Patients with pancreatic cancer have higher-than-normal blood levels of the refined sugar fructose, according to a recent study in the journal Pancreas (www.pancreasjournal.com), official journal of the American Pancreatic Association and the Japan Pancreas Society. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.
The study also lends new insights into the way the body handles fructose, compared to other sugars. The results may provide important clues to understanding the health effects of high fructose intake—including a recent study linking consumption of soft drinks to pancreatic cancer risk. The study was led by Anthony P. Heaney, M.D., of David Geffen School of Medicine at UCLA.
Body's Handling of Fructose Is 'Underdeveloped,' Test Suggests
The researchers developed and evaluated a new test to measure the level of fructose in blood samples. Fructose is a natural sugar that, in highly refined and concentrated forms, is widely used in commercially produced foods and beverages, including soft drinks.
After confirming the precision of the new test, the researchers used it to measure fructose levels in healthy volunteers. After an overnight fast, the volunteers drank two cans of sugared soda—which contains a high dose of fructose, in addition to glucose. After drinking the soda, the volunteers' serum fructose level rose dramatically—more than eight times higher within 30 minutes. Fructose level decreased gradually, remaining elevated for longer than two hours.
In contrast, the volunteers' serum glucose levels did not rise as sharply and returned to normal within one hour. The difference suggests that the body is unable to metabolize such a large dose of fructose as rapidly as glucose. "[T]he human capacity to deal with large fructose loads is underdeveloped in comparison to tight physiological glucose control," Dr. Heaney and coauthors write.
In Pancreatic Cancer Patients, Fructose Levels Are Higher
The same test was used to measure fasting fructose levels in patients with pancreatic cancer. Their fructose level was more than twice as high as in healthy volunteers. (The pancreatic cancer patients did not perform the soda/high-fructose test.)
This result takes on special importance in light of preliminary studies linking fructose intake to obesity, diabetes, and other health problems—including pancreatic cancer. Most recently, a study reported that people who regularly drink soda may be more likely to develop pancreatic cancer. In that study, published in the February issue of Cancer Epidemiology Biomarkers & Prevention, people who drank two or more sodas per week had an 87 percent increase in pancreatic cancer risk.
The new test provides a simple new approach to measuring serum fructose level, overcoming the difficulties of previous tests. Measuring fructose levels may provide new insights into the relationship between high sugar intake and pancreatic cancer risk, according to Dr. Heaney and colleagues. "Considering the dramatic increase that has occurred in human fructose consumption and preliminary connections made between fructose intake and obesity rates," they conclude, "we believe that further investigations are urgently necessary to advance our knowledge of human circulating and tissue fructose concentrations and to establish guidelines for the safe consumption of fructose in both healthy subjects and those with a disease."
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