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Strawberries Can Reverse Precancerous Progression

December 17, 2013 by Michael Greger M.D. in News with 12 Comments

Strawberries Can Reverse Precancerous Progression

In my last two posts, Which Fruit is Best at Fighting Cancer? and Anti-Cancer Nutrient Synergy in Cranberries I described what various common fruits could do to human cancer cells in a petri dish.  Studies showing which foods can best suppress the growth of cancer in a test tube are all well and good, but we need to know if they can do the same thing within the human body. It’s considered unethical to withhold conventional cancer therapies to test out some fruit or vegetable, so what do you do?

One direction researchers have taken is to use so-called “combinatorial strategies,” for example adding phytonutrients from the spice turmeric and green tea along with chemotherapy to see if that works better than chemo alone, but this gets complicated because chemo and radiation often work by killing cancer cells with free radicals and so though antioxidants may certainly reduce the toxicity of the treatment there’s a theoretical concern it could reduce the efficacy as well.

Another way you can study the effects of plants on cancer is by testing dietary interventions on slow growing cancers like prostate, which is how Ornish and colleagues were able to show his apparent reversal in cancer growth with a plant-based diet (see Cancer Reversal Through Diet?). They could get away with treating cancer with a vegan diet alone (no chemo/surgery/radiation) because prostate can be such a slow growing cancer that patients with early disease can be placed in a holding pattern. So if you’re not going to do anything but watch and wait, you might as well test out a dietary intervention. Are there other cancers like that we can try plants on?

Esophageal cancer is not the cancer to get. Five-year survival is only about 13 percent, with most people dying within the first year of diagnosis, but the development of esophageal cancer is a multistage process. We start out with a normal esophagus (the tube that connects you mouth to your stomach), then precancerous changes start to take place, then localized cancer starts to grow, then eventually it spreads and we most likely die.

Because of the well-defined, stepwise progression of esophageal, researchers jumped on it as a way to test the ability of berries—the healthiest fruits—to reverse the progression of cancer. A randomized phase 2 clinical trial of strawberries for patients with precancerous lesions of the esophagus was undertaken. Six months of eating the equivalent of over a pound of fresh strawberries a day, and the progression of disease was reversed in 80 percent of the high dose strawberry treatment.

At the beginning of the study, no subjects had a normal esophagus. They either had mild or moderate precancerous disease. But by the end of the study most lesions either regressed from moderate to mild, or disappeared completely. If you watch my 5-min video Strawberries versus Esophageal Cancer you can see some representative before and after pictures of the lesions literally disappearing. By the end of the study half of those on the high dose of strawberries walked away disease free.

This landmark study is one of the most important papers I’ve seen recently. Why isn’t this headline news? If there was instead some new drug that reversed cancer progression, you can bet it would be all over the place. But who’s going to profit from revelations about berries? Other than, of course, the millions of people at risk for this devastating cancer.

The findings were heralded as groundbreaking in an editorial in the journal of the American Association for Cancer Research. Given that it was written by a pair of pharmacy professors, though, they of course concluded “that the active components and molecular targets responsible for the efficacy of strawberries must be identified.” Instead of just eating strawberries they suggested that Big Pharma should try to make a strawberry-derived drug.

Recent population studies suggest that other plant foods may be protective against esophageal cancer as well. Diets with lots of meat and fat appear to double the odds of cancer; and lots of fruits and vegetables may cut one’s odds of esophageal cancer in half. Studies have shown diets rich in foods from animal origin and poor in plant foods appear to increase esophageal cancer risk. And now we know at least one plant that may even reverse the course of disease if caught early enough.

I touched previously on esophageal cancer in Bacon and Botulism and Poultry and Penis Cancer.

More on strawberries in Cancer Fighting Berries and Maxing Out on Antioxidants. My favorite way to eat them? My chocolate ice cream recipe.

Ornish’s line of anti-cancer work was continued by the Pritikin Foundation in an elegant series of experiments that I describe starting with Ex Vivo Cancer Proliferation Bioassay (along with the “prequel” Engineering a Cure).

For more berried treasure, see Black Raspberries versus Oral Cancer.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: Manchester-Monkey / Flickr

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Dr. Michael Greger

About Michael Greger M.D.

Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

View all videos by Michael Greger M.D.

