Does Soy Increase Breast Cancer Risk?

Written by Dr. Steve Chaney on . Posted in Soy and Breast Cancer

What Does the Latest Study Say?

Author: Dr. Stephen Chaney

does soy increase breast cancer riskDoes soy increase breast cancer risk?

“To soy or not to soy. That is the question.” If you are a woman, particularly a woman with breast cancer, it is an important question. Some experts say soy should be avoided at all costs. They say that soy will increase your risk of breast cancer. Other experts say soy is perfectly safe and may even reduce your risk of breast cancer.

If you are a breast cancer survivor, the question of whether soy increases or decreases your risk of disease recurrence is even more crucial. You have already endured surgery, chemotherapy, and/or radiation. You never want to go through that again.

 

Why Is There So Much Confusion About Soy?

soy confusionSoy 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.

On the other hand, soy isoflavones also bind to estrogen receptors and exhibit weak estrogenic activity. This effect has the potential to increase breast cancer risk.

Cell culture and animal studies have only confused the issue. Soy isoflavones stimulate the growth of breast cancer cells in a petri dish. Soy isoflavones also stimulate breast cancer growth in a special strain of mice lacking an immune system. However, in studies in both mice and rats with a functioning immune system, soy isoflavones decreased breast cancer risk.

The confusion has been amplified by claims and counter-claims on the internet. There are bloggers who are more interested in the spectacular than they are in accuracy (Today we call this fake news). They have taken the very weak evidence that soy isoflavones could possibly increase breast cancer risk and have blown it all out of proportion.

Their blogs claimed that soy definitely increased breast cancer risk and should be avoided at all cost. Their claims were picked up by other web sites. Eventually, the claims were repeated so many times that people started to believe them. A “myth”was created.  I call it a myth, because it was never based on convincing scientific evidence.

In the meantime, scientists looked at the cell culture and animal studies and took a more responsible approach. They said “If this is true, it is an important public health issue. We need to do clinical trials in humans to test this hypothesis.”

It is easy to see why the general public still asks “Does soy increase breast cancer risk?”

 

breast cancer soyWhat Have Previous Clinical Studies Shown?

The question “Does soy increased breast cancer risk” was settled a long time ago. Some studies have shown no effect of soy consumption on breast cancer risk. Others have reported that soy consumption decreased breast cancer risk. A meta-analysis of 18 previous clinical studies found that soy slightly decreased the risk of developing breast cancer (J Natl Cancer Inst, 98: 459-471, 2006 Meta-Analysis-of-Soy-Intake-and-Breast-Cancer-Risk). None of those studies found any evidence that soy increased the risk of breast cancer.

What about recurrence of breast cancer in women who are breast cancer survivors? Between 2006 and 2013 there have been five major clinical studies (soy-and-breast-cancer-recurrence) 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 a protective effect. None of them have shown any detrimental effects of soy consumption for breast cancer survivors.

A meta-analysis of all 5 studies was published in 2013 (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.

 

breast cancer soy studyWhat Did The Latest Study Show?

In previous clinical studies the protective effect of soy has been greater in Asian populations than in North American populations. This could have been because Asians consume more soy. However, it could be due to other population differences as well. To better evaluate the effect of soy consumption on breast cancer survivors in the North America, this group of investigators correlated soy consumption with all-cause mortality in breast cancer survivors in the US and Canada (Zhang et al, Cancer, DOI: 10.1002/cncr.30615, March 2017).

The data was collected from The Breast Cancer Family Registry, an international research infrastructure established in 1995. The women enrolled in this registry either had been recently diagnosed with breast cancer or had a family history of breast cancer.

This study included 6235 breast cancer survivors from the registry who lived in the San Francisco Bay area and the province of Ontario in Canada. The women represented an ethnically diverse population and had a median age of 51.8 at enrollment.  Soy consumption was assessed either at the time of enrollment or immediately following breast cancer diagnosis. The women were followed for 9.4 years, during which time 1224 of them died.

The results were as follows:

  • There was a 21% decrease in all-cause mortality for women who had the highest soy consumption compared to those with the lowest soy consumption.
  • The protective effect of soy was strongest for those women who had receptor negative breast cancer. This is significant because receptor-negative breast cancer is associated with poorer survival rates than hormone receptor-positive cases.
  • The protective effect was also greatest (35% reduction in all-cause mortality) for women with the highest soy consumption following breast cancer diagnosis. This suggests that soy may play an important role in breast cancer survival.
  • The authors concluded “In this large, ethnically diverse cohort of women with breast cancer, higher dietary intake of [soy] was associated with reduced total mortality.”

