Indoles
Indoles are a group of organic phytonutrients primarily found in cruciferous vegetables, which include broccoli, cabbage, kale, and brussels sprouts. These compounds are noted for their potential health benefits, particularly in cancer prevention and treatment, specifically against hormone-related cancers such as prostate, breast, thyroid, and cervical cancers, as well as colon cancer. Indoles, such as indole-2-carbinol and its derivative diindolylmethane, are believed to function by balancing estrogen levels in the body, potentially acting as estrogen blockers.
These phytonutrients may enhance the production of enzymes that help the body combat cancer. Indoles can be consumed through a diet rich in cruciferous vegetables, which can be prepared in various ways, including raw, steamed, or fermented. Though cooking methods can influence their flavor and odor, they can also affect nutrient retention. While naturally occurring indoles are preferred, dietary supplements derived from these vegetables are also available. However, the long-term effects of consuming high doses of indoles remain unclear, making moderation important.
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Indoles
DEFINITION: Dietary indoles are a family of organic phytonutrients found in plants that work with natural nutrients to protect against disease.
Cancers treated or prevented: May provide some protection from certain types of cancer, especially hormone-related cancers such as prostate, breast, thyroid, and cervical cancer, as well as colon cancer
Delivery routes: Oral ingestion through diet
How these compounds work: Cruciferous vegetables (named for the cross-shaped pattern on the underside of the stalk) contain the phytonutrients indole-2-carbonal (13C), its derivative 3,3'-diindolylmethane (DIM), and sulforaphane. One theory about why dietary indoles protect against cancer is that they contain phytonutrients that work as estrogen blockers. Researchers believe that the positive effect of dietary indoles may be related to improving the estrogen ratio of harmful estrogen to good or helpful estrogen. Indoles seem to lessen the effects, or rid the body, of the estrogen hormone and positively affect the estrogen metabolite balance. Research studies have demonstrated that dietary indoles participate in many biochemical processes in the human body and may increase the production of anticancer enzymes to improve the body’s natural ability to fight off cancer.
Dietary indoles can be found in Brassica or cruciferous vegetables such as cauliflower, brussels sprouts, cabbage, broccoli, bok choy, kale, and watercress, as well as collard, turnip, and mustard greens. These vegetables can be prepared in a variety of ways, including as raw vegetables added to salads, boiled, steamed, stir-fried, braised, or fermented, as in sauerkraut or pickled cabbage.
Some people avoid cabbage, as the cooking process releases a strong and somewhat unpleasant odor as a result of the sulfur compounds. To minimize the odor, the cabbage can be shredded so that it cooks faster, and a large pan can be used with the cabbage submerged in a large amount of water. The sulfur will dissolve into the water and minimize release into the air. The cabbage should be cooked only until tender, as overcooking contributes to the odor, and covering it immediately contains the smell. While cooking cabbage in a large amount of water can diffuse its strong taste and smell, steaming or quick cooking in smaller amounts of water retains nutrients.
Consuming naturally occurring dietary indoles is preferred, but cruciferous vegetable extract supplements may provide some benefit as well. They are available at reputable health food stores.
Side effects: It is unclear whether indoles cause side effects when taken in higher doses.
Bibliography
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