Soy And Breast Cancer Recurrence

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

The Truth About Soy And Breast Cancer

 Author: Dr. Stephen Chaney

SoybeanYou’ve probably heard the warnings: “Soy may increase the risk of breast cancer!” “Women with breast cancer shouldn’t use soy!”

The first warning was never true. Numerous clinical studies have shown that consumption of soy protein is associated with a lower risk of developing breast cancer.

Furthermore, the science behind the second warning has never been very strong. The concerns that soy might stimulate the growth of breast cancer cells was based primarily on cell culture experiments and one experiment in mice – even though a second experiment in mice came to the exact opposite conclusion.

Was The Hypothesis That Soy Could Increase The Risk Of Breast Cancer Recurrence Plausible?

The possibility that soy isoflavones could stimulate the growth of estrogen- responsive breast cancer was biochemically plausible because soy isoflavones bind to the estrogen receptor and have a very weak stimulatory effect (much weaker than estrogen itself).

Even that evidence was not definitive because soy isoflavones also turn on several tumor suppressor pathways in breast cells and help strengthen the immune system – so they could just as easily inhibit the growth of breast cancer cells.

However, because the concerns were plausible and had not been definitively disproved, most experts, including me, recommended for several years that women with estrogen- responsive breast cancer might want to avoid soy protein.

Has The Hypothesis Been Rigorously Tested?

In fact, the definitive clinical studies have been performed, and it turns out for women who are breast cancer survivors, consumption of soy foods does not increase either the risk of breast cancer recurrence or of dying from breast cancer.

The first of these studies was reported in the December 2009 issue of the Journal of the American Medical Association by researchers at Vanderbilt University and Shanghai Institute of Preventive Medicine (Shu et al, JAMA, 302: 2437-2443, 2009).

It was a large, well designed, study that enrolled 5042 Chinese women aged 20 to 75 years old who had been diagnosed with breast cancer and followed them for an average period of 3.9 years.

The women were divided into four groups based on the soy content of their diet (ranging from 5 grams/day to 15 grams/day). The results were clear cut. Breast cancer survivors with the highest soy intake had 25% less chance of breast cancer recurrence and 25% less chance of dying from breast cancer than the women with the lowest soy intake.

The effect was equally strong for women with estrogen receptor-positive and estrogen receptor negative cancers, for early stage and late stage breast cancer and for pre- and post-menopausal women. In short this was a very robust study.

The study also showed that soy protein intake did not interfere with tamoxifen, a drug that blocks the binding of estrogen to its receptor on cancer cells. Tamoxifen is used for both for treating estrogen-responsive breast cancer and preventing its recurrence. In this study, the reduction in the risk of breast cancer recurrence & death was just as great whether the breast cancer survivors were taking tamoxifen or not.

In fact, tamoxifen was protective only for women with low soy intake. It conferred no extra protection for the women at the highest level of soy intake because the soy isoflavones were also blocking the binding of estrogen to its receptor.

Other Clinical Studies

If that were the only published clinical study to test the soy-breast cancer hypothesis, I and other experts would be very cautious about making definitive statements. However, at least four more clinical studies have been published since then, both in Chinese and American populations. The studies have either shown no significant effect of soy on breast cancer recurrence or a protective effect. None of them have shown any detrimental effects of soy consumption by breast cancer survivors.

A meta-analysis of all 5 studies was published earlier this year (Chi et al, Asian Pac J Cancer Prev., 14: 2407-2412, 2013). 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.

The Bottom Line:

What does this mean for you if you are a breast cancer survivor?

1)     There are many reasons to include soy protein foods as part of a healthy diet. Soy foods are one of the highest quality vegetable protein sources and provide a great alternative to many of the high fat, high cholesterol animal proteins in the American diet.

2)     I personally feel that these studies are clear cut enough that breast cancer survivors no longer need to fear soy protein as part of a healthy diet.

3)     The responsible websites agree with this assessment. For example, WebMD and the American Institute for Cancer Research (AICR) both say that breast cancer survivors need no longer worry about eating moderate amounts of soy foods.

4)     The irresponsible websites (I won’t name names, but you know who they are) are still warning breast cancer survivors to avoid soy completely. As a scientist I really have problem with people who are unwilling to change their opinions in the face of overwhelming scientific evidence to the contrary.

5)     Of course, some of those bloggers have now shifted their arguments to say that it is unfermented or genetically modified soy that causes breast cancer. Those statements are equally bogus – but that’s another story for another time.

6)     Finally, I want to emphasize that the published studies merely show that soy does not increase the risk of breast cancer and is safe to use for breast cancer survivors. None of those studies suggest that soy is an effective treatment for breast cancer. The protective effects of soy are modest at best. If you have breast cancer, consult with your physician about the best treatment options for you.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Tags: , , , , , , , , ,

Trackback from your site.

Comments (6)

  • Pam

    |

    Dr. Chaney — THANK YOU for the clarification!! I found this article easy to understand!

    Reply

  • Marie

    |

    This is fantastic information! I am wondering how estrogen plays a role in soy consumption for the average person. Many doctors claim that pumping estrogen (by means of soy consumption) into men or nursing babies through their mother’s milk is dangerous and can be harmful, possibly sterilizing, men. Do these claims hold any truth?

    Reply

    • sysadmin_htftp

      |

      Dear Stella,
      That information is also misleading. Look for an article in a few weeks summarizing the latest clinical studies on the effects of soy consumption on men.
      Dr. Chaney

      Reply

  • Susan

    |

    I am so glad to see this article and the timing is perfect for me. I have discussed with my Medical Oncologist, my soy protein shakes. I am in chemotherapy , my hormonal status is estrogen positive and she advised, she would prefer I did not have any soy products.

    I am going to take a copy of your email to my chemo appointment next Tuesday and see if she will change her mind.

    Thank you so much for this wonderful information.

    Reply

    • sysadmin_htftp

      |

      Dear Susan,
      You are doing exactly the right thing by discussing this information with your doctor. I can only report on the results of published clinical studies that represent the average effects of soy on breast cancer recurrence in a large group of breast cancer survivors. However, you are unique. What applies to the group as a whole, may not apply to you as an individual. That is why your oncologist is the best person to evaluate the data and give you the advice that best applies to you as an individual.
      Dr. Chaney

      Reply

  • Teresa Robinson

    |

    Thanks, Dr. Chaney. Several in my family and several friends have had breast cancer. The topic is one that is always top of mind.

    Reply

Leave a comment

Recent Videos From Dr. Steve Chaney

READ THE ARTICLE
READ THE ARTICLE

Latest Article

Groin Pain Relief

Posted April 16, 2019 by Dr. Steve Chaney

What Is The Pectineus Muscle And Why Is It Important?

Author: Julie Donnelly, LMT –The Pain Relief Expert

Editor: Dr. Steve Chaney

 

Spring Is In The Air

spring floridaI remember as a child we sang “Though April showers may come your way…they bring the flowers that bloom in May…”

Of course, here in Florida we are blessed with flowers all year, but there’s still a lovely feeling that happens in Spring.  It’s still cool enough most days to go out running, and the humidity is still low.  Traffic will soon be easing up as our friends from the north start their trek back home, and daylight savings time is giving us more time to get to the beach for sunset.  Lovely!

Fun Facts About Spring….

  • The earliest known use of the term “spring cleaning” was in 1857
  • The word “spring” has been used for the season since the 16th century
  • The first day of spring is called the vernal equinox
  • On the first day of spring, the sunrise and sunset are about 12 hours apart everywhere on earth
  • Spring fever isn’t just a saying. Experts say the body changes due to the temperature and can cause an upset in your health.
  • The actual start of spring varies from March 19th to the 21st, but it is commonly celebrated on the 21st.

Do you like to garden?  Now is the perfect time to get your gardens planted so you’ll have home grown veggies for the entire summer.  For me, it’s also a great time to do some spring cleaning and get the house in order before the summer closes all the windows and the air conditioning becomes our indoor relief.

