Melanie Cole, MS (Host): Welcome to It's Your Health Radio with Henry Mayo Newhall Hospital. I'm Melanie Cole and joining me today to tell us about good digestive health is Dr. Neel Mann. She's an Associate Professor of Medicine and a Gastroenterologist at Keck School of Medicine of USC, and she's on the medical staff at Henry Mayo Newhall Hospital.

Dr. Mann, thank you so much for joining us today. I'd like to start with a sort of a working definition. When we say digestive health, what does that really even mean?

Neel Mann, MD, MPH: Well, I think what people are usually referring to when they say that, is something called the gut microbiome. And over the past decade, we've gained an appreciation for the vital role of microorganisms in the maintenance of health and disease. Diet, breastfeeding, environmental exposures and genetic factors help to shape how these microbes develop.

Generally speaking, after the age of three, your microbiome in the colon remain stable over time, but external factors prior to that can really help shape its makeup. Exposure to antibiotics, birth mode, diet. And the key is to really manage and maintain GI tract or gastrointestinal tract flora, or what we call the gut microbiome.

And that's an account of over 40 trillion cells. So there are much more of them than there are of human cells. And to maintain that in a natural way with a plant based high fiber diet that not only promotes gut flora diversity, but also reduces inflammation. So the gut microbiome in particular, is an important source of micronutrients that the human digestive system just cannot provide.

That's like B vitamins, folate, vitamin K. They help to regulate fat and cholesterol. They make something called short chain fatty acids, which is needed to maintain the integrity of the lining of the gut. They also defend against pathogens or harmful bacteria that can cause infection or disease. And they also have an important role in the gut immune system. So they work synergistically with the human digestive system to maintain health.

Host: Well certainly we're learning more and more about the gut microbiome and really the digestive system is such an important part that we didn't know as much about, but wow, what a field this has become. Now, how does someone know if they have good digestive health, what should our poops look like? For example, what is an indicator of good digestive health?

Neel Mann, MD, MPH: The best indicator overall is what you eat, your diet, to be honest. So getting back to fiber. Americans in particular as a whole are known to be fiber deficient. The recommended goal is at least 30 grams per day, and that can be insoluble fiber or roughage that's not completely broken down by the human digestive system.

For example, whole wheat, nuts, bran, cauliflower, green beans. They attract water into the stool, making it softer and easier to pass. And so if you are becoming more constipating, meaning, have a bowel movement less frequently, or your stools are becoming hard and pellet like, then the goal is to increase the fiber in your diet.

Fiber also helps to regulate glucose absorption by slowing down the gut, which then also decreases dramatic fluctuations in insulin release which if derangged, can lead to diabetes.

Soluble fiber dissolves in water and that includes apples, psyllium husk, beans, peas. Specific fruits that are high in fiber include kiwis, which is 2 grams, a pear, which is 6 grams, a cup of prunes, which is 12 grams. So remember the goal is 30 grams per day. I, in particular like to promote kiwis, two green kiwis per day without skin are excellent for those with constipation because kiwis are able to hold a high amount of water and bring that water into the lumen of the colon.

So overall fiber is really an important component for your overall health. In fact, for every 10 grams of fiber added to your diet, the risk of colon cancer decreases by 10%. And really both types of fiber are important for overall gut health, and I would recommend finding a fiber source really through your own diet rather than relying completely on supplements.

Things to look out for though that are alarming would be unintentional weight loss, a change in the caliber of your stool, anemia, iron deficiency, bleeding from your rectum, gas, bloating symptom, or distention of your abdomen. Those are symptoms that you need to bring to the attention of your physician.

Host: Well, thank you for that. That was a great answer. Now, as you talk about the symptoms, things we should watch out for to know whether we have this good digestive track. And you mentioned bleeding. Hemorrhoids cause bleeding and they scare the crap out of a lot of people. Right? You see that blood in the toilet.

And if you're a woman that's had babies or someone that has been overweight, there's a lot of reasons. So do we call our doctor when you see that? Is there a difference in what we would notice?

Neel Mann, MD, MPH: Not necessarily, and we don't always know that it's completely related to hemorrhoids, although it's one of the top reasons or causes for lower gastrointestinal bleeding. You don't want to rule out other things like colon cancer, a bleeding polyp or growth that could lead to cancer, inflammation of the rectum or colon called proctitis or colitis, an infection that can cause bleeding or what we call diverticula or little outpouchings or tics in the colon, those can also bleed.

So all in all, if you see blood in the toilet or on the toilet paper, make sure you bring that to the attention of your physician because it may or may not just be related to hemorrhoids. Having said that, that is one of the top reasons for lower gastrointestinal bleeding. The way to prevent hemorrhoids from bleeding would be to avoid straining or pushing to have a bowel movement.

