childhood soy intake
Published by Bronwyn Schweigerdt on March 30, 2009 at 9:15 PMWhen I speak on childhood nutrition, a common concern is soy intake and it's relationship to children's hormonal status. Many mothers have been taught (by people paid by the Dairy Council, I believe) that the plant estrogens in soy can mess up a child's development.
In fact, nothing could be further from the truth. A brand new study just proved this, again.
A study called "Childhood Soy Intake and Breast Cancer Risk in Asian-American Women", published online in the Cancer Epidemiology, Biomarkers and Prevention Journal (vol.18), shows that Asian women who consumed the greatest amount of soy as children (under age 12) had a 60% lower risk of developing breast cancer as adults.
The study also showed a lower risk of breast cancer in women who consumed the most soy in adolescence and adulthood (20-25% less risk).
One of the reasons why I believe we see this enormous benefit of plant estrogens in children is because those who consumed the most soy were likely to enter puberty later. Myriad studies show that the later girls enter puberty, the lower the incidence of breast cancer in adulthood. Because plant estrogens in soy and other plant foods (fruit, veg.s, whole grains and legumes) lower real estrogen levels when they are unnaturally high by blocking the receptor sites on cell membranes, girls consuming more plant estrogens - whether in soy or other plant-based foods - would enter puberty at an optimum time, believed to be around age 17.
If entering puberty at age 17 sound far-fetched to you, know that plenty of young girls eating a vegan or vegetarian diet have this experience. It also used to be common in Western countries up to the turn of the 20th century, when meat was a luxury, due to lack of refrigeration. This age is still common for girls today in developing countries, where a plant-based diet is the norm for families who are not wealthy. In contrast, breast cancer is extremely uncommon.
One more thing: I am not a huge proponent of processed soy foods on a regular basis. You know, where you just exchange a hamburger for a Boca burger. Don't get me wrong, a Boca burger is a million times better than a hamburger, but because it's processed, as opposed to tofu, tempeh, miso, edename, or soy milk, it's lost a lot of nutrients and I put it in the category of "processed foods" as opposed to "plant foods". So make those fake meats only an occasional part of your diet.
And help dispel the myth that soy estrogens are anything but beneficial!
Labels: soy estrogens
4 comments:
I wonder if the benefit from eating much soy at a younger age is due to the soy itself, or because soy is often replaced by dairy, which may be cancer promoting?
Also, you touch on another relevant factor, the onset of puberty. Is it the soy that delays puberty, which you seem to say here or, again, is it because soy is often used as a meat and dairy substitute in Asia? Haven't meat and dairy been linked to a reduction in the age when people enter puberty? If so, the benefits of soy may not be as big as some people claim.
Don't take this the wrong way. I'm not trying to bash soy here. I'm a vegan living in Asia, and a soy lover. I just want us to use factually correct information, rather than spreading exaggerated claims that could be used against us later on.
Hmmm very interesting! I think there may be a combination of factors at work here- it's hard to tell without the proper control groups, etc. as the above mentioned. I do notice that girls are developing much faster today than when I was their age! (I'm 38) Could that also be due to hormones/ steroids in dairy and meat?
Yes, you're right. It might be that soy takes the place of animal foods and that may be the ultimate benefit. This study isn't enough to show otherwise. I think there are some great studies (I just need to dig them up) that are very similar in Africa, where soy is not consumed throughout childhood, but they do consume primarly a plant-based diet, and puberty onset is much later - around age 17.
I would say it's a combination of plant estrogens (from soy or other plant foods) and lack of saturated fat/cholesterol from animal foods that delays puberty and therefore prevents breast cancer.
I've been eating soy ( traditional Asian soy foods ) since I went vegetarian at 14 about 29 years ago, so it is hard for me to take the anti-soy hysteria seriously.
I don't eat as much as other people and I only eat the highly processed stuff when I go out to eat. For some reason vegan restaurants like to dominate their menus with faux meats.
It is always good to see more studies coming out to vindicate soy.
I must be getting old. Children going into puberty at 17 was still normal when I was growing up.
I think it is (literally) sick that 12 year olds and younger are going into puberty.