You may have heard the expression “Knowledge is power.” Well – today – we’re going to give you more power to control your diet and lifestyle – by giving you the facts. Welcome to the NutritionFacts Podcast. I’m your host – Dr. Michael Greger.
Today, we continue our series on how industries impact dietary and health guidelines. And pick things up by taking a close look at corporate criticism of scientific nutrition literature.
While randomized controlled trials are highly reliable in assessing interventions like drugs, they’re harder to do with diet. Dietary diseases can take decades to develop. It’s not like you can give people placebo food, and it’s hard to get people to stick to assigned diets, especially for the years it would take to observe effects on hard endpoints like heart disease or cancer. That’s why we have to use observational studies of large numbers of people and their diets over time to see which foods appear to be linked to which diseases. And interestingly, if you compare data obtained from observational population studies versus randomized trials, on average, there is little evidence for significant differences between the findings. Not just in the same direction of effect, but of the same general magnitude of the effect, in about 90 percent of the treatments they looked at.
But wait, what about the hormone replacement therapy disparity I talked about in the last video? It turns out when you go back and look at the data, it was just a difference in timing in terms of when the Premarin was started, and they actually showed the same results after all.
But even if observational trials did provide lower-quality evidence, maybe we don’t need the same level of certainty when we’re telling someone to eat more broccoli or drink less soda, compared to whether or not you want to prescribe someone some drug. After all, prescription drugs are the third leading cause of death in the United States. It goes heart disease, cancer, then doctors. About 100,000 Americans are wiped out every year from the side effects of prescription drugs taken as directed. So, given the massive risks, you better have rock-solid evidence that there are benefits that outweigh the risks. You are playing with fire; so, darn right I want randomized double-blind, placebo-controlled trials for drugs. But when you’re just telling people to cut down on doughnuts, you don’t need the same level of proof.
In the end, the industry-funded sugar paper concluding that the dietary guidelines telling people to cut down aren’t trustworthy, because they’re based on such “low-quality evidence,” is an example of the inappropriate use of the drug trial paradigm in nutrition research. You say yeah, but what were the authors supposed to do? If GRADE is the way you judge guidelines, then you can’t blame them. But no, there are other tools––like, for example, NutriGrade, a scoring system specifically designed to assess and judge the level of evidence in nutrition research.
One of the things I like about NutriGrade is that it specifically takes funding bias into account; so, industry-funded trials are downgraded—no wonder the industry-funded authors chose the inappropriate drug method instead. HEALM is another one, Hierarchies of Evidence Applied to Lifestyle Medicine, specifically designed because existing tools such as GRADE are not viable options when it comes to questions that you can’t fully address through randomized controlled trials (RCTs). Each research method has its unique contribution. In a lab, you can explore the exact mechanisms, RCTs can prove cause and effect, and huge population studies can study hundreds of thousands of people at a time for decades.
Take the trans fat story, for example. We had randomized controlled trials showing trans fats increased risk factors for heart disease, and we had population studies showing that the more trans fats people ate, the more heart disease they had. So, taken together, these studies forged a strong case for the harmful effects of trans fat consumption on heart disease, and as a consequence, it was largely removed from the U.S. food supply, preventing as many as 200,000 heart attacks every year. Now, it’s true that we never had randomized controlled trials looking at hard endpoints, like heart attacks and death, because that would take years of randomizing people to eat like canisters of Crisco every day. You can’t let the perfect be the enemy of the good when there are tens of thousands of lives at stake.
Public health officials have to work with the best available balance of evidence there is. It’s like when we set tolerable upper limits for lead exposure or PCBs. It’s not like we randomized kids to drink different levels of lead and saw who grew up to have tolerable brain damage. You can’t run those kinds of experiments; so, you have to just pull in evidence from as many sources as possible and make your best approximation.
“Even if RCTs are unavailable or impossible to conduct, there is plenty of evidence from observational studies on the nutritional causes of many cancers, such as on red meat increasing the risk of colorectal cancer.“ So, if dietary guidelines aiming at cancer prevention were to be assessed with the drug-designed GRADE approach, they’d reach the same conclusion that the sugar paper did—low quality evidence. And so, it’s no surprise a meat-industry-funded institution hired the same dude who helped conceive and design the sugar-industry funded study. And boom, lead author saying we can ignore the dietary guidelines to reduce red and processed meat consumption, because they used GRADE methods to rate the certainty of evidence, and though current dietary guidelines recommend limiting meat consumption, their results predictably demonstrated that the evidence was of low quality.