Avoid prolonged sitting on the toilet. Don't sit on the toilet longer than two to three minutes at a time. Make sure you're very well hydrated. We recommend at least 64 ounces of fluids per day, 30 grams of fiber per day. Aerobic exercise at 30 minutes at a time, at least three to four times per week. If you're moving, your colon and your gut are moving as well.

Also, make sure that you're not low in iron. So, like we said before, if you see blood in the toilet, make sure your physician knows right away. It may or may not be related to hemorrhoids. We all have hemorrhoids. It's what keeps us continent, right? It prevents us from losing our stool by a mistake.

They become a problem though if they bleed or they become thrombosed with a clot or they prolapse, meaning they come out of your rectum and don't get pushed back in or they cause itching or discomfort. So again, hemorrhoids are normal, but if they bleed, that's abnormal. And again, we want to rule out or make sure you don't have other reasons for bleeding from the rectum.

Host: What about bloating, Dr. Mann? I mean, certainly as women, we get bloated at the drop of a hat because of our cycles, because of premenopause, postmenopause. I mean, it doesn't even matter. But when it's digestivebloating, when it's because of our gut; can you explain what some of the reasons for that might be and is that a visit to the physician as well?

Neel Mann, MD, MPH: Gas bloat is probably one of the most common reasons for or indications, referrals that I see in my clinic. It's very common in the United States. At least 10 to 15 percent of the U.S. population has some kind of what we call functional gut disorder or direct brain gut interaction, or what we used to call IBS. And gas bloat is part of that spectrum of functional gastrointestinal diseases. It's a complicated topic and one that really does necessitate a clinic visit with your gastroenterologist, but usually I will take a history regarding the patient's diet.

For example, there are some foods that are high in sugars that are easily fermentable and the by product of that fermentation is gas float. We call these foods high FODMAP type foods. That stands for fermentable oligosaccharides, monosaccharides, disaccharides, and polyols. That can include broccoli, cabbage, soy, kale, for example.

And when we go over a diet history, a lot of patients are eating these foods. It's not that they're necessarily bad for you per se, but if it causes discomfort, you may want to refrain from these foods for a short two to six week period of time. That's called stage one on a low FODMAP diet.

Stage two would be adding back one food one week at a time to see which food triggers the gas bloat. And then stage three would be going back to your regular diet and avoiding those two to three triggers. So one reason for gas bloat would be ingestion of gas forming foods or liquids, for example, sugarless gum or sugar sweeteners, those are also known to be gas forming.

Also, using a straw or chewing gum frequently is called aerophagia, so you're introducing air into the gut. The second cause is disordered handling of gas. So what we mean by that is in some people they have something called an abdominal phrenic dysregulation. So normally in health, when the diaphragm, when we take in a big deep breath, the diaphragm contracts and it pushes downward on the abdomen.

And those patients who have what we call a visceral hypersensitivity to smaller amounts of fluid or gas, the abdominal wall distends reflexively in relation to that amount of gas as the diaphragm contracts. So the second recommendation I recommend is diaphragmatic breathing exercises to aid in gas handling.

I recommend doing that for five full minutes before each meal.

Host: Ooh, that's really good advice.

Neel Mann, MD, MPH: And the third test, or I guess cause for gas bloat would be gas expulsion. So, if you have constipation, meaning infrequent bowel movements or hard pellet like stools, you will have gas bloat. They happen concomitantly or together, so you must treat your constipation and your ability to defecate fully and adequately in order to improve your gas bloat.

So, we come at it from a three pronged approach, gas introduction, gas handling, and gas removal.

Host: You're an awesome educator, Dr. Mann, really, really great. You explain things so well. Now, if somebody has problems and they can't eat those vegetables that give us the fiber that we need or that leafy greens, if it makes their stomach ache or causes gas and bloating, should they be taking probiotics? Should they be using a fiber supplement? What if we can't eat vegetables as many people with Crohn's or IBS can't?

Neel Mann, MD, MPH: Right. Well, just to go back to gas bloat, any woman that comes to my clinic or my office complaining of gas bloat, regardless of her age, she must get an evaluation of her pelvis, either an ultrasound of the pelvis or an MRI to make sure she doesn't have ovarian cancer. That needs to be ruled out first and foremost. If you have gas bloat and you still need to add fiber into your diet, there are fiber supplements that are more soluble.

The soluble type of fiber brings more water into the colon, unlike the insoluble fiber, because it dissolves in water. For example, kiwis, pears, apples. Insoluble fiber is that part of the plant that cannot be well digested, so it has to reach the colon, but in between your mouth and the colon is a small intestine, and that's where there can be fermentation of that fiber, which then leads to gas bloat.

So I recommend for my patients who suffer from gas bloat, who still want a high fiber diet to use a psyllium husk or ispaghula. It's a soluble type fiber, and there are other types of fiber in the foods which are not high FOD, high FODMAP that can also increase the fiber intake. Apples are notorious to cause gas bloat, but pears and kiwis are okay.

