A research team from the University of Texas MD Anderson Cancer Center has reported new evidence showing that phytoestrogens are associated with a decrease in risk of lung cancer, in the Journal of the American Medical Association (JAMA). 

A complete copy of the original contribution can be found online at the website for the Journal of the American Medical Association. 

The research team examined the relationship between dietary intake of phytoestrogens and risk of lung cancer within an ongoing U.S. case-control study of 1,674 patients with lung cancer and 1,735 matched healthy controls. All participants were interviewed frequently to determine the dietary intake of 12 individual phytoestrogens for a time period between July 1995 and October 2003. 

The research team found the risk cancer to be 46 per cent lower for those with the highest phytoestrogens intake from all foods, or 21 per cent if they had a high intake of phytosterols.  Phytosterols are components added to products to lower cholesterol.

The research team from the University of Texas MD Anderson Cancer Center noted the limitations and concerns regarding case-control studies of diet and cancer, though feel their data adds to the growing epidemiologic evidence that phytoestrogens are associated with a decrease in risk of lung cancer.

Confirmation of these findings is still required in large-scale, hypothesis-driven, prospective studies.

Phytoestrogens are naturally occurring plant compounds that are similar in some ways to estradiol, the most potent naturally occurring estrogen. However, phytoestrogens tend to have weaker effects than most estrogens, are not stored in the body, and can be easily broken down and eliminated.

Observational studies have found a lower prevalence of breast cancer, heart disease, and hip fracture rates among people living in places like Southeast Asia, where diets are typically high in phytoestrogens. As a result of these studies, a great deal of interest has been generated in the United States about the health benefits of phytoestrogens. According to the Food and Drug Administration, the sale of soy foods, a major source of phytoestrogens, has increased dramatically in the past decade.

Dietary Sources of Phytoestrogens

Phytoestrogens consist of more than 20 compounds and can be found in more than 300 plants, such as herbs, grains, and fruits. The three main classes of dietary phytoestrogens are isoflavones, lignans, and coumestans:

Isoflavones (genistein, daidzein, glycitein, and equol) are primarily found in soy beans and soy products, chickpeas, and other legumes.

Lignans (enterolactone and enterodiol) are found in oilseeds (primarily flaxseed), cereal bran, legumes, and alcohol (beer and bourbon).

Coumestans (coumestrol) can be found in alfalfa and clover.

Most food sources containing these compounds typically include more than one class of phytoestrogens.

More about Dietary Phytoestrogens