The Dr. Hyman Show - Does Red Meat Cause Type II Diabetes?
Episode Date: February 9, 2024View the Show Notes For This Episode Get Free Weekly Health Tips from Dr. Hyman Sign Up for Dr. Hyman’s Weekly Longevity Journal Get Ad-free Episodes & Dr. Hyman+ Audio Exclusives Recently, a study ...made headlines linking red meat consumption to an increased risk for type 2 diabetes. It’s no secret that navigating the realm of nutrition has become a challenge for the general public. That’s why, on today’s Health Bites episode, we’re diving deep into the findings from this study, “Red meat intake and risk of type 2 diabetes in a prospective cohort study of United States females and males,” published in The American Journal of Clinical Nutrition. I unpack the study’s design flaws, inaccuracies, and where the researchers got it straight up wrong. This episode is brought to you by Rupa University, Happy Egg, and Mitopure. Rupa University is hosting FREE classes and bootcamps for healthcare providers who want to learn more about Functional Medicine testing. Sign up at RupaUniversity.com. Shopping for better eggs shouldn’t be confusing. Look for the yellow carton at your local grocery store or visit happyegg.com/farmacy to find Happy Egg near you. Support essential mitochondrial health and save 10% on Mitopure. Visit TimelineNutrition.com/Drhyman and use code DRHYMAN10. In this episode, I discuss (audio version / Apple Subscriber version): What we can and cannot learn from observational research (3:42 / 1:56) “Red meat intake and risk of type 2 diabetes in a prospective cohort study of United States females and males” study design and findings (9:01 / 7:15) Issues with the study design and why it does not prove that red meat causes type 2 diabetes (20:01 / 16:23) What have other studies found? (39:20 / 35:42) The root cause of type 2 diabetes (44:02 / 40:24) Strategies to address type 2 diabetes (44:29 / 40:51)
Transcript
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Coming up on this week's episode of The Doctor's Pharmacy.
There was a large study of about 11,000 people who shopped at health food stores.
Half of them were vegetarian or vegan and half of them ate meat.
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back to this week's episode of The Doctor's Pharmacy. Welcome to The Doctor's Pharmacy. I'm Dr. Mark Hyman,
and this is a place where conversations that matter. Now, it's no secret that navigating
the realm of nutrition has become a challenge for the general public and even for people like
me and health professionals who've been studying this for 30 years. One week, eggs are good for us,
only to be vilified for allegedly raising cholesterol levels the next week.
The narrative on dietary fats is no less tumultuous.
And I wrote a whole book on this called E-Fat Get Good.
Some experts say that it's the chief culprit behind heart disease.
Others say it's critical for overall health and well-being.
Well, more recently, a study made headlines linking red beet consumption to an increased risk for type 2 diabetes,
leaving the public once again confused and understandably so.
And that's why in today's Health Bytes episode, we're diving deep into the findings from this paper
and unpacking the study's design flaws, its inaccuracies, and where the researchers got it straight up wrong.
This is something new that we're doing on The Doctor's Pharmacy,
and my mission
to help you sort through the whole slew of dietary misinformation. Now let's get started.
This podcast is about a study and putting it in context that really upended a lot of people's
thinking and was all over every major newspaper, every headline, every television
show, which was basically that red meat causes type 2 diabetes. Now let's examine that. Is it
true? What does the science show? What does the paper actually tell us? And what does it not tell
us? And what are the major flaws of the paper? And what are the conclusions we can draw and we
can't draw from this paper? The study was entitled Red Meat Intake and the Risk
of Type 2 Diabetes in a Prospective Cohort Study of United States Females and Males, published
in October of 2023. Now, this was a type of study design. It's important to understand
study design because you have to understand science before you can interpret science,
and you have to understand the type of studies that are done and which can show cause and effect and which can show
correlation, not causation. For example, every day I wake up and the sun comes up.
It's 100% correlated, but it's 0% causal. You know, if I died tomorrow, the sun's going to
keep coming up. If I slept through the middle of the day, the sun's going to keep coming up.
So it has nothing to do with each other. And essentially, that's what these observational studies like this particular study did.
They looked at correlation, not causation.
And that means that we can't prove cause and effect.
So when you hear the headline, red meat is linked to causing type 2 diabetes, it's BS.
Okay, we have to look at what the data show and what it doesn't.
And these studies are not wrong.
They're not bad to do. They're done in order to help us understand what might be a useful
avenue for further research, right? They're not the end of the research. They're useful for
generating hypothesis. For example, in the study of smoking and lung cancer, they did observational
studies, right? They weren't going to do a randomized controlled trial because they're not going to have people on cigarettes and have people not
on cigarettes. So basically, they found that there was a 20-fold increase, maybe 10 to 20-fold
increase in the risk of lung cancer in smokers. Now, to put that in perspective, that's a 1,000
to 2,000% increase in your risk of having a particular disease. And that ended up being correct because
it was such a strong correlation. Whereas in this red meat diabetes study to cut to the punch,
it was about a 20% increase, right? Which essentially is relatively meaningless. And
let's just say 200% increase in a correlation study, you pretty much want to ignore the data.
