Straining at stool over time may force part of the stomach up into the chest, contributing to GERD acid reflux disease. This may explain why hiatal hernia is extremely rare among populations eating high-fiber diets.
Diet and Hiatal Hernia
In terms of preventing acid reflux heartburn, I’ve talked about how high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal, but why does high fiber intake decrease the risk? One typically thinks of fiber helping out much lower in the digestive tract.
A systematic review and meta-analysis found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer.
This could be because of the phytates in high-fiber foods slowing cancer growth, or could be the anti-inflammatory effects, or fiber could be removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may decrease the risk of reflux in the first place. But how?
Hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux up into the esophagus and throat. It affects more than 1 in 5 American adults. In contrast, in rural African communities who were eating their traditional plant-based diets, it wasn’t 1 in 5; it was closer to one in a thousand—almost unheard of. It’s almost peculiar to those who consume Western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools; three or four times the volume of Westerners.
What does the size and consistency of one’s bowel movement have to do with hiatal hernia? A simple model may help illustrate the mechanism producing upward herniation of the stomach through the hole in the diaphragm, which separates the abdomen from the chest, called the esophageal hiatus. If a ball with a hole in its wall is filled with water and then squeezed, the water is expressed through the hole. The abdominal cavity may be likened to a ball, the hole in the ball corresponding to the esophageal hiatus in the diaphragm. So abdominal straining during efforts to evacuate firm feces corresponds to squeezing the ball, and may result in gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It’s like when you squeeze one of those stress balls. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.
When we bear down and strain at stool, it’s like squeezing our abdomen, and may herniate part of our stomach up. Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely sub-diaphragmatic, whereas it usually straddles the diaphragm in Westerners, and is above the diaphragm in the presence of hiatus hernia.
And the same abdominal pressure from straining that may cause hiatal hernias may cause a number of other problems. The straining can cause herniations in the wall of the colon itself, known as diverticulosis. And that same pressure can also back up blood flow into the veins around the anus, causing hemorrhoids, and push blood flow back into the legs, resulting in varicose veins as well.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
Please consider volunteering to help out on the site.
- AJ Bredenoord, JE Pandolfino, AJ Smout. Gastro-oesophageal reflux disease. Lancet. 2013 Jun 1;381(9881):1933-42.
- HG Coleman, LJ Murray, B Hicks, SK Bhat, A Kubo, DA Corley, CR Cardwell, MM Cantwell. Dietary fiber and the risk of precancerous lesions and cancer of the esophagus: a systematic review and meta-analysis. Nutr Rev. 2013 Jul;71(7):474-82.
- DP Burkitt. Hiatus hernia: is it preventable? Am J Clin Nutr. 1981 Mar;34(3):428-31.
- Burkitt DP. Diseases of the alimentary tract and western diets. Pathol Microbiol (Basel). 1973;39(3):177-86.
- H Beaumont. The acid pocket, hiatal hernia and TLESRs : essential players in thepathogenesis of gastro-esophageal reflux disease. 2009. 165.
- GE Boeckxstaens, WO Rohof. Pathophysiology of gastroesophageal reflux disease. Gastroenterol Clin North Am. 2014 Mar;43(1):15-25.
- DP Burkitt, PA James. Low-residue diets and hiatus hernia. Lancet. 1973 Jul 21;2(7821):128-30.
- DP Burkitt, AR Walker, NS Painter. Dietary fiber and disease. JAMA. 1974 Aug 19;229(8):1068-74.
- DP Burkitt. Two blind spots in medical knowledge. Nurs Times. 1976 Jan 1-8;72(1):24-7.
- K Iwakiri, M Kobayashi, M Kotoyori, H Yamada, T Sugiura, Y Nakagawa. Relationship between postprandial esophageal acid exposure and meal volume and fat content. Dig Dis Sci. 1996 May;41(5):926-30.
Images thanks to The Clear Communication People via Flickr and Sara Marchetto.
In terms of preventing acid reflux heartburn, I’ve talked about how high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal, but why does high fiber intake decrease the risk? One typically thinks of fiber helping out much lower in the digestive tract.
A systematic review and meta-analysis found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer.