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  • ChessiePique

    Here’s a question for Dr. Greger, or anyone else who knows: Am I better off eating conventionally grown strawberries if that’s all I can find at this time of year, or is it better to eat organic strawberries only when they are available? I’ve always thought that berries should be organic whenever possible because they are likely to carry pesticides and other nasty things. How about fresh versus frozen (whole, unsweetened) berries? Apologies if these questions are answered elsewhere on this site.

    • Thea

      Dr. Greger has a great blog post where he puts pesticide consumption into perspective. :
      “A new study calculated that if half the U.S. population ate just one more serving of conventional fruits and vegetables, 20,000 cases of cancer could be prevented. At the same time the added pesticide consumption could cause up to 10 extra cancer cases. So by eating conventional produce we may get a tiny bump in cancer risk, but that’s more than compensated by the dramatic drop in risk that accompanies whole food plant consumption. Even if all we had to eat was the most contaminated produce the benefits would far outweigh any risks.”

      from: http://nutritionfacts.org/2013/06/25/apple-peels-turn-on-anticancer-genes/
      I translate this bit of info into: Eat organic when you can, but don’t stress about it when you can’t.
      Happily, there is a way to take this advice a step further to minimize your risks without completely depleting the pocketbook. Every year, the Environmental Working Group actually measures pesticide levels in fruits and veggies–after those fruits and veggies have been prepared in the way people would normally eat them. (For example, peeling a banana or washing first.) If you scroll down on the following page, you will see a list for the “Dirty Dozen” and the “Clean Fifteen”.

      http://www.ewg.org/foodnews/summary.php

      I bring your attention to these lists because I think they are very helpful for people who can’t afford to eat organic for everything. You could use these lists to help you decide when it is worth putting down money for organic and when it might be safer to buy non-organic.

      One more thought for you: You mentioned “this time of year”. I would say that eating in the season is a good idea. So if you want to eat berries year-round (also a good idea), I personally would eat frozen berries rather than the fresh that is available in the middle of winter. Why? Because it is my understanding that frozen berries are picked when they are grown naturally and still have most of their nutrients and then are flash frozen, retaining those nutrients. Fresh this time of year I would think would have to travel long distances…

      I hope this helps!

      • Robert

        Living in Santa Cruz County which is one of the major strawberry growing regions in the country I can tell you that you might want to take a look at some of the environmental issues surrounding their cultivation. Prior to planting the fields are covered in plastic and methyl bromide is pumped into the ground to fumigate the soil. So your conventional strawberries are essentially grown in dead soil. Methyl bromide is also more damaging to the ozone layer than chlorofluorocarbons which are banned for this reason. It is acutely toxic thus dangerous for the farm workers who have to work around it and at times for their children who go to schools near the fields. We only buy organic strawberries from local farmers and there is no comparison in flavor.

        • Thea

          Robert: You also raise some good points. Like you, I care about the environment and farm workers. Just more things to consider when one is making purchasing choices.

          Thanks for sharing.

        • http://www.DonForresterMD.com/ Don Forrester MD

          Thanks for the information… the more you find out about conventional crops the more you tend to go organic. Buying organic is a way to vote for more production of organic non GMO crops.

      • ChessiePique

        Thank you so much for your response! Strawberries are on the EWG “dirty dozen” list, which is why I asked about it. I try to follow this as much as possible (celery = always organic; onions = meh, whatever’s cheapest, etc.) when shopping.

        What you say makes good sense. Thanks again.

    • http://www.DonForresterMD.com/ Don Forrester MD

      I would tend to avoid conventional and go organic when you can. Tending to eat more seasonally can help as well. Frozen berries and fruits are usually available that are organic are an excellent way to go. Since many of the berries and fruits that are frozen at the fields they tend to sometimes be better than the non frozen organic which can take some time to get to the stores.

    • Kristin

      There has been some great advice given already. I thought this video would be another useful piece of advice concerning pesticides in produce.

      http://nutritionfacts.org/video/can-pesticides-be-rinsed-off/

      Always best to eat organic whenever possible!

  • John
  • Guest

    This video is a berried treasure!
    JOhn S
    PDX OR

  • Eve Curtis

    When fresh are not available, are powdered organic strawberries helpful?

    • A,B,C,Vegan

      Dr Greger’s video on this topic discusses exactly that! The research was actually done *using* powdered strawberries – eating 1 to 2 ounces a day of freeze dried strawberries is like eating over a pound of fresh strawberries in a day! So I would take that to mean that yes, powdered strawberries would absolutely be helpful. Check it out:
      http://nutritionfacts.org/video/strawberries-versus-esophageal-cancer/

      :)

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