And Dr. Ioannidis from Stanford has written a lot about this. He's an incredible scientist. I dissected the value of different types of studies
and what we can learn from them and what we can't. So we have to start out really understanding
that the study was not designed by its very nature, which all scientists would agree,
to prove cause and effect. It's just the nature of science. Okay, so let's get into the study.
This is what we call a prospective cohort study. And it's an observational study,
a population study, an epidemiological study, all means the same thing. Essentially,
it studies a group of individuals over time to look at the association between certain exposures,
behaviors, diets, and risk factors on specific outcomes. So basically, they track thousands of people over many, many years,
looked at what they ate, and saw if there was a correlation with diabetes. And lo and behold,
they found one. But let's talk about the problems with why this may not actually be
as clear as the study seems to generate. Now, in this type of study, basically, people are
identified based on their exposure status, and then they're followed over time to observe and record outcomes.
In other words, what did people eat over many decades, and what was that diet, and was it correlated with any bad outcomes later in life?
So you follow people for 30 years, you have them track their diet records, which we'll talk about in a minute,
and then you see whether or not a particular food or types of food seems to correlate,
not cause, correlate with some bad outcome like diabetes.
And that's what they did.
And basically, the goal is just to assess relationships between various insults, exposures,
toxins, smoking, diet, whatever, and outcomes.
So it essentially looks for things that may be worth further studying with a randomized
control double-blind trial.
Okay, this was not done here. Now, it can be helpful, but they say, well, we're going to
control for variables we call confounding variables, which means things that kind of
can throw the study off. In other words, we'll talk about this, but for example, there was a
study done many years ago by the NIH and the ARP, the American Association of Retired Persons,
that looked at meat eating
and chronic disease and death and cancer and so forth.
They found a big correlation.
But that study showed also that the people who ate meat didn't care about their health
and smoked more, drank more, ate more calories, about an inch or more a day, were more overweight,
didn't eat fruits and vegetables, didn't exercise, drank more alcohol, didn't take
their vitamins.
Of course, they had more disease. It wasn't because of the meat. It was just a, we'll call it a problem that was shown
because of these confounding variables. And we'll talk about more about that. Now, this study was
published in the American Journal of Clinical Nutrition, and it was published by folks at
Harvard who are great scientists, but they're focused on epidemiology, particularly at the
School of Public Health, which is where the study was published out of. And unfortunately, people have bias. And the study
authors are very biased toward a plant-based diet. And so right off the bat, you kind of look at,
all right, well, they already have a bias and that affects the study, the outcome study.
So basically, the objective of the study was to assess the link between total processed and unprocessed red meat intake and type 2 diabetes,
and then to estimate the effect of substituting different protein sources like vegetable proteins, nuts, seeds, beans, grains, for red meat and type 2 diabetes risk.
So work doing, but again, just a hypothesis generating study.
Now, again, this was a population study.
It was based on the Nurses' Health Study, which was about 216,000 participants, the first and the second one, and the Health Professionals Follow-up
Study, which was including men. Now, the first study started in 1976, female nurses, and then
another one in 89, female nurses, and the Health Professionals Study started in 86. And they
followed people for a long period of time. They calculate the amount of years and people, and they come up with a number called about 5.4 million person years. So that's pretty
good. And what they did was really interesting. They looked at something called a food frequency
questionnaire. And this assesses that people's diet every two to four years from the baseline.
Now, can you remember what you had last Thursday for lunch? Can you remember the amount
of this or that you had over the last week? Probably not, right? And so these are flawed
tools. And there's a lot of research and science about how flawed these tools are
and how imperfect they are and how often they are very misleading. We see that in this study.
So the study findings, right, just to be clear, and this is association,
correlation, not causation, they found between the lowest and the highest red meat intake,
there was a risk of diabetes that went up by 62%, right? Not 200%, 62%. Processed meat
associated with 51% and unprocessed red meat was about 40% risk. If you substituted one
serving of nuts or beans, then your risk was 30% lower. If you substituted for processed red meat,
the risk was 41% lower, and unprocessed meat was about 29% lower. So they're basically saying if
you had one serving of dairy for total processed or unprocessed red meat, you had a lower risk of type 2 diabetes.
Now, this study is really important because it kind of misses a lot of the point.
What is the mechanism here?
Now, they try to explain some of the mechanisms, but it's pretty weak.
We know that the sugar that you eat, sugar and refined carbohydrates, is the primary cause of type 2 diabetes,
not red meat. And ancestrally, we've been eating meat for as long as we've been human. I just
came back from the Maasai population in Africa, as I mentioned on different podcasts.
And these people ate the blood, the milk, and the meat of their cows. That was their main diet.
They were healthy. They were super thin. They were very fit, and they had no diabetes. I recently visited their community and the Coca-Cola truck drives up every day,
they get processed cookies from the local town that are made by the industrial food system.
And now they're gaining weight and type 2 diabetes is rampant in this Maasai community in Africa.
