Relationship Between Dietary Protein Intake, Body Composition, and Physical Activity in Breast Cancer Survivors

While the overall survival rate for breast cancer has improved, breast cancer survivors (BCS) are still left with the negative side effects from cancer treatments that affect body composition. Cancer treatment side effects can cause a decrease in lean mass (LM), increase in fat mass (FM), and decrease in bone mineral density (BMD). PURPOSE: To evaluate the relationship between dietary protein intake habits and body composition (LM, FM, BMD) in BCS. METHODS: Thirty-two (59 ± 8 years) BCS participated. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Upper and lower body strength was measured via one repetition maximums (1RM) on chest press (CP) and leg extension (LE) machines, and handgrip (HG) strength was assessed using a HG dynamometer. Physical activity was assessed by pedometers. Dietary habits were recorded in a 3-day food log. Pearson product moment correlations and one-way analysis of variance was used to analyze and compare the data. All significance was accepted at p<0.05. RESULTS: The average BMI and steps/day classified the women as overweight (27.6 ± 5.6 kg/m2) and "low active" (6,286 ± 2,734 steps/day). The BCS consumed on average 1758 ± 517 kcal/day, with 16.4 ± 4% protein (1.00 ± 0.32 g/kg/day), 45.9 ± 7% carbohydrates, and 38.1 ± 5% fat. Average calcium and vitamin D intake (from food and supplements) were 2041.7 ± 710 mg/day and 1930.6 ± 1166 IU/day respectively. Significant correlations were found between protein and % body fat (r=-0.502) and LM:FM ratio (r=0.487). There were no significant relationships with other measurements of body composition, strength or steps/day. CONCLUSION: Our findings indicate that greater protein intake may attenuate increases in FM and improve the LM:FM ratio in BCS. Further research and larger samples are needed to elucidate potential benefits of protein on body composition in postmenopausal BCS.