In an accompanying editorial, Omer Kucuk, MD, of the Winship Cancer Institute of Emory University, noted that the United States is the number 1 soy producer in the world and is in a great position to initiate changes in health policy by encouraging soy intake.  He said “We now have evidence that soy foods not only prevent breast cancer but also benefit women who have breast cancer. Therefore, we can recommend women to consume soy foods because of soy’s many health benefits.”  In light of this study, has the question “Does soy increase breast cancer risk” been answered?

 

Does Soy Increase Breast Cancer Risk?

soy breast cancer mythEvery clinical study has its limitations. If there were only one or two studies, the question of whether soy increases breast cancer risk might still be in doubt. However, multiple clinical studies have come to the same conclusion. Either soy has no effect on breast cancer risk and breast cancer recurrence, or it has a protective effect.

Not a single clinical study has found any evidence that soy increases breast cancer risk. It is clear that consumption of soy foods is safe, and may be beneficial for women with breast cancer. The myth that soy increases breast cancer risk needs to be put to rest.

On the other hand, we should not think of soy as a miracle food. Breast cancer risk is also decreased by a diet that:

  • Contains lots of fruits and vegetables.
  • Is low in processed grains & sweets and high in whole grains.
  • Is low in saturated & trans fats and high in omega-3 and monounsaturated fats.
  • Is low in red & processed meats and high in beans, fish & chicken.

Furthermore, diet is just one component of a holistic approach for reducing the risk of breast cancer. In addition to a healthy diet, the American Cancer Society recommends that you:

  • Control your weight
  • Be physically active
  • Limit alcohol
  • Don’t smoke
  • Limit hormone replacement therapy unless absolutely necessary.
  • Reduce stress

Does soy increase breast cancer risk?  No.

The Bottom Line

 

  • It is time to put the myth that soy increases breast cancer risk to rest. This myth is based on cell culture and animal studies, and those studies were inconclusive.
  • Multiple clinical studies have shown that soy either has no effect on breast cancer risk, or that it reduces the risk.
  • Multiple clinical studies have also shown that soy either has no effect on breast cancer recurrence in women who are breast cancer survivors, or that it reduces recurrence.
  • The latest clinical study is fully consistent with previous studies. It reports:
    • There was a 21% decrease in all-cause mortality for women who had the highest soy consumption compared to those with the lowest soy consumption.
    • The protective effect of soy was strongest for those women who had receptor negative breast cancer. This is significant because receptor-negative breast cancer is associated with poorer survival rates than hormone receptor-positive cases.
    • The protective effect was also greatest (35% reduction in all-cause mortality) for women with the highest soy consumption following breast cancer diagnosis. This suggests that soy may play an important role in breast cancer survival.
  • No clinical studies have provided any evidence to support the claim that soy increases either breast cancer risk or breast cancer recurrence.
  • On the other hand, we should not think of soy as a miracle food. Breast cancer risk is also decreased by a diet that:
    • Contains lots of fruits and vegetables.
    • Is low in processed grains & sweets and high in whole grains.
    • Is low in saturated & trans fats and high in omega-3 and monounsaturated fats.
    • Is low in red & processed meats and high in beans, fish & chicken
  • Furthermore, diet is just one component of a holistic approach for reducing the risk of breast cancer. In addition to a healthy diet, the American Cancer Society recommends that you:
    • Control your weight
    • Be physically active
    • Limit alcohol
    • Don’t smoke
    • Limit hormone replacement therapy unless absolutely necessary.
    • Reduce stress

 

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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Latest Article

Calf Cramps Remedy

Posted February 20, 2018 by Dr. Steve Chaney

Don’t Let A Leg Cramp Stop You Short

Author: Julie Donnelly, LMT – The Pain Relief Expert

Editor: Dr. Steve Chaney

 

calf cramps remedyGetting a leg cramp while you are running can be the “straw that broke the camel’s back.”  If you don’t treat it properly and quickly when it is happening, you may limp to the finish line, and you can suffer from its effects for days afterward.  I will show you the best calf cramps remedy below.  First, let’s go over spasms and muscle cramps.

A spasm and a cramp are similar because it’s a shortening in the muscle fiber, but that’s where the similarity ends. A spasm is a slow-forming shortening of a group of fibers that tie up into a knot in the muscle. You can feel a spasm with your fingertips, it feels like a bump as you slide along the full length of the muscle. With a spasm, as you press down and slide, it doesn’t hurt until you get to the spasm, and then it can really hurt. But then it stops hurting as you slide off the spasm. A spasm refers pain to the insertion points of the muscle and frequently doesn’t hurt where the spasm has formed (that is, until you press on it).

