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United States Department of Agriculture

Agricultural Research Service

Title: The Metabolism, Distribution and Cancer-Prevention Properties of Broccoli Containing High Concentrations of Selenium

Authors
item Finley, John
item Davis, Cindy
item Feng, Yi - UNIV. OF NORTH DAKOTA

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 9, 1998
Publication Date: N/A

Technical Abstract: Broccoli and selenium consumption is related to a decrease in the rate and incidence of certain cancers. We have conducted a series of studies that have examined the metabolism and efficacy of cancer prevention of broccoli with high concentrations of selenium (high-Se broccoli). Rats fed a selenium-deficient diet for six weeks were repleted with Se (0.1 mg/kg diet) supplied as either selenate, selenite, selenomethionine (SeMet), or high-Se broccoli (grown hydroponically and containing 28 mg Se/kg dry). Absorption of Se from high-Se broccoli was significantly lower than from other sources. Selenite, selenate and SeMet were similarly effective in restoring most measures of Se status; high-Se broccoli was much less effective. However, selenium from high-Se broccoli was equally effective as the other forms in restoring kidney and plasma selenium concentrations. Healthy young men were fed a test meal that contained stable isotopes of selenium in the form of a salt (selenate) or intrinsically incorporated into broccoli. Less selenium from broccoli, than from selenate, was found in the plasma and urine. In a third study, rats were fed selenium deficient diets or diets supplemented with selenium as selenate or high-Se broccoli. Rats were injected with a carcinogen and, after eight weeks, examined for pre-neoplastic lesions in the colon. Rats supplemented with selenium from high-Se broccoli had significantly fewer lesions than control animals; selenate had no effect. We conclude that selenium from broccoli is not metabolized the same as selenite, selenate or SeMet, and this results in different patterns of selenium retention and distribution in the tissues of humans and rats. We also conclude that high-Se broccoli is potentially effective in preventing colon cancer.

Last Modified: 10/1/2014