En español | If you're a steak and burger lover, this week's headlines might have seemed too good to be true: Keep eating red meat — no reason to cut back. That's the upshot of a series of articles published in the prestigious Annals of Internal Medicine by an international group of 19 researchers who analyzed existing studies on red meat and health.
Before you celebrate at the steakhouse, get this: Most scientists interpret that exact same research in a very different way, linking red meat to a bevy of killer diseases. Reputable health organizations such as the American Heart Association and the World Health Organization, even the U.S. Department of Agriculture — tasked with the conflicting roles of protecting our health and promoting the meat industry — conclude that we should eat a lot less red meat (which includes beef, lamb, pork and processed meat such as bacon and pepperoni).
How could the same research — decades of it, 61 studies tracking the eating habits of more than 4 million people around the world — lend itself to such wildly divergent conclusions?
We posed that question to a man who knows more about this than most: physician and epidemiologist Frank Hu, chair of the Department of Nutrition at Harvard's School of Public Health and professor of medicine at Harvard Medical School. His research, including long-running studies tracking the diets of 300,000 people for up to four decades, has illuminated links between diet and health — including the role of red meat.
As he explains, the Annals authors applied a different and much higher standard — the kind used for drug testing — to the nutrition data they were analyzing. That standard, involving things like double-blind clinical trials, isn't truly possible to apply to nutrition research. Nor, he says, would it be ethical to do so since it would mean setting up experiments in which some people ate what you hypothesized could be bad for their health for a significant amount of time: “Imagine asking thousands of people to eat red meat every day for a decade and comparing their disease outcomes to people who were told to eat little to no red meat!”
Hu also notes that even if the data represented in the Annals reports doesn't include clinical trials, it does count as “high-quality” research since it tracked 4 million people's eating habits for long periods, often decades. “When you see the same findings in different demographics and populations with different eating habits, they have to be taken seriously,” he says.
Here's what Hu thinks people should know about red meat, based on the best research available.
AARP: So what do these studies indicate about red meat and disease risk?
Hu: People who eat the most red meat are more prone to developing cardiovascular disease, Type 2 diabetes, obesity, colorectal cancer and other cancers. There is remarkable consistency and reproducibility in the evidence. That's when you know a finding is real, and not just “noise.”
Ironically, that's what the Annals reports found: Cutting back on red meat by three servings weekly in the context of a healthy eating pattern would reduce total mortality (risk of dying in a particular time frame) by 13 percent, cardiovascular deaths by 14 percent, cancer deaths by 11 percent and risk of developing Type 2 diabetes by 24 percent. That's an enormous savings of life and health care dollars!
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AARP: How much red meat (beef, lamb, pork) are Americans eating, and how much is too much?
Hu: The average U.S. adult consumes 4 ½ servings a week; a serving is about 3 ½ ounces. Then there's that third of Americans eating more than one serving per day. While we don't yet have a clear evidenced-based recommendation, it appears that no more than two to three servings per week, along with a healthy, balanced diet, is probably OK.
AARP: A few years ago, the World Health Organization classified processed meat, such as bacon, ham and other cold cuts, hot dogs, pepperoni and sausage, as carcinogens — cancer-causing agents. What's your take on this, and how much processed meat can people get away with?
Hu: Processed meat shows up as even riskier than plain meat — probably because of its high levels of sodium and other additives. Again, no evidence-based guidelines yet, but keep amounts even lower than unprocessed meat.
AARP: What type of protein should we eat — what's healthiest?
Hu: Before we talk about protein, let's start with an overall healthy diet pattern — that's what matters most to your health. That's a diet based on vegetables, fruit, whole grains, healthy fats like olive oil, and healthy protein sources. Of the latter, the most protective are plant-based, such as legumes, nuts and seeds. Seafood and poultry are also healthy alternatives to red meat.
AARP: Will people age 50 and up see much benefit to switching over to the dietary pattern you're describing?
Hu: Absolutely! You can see major benefits in just four to five years, with significant reductions in the risk for Type 2 diabetes, heart attacks and stroke. And if you already have a disease, such as Type 2 diabetes, switching to a healthier diet can mean a much better prognosis.
But you'll only reap the benefits of cutting back on red meat if you replace it with plant protein, fish and chicken. There's no benefit to filling in the gap with bagels, bread and other refined flour foods, or sugary foods. Fortunately, taste is very adaptable — before long, you'll really start to enjoy legumes, nuts, seeds, fish and chicken.