And it's just heartbreaking to see that within minutes, this entire Coca-Cola truck, a big truck,
just was emptied out by the local population, not knowing what they were doing themselves.
And they didn't even know that it was connected.
So, you know, this basically, this study fueled a lot of clickbait headlines.
For example, a WebMD said just two servings of red meat per week raises diabetes risk.
Well, that doesn't.
It shows that it's correlated, but not causing.
Eating red meat more than once a week is linked to type 2 diabetes risk. Well, that doesn't. It shows that it's correlated, but not causing eating red meat.
More than once a week is linked to type 2 diabetes risk. That's CBS. This is just bad reporting and
bad journalism. And the social media was just all over the place, right? Some people were pro-red
meat, some people anti-red meat. People were super confused. And then nobody knows who to believe.
And everybody's distrusting public health and dietary guidelines. And it's just a mess. So
I'm going to try to unpack it for you so you really understand how to think about this
and also how to actually know what to believe around this whole issue of red meat and diabetes and what we know.
So basically, the problem with this study, as we mentioned, is an observational study.
And we just cannot draw conclusions from an observational study.
It doesn't prove causality.
And we have to look at also the limitations of the study, right? There were a lot of limitations. The study authors,
for example, as I mentioned, are very biased toward a plant-based diet and veganism.
How they pick the participants of the study, which may not be an issue. Industry funding,
we want to look at. That probably was an issue here. But there's this thing called recall bias,
which is common
with food frequency questionnaires. People are more likely to report healthy food than unhealthy
food. And desserts, sugar, sweetened beverages, alcohol are underreported. This is published.
We're going to put all the references for everything I'm saying in the show notes. So
have a look at those. Everything I'm saying is documented, is well-researched, and you can kind
of dive in. But it would take me about 10 hours if I covered every study in detail. So basically, you know, I've got to tell this
by practice. People overestimate how much extra they exercise, and they underestimate how much
they eat. It's pretty difficult. Mitochondria are pretty flawed. Now, a 2012 study
from red meat consumption and mortality, and looked at prospective cohort studies,
found that people that eat a lot of red meat,
about the highest 20%,
had a 45% high risk of dying from heart disease
compared to those who ate the least red meat,
the lowest 20%.
However, when they looked more closely at the people
in these extreme groups,
they noticed that besides eating red meat,
they had other habits
that made them
more likely to have heart disease, like don't exercise, they ate too much, they smoked,
their cholesterol was worse. Or they maybe had fish consumption, which affected their
health and risks. For example, maybe the people in their lowest risk group exercised and didn't eat
meat, but they also didn't smoke and they also ate healthier food.
So you can't quite tell what's going on.
So the study supports the idea that eating a lot of red meat is linked to high risk of heart disease.
People who choose to eat more or less red meat have other lifestyle issues that influence their health.
Now, there are other factors, these confounding variables I mentioned.
When you look at confounding variables, they try to control for these, but it's really tough.
And they only control what we just think to control for.
And it basically makes it really hard to determine a true cause and effect.
Like I mentioned with the ARP study, they smoked more, they drank more, they ate less fruits and vegetables, they didn't exercise, all these other issues.
That's why they had more disease, not because of the meat. So it's basically, you know,
other issues with the study could be design flaws. And maybe the study population is different from
the regular population. So it may not be widely generalizable. And also, they do all these weird
statistical calibrations to normalize the data. And we're going to talk about what that means.
And they did this in that study. There was, I think, a scientist named Roger Williams who said,
there's liars, damn liars, and statisticians.
Or maybe that was Mark Twain.
I don't know.
But I think it's true.
You can kind of manipulate the data to make it show what you want.
And that's clearly been done here.
And the other thing this study does is it actually supports dietary guidelines
to limit red meat consumption. And why does it say that? Well, I mean, the study basically said,
our study supports the current dietary recommendations for limiting the consumption
of red meat intake and emphasizes the importance of different alternative sources of protein for
type 2 diabetes prevention. But dietary guidelines, just like this study, are heavily
based on observational data, the data that can't prove cause and effect. And the systematic reviews
and meta-analysis of observational data are the weakest types of studies, right? There's confounders,
there's bias, there's a lot of problems in the studies. And often the researchers have ties to industry. The expert panels are not
independent. It's kind of a mess. So how do we know what to do in science? Well, randomized
control trials are the gold standard for drawing causal inferences between exposure and the
outcomes. For example, you know, you give people a placebo or a blood pressure drug who have high
blood pressure and you follow them for three months and you can see, okay, well, the people taking the placebo lower their blood
pressure or the people on the pill. That's a randomized control trial and you randomize people
so they're not stacking the deck in favor of a healthier, sicker population.
Now, they're hard to do in nutrition because you need to control everything. And it's really hard
to do. It's great in a lab rat, but it's not really easy in humans,
because they're what we call free living, and they do whatever they want.
So you say, well, I want you to eat a low-fat diet,
or I want you to eat a low-carb diet,
or I want you to exercise 150 minutes a week,
or I want you to not smoke,
or I want you to sleep eight hours a night,
or whatever you want, you tell them.
