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Abstract
Background: Epidemiological studies indicate that added sugar consumption and plasma concentrations of insulin-like growth factor (IGF-1) are associated with increased cancer risk, particularly for breast and colorectal cancers, but data are less clear for many other cancers (references). Insulin, which stimulates the production and release of IGF-1, is released post-prandially after glucose consumption, but not after fructose consumption. The objective of this study was to investigate whether known differential effects of glucose vs. fructose are linked to differential effects on fasting plasma IGF-1 and IGFBP-3 concentrations.
Methods: In this randomized, crossover, double-blind, controlled feeding study, twenty-four healthy, normal weight to obese men and women were fed identical diets in three eight-day diet phases separated by 20-day washout periods. The only difference between the dietary phases was that subjects consumed beverages sweetened with a different sugar (fructose vs. high-fructose corn syrup vs. glucose) in each phase. Beverages were administered in four servings totaling 25% of each subject’s total estimated energy requirement, and participants were required to drink all of each beverage each day. Solid-foods were also provided, at 125% of estimated energy requirement, and were consumed ad libitum. Fasting plasma samples were drawn at the end of each diet phase and tested for concentrations of IGF-1 and IGFBP-3. Our primary outcome measure was the ratio of IGF-1/IGFBP-3. Repeated measures analysis of variance (RM-ANOVA) was used to test for a linear trend in diet effect, as well as for any (non-linear) diet effect.
Results: We observed no significant difference in total energy intake or body weight between the three diet phases. We did not find any differential effect based on diet phase, either linear or non-linear, on any of our outcome measures.
Conclusion: In healthy normal weight to obese men and women, different types of added sugars consumed in the form of sweetened beverages over 8 days each did not differentially affect fasting plasma IGF-1 plasma concentrations.
