by Marion Nestle
Jan 15 2008

Oh no! Chocolate-eating linked to weak bones?

Ordinarily I don’t pay too much attention to studies of single foods or nutrients on health because so many of them are “nutri-fluff”–attention getting, but not necessarily meaningful to health. But this one is such a good example of the genre that I thought I’d share it. Today’s (Europe) talks about a study of chocolate consumption and bone density in 1000 older women (aged 70 to 85). Those who consumed the most chocolate (type not specified) had the thinnest and weakest bones.  Does this mean that eating chocolate is bad for bones?  Of course not.  It could mean that women who eat a lot of chocolate are not eating healthfully, getting enough physical activity, or doing any number of other things that do not promote bone strength.  When it comes to studies of single foods or nutrients, context is everything!

  • Thank you for pointing out the limitations of this kind of research. Here are a few other interpretations to add to your list.

    The study could mean that people who eat a lot of any one thing are displacing other foods with valuable nutrients. Heck, everyone agrees that green leafy vegetables are good for you, but if you eat so many that you don’t have room for protein-rich foods, you’re not going to have strong bones or good muscle tone.

    Since, as you note, type was not specified, it could be that sugar is the culprit.

    And then, there is the stereotype of the pampered woman sitting (or lying) on the couch all day eating bonbons. Maybe women who eat excessive amounts of chocolate are not getting enough weight-bearing exercise.

    Maybe women who eat a lot of chocolate have poor teeth (because of the sugar) and therefore have trouble eating a varied diet.

    This game is fun – I wish they taught it in the schools. “Junior, please come up with alternate explanations for this research.”

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  • It’s definately about context!
    Just as I learned from T.Colin Campbell (of The China Study), even some large studies take things out of context. In the Nurses’ Health Study had conclusions that following a low-fat diet and eating fruits and vegetables don’t protect against cancer.
    So many nurses switched from fatty meats & dairy to low/no fat versions, instead of eating less dairy/meat, that they were actually consuming MORE animal protein than even the average American!
    What about a Nurses’ Study III with nurses following a plant-based (vegetables, fruits, whole grains, nuts, seeds) diet while also being low in Sat/trans fat? That would be a good way to study the effects that eating whole, plant-based foods has on the body, especially in relationship with Obesity, cardio-vascular disease and diabetes.

  • @ Migraineur: *sigh* We do teach it in schools, just not until college! It’s usually called “Critical Thinking” or “Logic and Reasoning” or some such, and it is beyond insane that our students aren’t encountering this material in a rigorous fashion until post-secondary education. They might get some of this in high school English classes, especially comp & rhetoric classes. Kids who do debate will be familiar with all of it. But otherwise, nope, nada until college. And yeah, it is fun. A pain in the butt to teach to college students, but fun.

  • Importantly, the study “did not distiguish” between the type of chocolate or its source.

    Sorry, I am skeptical of a study that doesn’t distingush between industrial, corn-syrup-coated “milk” chocolate that one eats by the handful and the beautiful, organic, fair trade, dark chocolate that one eats by slowly savoring each square.

  • Daniel

    I love the point made about distinguishing the different types of chocolate, which Ms. Lichtman did, but the study failed to do.
    From reading Food Politics/What to Eat, I see how a study published showing some health benefits of dark chocolate can be extracted into the standard media and lead people to believe (or out right give misinterpretation) that all chocolate is the same (many “dark” chocolates have added milk fat, clearly not the same as “beautiful, organic, fair trade, dark chocolate”.)