The effects of exercise and diet on oxidative stress and telomere length in breast cancer survivors

Purpose: Cancer and its treatments accelerate biological aging. This analysis tested the hypothesis that exercise and diet reduce oxidative stress and prevent telomere shortening in breast cancer survivors. Methods: In a 2 × 2 factorial design, 342 breast cancer survivors who were insufficiently physically active and had overweight or obesity at enrollment were randomized to one of four treatment groups for 52 weeks: control, exercise alone, diet alone, or exercise plus diet. The endpoints of this analysis were the change from baseline to week 52 in 8-iso-prostaglandin F_2α (8-iso-PGF_2α) and lymphocyte telomere length. Results: Baseline telomere length was shorter than age-adjusted normative values (median difference: − 1.8 kilobases; 95% CI − 2.4, − 1.1); equivalent to 21 years (95% CI 17, 25) of accelerated chronological aging. Compared to control, exercise alone did not change 8-iso-PGF_2α [9.9%; 95% confidence interval (CI) − 1.0, 20.8] or telomere length (13.8%; 95% CI − 15.6, 43.3). Compared to control, diet alone was associated with reduced 8-iso-PGF_2α (− 10.5%; 95% CI − 19.5, − 1.5) but did not change telomere length (12.1%; 95% CI − 17.2, 41.3). Compared to control, exercise plus diet was associated with reduced 8-iso-PGF_2α (− 9.8%; 95% CI − 18.7, − 0.9) but did not change telomere length (− 8.5%; 95% CI − 32.1, 15.2). Change in 8-iso-PGF_2α did not correlate with change in telomere length (r = 0.07; 95% CI − 0.07, 0.20). Conclusion: In breast cancer survivors, diet alone or exercise plus diet were associated with reduced oxidative stress but did not change telomere length. This analysis may inform future trials that aim to optimize healthy aging in cancer survivors.