Eating Soy May Turn on Genes Linked to Cancer Grow
2016-08-26 15:39阅读:
伊利诺大学医学院-神经内科-主治医师 mingtao
wang
Eating Soy May Turn on Genes Linked to Cancer Growth
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- Topic: Diagnosis,
Risk
Factors, and Nutrition
- Tags: Early-stage:
Stage 0 -- DCIS (Ductal Carcinoma in Situ), Early-stage:
Stage IA, Early-stage:
Stage IB, Early-stage:
Stage IIA, Early-stage:
Stage IIB, Ductal
Carcinoma In Situ, Invasive
or Infiltrating Ductal Carcinoma, Invasive
or Infiltrating Lobular Carcinoma, Soy,
and
Diet
Soybeans are the most widely used, least expensive, and least
caloric way to get large amounts of protein. You can eat soybeans
in many forms, including tofu, the beans themselves (also called
edamame), soy milk, miso, and soy powder.
Soy foods have a lot of isoflavones, which are weak estrogen-like
compounds found in plants. Because estrogen can promote the
development, growth, and spread of breast cancers, doctors have
worried that eating a lot of soy foods or soy isoflavones (which
can be taken as a dietary supplement) might worsen the prognosis of
women diagnosed with breast cancer.
While past research results have been mixed, a small study done by
researchers at the Memorial Sloan Kettering Cancer Center and Weill
Cornell Medical College suggests that for some women, adding a
medium amount of soy to their diets turns on genes that can cause
cancer to grow.
The research was published in the Sept. 4, 2014 issue of the
Journal of the National Cancer Institute. Read the
abstract of
“The Effects of Soy Supplementation on Gene Expression in Breast
Cancer: A Randomized Placebo-Controlled Study.”
The study involved 140 women who were newly diagnosed with stage I
or stage II breast cancer between 2003 and 2007. Each woman had
recently had a breast biopsy and was scheduled to have either
mastectomy or lumpectomy in 2 to 3 weeks.
During those 2 to 3 weeks, the women were randomly assigned to
receive either:
- soy protein (70 women)
- a placebo that looked like the soy protein (70 women)
The women in the soy protein group were given about 52 grams of soy
protein – equal to about 4 cups of soy milk – per day. The
researchers chose this amount because it would be reasonable for
people who regularly eat soy to eat that much in one day.
After the women had surgery to remove the breast cancer, the
researchers compared tissue from the biopsy (before the women
consumed the soy supplement) to tissue from the cancer (after the
women consumed the soy).
The results showed that several genes that encourage cell growth
were turned on in women in the soy protein group.
The study didn’t last long enough to know whether these genetic
changes would cause cancer to grow.
The study also didn’t look at:
- whether soy does or doesn’t reduce the risk of breast
cancer
- whether eating soy would have any effect on women who don’t
have breast cancer or who have non-cancerous breast lesions
The researchers didn’t recommend that women avoid soy. But they did
say that soy should be eaten in moderation.
“If you currently have early-stage breast cancer, don’t eat soy in
large amounts,” said Jacqueline Bromberg, M.D., Ph.D., who was one
of the study’s authors. “If you’ve had breast cancer, you can eat
soy, but in moderation.”
So in general, it’s fine to eat moderate amounts of soy foods –
about one to three servings per day as part of a balanced diet (a
serving is about a half cup). If you’ve been diagnosed with breast
cancer and are concerned about any isoflavone effects, ask your
doctor or a registered dietician about how much soy you can
eat.
In the Breastcancer.org
Nutrition section,
you can learn more about healthy eating before, during, and after
breast cancer treatment.
Published on September 5, 2014 at 1:12 PM