Featured Research

from universities, journals, and other organizations

Soy Phytoestrogens May Block Estrogen Effects

Date:
January 16, 2006
Source:
Wake Forest University Baptist Medical Center
Summary:
Research in monkeys suggests that the natural plant estrogens found in soy do not increase markers of breast cancer risk in postmenopausal women. In fact, they may provide a protective effect in some women. The research is reported today in Cancer Research.

Research in monkeys suggests that the natural plant estrogens found in soy do not increase markers of breast cancer risk in postmenopausal women. In fact, they may provide a protective effect in some women. The research is reported today in Cancer Research.

"Even at high doses, we found no evidence that the estrogen-like compounds in soy, called isoflavones, stimulate cell growth or other markers for cancer risk in breast tissue," said Charles E. Wood, D.V.M., Ph.D., lead researcher, from Wake Forest University Baptist Medical Center. "The study also suggests that women who have higher levels of estrogen may actually gain a protective effect from higher doses of soy isoflavones."

Wood said there has been much debate about whether higher levels of dietary soy are safe or beneficial for postmenopausal women. Some evidence has suggested that isoflavones may protect against the more powerful estrogen produced by the body, which is an important risk factor for breast cancer in postmenopausal women. For example, population studies show that women who consume diets high in soy generally have lower rates of breast cancer.

On the other hand, soy isoflavones have been shown to stimulate breast cancer cells in mice and in cells grown in the laboratory.

"Our study sought to make sense of these seemingly contradictory data," said Wood. "Our hypothesis was that estrogen levels in the body may influence the effects of soy isoflavones."

Wood and colleagues evaluated the effects of dietary isoflavones in the presence of different levels of estrogen by rotating 31 postmenopausal cynomolgus monkeys through eight different diets. Each diet contained one of four different isoflavone doses along with either a low or a high dose of estrogen.

Isoflavone doses were equivalent to the following human levels: no isoflavones, 60 milligrams (comparable to the typical Asian diet), 120 milligrams (the highest levels that can be consumed through diet alone), or 240 milligrams (levels obtained through supplements). Estrogen doses were designed to mimic either a low or high-estrogen environment found in postmenopausal women. Estrogen levels in postmenopausal women can vary depending on their amounts of body fat, which produces estrogen, and whether they are taking hormone therapy.

The researchers measured how the diets affected markers for breast cancer risk, including breast cell proliferation. In the low-estrogen environment, no evidence of increased proliferation was seen at any level of isoflavone exposure, even at doses almost several times higher than in a typical Asian diet.

In the high-estrogen environment, there was higher breast cell proliferation both when isoflavones weren't in the diet and when they were present in lower doses. However, the addition of high levels of dietary soy isoflavones tended to block estrogen effects in breast tissue. This finding suggests that postmenopausal women with higher levels of estrogen may derive the greatest benefit from soy.

"For women at increased risk of breast cancer due to higher estrogen levels, a diet rich in soy isoflavones may offer a modest breast-protective effect," said Wood. However, he said the study may not apply to premenopausal women, who have higher and more dynamic hormone levels, or to women taking combined hormone therapy with an estrogen and a progestin.

The senior investigator of the study was J. Mark Cline, D.V.M., Ph.D. Other researchers involved in the study were Thomas C. Register, Ph.D., and Mary S. Anthony, Ph.D., both from Wake Forest Baptist, and Adrian A. Franke, Ph.D., from the Cancer Center of Hawaii.

###

The research was funded by the National Center for Complementary and Alternative Medicine.

Wake Forest University Baptist Medical Center is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,187 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.


Story Source:

The above story is based on materials provided by Wake Forest University Baptist Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

Wake Forest University Baptist Medical Center. "Soy Phytoestrogens May Block Estrogen Effects." ScienceDaily. ScienceDaily, 16 January 2006. <www.sciencedaily.com/releases/2006/01/060115154340.htm>.
Wake Forest University Baptist Medical Center. (2006, January 16). Soy Phytoestrogens May Block Estrogen Effects. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2006/01/060115154340.htm
Wake Forest University Baptist Medical Center. "Soy Phytoestrogens May Block Estrogen Effects." ScienceDaily. www.sciencedaily.com/releases/2006/01/060115154340.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Poses Little Threat To U.S.: CDC

Ebola Outbreak Poses Little Threat To U.S.: CDC

Newsy (July 29, 2014) The Ebola outbreak in West Africa poses little threat to Americans, according to officials with the Centers for Disease Control and Prevention. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins