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.

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Comments (6)

  • Pam

    |

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

    Reply

  • Marie

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    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

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Latest Article

Relieve Hip Pain After Sitting or Driving

Posted June 20, 2017 by Dr. Steve Chaney

Relief is Just a Few Movements Away!

Author: Julie Donnelly, LMT – The Pain Relief Expert

Editor: Dr. Steve Chaney

 

relieve hip pain after sittingI’m on a long business trip, speaking and teaching in Tennessee and New York, and the drive from Sarasota, FL meant many hours of driving over several days.  One of my stops was to visit with Suzanne and Dr. Steve Chaney at their home in North Carolina.  It was that long drive that became the inspiration for this blog.

After all those hours of driving, my hip was really sore. It was painful to stand up. While talking to Suzanne and Dr. Chaney I was using my elbow to work on the sore area, and when we were discussing the blog for this month it only made sense to share this technique with you.  So, Dr. Chaney took pictures and I sat at his computer to write.  I thought others may want to how to relieve hip pain after sitting or driving for long periods.

What Causes Anterior Hip Pain?

As I’ve mentioned in posts in the past, sitting is the #1 cause of low back pain, and it also causes anterior hip pain (pain localized towards the front of the hip) because the muscles (psoas and iliacus) pass through the hip and insert into the tendons that then insert into the top of the thigh bone.  When hip pain reliefyou try to stand up, the tight muscle tendons will pull on your thigh bone.  The other thing that happens is the point where the muscle merges into the tendon will be very tight and tender to touch. You aren’t having pain at your hip or thigh bone, but at the muscular point where the muscle and tendon merge.

It’s a bit confusing to describe, but you’ll find it if you sit down and put your fingers onto the tip of your pelvis, then just slide your fingers down toward your thigh and out about 2”. The point is right along the crease where your leg meets your trunk.

The muscle you are treating is the Rectus Femoris, where it merges from the tendon into the muscle fibers.  Follow this link, thigh muscle, to see the muscle and it will be a bit easier to visualize.

You need to be pressing deeply into the muscle, like you’re trying to press the bone and the muscle just happens to be in the way.  Move your fingers around a bit and you’ll find it.

Easy Treatment for Anterior Hip Pain After Sitting

relieve hip painHere is an easy treatment for hip pain after sitting you can administer yourself.  First, sit as I am, with your leg out and slightly turned.

Find the tender point with your fingers and then put your elbow into it as shown.

It’s important to have your arm opened so the point of your elbow is on top of the spasm.  It’s a bit tricky, but if you move about a bit you’ll come on to it, and it will hurt.  Keep the pressure so it’s tolerable, not excruciating.

After you have worked on this point for a few minutes you can move to the second part of the treatment.

hip pain treatmentPut the heel of your “same-side” hand onto your thigh as close to the spasm as you can get.  Lift up your fingers so the pressure is only on the heel of your hand.  You can use your opposite hand to help give more pressure.

Press down hard and deeply slide down the muscle, going toward your knee.  You can also kneed it like you would kneed bread dough, really forcing the muscle fibers to relax.

I’m putting in a picture from a previous blog to explain how you can also treat this point of your rectus femoris by using a ball on the floor.

As shown in this picture, lie on the floor with the ball on your hip muscle, and then slightly turn your body toward the floor so the ball rolls toward the front of your body. You may need to move the ball down an inch or so to get to your Rectus Femoris.

When you feel the pain, you’re on the muscle.  Just stay there for a minute or so, and if you want you can move so the ball goes along the muscle fibers all the way to your knee.

pain free living book coverIt may be a challenge to find this point, but it’s well-worth the effort!

In my book, Treat Yourself to Pain Free Living, I teach how to treat all the muscles that cause pain from your head to your feet.

Wishing you well,

Julie Donnelly

julie donnelly

About 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.

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.

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