Effect of a Low Glycemic Index Diet on Prostate Specific Antigen

Abstract

BackgroundEpidemiological studies have shown an association between consumption of a low glycemic index (GI) diet with reduced prostate cancer risk; however, clinical trials are lacking.
ObjectiveTo determine the effect of a low GI diet compared to a control, high fiber, diet on serum prostate specific antigen (PSA) levels, a biomarker of prostate carcinoma. 
MethodsIn a randomized parallel trial, men with type 2 diabetes were assigned to either a low GI or a high fiber diet for 6 months. PSA levels were assessed in a secondary analysis from blood samples obtained at baseline and end of study. 
ResultsOf the 100 completers, 84 men had PSA levels available at baseline and end of study. Overall, the mean baseline PSA level was 2.10+0.59 ng/mL which decreased by 0.08 + 0.11 ng/mL on the low GI diet and by 0.03 + 0.12 ng/mL on the control diet over the 6 months. No treatment differences were observed (P>0.05). 
LimitationsThis study was not appropriately powered for the outcomes measured in this secondary analysis.ConclusionLow GI diets have been associated with decreased prostate cancer risk; however, future trials should study the effects on PSA and other markers of prostate cancer in higher risk populations.FundingBarilla