They're not going to probably do it.
And it's hard to do.
You'd have to basically put people in a locked metabolic ward
and put them there for years and give them the food that they eat and track everything they do
in order to actually know what's going on like a lab rat. But we really can't do that. We can't
take 10,000 people and feed them a vegan diet and 10,000 people and feed them an omnivore diet,
including red meat and healthy foods, follow them for 30 years and give them all the food
and track that. It would be billions and billions of dollars and impossible to do.
So it's not practical.
It's not ethical.
It's expensive.
It's hard to recruit volunteers for this.
And people just, it's hard to do these nutritional studies.
So we have to do the best with the data we have, which are systematic reviews and meta-analysis
of randomized control trials, mechanistic studies, lab studies.
There's many different levels of evidence.
And you have to look at the total cumulative benefit of all the evidence.
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And now let's get back to this week's episode of The Doctor's Pharmacy.
So now let's dive into this problem of study design
and what was wrong with this paper and
why it does not prove that red meat causes type 2 diabetes. So what they did, as I mentioned before,
they gave them a food frequency questionnaire. They're highly inaccurate, right? Every two to
three years, people get asked, what do they eat? And they got a questionnaire. What's their average
intake of food and beverage over the last 12 months? Do you know what you ate over the last 12 months?
I couldn't have a clue. I mean, how often do you remember eating X and Y food, right? Do you eat
chicken with the skin on it or without the skin? Do you eat hamburgers, hot dogs, processed meats?
They give all these questions. They also kind of weirdly track things like beef, pork, and lamb as
a sandwich or mixed dish, but no serving sizes were noted. Sandwiches and lasagna have also bread and pasta,
processed carbs. So is that part of it? We don't know. So they basically kind of looked at what
they were eating. The second issue is, and by the way, I can go way more into these food frequency
questionnaires, but just trust me, based on the data, we'll put the links in the show notes.
They're really highly inaccurate. They've really been proven to not be a good tool for looking at
nutritional intakes over time and don't really correlate with a valid metric for
tracking outcomes. So right off the bat, it's a tough study to do.
The second issue, and I kind of mentioned it, is that the red meat definition included
sandwiches and lasagna, which basically were counted twice as processed and unprocessed red
meat. Now, processed red meat is hot dogs, bacon, meat sandwiches, sausage. Unprocessed red meat is
like hamburgers, beef, pork, lamb, a sandwich. So it's kind of weird. They kind of included other
foods in the meat. So we have to be clear.
The third issue is the serving sizes change over time. And why?
Because the food frequency questionnaires were different in the different parts of the study.
So one was in 1980.
One was in 84.
One had 61 items.
One had 120 items.
And they basically changed the definitions of what a serving is, even in these food frequency
questionnaires.
So it's super confusing.
So the nurses in the study asked how often they consume two slices of bacon.
Now the serving size of bacon is one slice, but before it was two slices, right?
How do they adjust for this?
One serving of processed red meat is considered 45 grams.
How do they measure it?
Did they weigh their lunch meat?
Did they take their bologna or salami and put it on a scale? I doubt it. What about chicken, beef,
pork, or lamb? They say six to eight ounces was a serving. Today, one serving is three ounces.
Did they know this? Did they translate a three-ounce serving to a six to eight-ounce
equivalent? Probably not. And it creates more error in the studies. Issue four in the study was that this is really crazy. They use statistics to massage the data
to have the outcome they want. It calls this process calibration. We're calibrating the results
using a seven-day weighted diet record and food frequency questionnaires from two other
population studies. In other words, they kind of acknowledge that food frequency questionnaires from two other population studies. In other words, they kind of acknowledge that food frequency questionnaires are not that
accurate, so they're going to use other ones to correlate and see if they can kind of create
this mishmash of data to show what they want.
So what they found was that this is kind of crazy.
The calibration doubled the effect for total red meat, processed meat, and unprocessed
red meat, processed meat, and unprocessed red meat.
So before the calibration, you know, for example, one serving, an increment of total red meat was associated with a 28% high risk of diabetes.
After the calibration, it was 47%. Before the calibration, one serving increment of processed red meat was associated with a 50% high risk of diabetes.
After, it was 101%.
So it's like, what are you doing here, right? So guess what number was reported in the headlines?
Not the uncalibrated, but the calibrated number, right? Too much red meat is linked to a 50%
increase in type 2 diabetes. Well, in NPR, they didn't really do a good job of doing a review of
the study. They didn't do investigative journalism, which I think is sorely lacking. And basically, they found that there's a 50% increase in red meat. So like I
said, before the calibration, it was 28%. After, it was 47%. So the next issue was the authors
compared the lowest intake of red meat to the highest intake, but have historically reported
the risk using servings, and for example, which is a more quantitative metric.
