Women who include the natural oestrogens isoflavones and lignans in their diet could be at reduced risk of endometrial cancer, the fifth most common cancer among women worldwide, report researchers.
The development of endometrial cancer is related to prolonged exposure to oestrogens without cyclic exposure to progesterone. Phytoestrogens, or oestrogens derived from plant foods such as soy, can remedy this balance and appear to reduce the risk of the cancer which causes between 4000 - 5000 deaths in the US each year, shows the study in today's issue of the Journal of the National Cancer Institute.
Dr Pamela L. Horn-Ross and colleagues from the Northern California Cancer Center in Union City, US evaluated the associations between dietary intake of seven specific compounds representing three classes of phytoestrogens (isoflavones, coumestans, and lignans) and the risk of endometrial cancer in a case-control study of women aged 35 to 79 in the San Francisco area.
Consumption of isoflavones and lignans, but not coumestans, was associated with a reduced risk of endometrial cancer, particularly among postmenopausal women. Obese postmenopausal women consuming relatively low amounts of phytoestrogens had the highest risk of endometrial cancer; however, the interaction between obesity and phytoestrogen intake was not statistically significant, reported the team.
"Some phytoestrogenic compounds, at the levels consumed in the typical American-style diet, are associated with reduced risk of endometrial cancer," they write. Soy-rich diets have previously been shown to reduce the risk of breast cancer in women.
Phytoestrogens are found in soy-based foods, but also in foods with added soy (such as white bread), and in lower amounts in coffee and orange juice.