CLEVELAND — The recent scientific reviews on red meat in the prestigious “Annals of Internal Medicine” found a lack of high-quality evidence for one of the historical pillars of our nutrition policy – the warning that we should eat relatively little red meat to protect heart health. This prompted great surprise in the media but little shock among the community of evidence-driven scientists. We have long known that many of the nation’s nutrition recommendations are rooted in weak science, largely uncorroborated by rigorous controlled studies.
It is time we compel these highly influential recommendations to stand up to scrutiny, so that Americans can have better information, backed by rigorous science, about what to eat.
America’s nutrition is deeply important. It drives rates of chronic disease and growing health disparities that plague our nation. We certainly cannot prove that U.S. nutrition policy — the Dietary Guidelines for Americans — have caused these epidemics. Yet the precipitous rise of the obesity rate, which began to spike in the very year, 1980, that the Dietary Guidelines were first issued — and recommended an increase in carbohydrates and a reduction of fat — is, at the least, a troubling coincidence.
Some 60 percent of Americans now suffer from one or more diet-related disease, which are the leading drivers of the nation’s $3.3 trillion in annual health care costs.
Ohioans suffer more than most: The state’s obesity rate has more than tripled since 1990, and its diabetes rate is 43 percent higher than the national average. Heart disease alone claims more than 27,000 lives in Ohio each year.
Last year, then-gubernatorial candidate Mike DeWine announced a plan to cut health care costs for state employees and, eventually, Medicaid recipients by targeting chronic disease, pronouncing, “Our goal is to get Ohio healthy, to prevent chronic disease from developing, and help Ohioans take control of their health ….”
If this is our goal, then Ohioans should encourage federal officials to redo the Dietary Guidelines for Americans to ensure that they are grounded in strong scientific evidence, so that doctors, patients, families and educators in our state have accurate, reliable information about what constitutes “healthy” eating.
Although the guidelines do not explicitly dictate what each of us individually eats, their impact is ubiquitous. They affect everything from campus food to prison meals, from hospital diets to cafeteria lines on military bases. The guidelines also underpin America’s public health initiatives and have a disproportionate impact in low-income communities, which rely most on food-based public assistance programs like SNAP (food stamps) and the National School Lunch Program.
The National Academies of Sciences, Engineering and Medicine conducted the first-ever peer review of the Dietary Guidelines process in 2017, concluding they required a new process to “maximize scientific rigor.” The failure to assure scientific rigor has led to unreliable results and, ultimately, the confusing flip-flopping dietary advice we’ve seen, on cholesterol, total fat, and now, it seems, red meat.
According to a 2015 analysis in The BMJ, our Guidelines are not backed by any strong evidence to show they can help fight obesity, type 2 diabetes or other major diet-related diseases. Why should we follow guidelines that seem unlikely to protect our health?
A fundamental problem is that the guidelines rely largely on epidemiological data, a weaker kind of science that does not demonstrate cause-and-effect. Epidemiology often uses questionnaires, which ask people to remember what they ate for the last six or twelve months. Not surprisingly, studies show this kind of data to be deeply flawed.
By contrast, the new Annals reviews on red meat used a standard that has been adopted by more than 100 public health institutions worldwide. These reviews concluded that there is only weak evidence, at best, supporting the notion that red or processed meat is unhealthy. The Annals study is not a manifesto to eat more red meat. Its lesson is more fundamental: We cannot base dietary policy on hunches and weak science.
What the data do tell us is that Americans are, broadly speaking, not eating as healthfully as we should. That may not be the fault of our citizenry, who deserve better advice than what they are getting today. The conclusion of the Annals study is a wake-up call.
As the Dietary Guidelines for 2020-2025 are now being crafted, and since we know the current guidelines do not meet the grade, those in Washington charged with shepherding new nutritional recommendations must set a higher standard for facts and evidence for this next round. Ohioans, whose health seems to be worsening each year, cannot settle for anything less.
Dr. Mark Hyman is head of strategy and innovation at the Cleveland Clinic Center for Functional Medicine.