may notice more sounds when under stress. Those stomach “butterflies” can also cause discernible sounds. 

S: But the bottom line, stomach growls, rumblings – they are absolutely normal. 

M: But if you want to minimize the noises your digestive system makes there are some things you can do. 

S: One of my favorites is to take a walk after eating, not super strenuous exercise but just a nice leisurely walk to increase blood flow to all body parts. And if you’re in the UK, this is often called an “evening constitutional”. This is a walk after dinner to benefit health and improve digestion. 

M: Oh I like that.

S: Me too.

M: Another way to help reduce these sounds is to manage stress with slow deep breaths or even meditation. 

S: And of course, there are food-related ways to reduce the sounds. One way is to drink water throughout the day but another way of course, is to eat something, especially if the sounds are because you’re hungry. Eat a snack.

M: And if you do eat something, avoid gassy foods like carbonated beverages and those with sugar alcohols. Eat slowly and keep mouth closed when chewing to reduce swallowed air. And avoid alcohol, sugar, and highly acidic food.

S: You know, if you find you have more sounds than usual along with the symptoms we mentioned like abdominal pain, nausea/vomiting, or diarrhea or constipation, check with your doctor. 

M: Otherwise, embrace the sounds as an indicator that your digestive system is working the way it’s supposed to. 

S: I like that. Embrace it. Thanks for joining us today! Keep sending us those interesting nutrition questions!

M: Join us next time when we will actually be answering a few questions in an episode we’re called a sampler platter.

S: I’m looking forward to it.

M: Yep.

Both: Class dismissed.

S: We hope you enjoyed this episode. You can find the show notes and a list of sources on our website, yournutritionprofs.com. 

M: Your homework is to follow us at your nutrition profs on Instagram and to listen to our next episode. You can listen on Amazon Prime, Apple Podcasts, Spotify, YouTube, or anywhere podcasts are found. We’d appreciate it if you’d “like” us, write a review, subscribe, and invite your family and friends to join us too. 

S: If you have a nutrition or health question you’d like answered, let us know! We may even do a show about it! Send an email to yournutritionprofs@gmail.com or click on the “Contact Us” page on our website.

M: Thanks to Brian Pittman for creating our artwork. You can find him on instagram @BrianPittman77

Both: See you next time!