This could be because of the phytates in high-fiber foods slowing cancer growth, or could be the anti-inflammatory effects, or fiber could be removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may decrease the risk of reflux in the first place. But how?
Hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux up into the esophagus and throat. It affects more than 1 in 5 American adults. In contrast, in rural African communities who were eating their traditional plant-based diets, it wasn’t 1 in 5; it was closer to one in a thousand—almost unheard of. It’s almost peculiar to those who consume Western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools; three or four times the volume of Westerners.
What does the size and consistency of one’s bowel movement have to do with hiatal hernia? A simple model may help illustrate the mechanism producing upward herniation of the stomach through the hole in the diaphragm, which separates the abdomen from the chest, called the esophageal hiatus. If a ball with a hole in its wall is filled with water and then squeezed, the water is expressed through the hole. The abdominal cavity may be likened to a ball, the hole in the ball corresponding to the esophageal hiatus in the diaphragm. So abdominal straining during efforts to evacuate firm feces corresponds to squeezing the ball, and may result in gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It’s like when you squeeze one of those stress balls. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.
When we bear down and strain at stool, it’s like squeezing our abdomen, and may herniate part of our stomach up. Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely sub-diaphragmatic, whereas it usually straddles the diaphragm in Westerners, and is above the diaphragm in the presence of hiatus hernia.
And the same abdominal pressure from straining that may cause hiatal hernias may cause a number of other problems. The straining can cause herniations in the wall of the colon itself, known as diverticulosis. And that same pressure can also back up blood flow into the veins around the anus, causing hemorrhoids, and push blood flow back into the legs, resulting in varicose veins as well.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
Please consider volunteering to help out on the site.
- AJ Bredenoord, JE Pandolfino, AJ Smout. Gastro-oesophageal reflux disease. Lancet. 2013 Jun 1;381(9881):1933-42.
- HG Coleman, LJ Murray, B Hicks, SK Bhat, A Kubo, DA Corley, CR Cardwell, MM Cantwell. Dietary fiber and the risk of precancerous lesions and cancer of the esophagus: a systematic review and meta-analysis. Nutr Rev. 2013 Jul;71(7):474-82.
- DP Burkitt. Hiatus hernia: is it preventable? Am J Clin Nutr. 1981 Mar;34(3):428-31.
- Burkitt DP. Diseases of the alimentary tract and western diets. Pathol Microbiol (Basel). 1973;39(3):177-86.
- H Beaumont. The acid pocket, hiatal hernia and TLESRs : essential players in thepathogenesis of gastro-esophageal reflux disease. 2009. 165.
- GE Boeckxstaens, WO Rohof. Pathophysiology of gastroesophageal reflux disease. Gastroenterol Clin North Am. 2014 Mar;43(1):15-25.
- DP Burkitt, PA James. Low-residue diets and hiatus hernia. Lancet. 1973 Jul 21;2(7821):128-30.
- DP Burkitt, AR Walker, NS Painter. Dietary fiber and disease. JAMA. 1974 Aug 19;229(8):1068-74.
- DP Burkitt. Two blind spots in medical knowledge. Nurs Times. 1976 Jan 1-8;72(1):24-7.
- K Iwakiri, M Kobayashi, M Kotoyori, H Yamada, T Sugiura, Y Nakagawa. Relationship between postprandial esophageal acid exposure and meal volume and fat content. Dig Dis Sci. 1996 May;41(5):926-30.
Images thanks to The Clear Communication People via Flickr and Sara Marchetto.
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Diet and Hiatal Hernia
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Content URLDoctor's Note
This can be considered a companion video to Diet and GERD Acid Reflux Heartburn.
Hiatal hernia is not the only condition that high fiber diets may protect against. See:
- Dr. Burkitt’s F-Word Diet
- One in a Thousand: Ending the Heart Disease Epidemic
- How to Prevent High Blood Pressure with Diet
I’ve got a load of other bowel movement videos dropping soon. Stay tuned for:
- How Many Bowel Movements Should You Have Every Day?
- Should You Sit, Squat, or Lean During a Bowel Movement?
- Diverticulosis: When Our Most Common Gut Disorder Hardly Existed
- Does Fiber Really Prevent Diverticulosis?
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