So to explain what that means, in the 2011 paper, another one called Red Meat Consumption and the Risk of Type 2 Diabetes,
three cohorts of U.S. adults and an updated meta-analysis,
they reported 12% risk of diabetes for one serving and 32% for processed meat and 14% for total red meat. But this paper compared the
highest and lowest intakes, claiming a 51% increased risk for eating unprocessed and 101%
increased risk for processed and 40% for total. But basically, this method using qualitative
versus quantitative generated a lot more headline-worthy statistics. So, in other words, the way they
reported this, it just makes it more sensational and look better for the agenda of having a study
show that red meat causes diabetes. Another thing with this study is the women in this study,
right, the NERSC-L study compared to the men in this study, show that the women ate more red meat
than the men. Now, this is the first study ever to claim this. Now, typically, every other study has shown the opposite. So what does that mean? Well,
I don't know, but it just seems to kind of be a clue that maybe the study is a little wacky
and doesn't comport with all the other data we have around meat consumption and being female
and male. The next issue was the total red meat intake had a higher risk of diabetes than both processed and unprocessed red meat.
So that doesn't make sense, right?
If you, how could the total red meat be worse than the individual types of red meat when the total is a sum of both of them, right?
So you don't get like one plus one equals three.
It doesn't make sense. So most studies are looking
at the risks associated with red meat show that processed meat is riskier than unprocessed red
meat. In total red meat, the sum falls in between, right? So if you have processed red meat being a
higher risk and unprocessed lower risk, the average risk is going to be lower, right? Kind
of a combination. But in this study, they found the
opposite, which doesn't make any sense. If red meat, this process makes you have a higher risk
of diabetes and unpressed, you have to make it lower. Then if you add them together, you shouldn't
have a higher risk when you combine them. So it doesn't make sense. The next issue of the study
was what we call healthy user bias. And I think this is really, really important. Essentially, it's talking about what I mentioned earlier, which is the idea of confounders.
This idea of why were the people in the study having more diabetes or not? Was it because of
the meat they were eating or a bunch of other habits, right? The people in this study,
when you look at their characteristics, they had much higher body mass index.
In other words, they were heavier.
They were less physically active.
They were more likely to be smokers, and they were less likely to take vitamins.
So, of course, they're going to have more risk.
So the healthier people didn't eat red meat.
Why? Because they thought that red meat is bad.
That's the propaganda that we have
in our society, which is red meat causes heart disease, red meat causes cancer, so we should be
eating less meat. In fact, we are, which is really another really important point. When you look at
the amount of meat we're eating, it's dramatically decreased over the last 30, 40 years, dramatically,
because the message in the public health domain has been to eat less meat. But at the same time,
what's happened? The risk of diabetes has skyrocketed, right? Just doubled, tripled in different populations. So
how could that make sense? Red meat's going down, diabetes going up. Okay, well, that's a problem.
How do we explain that with this study? What was so interesting to me in this study was that
they didn't adjust for body weight, or what we call BMI. That's nuts because the group that actually had
more diabetes was more overweight. Now, was that attributed to the red meat intake? That's what
they say, that red meat causes you to gain weight, but there's just no data to support that. I mean,
they basically said because the likelihood that weight gain mediates at least part of the
association between red meat intake and type 2 diabetes,
we did not adjust for adiposity in the primary analysis. In other words,
they did not actually account for the fact that the people who ate more red meat were more overweight. Now, a lot of other things can cause that, and particularly they do, particularly
ultra-processed foods, sugar, and refined carbohydrates. That's clear from the data,
not meat. The next issue was grains and sugar were excluded from the characteristics table.
That's crazy. How do you actually evaluate the effect of diet if you exclude the very thing
that's causing diabetes, namely sugar and refined carbohydrates? They just said,
we're not going to include that. Okay, we're not going to look at that. Why? Well, I don't know, but it doesn't make any sense to me.
The next problem with the study is that calorie intake was reported extremely low. Now,
this doesn't make sense because people we know eat a certain amount of food. They're all starving
themselves. And in the study, they basically excluded people who ate less than 500 calories
a day for women or more than 3,500 calories. They just got rid of them from the house.
It's the same thing for men. Men who consume less than 800 calories a day or women are more than 3,500 calories. They just got rid of them from the house. It's the same thing for men.
Men who consume less than 800 calories a day or more than 4,200 calories a day were excluded.
And you can see, how do you get these numbers?
Well, it's because the food frequency questionnaires are so problematic.
People will do all kinds of things that show that they're not actually truly reporting
on how much or what they ate because they're getting all these extremes.
Oh, men are eating 800 calories a day or 4,200 calories a day.
It doesn't make any sense. But what was really interesting is the average calorie intake for women was 1,200 calories and for men it was 1,600 calories.
That's not a sustainable diet for people. They're not going to eat that much. They're going to be
starving all the time. So it just shows you the flaw in these food frequency questionnaires. They
don't show you what people are actually eating. You know, very low averages for healthcare practitioners. People, especially nurses,
are on their feet all day. So that just kind of makes me want to throw out the study altogether.
Because again, how do you rely on data that's so imperfect, where your calorie count is so off?