Before I dive deep into the meat papers, one last irony about the sugar paper. The authors used the inconsistency of the exact recommendations across sugar guidelines over a 20-year period to raise concerns about the quality of the guidelines. Now obviously, we would expect guidelines to evolve, but the most recent guidelines show remarkable consistency, with one exception: the 2002 Institute of Medicine guideline that said a quarter of your diet could be straight sugar without running into deficiencies. But that outlier was partly funded by the Coke, Pepsi, cookie, candy-funded institute that is now saying see, since recommendations are all over the place (thanks in part to us), they can’t be trusted.
In our next story – the meat industry comes up with a perversion of evidence-based medicine.
A series of articles published in the Annals of Internal Medicine culminated in a recommendation suggesting people keep eating their red and processed meat. Nutrition researchers savaged these articles. The chair of the Nutrition department at Harvard called it “a very irresponsible public health recommendation,” and the past Harvard Nutrition chair was even less restrained. “It’s the most egregious abuse of data I’ve ever seen,” said Walter Willett, “There are just layers and layers of problems.” Let us start to pick through these layers.
The first of several serious weaknesses was that the analyses and recommendations were largely based on the so-called GRADE criteria (Grading of Recommendations, Assessment, Development, and Evaluation), which I talked about in my last video. The authors erred in applying the GRADE tool, since that was designed for drug trials.
GRADE automatically scores observational studies as “low- or very-low” scores for “certainty of evidence,” which is exactly what you want when you’re evaluating evidence from drug trials. You want a randomized double-blind, placebo-controlled trial to prove the drug’s risks and benefits. However, the infeasibility for conducting randomized clinical trials on most dietary, lifestyle, and environmental exposures makes the criteria inappropriate in these areas, since it would involve controlling people’s daily diet and following them for decades.
“You can’t do a double-blind, placebo-controlled trial of red meat and other foods on heart attacks or cancer. “For dietary and lifestyle factors, it’s impossible to use the same standards for drug trials.” Imagine telling one group of people to smoke a pack of cigarettes every day for the next 20 years to prove that cigarettes cause lung cancer. And how could you make it double-blind—have the control group smoke placebo cigarettes?
Yet, in the meat papers, they were downgrading studies due to lack of blinding. Well duh, in nutritional trials how are you going to blind people to the facts of what they’re eating? GRADE is just the wrong tool for diet studies. In fact, the authors admit that the reason their recommendations differ from all the others is that other guidelines have not used the GRADE approach. And the reason is “you can’t randomize people to smoke, avoid physical exercise, breathe polluted air, or eat a lot of sugar or red meat and then follow them for 40 years to see if they die. Now, that doesn’t mean you have no evidence. It just means you look at the evidence in a more sophisticated way.” And alternative approaches to GRADE exist, like, for example, NutriGrade, which have specifically been developed to evaluate evidence from studies of nutritional and lifestyle factors.
So, are the author’s appeals to standards of evidence motivated by a genuine interest in getting to the bottom of it, or just to advance the financial interests of industry, as the same lead author had done previously at the behest of soda and candy companies? “The tool he employed in his meat and sugar studies could be misused to discredit all sorts of well established public health warnings, like the link between secondhand smoke and heart disease, air pollution and health problems, physical inactivity and chronic disease, and trans fats and heart disease.” Industries could use it to sow doubt in any field where randomized controlled trials are not feasible, such as climate change. What are you going to have, some placebo planet? Strict adherence to GRADE guidelines could even be used to question the link between smoking and lung cancer.
I know you can’t randomize people to smoke, but can’t you randomize people to quit? Here’s a randomized controlled trial of the effect on aged men of advice to stop smoking. Of those randomized to quit, 13.7 percent died within the study window, whereas of those in the control group who got no special instruction, only 12.9 percent died. In other words, it didn’t work. Disappointingly, the researchers concluded, we find no evidence at all of any reduction in total mortality. Wait, so is smoking not bad for you after all? Of course not. Does anyone see the fatal flaw? They didn’t randomize people to quit. They randomized people to advice to quit smoking. It’s not like they could lock people in a room for a few years. At the last follow-up, the stop smoking group was smoking 8 cigarettes a day compared to 12 cigarettes a day in the control group; so, it’s no surprise there was no difference in mortality since there was hardly any difference in smoking. And the same thing with diet.
There have been massive randomized dietary trials: the Women’s Health initiative, the Multiple Risk Factor Intervention Trial that wasted hundreds of millions of dollars, because people just flat out failed to follow the dietary advice. So, the groups ended up eating similar diets at the end, so had similar disease outcomes, just like the randomized smoking-quit trial. It’s not like the failure was a result of inexperienced investigators; these trials were conducted by some of the very best research teams, who invested enormous efforts to achieve their goals. But it just shows you can’t really run decade-long randomized trials that require changes in eating behavior. People just won’t do it. Randomized controlled trials couldn’t even show an effect on mortality of smoking, which is pretty remarkable, considering that smoking is one of the most powerful known risk factors in the world.
