Marc J. Gunter, Naomi J. Guppy, Austin Obichere, Neil Murphy, Abigail Fisher, Andrew Steptoe, Nicholas Finer, Malgorzata Heinrich, Helen Croker, Jane Wardle, Robert Goldin, Rose Wilson, Rebecca J. Beeken
The aim of this study was to explore the potential effects of diet-induced weight loss on molecular biomarkers of colorectal cancer risk in serum and colorectal tissue.
This single-arm exploratory study included 20 adults with BMI ≥ 30 kg/m2 completing an 8-week, complete, low-energy liquid diet. Pre- and postintervention anthropometric measurements, fasting blood draws, and endoscopic examinations to procure colorectal biopsies were performed. Fasting insulin, glucose, insulinlike growth factor 1 (IGF-1), C-reactive protein (CRP), and blood lipids were measured in serum, and tissue markers of apoptosis (M30), colonocyte proliferation (Ki-67), and insulin signaling (phospho-mTOR) were assessed using immunohistochemical staining.
Participants achieved substantial weight loss (mean = 13.56%). Mean concentrations of insulin, glucose, and cholesterol were significantly reduced (P < 0.05), but IGF-1 and CRP were not. Colorectal tissue expression of Ki-67 was significantly reduced (preintervention mean score = 7, postintervention mean score = 3.9, mean % change −43.8; P = 0.027). There were no significant changes in M30 or phospho-mTOR.
Weight loss in individuals with obesity was associated with improvements in insulin sensitivity and blood lipid profiles and a significant reduction in tissue Ki-67 expression. This is one of the first studies to demonstrate potential cancer-relevant changes in colorectal tissue following weight loss achieved through diet.