Is our cookbook trying to kill us?

There are thousands of studies on the benefits or harms of various foods. Studies that show something (benefit or harm) tend to get media attention. Most of these have no scientific validity.

A recent study looked at scientific publications showing the association of various foods with cancer. They randomly picked 50 ingredients from a cookbook. Lo and behold, 40 out of the 50 ingredients (80%) had studies showing either risk of harm or protective benefit. But here’s the real kicker…. most ingredients had multiple contradictory studies – some showed harm and others found benefit (see here).

This isn’t to say that foods are irrelevant. But simple foods and spices don’t cause cancer. Nor do they prevent it. Studies that say otherwise should be viewed with a massive amount of skepticism.

Bottom line… it sells newspapers and gets attention to make claims that foods cause cancer, but they probably don’t. If it’s not a really large study (10,000 people or more) ignore the headline.

Kudos to Schoenfeld and Loannidis for a great article. The article is worth glancing at as part of a balanced diet of information. However, one should maintain a healthy skepticism when reading dubious headlines.

Comic courtesy of xkcd.com: http://xkcd.com/882/

 

Sources: The American Journal of Clinical Nutrition “Is everything we eat associated with cancer? A systematic cookbook review”; National Cancer Institute “Colorectal Cancer Prevention”; Mayo Clinic “Cancer Causes: Popular myths about the causes of cancer”; Agency for Toxic Substances & Disease Registry “Cancer Fact Sheet”; CA: A Cancer Journal for Clinicians “American Cancer Society guidelines on nutrition and physical activity for cancer prevention”

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2 comments for “Is our cookbook trying to kill us?

  1. Nat
    May 12, 2015 at 1:13 pm

    Interesting post. What about all of the chemicals in our foods that are unidentified? Endocrine disrupters, pesticides etc. There are still known carcinogens in our food supply.

  2. May 15, 2015 at 5:47 pm

    Thanks, Nat. I’m of the belief that prevailing pesticide use for the vast majority of food products (essentially anything that would be blessed by standard food channels in the US) are generally safe. There certainly have in the past been cases of unsafe pesticide use, but such products have been rapidly eliminated upon being identified. I recognize that antibiotics and hormone supplementation in livestock feed have both generally had some impact in certain populations. It’s generally been a small impact, but there are a few select individuals in whom there has been a difference. Fortunately there has been economic pressure to avoid or curtail use of products that have such an impact.

    To the extent that someone would assert that any safety issue/risk whatsoever is unacceptable, I would counter that our society lives in an economic reality that mandates cost efficient mass production of food. It goes beyond my expertise to know the degree to which costs for produce and livestock would rise without protective products. If there is no cost difference and no drop in yield, then a good argument for eliminating them could be made. I doubt that’s the case. I suspect that current use (including FDA scrutiny of products used) has undergone careful scrutiny as well as assessment of economic factors.

    In total, the evidence I’ve seen supports that most pesticides and additives are adequately safe. People probably incur more health risk from generally unhealthy diets or lifestyles than they do from ingesting additives or pesticides. Stated another way, there are enough things in life to worry about. I don’t lose sleep over what I eat.

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