So how do you know what actually people are eating? Now, the other thing they do is this
statistical kind of dance where they
focus on what we call the relative risk, not the absolute risk. Now, the relative risk is
relative to the other population. How much did your risk go up? So when you see 51% or 61%,
that's what we call relative risk. The relative risk isn't two, right? It's probably not significant in an
observational study. The absolute risk is how much is the absolute increase in the risk of that
disease in a population. So for example, if the absolute risk of developing a certain disease is
5%, it means that five out of a hundred individuals in that population are expected to get sick.
Now we did this with, for example, processed meat and colon cancer.
We said, oh, your risk of colon cancer goes up by about 20% if you eat bacon and processed food.
And this is based on observational data.
What did it actually show?
Your risk of colon cancer went from 5% to 6%.
Now, that's a 20% increase, right? But your absolute risk goes from 5% to 6%
in the total population getting cancer of the colon if you eat two pieces of bacon a day your
whole life. So, okay, what are you gonna do with that information? Absolute risk is really important.
Now, relative risk, as I said, basically is the probability of an event occurring in one group that's
divided by the probability of that occurring in another group.
So it's basically a ratio, but not an absolute risk.
So if it's over one, there's no difference.
If it's one, there's no difference, right?
If it's greater than one, it shows an increased risk.
If it's less than one, it shows a decreased risk.
For example, we talked about the relative risk of smoking and lung cancer with observational studies where it was a 10 to 20 fold increase, which means a 1,000 to 2,000% increase, right?
And heart disease is also a pretty big risk.
If you look at smokers, their relative risk is two, as I said, 200%.
So smokers have about twice as high risk of getting heart disease
than non-smokers. But relative risk sounds good, but it doesn't actually tell the true story.
So when you look at the highest versus the lowest red mean intake in this study, the absolute risk,
now this is not the relative risk, the absolute risk was your risk of getting diabetes went from 0.32% to 0.52%, which is so little, right? You're
talking about two-tenths of a percent increase in your risk of getting type 2 diabetes if you eat
red meat, okay? Not a very big risk. When they looked at the relative risk in this study,
sounds much better, right? The highest versus the lowest total red meat intake showed a risk
was 62% higher of getting type 2 diabetes in the high risk group versus the lowest group,
right? The lowest intake of red meat versus the highest intake. 62%, not 0.2%. Okay. So, this is what I mean by the statistics, right? There's liars,
there's damn liars, and there's statisticians. So, I think you have to really be careful and look at
also absolute risk, not relative risk. It sounds better when you say relative risk if you're trying
to prove something. The next issue is there are a lot of vested interests in this study.
Walter Willett, who's a study author, great scientist. I know him personally. He's a good guy. But I think he's very biased
towards a vegetarian diet, including little to no red meat since the early 90s. And he's been
leaning much more towards veganism recently. And he was the leader of the Eat Lancet section on
diet and health, which essentially said we should all be vegan. Now, he's published more than 200
papers on epidemiological studies, which show association but can't demonstrate cause and effect.
So he's, for example, found that red meat is bad for your health,
that animal fats are bad for your health,
that a diet of grains, fruits, and vegetables and vegetarianism
is better for your health.
And he's also published three books that argue these things.
And he has multiple serious potential conflicts of interest,
which casts doubt on his ability to bring a really unbiased viewpoint to the question of whether a vegan or vegetarian diet is preferable for good health.
Now, Harvard in general condemns animal foods, pushes plant-based diet.
And, you know, when you look at who's funding these studies, you know, the American General Nutrition that actually published a study receives funding from General Mills, which is a big grain maker, the Mars and Bayer. There's a lot of conflicts of interest here. Now, the next
issue of the study was, what's the mechanism of red meat causing type 2 diabetes, right?
They do have some explanations, but they're kind of bogus. And all these mechanisms propose that
it's a problem of meat driving issues with insulin
sensitivity causing type 2 diabetes.
But it doesn't mention the role of sugar and refined carbohydrates, which is so well
established in the research in randomized control trials and observational trials.
So here's the mechanism.
Well, maybe saturated fat injures the beta cell function and insulin sensitivity.
Now, saturated fat, just for a
fact, is not a prominent fat in red meat. It's oleic acid, which is a monounsaturated fat.
And diets high in oleic acid are linked to much better cardiometabolic health.
Palmitic acid, which is in meat, also may be linked to insulin resistance by inflammation.
And stearic acid is protective against insulin
resistance and doesn't really impact your cholesterol. And there's also something called
CLA, which is conjugated linoleic acid, which is very protective against cancer, improving metabolic
health, and many other things. So the saturated fat-diabetes connection is a little shaky.
And also, there's really not a clear mechanism here. And I think meat is relatively low
in saturated fat. So that's kind of makes the argument a little bit kind of less relevant.
There are also many, many meta-analyses showing that low-carb diets are far more effective than
high-carb diets for reversing insulin resistance. So there's really so much clarity in the literature
that if you take someone who's diabetic and you put them on a low-carb diet, they burn more
calories, they lose more weight, they potentially reverse their diabetes.
The ketogenic diets have been used by a group called Virta Health online and found profound
changes in risk reduction of diabetes.
For example, 100% get off the main diabetes med, 90 plus percent get off insulin.
