Dietary antioxidants and risk of Barrett's esophagus and adenocarcinoma of the esophagus in an Australian population

While dietary antioxidants are emerging as potentially modifiable risk factors for esophageal adenocarcinoma (EAC), studies on dietary antioxidants and its precursor Barrett's esophagus (BE) are limited. The present study extends previous work on BE by investigating risks of nondysplastic BE, dysplastic BE and EAC associated with intake of antioxidants such as vitamin C, vitamin E, β-carotene, and selenium. Age and sex matched control subjects (n=577 for BE; n=1,507 for EAC) were sampled from an Australian population register. Information on demography, and well established EAC risk factors were obtained using self-administered questionnaires. Intake of antioxidants for patients newly diagnosed with nondysplastic BE (n=266), dysplastic BE (n=101), or EAC (n=299), aged 18-79 years, were obtained using a food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable adjusted logistic regression models. High intake of β-carotene from food and supplement sources combined was inversely associated with risk of dysplastic BE (OR Q4 vs. Q1=0.45; 95%CI: 0.20-1.00). High intake of vitamin E from food sources (OR Q4 vs. Q1=0.43; 95%CI: 0.28-0.67), from food and supplements combined (OR Q4 vs. Q1=0.64; 95%CI: 0.43-0.96), and a high antioxidant index score were inversely associated with risk of EAC. We found no significant trends between intake of β-carotene, vitamin C, vitamin E, and selenium and risk of nondysplastic or dysplastic BE. However, our data suggest that a high intake of β-carotene may be associated with decreased risk of dysplastic BE. What's new? Barrett's Esophagus (BE) is a premalignant condition caused by gastro-esophageal reflux that can progress to dysplasia and esophageal adenocarcinoma (EAC). The mechanisms behind this progression are unknown but oxidative stress has been implicated as a possible driver. The authors show that higher intake of beta-carotene is associated with reduced risk of dysplastic BE. A similar inverse association was observed for vitamin E consumption and EAC. In contrast, no association was observed between antioxidants and non-dysplastic BE. They point out that more research is necessary to understand how antioxidants protect the esophageal epithelium from malignant transformation.