Can Soy Increase Your Risk for Breast Cancer?

Today’s blog post is from Chris Page. He is a nutrition supplement guru and wanted to share his research findings in honor of Breast Cancer Awareness Month.

Can Soy Increase A Woman’s Risk Of Breast Cancer?
It’s a common questions from breast cancer survivors. October is Breast Cancer Awareness month, so we thought it was only appropriate to shed light on the old myths surrounding the dangers of soy. The most
common being that soy may increase a woman’s risk of developing breast
This has been proven repeatedly to be FALSE…!
The belief that soy may increase a woman’s risk of developing breast
cancer was never true. The following published studies have shown that; soy protein does not increase a woman’s risk of breast cancer, women
who consume soy protein actually have a lower risk of developing breast cancer and furthermore, studies show soy protein is safe to use for
breast cancer survivors.

Soy Does Not Increase The Recurrence Risk Of Breast Cancer
Interestingly, for women who are breast cancer survivors, definitive
clinical studies regarding the consumption of soy foods have shown that
soy does not increase one’s risk of breast cancer recurrence or their risk
of dying from breast cancer. In December 2009, the first of these studies was published in the Journal of the American Medical Association by
researchers at Vanderbilt University and Shanghai Institute of Preventive Medicine.[1]
The study enrolled 5042 Chinese women who had been diagnosed with
breast cancer and followed them for an average of 3.9 years. The women were divided into four groups and based on the amount of soy in their
diet. The results showed unequivocally that breast cancer survivors with the greatest intake of soy had a 25% lower risk of breast cancer
recurrence as well as a 25% lower risk of dying from breast cancer
compared to the group with the lowest soy consumption. Just as
impressive, these findings were similar for those with estrogen
receptor-positive and negative cancers, for early stage and late stage
breast cancer, as well as for those women who were pre- and
Other studies have shown no significant effects of soy on breast cancer
recurrence or even a protective effect. In fact, there have been no studies
showing any detrimental effects of soy consumption by breast cancer
survivors.A meta-analysis combining data from over 11,000 survivors of
breast cancer in the US and China was published in 2013.
Again, those individuals consumed the highest intake of soy had a 23%
decrease in recurrence and a 15% decrease in mortality from breast

What we’ve found is there are still many people who still believe many
unsubstantiated old soy myths. We’re going to put those myths to rest
right now.
First, all of the negatives surrounding soy come from decades old, and
poorly executed, studies based primarily on cell culture experiments
from rats and mice, whose physiology is unlike human physiology. To the contrary, other studies report consumption of soy protein diets inhibits
the growth of various tumors in rats. Additionally, metastatic growth to
the lungs of a primary rhabdomyosarcoma tumor was inhibited by
feeding a soy protein diet.[3]
In this population of breast cancer survivors, higher soy and cruciferous vegetable intake was associated with less treatment-related menopausal symptoms and fatigue.[4]

Additional Research Facts Surrounding Soy
Soy has what are called phytoestrogens which are plant-based estrogens. When certain phytoestrogen compounds were studied in isolation, some were shown to increase cancer cell growth. However, that has never
been shown in human’s. A newer study published in the 2017 edition of Cancer found soy to be a lifesaver when it comes to breast cancer
survivors.[5] The health effects of soy foods have been rigorously
investigated for more than 25 years. More than 2000 soy-related
peer-reviewed articles are published annually. Much of this research has been conducted because independent of its nutrient content there is
evidence that soy exerts a variety of health benefits, especially related to
the prevention of chronic disease.[6]

The Proven Health Benefits Of Soy Dwarf Those Of Any Other Vegetable Or Animal Protein
Here are just a few of these benefits…Directly lowers blood cholesterol
levels, Lowers the risk of heart disease, Modestly elevate HDL (the good) and decreases triglyceride levels (the bad).
Helps in the prevention of osteoporosis, Protects against various forms of cancer. In fact, human data indicate that isoflavones, regardless of the
source of soy, do not exert harmful effects on breast tissue. Studies for
post-diagnosis soy intake improves the prognosis in women who have
had breast cancer. Soy intake during adolescence lowers breast cancer
risk later in life. Epidemiological evidence suggests that men who eat soy daily are less likely to develop prostate cancer than those who do not. No study have ever shown negative effects on circulating reproductive
hormone levels in men or women.
Soy isoflavones promote prostate health and reduce prostate cancer risk.
Soy protein has been shown to help prevent age-related loss in skeletal
muscle. There is no clinical evidence to suggest soy protein lowers serum testosterone levels or exerts any estrogen-like or feminizing effects in
men. Soy isoflavones decrease estrogen production, strengthen the
immune system, inhibit cell proliferation, and reduce the production of
reactive oxygen species. These are all effects that might reduce breast cancer risk!

Settled: The Debate On Soy
The Debate On Soy And Its Risk Of Increasing Breast Cancer Was Settled A Long Time Ago. In 2005, the American Heart Association, the American
Medical Association, the American Cancer Society, the National Institute
of Health and the World Health Organization, just to name a few, all
reversed their stance on soy intake. Literally, the entire medical
community believes in the overwhelming benefits of soy.

What Do The Latest Studies On Soy Consumption Show Regarding Breast Cancer?
Some studies have shown no effect of soy consumption on breast cancer
risk. Others have reported that soy consumption decreased breast cancer risk. Yes, you read that correctly. A meta-analysis of 18 previous clinical
studies found that soy decreased the risk of developing breast cancer.[7] Most importantly, none of those studies found any evidence that soy
increased the risk of breast cancer.

