| Fructose intake may cause gastrointestinal distress
Fructose intake may cause gastrointestinal distress
Nutrition Research Newsletter, Nov, 2005
Fructose, also known as D-fructose or levulose, is found naturally in foods as a monosaccharide, as part of the disaccharide sucrose, and as a component of plant oligosaccharides. Fructose is considerably sweeter than sucrose and its use enhances the flavors and physical appeal (for example, color stability, humectancy, and freezing point depression) of many foods and beverages. The consumption of fructose has increased greatly in the United States, primarily as a result of increased use of high-fructose corn syrup in soft drinks and various confections. Portion sizes in general have increased in the United States, and consumption of fruit juices and drinks has also contributed to the increase in fructose intake. A potential consequence of increased consumption of fructose is gastrointestinal (GI) distress. Fructose empties from the stomach more rapidly than other sugars, fructose is more slowly absorbed than glucose, and less water and fewer electrolytes are absorbed during its transport across the intestine than during absorption of the same amount of glucose. The goals of this study included the determination of the frequency of fructose malabsorption and GI symptoms in normal, healthy people using two doses of fructose (25 g and 50 g) that were within amounts consumed in common beverages or foods today.
Fructose absorption was measured using three-hour breath hydrogen tests and symptom stores were used to rate subjective responses for gas, borborygmus, abdominal pain, and loose stools. The study included 15 normal, free-living volunteers from a medical center community and was performed in a gastrointestinal specialty clinic. Subjects consumed 25-gram and 50-gram doses of crystalline fructose with water after an overnight fast on separate test days. Mean peak breath hydrogen, time of peak, area under the curve (AUC) for breath hydrogen and gastrointestinal symptoms were measured during a three-hour period after subjects consumed both 25-gram and 50-gram doses of fructose.
More than half of the 15 adults tested showed evidence of fructose malabsorption after 25 g fructose and greater than two-thirds showed malabsorption after 50 g fructose. AUC, representing overall breath hydrogen response, was significantly greater after the 50 g dose. Overall symptom scores were significantly greater than baseline after each dose, but scores were only marginally greater after 50 g than 25 g. Peak hydrogen levels and AUC were highly correlated, but neither was significantly related to symptoms. This demonstrates that fructose, in amounts commonly consumed, may result in mild gastrointestinal distress in normal people. Additional study is warranted to evaluate the response to fructose-glucose mixtures (as in high-fructose corn syrup) and fructose taken with food in both normal people and those with gastrointestinal dysfunction. Breath hydrogen peaks occurred at 90 mins to 114 mins and were highly correlated with 180-minute breath hydrogen AUC, so the use of peak hydrogen measures may be considered to shorten the duration of the exam. This study supports that it is likely that the amounts of fructose consumed today, at least in some forms, could be responsible for adverse GI complaints in normal, healthy people.
P. Beyer, E. Caviar, R. McCallum. Fructose intake at current levels in the United States may cause gastrointestinal distress in normal adults. JADA; 105 (10): 1559-1566 (October 2005) [Correspondence: Peter L. Beyer, MS, RD, Associate Professor, Dietetics and Nutrition, Mailstop 4013, University of Kansas Medical Center, 3901 Rainbow, Kansas City, KS 66160]
__________________  |