There's about a 12% weight loss, 60% get complete reversal of type 2 diabetes, totally normal
after being severe diabetics.
So this is on a very basic, almost zero-carbohydrate diet.
In 2006, in the British Medical Journal,
low-carbohydrate diet showed a lower A1c compared to the high-carb diet.
The greater the restriction of carbs, the greater the glucose-lowering effect.
And what was so weird about the studies, they didn't even look at carbohydrate intake,
which kind of is strange because that's the main thing we know causes diabetes. They also talk about heme iron, how that increases oxidative stress and insulin resistance, impairs beta cell
function. But heme iron is more of a proxy for a crappy diet. Again, healthy user bias, as we
talked about. In a meta-analysis by Feng in 2015, he found that he minor in the
context of a standard American diet was linked to cancer, mainly fast food, fried food, but not in
the Netherlands, Canada, Italy, France, Japan, and Sweden, because they generally have healthier diets.
They're not eating the typical standard American or sad diet. So it's not only what you're eating,
it's what you eat it with. The next mechanism they proposed was processed meat having a high concentration of nitrates and its byproducts, and those may
promote insulin resistance. These nitrates and nitrites, which are basically food additives,
they react to form nitrosamines under high heat, and those are carcinogenic, and they can increase
insulin resistance. So is it the processed meat or the way the meat is processed? What are the
additives?
For example, uncured meats in Italy and Sardinia, I've written a lot about this,
how very low rates of diabetes, a lot of this. I was there and I ate lots of prosciutto and homemade cured meats. It was quite a scene. In Ikaria, we had, for example, this meat that was
cured with all these incredible grape leaves and all kinds of stuff, salt from the ocean,
and this and that. It was like, it was great. And they don't have any real risk of type 2 diabetes,
except when they start eating our diet. So it doesn't mention sugar as a mechanism,
which is often consumed with red meat, right? If you're eating processed red meat, you're eating
a sandwich, you're eating bun, rolls, sugary drinks. So you can't blame what you don't measure.
And it's really unfortunate that we don't have this report in the study because, you know, we don't know if the people eating red meat also
ate a ton of refined sugar and carbs, likely because they were more overweight, right?
So the whole thing is kind of, I don't know, just kind of a messy, horribly done,
misinterpreted study. So, but we know that red meat contains no glucose.
It doesn't raise your blood sugar. A little confusing why it would increase your risk of
type 2 diabetes. And type 2 diabetes is caused by insulin resistance, by high blood sugar,
and fluoroglycemic control. And basically, red meat has no glucose. Now, let's look at the other
body of research, because you can't just look at one study. You have to look at it in the context of everything.
Now, red meat consumption has been looked at.
And there was a study that was sort of a gold standard study, which is a review of meta-analyses of randomized controlled trials.
So it wasn't an observational study.
It was a randomized controlled trial.
This was published in the European Journal of Clinical Nutrition in 23.
We're going to put it in the show notes. There was no significant impact of diets that contained red meat versus diets with less or no meat on the following things.
Insulin sensitivity, fasting glucose, fasting insulin, A1C, which is basically your average blood sugar,
the beta cell function of your pancreas or GLP-1, which we know now is related to weight metabolism
and all the new weight loss drugs like Osempic or GLP-1 agonists.
Red meat resulted in a significantly lower postprandial glucose level compared to diets
with less or no red meat. In other words, when you eat meat, it blunts the response of your blood
sugar rise. So these are not observational trials. It's a meta-analysis of randomized
controlled trials. So this is
completely opposite of what the study showed, but it wasn't reported. What was reported was
the study that showed red meat causes diabetes, right? If you have a negative study, it's usually
not reported. Such and such doesn't do this. Well, that's kind of boring. But if, oh, red meat's
going to kill you, okay, well, let's publish that. Let's get PR on that. What they found was actually small and
marginally significant improvements in insulin sensitivity with red meat intake and type 2
diabetes. In other words, those people who had diabetes and ate red meat had better improvement
in insulin sensitivity. Another major study was looking at the effects of total red meat intake
on glycemic control and inflammatory biomarkers. Now,
inflammation causes diabetes, heart disease, cancer, dementia. And this was a meta-analysis
of randomized controlled trials published in Advances in Nutrition in 2021. So what did that
study show? Well, total red meat consumption for up to 16 weeks did not affect changes in the
biomarkers of glycemic control or inflammation in adults free of but at risk for cardiometabolic
disease. In other words, if you ate meat for 16 weeks in this randomized controlled trial,
it didn't affect any of the biomarker related to your blood sugar or inflammation
who were at risk for heart disease. Well, that's important, right? The results showed no effect of
total red media intake on your blood sugar, insulin, something called HOMA-IR, which is a
measure of insulin resistance on your A1C average blood sugar, on inflammatory biomarkers that we
really look at carefully, like C-reactive protein, interleukin-6, TNF-alpha. These are really
important biomarkers that correlate with heart disease and cancer and dementia. There were no
changes in any of these from these randomized trials that were up to 16 weeks in duration.
