Does eating red meat really increase cancer risk?
There are a number of points that this study raises which it doesn't
We, as a species have been eating red meats for several thousands of
years - without any history of colon cancer. Many peoples in the world
still do. So why should they be carcinogenic now?
Table 2A of the study shows that red meat intake does not increase
the risk in Aarhus and Potsdam (HR=1.00) and it is protective in Italy
(HR=0.96). In the other countries, there is a slight increase (HR=1.01-
1.04). So in some countries eating red meat seems to be harmful, in
another it is beneficial, and in others it has no effect one way or the
95% confidence intervals all cross 1.00, so some of the subjects in
all centres used in this trial benefitted from eating red meat even in
those countries where it appeared to increase the risk.
All these countries have different dietary cultures and even people
within them eat different foods and combinations of foods. They also will
prepare, store and process them in different ways. As the numbers are all
pretty close to 1.00 (which would indicate no effect one way or the
other), I suspect that they are merely artifacts which have little if any
practical meaning, particularly as lumping fresh meats and processed meats
together makes a nonsense of the whole exercise.
And the authors do admit that:
"Our study has several limitations. Most important, methods used in
nutritional epidemiology are known to provide imprecise estimates of food
intake. Random measurement errors of food intake lead to the attenuation
of the disease risk estimates"
So any or all of those could be the answer.
Will I cut down on red meat? No! Although, having said that, I tend
not to eat processed foods
And there is one other confounding factor: It has been shown many
times over the last century that lean meat is not as healthy as fat meat.
The Italians might have benefitted because they eat a lot more animal fat
than we do.
So, the real message might actually be that we should eat fat meat to
prevent colon cancer. Just a thought.
Competing interests: No competing interests