Nutrition and evidence-based science

Last week the press was flooded with information from a study linking fructose to Pancreatic Cancer. As you can imagine, this caught my attention. When study findings are released that build up the results beyond their importance it can be harmful to the public. This study which was published in the August issue of Cancer Research did just that, and has resulted in premature and potentially misleading conclusions.

What is fructose? Table sugar is sucrose, which is a disaccharide made up of is half fructose and half glucose. High fructose corn syrup is a sweetener made from corn and can be found in numerous foods and beverages. High fructose corn syrup is made of half fructose, with the remaining sugars being primarily glucose.

In terms of composition, high fructose corn syrup is nearly identical to table sugar. Fructose is found naturally in fruits, vegetables, maple syrup and honey. All fructose works the same in the body, whether it comes from corn syrup, cane sugar, fruit, or vegetables. Only the amounts are different.

In this study, pancreatic cancer cells in lab dishes (not in humans) utilized fructose as an alternate energy source to glucose for fueling growth. The scientists compared pure fructose to pure glucose, neither of which is consumed in isolation in the diets of humans. In the U.S. we consume far more fructose from sugar than from high fructose corn syrup. And we do consume a lot of sugar! The link to obesity and pancreatic cancer is currently being studied "in humans" at the National Institutes of Health and other university research institutes and there may be a correlation. But, the implication that a high fructose diet causes pancreatic cancer or somehow makes it worse is erroneous. Many more studies on rats and humans are needed to make this claim.

In the research field, one study does not make for evidence. To make conclusions about nutrients and cancer, nutrition scientists usually use one of three methods-cross over design studies on humans where participants are given specific nutrients in specific amounts and biomarkers for cancer in the blood are measured; rat studies where tumors are initiated and the effects of specific nutrients on the tumors are studied; and epidemiological studies that look at diets and populations over time.

If you became concerned about fructose after hearing the news last week, rest assured that more studies will be underway. Please don't stop eating those fruits and vegetables-the antioxidants, fiber and other nutrients are too important for the diet.