Phytoestrogens are plant-derived nonsteroidal compounds found in soy products, grains, carrots, spinach, broccoli, and other fruits and vegetables, according to background information in the article. They have weak estrogen-like activity. The three main classes of phytoestrogens are isoflavones, lignans, and cumestrans. A fourth group of plant-derived steroidal compounds believed to have estrogenic properties are the phytosterols. Phytoestrogens have been shown to have a protective effect against some solid tumors, but there has been little epidemiologic research focused on dietary intake of phytoestrogens and lung cancer risk.
Matthew B. Schabath, Ph.D., and colleagues at the University of Texas M.D. Anderson Cancer Center, Houston, analyzed data from an ongoing case-control study to examine the relationship between dietary intake of phytoestrogens and the risk of lung cancer. The study included 1,674 patients with lung cancer (cases) and 1,735 matched healthy controls. From July 1995 through October 2003, study participants were personally interviewed to obtain information on demographics, socioeconomics, and smoking history. Women were asked whether they had taken hormone therapy in the previous six months. A food frequency questionnaire was used to collect dietary data on intake of 12 individual phytoestrogens.
"Our main findings were that patients with lung cancer tended to consume lower amounts of phytoestrogens than controls, that there were sex-specific differences both in intake and in protective effects, and that the apparent benefits were evident in both never and current smokers but less so in former smokers," the authors report.
Reduction in lung cancer risk tended to increase with increasing phytoestrogen intake. "The highest quartiles of total phytoster
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