So basically, the foregone conclusion putting any kind of junk to the test in this manner would echo the new meat report conclusion that people should “eat whatever they want and do whatever they want.” It’s like a hijacking of evidence-based medicine. Of course, we want the best evidence possible, but the whole process is now being “manipulated and misused to support subverted or perverted agendas.”
“It’s very exciting and attention-grabbing to say there’s no need to reduce meat intake. It’s less exciting to say we reviewed studies to evaluate the validity using a system not meant to evaluate the validity of these studies, and what we found is nothing.” When asked whether physicians can advise persons whether a salad is healthier than a bowl full of sugar, one of the senior co-authors of the meat papers responded that physicians should tell persons that “the quality of evidence is low; so, it depends almost entirely on their preferences.” “When GRADE criteria do not allow us to strongly recommend against smoking a cigarette with your bowl of sugar, we believe that alternative grading systems are preferable.”
Did you know that the same person paid by Big Sugar to downplay the risks of sugar was paid by Big Meat to downplay the risks of meat? Here’s the story.
A series of articles published in the Annals of Internal Medicine recommending people just keep eating their meat was decried by nutrition researchers as “irresponsible and unethical,” a “travesty of science,” an “assault on public health,” and the “most egregious abuse of evidence” that they had ever seen. There were calls for retraction even before it was published from eminent public health leaders, from a former U.S. surgeon general, a former president of the American College of Cardiology, the directors of Preventive Medicine and Nutrition institutes from Harvard, Yale, Tufts, and Stanford universities. In my last video, I explained the how, the method by which they manipulated the science, but never really got to the why.
The lead author’s similar attempt to discredit the sugar guidelines was explicitly paid for by an industry front group funded by the likes of Coca-Cola, Dr. Pepper, Mars candy bars, and Pepsi. But if you look at the meat paper, the panelists’ declared conflicts of interest, they all say they didn’t have any––including the lead author (Bradley Johnston), who was involved in the sugar study, whose primary funder wasn’t just representing Big Soda and Candy, but the likes of McDonald’s and one of the largest meat packers in the world.
Yet, Johnston didn’t disclose that as a potential conflict of interest when he switched from exonerating sugar to exonerating meat. What did he have to say for himself? Even though the sugar study was published in 2016, he got the money for it in 2015, outside of the three-year mandatory disclosure window. This is the same guy who said the industry front group had no role in writing their paper until the Associated Press revealed the truth, and the journal had to publish a correction.
But Johnston doubled down this time, saying “it is tenuous at best” to suggest that his earlier work on sugar had any influence on how his team made the new meat recommendations. The important thing is, “We have no relationship with the meat industry.” Oh really? A few months later the truth came out. Correction in the so-called NutrRECS panel meat recommendation. Oops, Bradley Johnston failed to indicate he had gotten a grant from Texas A&M AgriLife Research, which gets millions of dollars a year from the meat industry to do things like run Beef Boot Camp, or espouse the health benefits of beef brisket, or promote the celebration of National Bacon Day. After all, Texas A&M AgriLife Extension serves pork producers to improve pork producer profitability. This is the group that not only gave Dr. “no-relationship-with-the-meat-industry” Johnston a direct grant for over $75,000, but they officially joined the whole NutriRECS consortium to provide, as Dr. Johnston explained, generous support to impact nutrition-related decision-making and policy in North America and beyond.
Yet none of this was disclosed in the paper. No even any potential conflicts of interest, yet they had formed a partnership with an arm of Texas A&M partially funded by the beef industry to the tunes of millions of dollars a year from the beef industry alone. Oops. In fact, Patrick Stover, Mr. “no-conflicts-of-interest,” is the director of AgriLife. And a month before the meat paper was published, Bradley Johnston who was offered and accepted a tenured position at Texas A&M AgriLife, was already working for them when it was published, but didn’t think to mention it.
So, when the Annals of Internal Medicine initially sent out a press release, which they later corrected, saying no need to reduce red or processed meat consumption for good health, they may have been simply acting as a mouthpiece for meat industry propaganda. “The pseudoscience presented in the Annals meat papers appears to have been written solely to create doubt and confusion in the wider population.” The “misleading recommendations were not intended to convince scientists, who clearly understand the nature of the relationship between meat and health and, for that matter, sugar and health. This pseudoscience is presented solely to create doubt and confusion in the wider population.” Frankly, “ndustry will do what it needs to do to push as much of its product into the world as it can, [and so it] will do what it needs to do to obfuscate the relationship between its products and human and planetary health; they have done it with tobacco, fossil fuels, Monsanto’s Roundup], sugar, and now meat.’’
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