I wasn’t planning to write another post this week because I’m busy at work and trying to make headway on the book Chareva and I are producing. But a meat-and-mortality study showed up in my inbox, which prompted me to dig up a few more. In my post dedicated to our vegetarian-zealot friends, I made the point that observational studies (the kind they cherry-pick to “prove” that meat will kill you) are unreliable and inconsistent. Here are some studies that underscore that point.
Moderate meat consumption, up to ~100 g/day, was not associated with increased mortality from ischemic heart disease, stroke or total cardiovascular disease among either gender.
What their data showed is that compared to men with the lowest meat intake, men with the highest meat intake had lower mortality rates from heart disease, a very slightly higher mortality rate from stroke, and the same mortality rate from all cardiovascular diseases combined. Women who ate the most meat had a slightly higher rate of mortality from heart disease, but a lower mortality rate from stroke.
So here’s the story so far: meat reduces heart-disease mortality in men, but raises it in women. But the differences aren’t really significant either way.
Red meat intake was associated with increased risk of ischemic heart disease mortality and with decreased risk of hemorrhagic stroke mortality. There were suggestive inverse associations of poultry intake with risk of total and all-CVD mortality among men, but not among women.
Okay, then. Red meat causes heart disease – for both men and women — but prevents strokes. Poultry also prevents heart disease for men, but not for women. Got it.
Regarding cause-specific mortality, men and women had elevated risks for cancer mortality for red and processed meat intakes. Furthermore, cardiovascular disease risk was elevated for men and women in the highest quintile of red and processed meat intakes. When comparing the highest with the lowest quintile of white meat intake, there was an inverse association for total mortality and cancer mortality, as well as all other deaths for both men and women.
Stop the presses! Turns out red meat causes cancer and heart disease for both men and women after all. Poultry, on the other hand, prevents cancer and a premature death – for both men and women.
In a dose-response meta-analysis, consumption of processed meat and total red meat, but not unprocessed red meat, was statistically significantly positively associated with all-cause mortality in a nonlinear fashion.
Notice what they wrote about unprocessed red meat: it’s not associated with higher all-cause mortality. Now look at the conclusion:
These results indicate that high consumption of red meat, especially processed meat, may increase all-cause mortality.
Somehow red meat is still to blame, but especially processed meat. The accurate statement (based on their data, anyway) would have been that only processed meat is the problem.
So the updated story: red meat and especially processed meat will kill you.
After multivariable adjustment, neither red and processed meat, nor white meat consumption were consistently associated with all-cause or cause-specific mortality. In men, white meat consumption tended to be inversely associated with total mortality, but there was no such association among women.
I see. Red meat, white meat, and processed meat aren’t associated with all-cause mortality, or with mortality from any specific cause. White meat prevents premature death among men, but not women.
So here’s what we know from observational studies: Meat – especially red meat and most especially processed meat – will kill you. However, meat (including red meat) prevents heart disease among men while having no effect on premature death. Unfortunately, the same red meat causes heart disease among women — and among men, except for the men.
White meat prevents heart disease among men, but not women. However, it prevents cancer and premature death for both men and women, but not women.
Oh, and all meats – red, white, processed and unprocessed – also have no effect on specific or all-cause mortality for anybody.
That’s why observational studies are a joke – as are the people who cherry-pick them to (ahem) prove a point about meat and health.