DEAR DR. BLONZ: Can you help us understand the World Health Organization's (WHO) announcement on cancer and meat? Did the WHO study control for processed meats with and without nitrites? A nutritionist once told me that vitamin C blocks the formation of cancer-causing nitrosamines, and that if I choose to eat bacon, I should also have a lot of orange juice. -- M.C., via email
DEAR M.C.: One study I recall from graduate school revealed that physicians who ate more meat and consumed more alcohol had a one-third lower risk of dying in a plane crash. Does this mean it would have been beneficial to encourage doctors to grab a burger and a beer before they boarded a flight? Needless to say, we need to understand a plausible mechanism before we can give full credence to any population study.
The announcement from the World Health Organization provides useful, but not surprising, information. At the same time, it reflects problems inherent with population studies that extract and correlate data on the impact of a single class of food. With such efforts, there is no way of knowing what was in the rest of people's diets, or the general health status of the individuals from whom the data was collected.
The WHO pronouncement, which covered meats in general, came after a review of hundreds of studies, each with its own methodology. There was a comparison, on a spectrum of health statistics, between people who ate no meat and people who ate lots of it -- and everyone in between. Find a significant difference along that gradient and you have an "association" to report between the level of meat intake and the risk of disease.
Here, we must ask if the key factor is all meat, or only processed meats. Or, does meat only become an issue when paired with a less-than-optimal intake of healthful foods? Or a progressively unhealthful, more stress-filled lifestyle? Or an interaction of these and other factors? It is difficult to control for such fine points, and population studies are not able to report cause and effect.
It is predictable that, analyzing the spectrum from no- and low-meat intakes up to hefty daily doses of the stuff, a general theme would emerge that excessive meat consumption is risky business. Many news stories left off all qualifiers and simply pronounced that "meat causes cancer," period.
A healthful diet, lifestyle and attitude are powerful mitigating factors against potential negatives, but when it comes to food, there is only so much room in our stomach. If meat is on your menu, then enjoy it, keep a handle on the portion size and don't lose sight of your plant-based, whole-foods perspective.
As for your mention of preservatives, fresh meats are less risky than nitrite-preserved meat. Nitrites can combine with the amino acids in meats to form cancer-causing nitrosamines. Vitamin C can help inhibit the formation of nitrosamines, but having orange juice with bacon shouldn't be considered a fix. Routinely having fruit or berries at any meal is always a positive.
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