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 Nutrition Facts 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.
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.
In a way 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 fat
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 US 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 cannisters 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 (randomized control trials) 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, 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 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.
First of several serious weaknesses was that the analyses
and recommendations were largely based the so-called GRADE criteria
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‑blinded 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 nutrition trials how are you going to blind people
to the fact 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, breath 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 on 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, or trans fat.”
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. 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 US surgeon general,
a former president of the American College of Cardiology,
and the directors of preventive medicine and nutrition institutes
from Harvard, Yale, Tufts, and Stanford.
In my last video I explained the how, the method by which
they manipulated the science, but never really got to the why.
I mean, 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 at the panelists' declared
conflicts of interest, they all say they didn't have any,
including the lead author
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 NutriRECS panel meat recommendations.
Oops, Bradley Johnston failed to indicate he had gotten a grant
from Texas A&M AgriLife, 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 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 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 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 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
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.
The pseudoscience is presented solely to create doubt and confusion
in the wider population. Frankly, industry will do
what it needs to do to push as much of its product
into the world as it can, and so will do what it needs to do
to obfuscate the relationship between its products
and human and planetary health;
they've done it with tobacco, fossil fuels,
Monsanto's Roundup, sugar, and now meat.
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