Now, in this study, the research participants in most of these studies were up to 16 weeks in duration. Now, in this study,
the research participants in most of these studies were asked to consume lean and unprocessed red
meat in most of the articles. Now, the quote from the study, the review was, overall red meat intake
does not independently influence changes in cardiometabolic disease risk factors in the
short term. For those who should choose to consume red meat, red meat, as with all
other protein-rich food sources, should be consumed in the context of a healthy eating pattern,
high in fruits and vegetables and whole grains, and within the energy needs to reduce
cardiometabolic disease risk. Fair enough. In fact, just to kind of explain that a little bit more,
there was a large study of about 11,000 people who shopped at health food stores.
Half of them were vegetarian or vegan, and half of them ate meat. But they ate meat in the context of a healthy diet. If your meat intake
is with hamburgers and fries and Coke, well, it's probably not the hamburger, right? It's all this
other stuff. So what they found was that in both these groups who basically could be assumed to
eating a healthy diet because they shopped at health food stores, both of their risk of death
was reduced in half. Well, how do you explain that, right? They're
basically saying that you eat red meat in the context of a healthy diet, there's really no
big deal. There was another study, again, randomized controlled trials that showed the
same thing, right? And this study was titled, The Effects of Total Red Meat Consumption on
Glycemic Control and Inflammation, a Systematically Searched Meta-Analysis and Meta-Regression of
Randomized Controlled Trials, blah, blah, blah. It doesn't matter. Basically, it's a randomized control
trial review. So what they found in this study was those who ate above what's commonly recommended,
which is about 0.5 servings of total red meat a day, which is about three ounce servings per week,
does not negatively influence markers of glycemic control inflammation in groups of adults
without diagnosed cardiometabolic disease. In other words, if you don't have heart disease negatively influence markers of glycemic control or inflammation in groups of adults without
diagnosed cardiometabolic disease. In other words, if you don't have heart disease or diabetes and
you eat more than the recommended amount of meat, it has no impact on your blood sugar control or
inflammatory markers. So how do we think about type 2 diabetes from a functional medicine
perspective? What's the root cause? Functional medicine is all about root cause. The root cause is something called insulin resistance. And this comes from eating
a diet that's high in sugar, refined flour, grains, ultra processed food. There's no doubt about this.
Also from lack of exercise and being sedentary, not moving enough, or being under-muscled, right? Muscle is your metabolic spanks, according to my friend JJ Virgin. And how do you address that? Well, you eliminate
ultra-processed food, processed grains, refined grains and starches, sweets, sugar, sweetened
beverages especially, and that improves your blood sugar balance and your insulin sensitivity.
And what should you be eating then? Good quality protein, and it can be meat. That's my view of the literature, not my opinion, but it's pretty
much evidenced by the randomized control trials that we talked about. Fiber, fruits, vegetables,
nuts, seeds, sometimes whole grains if you're not fully blown diabetic. Healthy fats, olive oil,
avocado oil, macadamia oil, None of these will affect your blood sugar.
And then you want to use testing to test your fasting glucose, your fasting insulin, your A1C,
triglycerides, and other markers to understand if you're insulin resistant. Now, I co-founded a company called Function Health. You can go to functionhealth.com. We've created an initial test
of over 110 biomarkers. It's $4.99 a year membership and includes testing twice a year.
And you get all the metabolic markers you need. You get insulin, which your doctor almost never
tests, A1C, your blood sugar, but you also look at lipid particle size. We call it lipoprotein
fractionation. Not just your regular cholesterol profile, but whether or not you have small
particles, dense particles, large or small triglycerides or HDL. All these will tell you
about your cardiometabolic health. We also measure inflammatory markers like C-reactive protein and
others. So you get a really good understanding of where you're at. So if you want to check it out,
go to functionhealth.com. You can use the code YOUNGFOREVER if you want to jump the wait list.
But it's really a way to get testing to see what's going on with you and what's going on
with your diet. So again, test, don't guess. Now, over the years, my perspective on my meat has changed. I used to
be vegetarian, vegan, but I've noticed after looking at the literature and doing experiments
myself, my patients and treating them using this approach of a high quality, low glycemic,
fiber rich, food and vegetable rich diet with lots of nuts and seeds, good fats, and
moderate amounts of healthy
animal protein, which I would say is
regeneratively raised meat, pasture-raised chicken,
safely raised fish,
regeneratively raised fish, or
small fish, it's
fine. There's nothing to worry about.
And just in conclusion,
you really have to take
these observational studies
with caution. Lean red meat doesn't contain sugar. It's not a plausible link to diabetes.
And it's sugar and refined starches and grains and ultra-processed food that cause diabetes.
So all the studies are listed in this show notes. I encourage you to check them out.
Thank you for joining me today on the Doctors Pharmacy Podcast on this special episode called Health Byte. If you're enjoying and learning
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And I thank you for joining us today for this deep discussion about red meat and diabetes.
And what I would say is pretty much junk science.
Thanks so much.
And we'll see you next time on the doctor's pharmacy.
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Hyman.
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