Increased serum amylase and lipase in fructose malabsorbers

Fructose malabsorption is frequently seen in the general population and is characterised by the inability to absorb fructose efficiently. Due to fructose malabsorption, fructose reaches the colon where it is broken down by bacteria to short fatty acids, CO(2) and H(2). Bloating, cramps, osmotic diarrhea and other symptoms of irritable bowel syndrome are the consequence. We recently found that fructose malabsorption is associated with low plasma folic acid concentrations and low serum tryptophan and zinc. Because fructose malabsorption apparently is associated not only with malabsorption of other nutrients, but also with abdominal discomfort, it was of interest to examine whether mild pancreatitis may be involved.

We retrospectively examined our data in 159 otherwise healthy adults (110 females, 49 males) aged 14-84 years (mean 45.6+/-14.4 S.D.) with gastrointestinal complaints for serum amylase and serum lipase concentrations. The patients have been tested earlier for fructose malabsorption and lactose maldigestion by measuring breath H(2) concentrations after an oral dose of 25 g fructose and 50 g lactose, respectively, 1 week apart.

Fructose malabsorption (H(2) concentrations > or =20 ppm over baseline values) was detected in 107 of 159 individuals (67.3%). These subjects with fructose malabsorption presented with significantly higher serum amylase concentrations (73.1 U/l+/-25.7 S.D.) compared to individuals with normal fructose absorption (59.6 U/l+17.9 S.D; p=0.0009). Fructose malabsorbers also presented with higher serum lipase concentrations (122.0 U/l+/-100.3 S.D.) compared to normals (89.5 U/l+/-46.5 S.D.; p<0.05). To determine whether this finding is a consequence of any sort of malabsorption syndrome or whether it is specific for fructose malabsorption, all subjects were screened for lactose maldigestion. Lactose maldigestion (H(2) concentrations>20 ppm over baseline after lactose loading) was found in 50 of 159 individuals (31.4%). There were no significant differences in either amylase or lipase concentrations in lactose maldigestors.

Serum amylase and lipase concentrations are higher in subjects with fructose malabsorption compared to normals. Therefore, fructose malabsorption should be considered as a differential diagnosis in moderately elevated serum amylase.