Oops! Their bad.
Remember how the government said fat and cholesterol were dangerous to your health? Never mind.
As Nina Teicholz explains in an NYTimes Op-Ed (The Government’s Bad Diet Advice):
For two generations, Americans ate fewer eggs and other animal products because policy makers told them that fat and cholesterol were bad for their health. Now both dogmas have been debunked in quick succession.
First, last fall, experts on the committee that develops the country’s dietary guidelines acknowledged that they had ditched the low-fat diet. On Thursday, that committee’s report was released, with an even bigger change: It lifted the longstanding caps on dietary cholesterol, saying there was “no appreciable relationship” between dietary cholesterol and blood cholesterol. Americans, it seems, had needlessly been avoiding egg yolks, liver and shellfish for decades. The new guidelines, the first to be issued in five years, will influence everything from school lunches to doctors’ dieting advice.
She asks the obvious question: how did experts go so wrong?
The answer is that the government placed too much reliance on population based studies:
But even the most rigorous epidemiological studies suffer from a fundamental limitation. At best they can show only association, not causation. Epidemiological data can be used to suggest hypotheses but not to prove them.
Instead of accepting that this evidence was inadequate to give sound advice, strong-willed scientists overstated the significance of their studies.
Aaron Carroll addresses the same issue in today’s Upshot column in the NY Times:
For decades, many dietary recommendations have revolved around consuming a low percentage of your daily calories from fat. It has been widely thought that doing so would reduce your chance of having coronary heart disease. Most of the evidence for that recommendation has come from epidemiologic studies, which can be flawed.
Use of these types of studies happens far more often than we would like, leading to dietary guidelines that may not be based on the best available evidence.
And although we have finally learned the error of our ways regarding fat and cholesterol, we are aggressively making the same mistake when it comes to the diet of infants.
The evidence on which breastfeeding recommendations are based is no better than that on which the cholesterol recommendations were based.
The science is extremely weak, contradictory and plagued by confounding variables. Despite this, we are promoting breastfeeding as every bit as important to good health and long life as limiting dietary cholesterol and fat. Indeed, we are going farther, with government attempts to cajole and shame women who choose to formula feed, and dangerous hospital policies like the oxymoronic Baby Friendly Hospital Initiative which, in direct defiance of everything we know about babies suffocating and falling out of hospital beds, promotes 24 hour rooming in of infants, giving exhausted, potentially sedated new mothers little choice but to keep their babies in bed with them.
There were many scientists and physicians who questioned the dietary fat and cholesterol guidelines over the past decades, arguing that the scientific evidence simply did not justify sweeping dietary recommendations, but their voices were drowned out by those who insisted that we could improve the health of the American public by telling them what to eat. Everyone “knew” restricting fat and cholesterol was good for you, and scientific evidence that didn’t comport with what everyone “knew” was ignored.
The exact same thing is happening at this very moment with breastfeeding recommendations. Everyone “knows” that breastfeeding makes children smarter, healthier, thinner, less likely to developed the chronic diseases of old age. Except that’s NOT what the scientific evidence shows. The scientific evidence shows that for full term infants in first world countries, the ONLY health benefits are a minor reduction in incidence of colds and diarrheal illness in the first year of life. That it.
As Carroll notes:
It is frustrating enough when we over-read the results of epidemiologic studies and make the mistake of believing that correlation is the same as causation… In reviewing the literature, it’s hard to come away with a sense that anyone knows for sure what diet should be recommended to all Americans.
I understand people’s frustration at the continuing shifts in nutrition recommendations. For decades, they’ve been told what to eat because “science says so.” Unfortunately, that doesn’t appear to be true. That’s disappointing not only because it reduces people’s faith in science as a whole, but also because it may have cost some people better health, or potentially even their lives.
He’s right.
We’ve made a terrible mistake with dietary recommendations promoting low fat and low cholesterol diets; we went far ahead of what the science showed and we ignored any science that did not support what we “knew”.
We’re making the exact same mistake by promoting breastfeeding recommendations based on weak science.
If we learn anything from the fiasco on fat and cholesterol recommendations it should be this:
Our recommendations on breastfeeding should reflect what the scientific evidence actually shows, not what we think we “know.”
