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I would like to know if a daily breakfast diet of Mung beans would be allowed for a woman who is estrogen receptor positive for breast cancer. I see that Mung beans are closely related to soy products, which have phytoestrogens. Soy products are not allowed for women who are estrogen receptor positive breast cancer patients.
This is a very interesting question. Phytoestrogens are naturally occurring chemicals that resemble natural estrogen. There is a lot of controversy about this topic and many oncologists feel strongly about the chance of these chemicals increasing the risk of recurrent cancer for those women with estrogen receptor positive breast cancer. Some of the controversy arises from the fact that there are a lot of different phytoestrogen compounds found in foods.
Whether or not soy products are an issue, there are a lot of phytoestrogens in soybeans. 103,920 micrograms (mcg) in 100 grams to be exact. It seems that some brilliant researchers in Canada looked at the phytoestrogen content in a number of foods (121 to be exact). Flax seed oil tops out at 379,380 mcg in 100 grams, being over triple the amount in the soybeans. (Mind you that's about a half cup of soybeans vs. about a half cup of flax seed oil and I am not sure I want that much flax seed oil.)
Anyway, mung bean sprouts come in at about 94 mcg in 1/4 cup. Not bad when you compare it to the over 100,000 mcg in the half cup of soy beans. That's only 4 times as much as a tablespoon of soy sauce but less than is in 1/4 cup of pistachios at 126 mcg. A 10 ounce cup of coffee comes in at about 18 mcg and a cup of orange juice 22 micrograms. Amazingly their results show doughnuts to have 1,568 mcg each and a slice of multigrain bread contains 2,270 mcg of various phytoestrogens.
Given these results it's less likely for your mung beans to have enough estrogen-like activity to be an issue. Certainly, you're a lot better off with them than a doughnut for breakfast. That said, if your oncologist feels that you should avoid mung beans for breakfast, you should follow their advice.
Thanks for writing,
Timothy S. Harlan, MD, FACP