But these activities can also cause a strain on muscles, so don’t forget to take care of yourself. If you put too much strain on muscles you haven’t used all winter, you can develop problems and need groin pain relief.

 

A Tiny Muscle Can Cause Groin Pain

groin pain relief pectineusLately I’ve had several clients come in because of groin pain that has their medical practitioners stumped.  Their symptoms are varied, but most complain that it feels like they hit their pubic bone with a rubber mallet.  Ouch!

One client loves to ride her horse, but the pain had prevented that for several weeks. Another was considering selling the motorcycle that she and her husband love because she just can’t sit on it anymore.

Several years ago, I had a male client tell me that he had this same pain and he was told it could be his prostrate causing the issue.  Fortunately, that wasn’t he problem at all.

The muscle that caused all these problems, and a lot more, is the Pectineus.

The Pectineus muscle originates on your pubic bone and inserts into the very top of your inner thigh bone (femur).

You can see the Pectineus and surrounding muscles more clearly by going to https://en.wikipedia.org/wiki/Pectineus_muscle

Most muscles have more than one function, and this is true for the Pectineus.  The function we’ll look at today is called adduction.  It brings your leg in toward midline.  If you think of a soccer player kicking the ball with the inside of his ankle, it was the Pectineus that helped draw his leg in so he could do the shot.

Each of my clients had pain while trying to bring their leg out so they could sit on their horse, or on their motorcycle.  The tight muscle was pulling on their pubic bone and causing a severe strain.

This muscle is easier to have someone else treat it for you because of its location but give it a try and see if you can locate & treat it yourself.

 

Groin Pain Relief

groin pain relief treatmentThe picture to the left is showing an athlete self-treating her adductors.  These muscles, and the Pectineus muscle, all originate at the same point on the pubic bone.  The picture is showing her massaging the middle of the adductors.

To reach the Pectineus, move the ball all the way up to the crease in your leg.  You can do the treatment with a ball, but because of the size of the muscle and its location, it’s easier to do it with your fingertips.

Sit as this athlete is sitting, and even bring your opposite leg up so your foot is flat on the floor.  For example, in this picture, the athlete would bring her right leg up so her right foot is on the floor, and then lean a bit further onto her left hip.  That opens up the area so she can reach a bit easier into the muscle while using her fingertips.

Press into the muscle, being careful to feel for a pulse, and moving if you feel one.  If the Pectineus is in spasm, you’ll know it immediately when you press on it.  If it’s not in spasm, you won’t be able to find it at all.

Remember to stay within your pain tolerance level, this isn’t a “no pain, no gain” situation.  Never go deeper than what feels tender, but not so much that you want to faint. Hold the pressure for 15 seconds. Then let up on the pressure, but keep your fingers in the same place.

Repeat this movement several times. Each time it will hurt less, and eventually it won’t hurt at all.  That’s when the muscle has completely released, and you will have relief from the pain.

It’s as simple as that!

Why stay in pain when it’s so easy to find the muscular source of the problem and eliminate it?

calf cramps remedy bookTreat Yourself to Pain-Free Living (https://julstromethod.com/product/treat-yourself-to-pain-free-living-hardcopy/). It is filled with over 100 pictures and descriptions proven to show you how to find and self-treat muscle spasms from head to foot!

Join the 1000’s of people worldwide who have discovered that tight muscles were the true source of pains they thought were from arthritis, fibromyalgia, and other serious conditions.  You have nothing to lose, and everything to gain by releasing tight muscles.

Treat Yourself to Pain-Free Living is your step-by-step guide to pain relief!

 

Wishing you well,

 

Julie Donnelly

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 

julie donnellyAbout The Author

Julie Donnelly is a Deep Muscle Massage Therapist with 20 years of experience specializing in the treatment of chronic joint pain and sports injuries. She has worked extensively with elite athletes and patients who have been unsuccessful at finding relief through the more conventional therapies.

She has been widely published, both on – and off – line, in magazines, newsletters, and newspapers around the country. She is also often chosen to speak at national conventions, medical schools, and health facilities nationwide.

UA-43257393-1