Eating Chocolate Stops Colon Cancer. Really?

With Valentine’s Day on its way, I was intrigued to see lots of information in the media about how eating chocolate could prevent colon cancer.

The headlines were almost as enticing as unwrapping a large bar of Godiva with hazelnuts.

  • Eating chocolate can stave off bowel cancer, say scientists.
  • Chocolate shown to protect against colon cancer: study
  • Study Shows Chocolate Prevents Colon Cancer

As the news spread like chocolate melting in August from a medical journal article to a news release to online media to blogs to Twitter, I didn’t know whether to consider the rats who were fed cocoa for 12 weeks and had changes in their intestinal tract or that having diabetes increases the risk of dying from colorectal cancer by 30 percent or convincing evidence from the World Cancer Research Fund that maintaining a healthy weight is linked to lowering colon and rectal cancer risk.

Digging deeper into the research that was actually done:

  • The study wasn’t done in humans but in rats who bred to be at high risk for colon cancer.
  • The rats didn’t get to chow down on chocolate bars but were fed plain cocoa as 12 percent of their diets.
  • After 8 weeks with half the animals eating extra cocoa, the rats were given azoxymethane (AOM) which induces colon cancer in susceptible rats.
  • Four weeks later there were changes in some rat colons called aberrant crypt foci, a very early change that can lead to polyp formation.
  • In the rats who were not fed cocoa, there were also changes in proteins that increase cell division and reduce cell death potentially promoting growth of tumors.
  • Cocoa in these experimental rats reduced the risk of developing polyps and perhaps colorectal cancer at a very early stage. The study didn’t continue to see if the little guys actually got colon or rectal cancer.

Can we jump from plain cocoa in high-risk rats to chocolate, with its sugar and fat, in humans in an effort to prevent colorectal cancer?

And is that the best prevention strategy?

Given that we don’t eat cocoa powder alone but with added fat and sugar, the calorie intense treats should be only that — occasionally treats at the top of the food pyramid.  Surely we don’t want 12 percent of our daily calories to come from cocoa like the rat diet. Consider:

  • Hershey bar:  210 calories, 13 grams of fat, 24 grams of sugar
  • Two Godiva Truffles: 210 calories, 13 grams fat, 17 grams sugar

Bottom Line: What Really Can Prevent Colorectal Cancer?

A few last facts to consider:

  • Americans eat 2.8 billion pounds of chocolate annually, about half of all the world’s supply.  It costs us $7 billion dollars every year.
  • Annually we eat 12 pounds of chocolate per person.
  • The fiscal year 2012 budget for the National Cancer Institute is a little over $5 billion.
  • AND in 2012, 143,460 men and women in the United States will be diagnosed with colon or rectal cancer and 51,690 will die.

There’s lots of work to do, and chocolate truffles are not the answer.

Get Screened and Get Your Friends Screened.






  1. says

    I had read other studies done in Europe in regards to chocolate and colon cancer. The chocolate should be higher than 72% cacao. I had precancerous polyps and was required to return in 3 years after my first colonoscopy. I started the chocolate regiment. I eat only two squares a day of the high cacao chocolate. The next colonoscopy was clean. My doc was skeptical and I will after another exam after 5 years and if that is also clean, I will move to every 10 years. Colon cancer is very prevalent in my family.

  2. SB says

    Most of my adult life, I followed all the recommendations (no smoking, rarely ate red meat and/or barbecued meats, mostly vegetarian but did include fish and eggs, mostly organic foods, ran a mile every day and did yoga) for avoiding/preventing colon cancer, and I still got it. Only thing I didn’t do was the screening. I live in France, and no one talked about it…only the mention of breast cancer but not colon cancer.

    I went through 6 months of chemotherapy (every 2 weeks which involved a morning’s stay in the hospital and for 2 days of a chemical pump each time, etc.) and now suffer from neuropathy of the hands (pins and needles sensation in hands and feet). Probably gave me my detached retina because of the dryness. Who knows what other effects chemo can give?

  3. Melissa says

    My mom is going through chemo right now for stage 4 colon cancer and she has actually found chocolate increases he diarrhea (already a HUGE deal due to the chemo drugs the doctor is using). I think, even if the studies were true, my mom still would not eat a ton of chocolate due to how it makes her feel.

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