What About The Recurrence Of Breast Cancer In Women Who Are Breast Cancer Survivors?
Between 2006 and 2013 there have been five major clinical studies
looking at the effects of soy consumption on breast cancer recurrence in both Chinese and American populations. Once again, the studies have
shown either no effect of soy on breast cancer recurrence or they showed a protective effect. None of them have shown any detrimental effects of
soy consumption for breast cancer survivors. In 2013 a meta-analysis of all 5 studies was published. This study combined the data from 11,206
breast cancer survivors in the US and China. Those with the highest soy
consumption had a 23% decrease in recurrence and a 15% decrease in
mortality from breast cancer.[8]

Soy vs Whey Study

Over a decade of University studies have shown soy protein is an
excellent anabolic aid for stimulating gains in muscle. The first of these
studies, presented at the American College of Sports Medicine (ACSM)
Meeting in 2004, and sponsored by the U.S. National Dairy Council no
less. It found the post-workout consumption of an isonitrogenous and
isoenergetic soy drink to be statistically significant in hastening mass, fat-bone free mass (FBFM), and increases in strength, when compared to
other post-workout formulations of skim milk and a maltodextrin
beverage, both of which had a similar degree of efficacy.[9]
This study demonstrated that intact proteins from soy are highly effective in supporting muscle hypertrophy, lending support to soy as a legitimate post-workout nutritional supplement.Another reason to choose soy over whey is due to evidence to support lactose intolerance regarding ones age, race, and gender. Approximately 65 percent of the human population
has a reduced ability to digest lactose after infancy and is most prevalent in people of East Asian descent, affecting more than 90 percent of adults and very common in people of West African, Arab, Jewish, Greek, and
Italian descent.[10]
Lactose intolerance is an impaired ability to digest lactose, a sugar found in milk and other dairy products. Lactose is normally broken down by an enzyme called lactase, which is produced by cells in the lining of the
small intestine. If individuals with lactose intolerance consume
lactose-containing dairy products, they may experience abdominal pain, bloating, flatulence, nausea, and diarrhea. To the contrary, very few
humans actually suffer from a soy allergy even in infancy and childhood, when it is more common. According to the Food Allergy Research and
Education, soy allergies are limited to just 0.4 percent of children and
often is outgrown by age three. According to the American College of
Allergy, Asthma & Immunology the majority of children will outgrow
their allergy to soy by the age of 10.[11]
This is great news for adults, especially those looking to supplement their diet and improve muscle recovery from strenuous exercise.

Follow The Research
We believe in sound science and due diligence versus leaning on beliefs
that have been propagated by the media. The overall confusion surrounding soy has been amplified by claims and counter-claims on the internet. There are bloggers and columnists who were and still are more
interested in the spectacular than they are in accuracy (today we call this fake news).These bloggers and columnists take the very weak evidence,
from outdated and poorly executed research, and blow it out of
proportion. Those who promote these myths never have a scientific
research background and they are never PhD’s from reputable scientific organizations.They have taken the very weak evidence, from outdated
and poorly executed research, that soy isoflavones could possibly
increase breast cancer risk and have blown it all out of proportion. More so, positive soy studies have largely been ignored. It is this negative
reporting from misinterpreted studies that have created the negative soy myths. And once that myth was created, it was repeated over and over
and became accepted as true, even though the studies were flawed and
there were thousands of other studies that have come to the exact
opposite conclusion. It is time to stop believing the old propagated myths surrounding soy.

Now go ahead and order up that plate of edamame or make yourself a
nutritious soy protein shake… one with added leucine… and enjoy!

If you have (or are a survivor of) breast cancer, always consult with your physician regarding treatment options which are right for you.
If you want more information regarding which protein powder is right
for you comment below or email me at
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The statements in this article have not been evaluated by the Food and Drug Administration. This information, including supplements, are not intended to diagnose, treat, cure or prevent any disease, is not intended to be nor should be interpreted as medical advice, instruction, or guidance. Any dietary or health care changes should be made only after consulting with your Doctor and licensed Health Care Advisor.Disclaimer: S3 Supplement Success only recommends products that we’ve either personally validated or that come from people we have vetted, know and trust.1. Shu et al, JAMA, 302: 2437-2443, 2009
2. Chi et al, Asian Pac J Cancer Prev., 14: 2407-2412, 2013
3. J Nutr. 1995 Mar; 125(3 Suppl): 698S-708S. doi: 10.1093/jn/125.suppl_3.698S
4. SJO Nomura et al, Breast Cancer Research and Treatment, 168: 467-479
5. Zhang FF et al, Cancer 2017
6. M. Messina, Nutrients, doi: 10.3390/nu8120754, 2016 Dec; 8(12): 754
7. J Natl Cancer Inst, 98: 459-471, 2006 Meta-Analysis-of-Soy-Intake-and-Breast-Cancer-Risk
8. Chi et al, Asian Pac J Cancer Prev., 14: 2407-2412, 2013)
9. Friedman, M. (1994). Improvement in the safety of foods by sulfhydryl-containing amino acids and peptides. A review. Journal of Agricultural and Food Chemistry, 42(1), 3-20
10. Nutrients. 2018 Dec 11;10(12). pii: E1956. doi: 10.3390/nu10121956
11. Savage JH, Kaeding AJ, Matsui EC, Wood RA. The natural history of soy allergy. J Allergy Clin Immunol, 2010;125:683-86.