Selenium in broccoli has cancer-protective effects.




J Agric Food Chem

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Consumer Data: Selenium
Professional Data: Selenium


Until the late 1950s, selenium was thought to be toxic. Although it can be toxic at high doses, it is now recognized as an important nutritional trace mineral. Selenium plays important roles in detoxification and antioxidant defense mechanisms in the body. Epidemiological studies have correlated low dietary selenium intakes with higher rates of cancer, and selenium helps to reduce lipid peroxidation and neutralizes destructive hydrogen peroxide radicals. It also potentiates the antioxidant activity of vitamin E. The symptoms of selenium deficiency include: destructive changes to the heart and pancreas, sore muscles, increased red blood cell fragility, and a weakened immune system. Whole grains are the best dietary source of selenium followed by seafood, garlic, liver, eggs, dairy products, and some vegetables including cabbage, celery, cucumbers, broccoli, and radishes.

A recent study was conducted by the United States Department of Agriculture. The purpose was to examine the protective properties of high-selenium (HS) broccoli and high-selenium broccoli sprouts against chemically induced mammary or colon cancer. The researchers stated that HS broccoli reduces colon cancer, but this vegetable has never been tested on mammary cancer. In addition, broccoli sprouts have not been tested for their anti-carcinogenic properties in colon cancer, although they could be of benefit due to their secondary plant compounds that are known to protect against cancer. In an animal study, mice were given either 3 mcg of selenium supplied by broccoli, or 0.1 mcg of selenium as selenite, with or without broccoli. The HS broccoli group had significantly fewer mammary tumors than the group given selenite. In another part of this study, mice were fed 2 mcg of selenium ether as broccoli florets or sprouts, and they had considerably less aberrant colon crypts than mice fed with 0.1 to 0.2 mcg of selenite with or without broccoli administered. The authors concluded that protective forms of broccoli include sprouts against colon cancer. Also, high selenium broccoli demonstrated cancer protective effects in mammary cancer as well.1


1. Finley JW, et al. Cancer-protective properties of high-selenium broccoli. J Agric Food Chem. 2001 May;49(5):2679-83.