Why Do Your Muscles Cramp?

calf cramps remedy muscle crampsA cramp (Charlie horse) is when all the fibers of the entire muscle suddenly and violently contract. The muscle will quickly shorten and can go into a huge knot, or it will just totally shorten.

Usually a cramp happens in your calf muscle, although it can happen to any muscle in the body.  Your calf is comprised of two major muscles, the gastrocnemius and soleus. The gastrocnemius, which is shown in this graphic, originates behind your knee and inserts into your Achilles tendon.

Visualize the muscle suddenly shortening, pulling up on your Achilles tendon, and becoming a mass of tight knots through the entire muscle.

Muscles have an “all or nothing” response.  This means that when a muscle fiber contracts, it will shorten 100% of its length.  It never starts to shorten and then make a U-turn and lengthen.  A cramp is seriously painful, and if you try to stretch it out as it’s happening, you can tear the muscle fibers. In fact, that’s the reason it hurts for sometimes days after the cramp.

A Calf Cramps Remedy You Can Administer Yourself

calf cramps remedy squeezeThe best thing to do is to squeeze the two ends of your calf muscle together, which will help the cramp complete as quickly as possible. This will hurt, but for less time than the normal cramping process.  Hold your calf tightly, as shown in this picture, and continue to press the two ends toward each other.

Hold it until you can breathe normally (about 30-45 seconds), and then release. Breathe for a minute or so, and then push the two ends together again.  This second time won’t hurt, you are only doing it to make sure that all the fibers have completed the contraction.

calf cramps remedy hold sittingOnce you have stopped the cramp, don’t stretch…yet. You need to flush out the hydrogen ions (AKA lactic acid) that rapidly built-up in the muscle during the cramp.

There are many ways to self-treat your calf. If you are out on the road you can either sit on a bench or lie on the ground and put the sore calf onto your opposite knee.  Press down and hold the pressure for 30 seconds. Then deeply press along the muscle going from the back of your knee toward your ankle.

calf cramps remedy opposite footYou can also use your opposite heel and press deeply, straight into your calf.

Start at the top of the muscle and move down toward your ankle. Stop whenever you come to a point that is especially painful. The point should be close to the area shown in this picture.

Hold the pressure for 30-60 seconds, or until it doesn’t hurt anymore.  Release, and then repeat 2-3 times.

Complete this self-treatment by squeezing your calf muscle, like you are wringing out a wet towel.  This will force blood into your muscle and get your circulation moving again.

Proof That My Treatments Work

I once taught this technique at an Ironman Triathlon during a 15-minute session I was giving to the triathletes.  Several days later a triathlete emailed me and told me that he had a cramp as he was running, and he did the treatment I’d taught him.  It cost him a few minutes (he wasn’t in the top three, so the time loss wasn’t a huge issue) but he was able to get up and get back to running, totally without pain.

About a mile later he got a cramp in the other leg, but he automatically started to just stretch it like he’d always done before.  He ended up limping all the way to the finish line, and days later it was still hurting.  He wanted to let me know that my cramp treatment really worked great.  This was especially helpful because I’d always wondered what body chemistry did to the outcome of treating a cramp, and here I found out that chemistry wasn’t involved in the treatment of the muscle fibers.

What To Do After The Calf Cramps Remedy

If the cramp happens during a race or athletic event, knowing how to stop it, and these quick massage techniques, will get you back into the game. But it hasn’t totally resolved the issue. Finally, when you have the time to be detailed (after the race, in the evening, etc.), it is important to work out all the spasms and then stretch properly.

When you are treating the muscles afterward, I suggest you consider getting an analgesic cream that goes way deep into the muscle fibers. Use it when you are massaging the muscle, but don’t put it on before you play, run, or before/after a shower because it will go too deep into the muscle and burn like crazy. After you do the treatments, use ice &/or arnica gel (get it at a good health food store) to heal the bruised muscle fibers and help with pain and swelling. Arnica is fantastic, it’s an amazing homeopathic remedy that has been around for ages and really works.

Naturally you will also want to make sure you hydrate properly and that your diet, vitamins and minerals are all in balance.

calf cramps remedy bookCramping is a common problem athletes face, but with a little bit of effort you can prevent muscle injury and get back in the race quickly!

You can find the full treatments for your muscle cramps by going to my book, Treat Yourself to Pain-Free Living . This book has treatments for your entire body, from your head to your feet.  YOU are your own Best Therapist!  Stop pain quickly and easily with self-treatments you can do anytime, anyplace.

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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