- Soy consumption
has previously been linked to cancer. But a new study has shown that soy could lower risk for breast cancer
- The fiber rich
food contains isoflavones which lower
- High consumption of soy was found to reduce the risk of
breast cancer by 21%
link between consuming soy products and the risk of breast cancer has been laid
to rest after a study published in the Journal Cancer
which has shown that dietary soy products are beneficial and safe
for women suffering
. These foods that are considered to be one of the healthiest
foods, were believed to increase the risk of
breast cancer due to their estrogen-like properties. The greatest risk is
associated with hormone receptor positive cancer, which is thought to thrive in the presence of elevated estrogen
Soy and Breast Cancer
Fang Fang Zhang from the Friedman School of Nutrition Science and Policy at
Tufts University said that the isoflavones which are the components of soy with
estrogen-like properties are associated
with a reduction in the rate of
growth of breast cancer cells under laboratory conditions. Dr. Zhang further stated that an epidemiological analysis of East Asian women
with breast cancer showed that elevated intake of isoflavones was associated with
reduced mortality. The major limitation is that the isoflavanols with the
estrogen-like effects lowered the efficiency of the hormone therapy for breast
cancer. This has led to the confusion about whether the intake of soy should be
recommended or whether it should be restricted.
‘Regular inclusion of soy in the diet is necessary to lower risk for breast cancer and to prevent recurrence.’
Dietary Intake of
The association between intake of dietary
soy and death that occurs due to any cause was studied by Dr. Zhang and her
colleagues. The study was conducted on 6235 Canadian and American women who
were diagnosed with breast cancer, for a period of nine years. The findings of
the study showed that
- There was a 21%
lower risk of death among women with breast cancer with high intake of
isoflavones when compared with women who consumed low amounts.
- The reduction in
risk was found to be mostly associated with women who had hormone receptor-negative tumors and who were not on tamoxifen therapy.
- There was no
increase in mortality when there was an increased intake of isoflavones among women who received hormone therapy, which is contrary to
- High soy intake
was found to have a protective effect among women with hormone
receptor-negative breast cancer.
Zhang said that the studies showed that there was no detrimental effect that
was identified among women with breast cancer who consumed
a large amount of soy food.
survival rate among women with hormone receptor-negative breast cancer was more than 20%, as it is a more aggressive
form of cancer. Dr. Esther John from the Cancer Prevention Institute of
California said that the results of the study showed that increased intake of
isoflavones improved survival rates. The study involved the intake of dietary
soy from foods and not from supplements.
exact mechanism of action of these isoflavones and their interaction with
breast cancer cells is not well understood but previous studies indicate the
following properties of the soy foods
Effect of Soy on
studies have shown that soy
are important for women's health.
- It is a primary
source of isoflavones and is found to protect against multiple myeloma ovarian cancer and breast
- Intake of soy
foods by women with breast cancer have reduced cancer recurrence
- 38% reduction in
mortality among women who drink at
least one cup of soy.
- Soy has a protective
effect against endometrial cancer.
- 30% lowered
endometrial cancer risk among women who consumed soy.
- Ovarian cancer
risk reduced by half among women who consumed soy.
- Soy intake is
found to reduce hot flashes, lower delay in the onset of premature menarche
- Intake of soy is
associated with lowered osteoarthritis symptoms with significant boost in
bone mineral density. It could also prevent bone loss and improve new bone
milk is found to contain the same amount of calcium but twice the antioxidant
content found in cow's milk. Good sources of soy are tofu, edamame, soymilk and
Soy Intake and Risk of
Breast Cancer in Asian Americans
Anna M. Whu and colleagues from the Department of Preventive Medicine studied
the risk of soy intake among adolescents and adults in Asian Americans. The
scientists carried out a case control study to identify the role of traditional
whole soy food of Asians on breast cancer risk.
results of this study showed that there was a significant reduction in the risk
for breast cancer among adolescents and adults who consumed whole soy food.
study showed that:
- The effect of soy
intake on breast cancer risk was more pronounced among adolescents than
- The scientists
found a lasting protection when adolescents consumed soy
- Participants who
consumed low amounts of soy in their
diet during adulthood, but who were high consumers of soy during adolescence showed a
21% reduction in risk for
- Studies conducted
on a small sample size showed that low consumption during adolescence and
high consumption during adulthood did not have a significant association
with breast cancer risk. Though further studies are required to support
this finding, if found to be true, it could lead better dietary inclusion
of soy during adolescence.
Soy is a plant protein which is rich in
fiber, magnesium, potassium and other vitamins. Dr. Clare McKindley who is a
clinical dietitian working with MD Anderson's Cancer Prevention Center says
that soy contains all the essential amino acids which are necessary to support
the body's vital functions. People on a vegan or vegetarian diet, especially
people with food allergies can include soy in their diet to get the optimum level
of amino acids. A moderate amount of soy in the diet is 3 daily servings, one
serving could be
- 1 cup of soy milk
- 1/3 cup of tofu
- 1/2 cup of
- 1/2 cup cooked
inclusion of soy in the diet is a healthy way to gain the required amino acids
as well as to lower the risk for breast cancer. The current study aided in
understanding the reduction in risk for breast cancer on the inclusion of soy
in the diet and the effect on mortality rates. This information could be used
to increase awareness about the benefits of consumption of whole soy.
- Soy and Breast Cancer - (https://www.oncologynutrition.org/erfc/hot-topics/soy-and-breast-cancer/)
- Do soy foods increase cancer risk? - (https://www.mdanderson.org/publications/focused-on-health/september-2014/soy-cancer.html)
- Soy - (http://nutritionfacts.org/topics/soy/)
- Anna.H.Wu, Peggy Wan, Jean Hankin, Chieu, Chen Tseng, Mimi, C. Yu and Malcolm C. Pike "Adolescent and Adult Soy Intake and Risk of Breast Cancer in Asian Americans"; Carcinogenesis, 2002