So I would just talk to your gastroenterologist with the aid of a nutrition or dietician, nutritionist or dietitian to make sure you're getting nutrients and fiber, but also to avoid foods that are possibly gas forming. But there is a way to still get a high fiber diet. Now, when it comes to probiotics, by definition per the National Institutes of Health, probiotics are considered to be live microorganisms, which when administered in adequate amounts confer or give you a health benefit to the host, or in this case, human beings.

So that includes bacteria, viruses, yeast. We don't really know how probiotics work, but we know that it makes it, quote unquote, harder for bad bugs to live in your gut. And bad bugs can give you gas, bloat, or diarrhea. Some good bugs can help your immune system fight infection. And other good bugs help keep the bad bugs from going to the rest of your body, which could cause an infection.

A prime example of that is something called Clostridioides difficile infection. And that's an infection of the colon after someone has been exposed to antibiotics. So at this point, we don't really know if one type or dose of probiotics is better than the other. The FDA does not regulate probiotics, so this means we do not know if probiotics are helpful or even safe for certain GI symptoms or illnesses.

Additionally, there's no recommendation from our academic gastroenterology societies to recommend probiotics in GI illnesses or even for overall health at this time. So instead, I recommend food based prebiotics that aid in growing and diversifying your own gut flora, like live cultured fermented milk such as kefir, fermented foods like sauerkraut, kombucha, kimchi.

These are fermented foods. Probiotics are food ingredients, unlike probiotics, which are live microorganisms, and they stimulate the growth of health promoting bacteria in the intestine.

Host: Ooh, I'm glad you mentioned kimchi and sauerkraut and kefir. I love all of those things. And we're learning so much more while we were speaking about probiotics, as far as the immune system and the digestive tract's relationship and all of that gut flora and microbiome, the relationship to our immune system.

So it really is fascinating. And I'd love for you to come on sometime and we can just talk about immune function and your field and what's going on there, but before we wrap up here I'd like to just speak a little bit about colonoscopies because obviously this is the gold standard. It's one of the very few cancer preventive procedures that we actually have. You know people are afraid of them. It's just prep, mostly. It's a good nap. You'll lose a pound. Can you speak about the age and your best advice for colonoscopies?

Neel Mann, MD, MPH: So, currently, there are 100 million people in this country who are age 50 to 75 and 20 million who are 45 to 49 and are eligible for colon cancer screening. Yet 53 million people remain unscreened and that's almost half of that population. Colon cancer is the third leading cause of cancer death in the U.S. overall. But it can be cured if caught early enough. There is a 91 percent 5-year survival if found early compared to 14 percent if it's already spread. Now, the good news is that the incidence of colorectal cancer in those 50 and above, so those in the boomer generation and older Gen X, has decreased in both men and women.

Unfortunately, however, it has increased in those age 20 to 49. In fact, colon cancer is the number one cause for cancer death in men less than the age of 50. So, this is why our guidelines for colon cancer screening changed in 2018 to start screening the general population at a younger age; 45 is now the new 50 is the tagline.

So, at this time, our GI Society guidelines recommend screening for colon cancer in the average risk person starting at age 45. And as you alluded to earlier, colonoscopy is the gold standard test because you can not only diagnose cancer, but also remove polyps or growths and thereby prevent the progression of cancer.

It is the only cancer screening test to do that. So, breast cancer screening, cervical cancer screening, prostate cancer screening, they pick up on the cancer itself, as opposed to colonoscopy, which picks up on lesions that could become cancer. Additionally, like you said, it's a very safe procedure, and if you have a high quality colonoscopy with an excellent bowel prep, then you won't need another one for 10 years.

Essentially, the point of cancer screening is not to prolong life, really, but to prevent early death. In fact, in the Minnesota Colon Cancer Control Study, there was a 70 percent reduction in colon cancer risk when we removed these polyps, the precursor lesion of colon cancer. And colon cancer screening just overall reduced mortality in general, from all causes.

 But adherence is the key to screening and surveillance. So if you decide to go with a stool based test, then you must do it either every year or every three years, depending on which stool test you take. Or if you go with the new blood test for DNA, then that must be done every three years. Or if you decide to go with the colonoscopy, then you must do it at least every 10 years or less, and that depends on the number, size, and pathology of the growths or polyps that are removed. And I'd like to add, to make an appointment or refer a patient, call 1-800-USC-CARE. C-A-R-E.

Host: Thank you so much, Dr. Mann. What an enlightening conversation this was. We learned so much. Thank you again for really sharing your incredible expertise and to take a colorectal cancer risk assessment, or to learn more about digestive health, you can visit the free health information library at library.henrymayo.com. And that concludes this episode of It's Your Health Radio with Henry Mayo Newhall Hospital. Please always remember to subscribe, rate, and review It's Your Health Radio on Apple Podcasts, Spotify, iHeart, and Pandora. I'm Melanie Cole. Until next time, thanks so much for joining us.