Rice hurts the stomach by itsstickiness

X. Wang

Cornell University Medical College, New York, USA

Summary Rice masses remove mucus from the stomach and duodenum as the sticky starch binds the stickymucus, weakening the defense against acid and pepsin which may in turn cause heartburn and ulcer. Such unwantedeffect can be avoided by taking enough water with rice meal as water converts rice masses into slurry. © 2000Harcourt Publishers Ltd

Medical Hypotheses (2000) 54(3), 430–431© 2000 Harcourt Publishers Ltd

DOI: 10.1054/mehy.1999.0868, available online at http://www.idealibrary.com on

Rice has been related to the formation of peptic ulcers (1,2). For many people who do not eventually develop anulcer, it is also a common experience that having rice,especially glutinous rice, may cause stomach discomfortor heartburn. Studies carried out to understand theunderlying mechanism have been mainly focused on thebran of rice (1). It has been found that bran oil becomesulcerogenic upon storage (1,2). The present workattempts to approach this question in a different way,offering an alternative explanation for the mechanismand, on the basis of it, a suggestion as to how to minimizethe unwanted effect of rice.

The gastrointestinal tract is protected by its mucosaepithelium and mucus layer, with the latter functioningas a mechanical and chemical buffer as well as a lubrica-tive (3). Mucin molecules, the major constituent ofmucus, are protein densely coated with oligosaccharides,which afford the stickiness and viscosity. Starch, whichmakes up most mass of rice, is polysaccharide. Uponhydration through cooking, rice becomes sticky. Whenrice is ingested into the stomach, it readily forms foodmasses that are sticky. As the food masses move along thestomach that undergoes peristalsis, the sticky rice takes

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Received 22 June 1998Accepted 22 March 1999

Correspondence to: Dr Xiao Wang, 450 East 63rd Street, Room 7G, NewYork, NY 10021, USA. Phone: +1 212 223 0997; Fax: +1 212 421 1122

the sticky gastric mucus with it through adhesion.Snowball effect results in removal of increasing amountsof mucus from the stomach wall. Moreover, as the foodmasses are mixed in this process, rice previously in themiddle of food masses is turned out and can bind moremucus, while the mucus bound rice is moved into themasses. Depending on the degree of stickiness and theamount of rice, the end result can be an effective peelingoff of gastric mucus, making the stomach vulnerable tothe damaging power of gastric acid and pepsin, which areall at their peak phase of secretion. Duodenum may beaffected in a similar way. Any kind of food will take a cer-tain amount of mucus with it, and the stomach secretesnew mucus to meet its normal needs. Problems arisewhen the removal of mucus becomes excessive and sur-passes the speed of new mucus secretion. Accordingly,glutinous rice would cause heartburn more readily thannonglutinous rice does, which is consistent with theexperience of the general public, especially Asians.

On the basis of the above discussion, it becomes clearthat unrefined cereals, when compared with refined riceand wheat, are associated with lower ulcer rates (2)because bran reduces the stickiness. It is, however, notnecessary for rice eaters to give up their favorite rice andshift to unrefined nonglutinous rice. A simple and effi-cient solution is to drink enough water or other liquidswhile having rice meal. Sufficient amounts of water canconvert rice masses into rice slurry in the stomach, whichis no longer able to remove large quantities of mucus.

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REFERENCES

1. Jayaraj A. P., Tovey F. I., Clark C. G., Rees K. R.., White J. S., LewinM.R. The ulcerogenic and protective action of rice and ricefractions in experimental peptic ulceration. Clin Sci 1987; 72:463–466.

© 2000 Harcourt Publishers Ltd

2. Tovey F. I. Duodenal ulcer in China. J Gastroenterol Hepatol1992; 7: 427–431.

3. Wang X. Aspirin-like drugs cause gastrointestinal injuries bymetallic cation chelation. Med Hypotheses 1998; 50: 227–238.

Medical Hypotheses (2000) 54(3), 430–431