Selenium in rice and esophageal cancer.

To the Editor

The recent publication on “Selenium levels in rice samples from high and low risk areas for esophageal cancer”1 is very interesting. Rahimzadeh-Barzoki et al,1 reported that “high soil and rice selenium levels may play a possible role in the pathogenesis of esophageal cancer.” Rice is the main food source for millions of the world’s population. It is routinely consumed in Asian countries. The problem of contamination in rice is widely discussed. The present report implies the important consideration of selenium and possible relationship to cancer problems in Iran.1 Nevertheless, it should be noted that there are many other possible contaminations that are not well studied in the present report, those contaminants could also cause cancer. A good example is arsenic,2 which is an important contaminant found in many Southeast Asian countries. Monitoring for contaminants in rice and estimation of cancer risk should be checked routinely, and should be an important policy for promoting rice safety.2

Primary Care Unit, KMT Center

Bangkok, Thailand

Hainan Medical University

Hainan, China

Special thanks to Dr. Yasri and Dr. Wiwanitkit, for their comments on our recent paper.1 We would like to address the following points.

Regarding previous reports from the Golestan province of Iran on the possible relationship between esophageal cancer and selenium levels in serum3 and soil4 samples, we aimed to assess such correlation in rice samples from our region.

We agree that different contaminations may occur in agricultural products including rice, and some of these contaminations may play possible roles in carcinogenesis. In this regard, several studies have been conducted and are being run in our region to assess the levels of different contaminants in rice samples including heavy metals such as arsenic, and some types of toxins such as aflatoxins. Results of these studies will help us to better understand the role of environmental factors in the pathogenesis of esophageal cancer in the Golestan province of Iran.

Environmental Health Research Center

Golestan Research Center of

Gastroenterology and Hepatology

Golestan University of Medical Sciences

Gorgan, Iran