Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

Tell Me More
Stay Connected
April 10, 2013

Does Red Meat Clog Your Arteries After All?

By Mark Sisson
191 Comments

T-boneI’ve been asked to comment on the latest media deluge to suggest that red meat is again the primary cause of atherosclerosis, heart disease, and your impending doom. At least this time they’re targeting something other than cholesterol: this time it’s carnitine.

Carnitine is found in red meat, mostly, as well as dairy, tempeh, and some other meats, and it performs a number of important roles in the human body, foremost of which is the transportation of fatty acids into the mitochondria for breakdown into useable energy. It’s so important to basic function that we make endogenous carnitine by synthesizing it from the amino acids lysine and methionine. Vegans and vegetarians, who tend to run deficient in carnitine, benefit greatly from supplementation (or a nice steak). It’s even been used to reduce atherosclerosis (albeit in rabbits), improve arterial function, and help heart failure patients recover. Carnitine is not some evil compound.

Oh, the study. Let’s get into it. It consisted of several sections, actually.

First, they fed humans eight ounce steaks (amounting to roughly 180 mg carnitine) with a side of 250 mg carnitine tabs. Omnivores showed increased blood and urine levels of Trimethylamine oxide (TMAO), a compound associated with cardiovascular disease, while vegetarians and vegans (who were somehow able to get the steak down) showed far lower levels of TMAO in their blood and urine.

Next, they tested what was producing the TMAO by administering antibiotics. Eliminating gut flora populations with antibiotics also eliminated the food-induced increase in TMAO, showing that the intestinal microbiota were metabolizing carnitine into TMAO. After allowing the subjects’ guts to repopulate, they ate more steak. The increase in TMAO after eating steak reappeared, confirming that gut flora metabolism of carnitine was responsible. Subjects with higher levels of Prevotella bacteria in their guts saw the biggest increases in TMAO.

(As it turns out, gut flora convert carnitine to TMA, which the liver then converts to TMAO using a hepatic enzyme called FMO3, but it’s easier to just say carnitine converts to TMAO.)

They also tested ApoE-deficient mice and got similar results. Feeding mice carnitine increased TMAO levels in serum and doubled arterial plaque formation over control, while giving antibiotics abolished this effect. So, in a certain strain of mice, dietary carnitine increases TMAO levels, which accelerates atherosclerosis. If you recall from this week’s Dear Mark, ApoE status is strongly associated with cardiovascular disease risk, and these mice were totally deficient in it. They were bred to be extremely sensitive to atherosclerosis in order to facilitate research. It’s a common and useful tool – it’s not like they’re trying to pull a fast one – but we should be aware of it.

They also examined how TMAO increases atherosclerosis in mice: by reducing reverse cholesterol transport. In other words, it impaired the mouse’s ability to remove cholesterol from the arterial wall without decreasing cholesterol uptake or synthesis to the same degree, creating a net surplus of cholesterol in the wall and speeding up atherosclerosis.

Now, before you unplug your chest freezer full of grass-fed beef and start buying wheat futures, keep reading.

The initial association between TMAO and cardiovascular disease in humans is just that – an association. Causation is not established, and it may even be that cardiovascular disease or some other common event increases TMAO as a response to injury or disease. An increase in serum TMAO is, for example, a marker of certain kidney injuries (PDF). It could merely be correlation or even reverse causation. We simply don’t know.

We don’t know if the experimental results in rodents apply to humans. Sure, the omnivorous people who ate steak and took supplements saw an increase in serum TMAO, but atherosclerosis was not measured. The same mechanisms that affect ApoE-deficient mice may not apply to humans.

It was the gut flora, not the carnitine. While subjects who typically ate meat saw the biggest increases in TMAO – which the researchers saw as evidence of the gut flora adapting to the host diet – and were characterized as having Prevotella-dominant guts, most evidence suggests that Prevotella bacteria are associated with carbohydrate-rich diets. That said, accumulating evidence suggests that the hundreds of species living in our guts can’t be quite so easily and neatly cataloged or categorized.

You know what else raises TMAO? Fish. That’s right – heart attack-inducing, artery-clogging, linked-to-every-disease-state-known-to-man fish actually contains TMA, the metabolite that converts to TMAO in the body. TMA is what gives fish the “fishy smell,” and when people eat fish, urine TMAO increases. Strangely, the latest research shows that fish is consistently associated with better cardiovascular health, not worse (despite the TMA content and effect on TMAO levels).

FMO3, which as you’ll recall from the parenthetical above is responsible for the conversion of TMA to TMAO, does things other than produce heart disease. It is also involved in the metabolism of selenium (an important cardioprotective, thyroid-protective, and cancer-protective nutrient).

TMAO itself may not be “all bad.” It’s an osmolyte – a protein stabilizer. It’s even been used to prevent cataract formation in mammalian eye lenses.

Choline, another important nutrient found in eggs, meat, dairy, and offal with a similar structure to carnitine, was shown a couple years ago to convert to TMAO after exposure to certain types of gut flora, causing researchers to suggest it too promotes atherosclerosis (see Chris Masterjohn’s take on it). And yet eggs have been vindicated over and over again for their beneficial or neutral effects on heart health, including the most recent one I mentioned this past Sunday.

It’s complicated, in other words.

That’s not to discredit the results of this latest study; sufficient amounts of TMAO do appear to accelerate atherosclerosis in rodents. Impaired reverse cholesterol transport, which TMAO produces (again, in rodents), probably accelerates atherosclerosis regardless of species, all else being equal. We should definitely keep an eye on this and any other future research. I’m particularly interested in what this means for research into the effects of gut flora on human health.

Ultimately, this admittedly interesting research is all very preliminary. Rodents bred to be especially sensitive to cardiovascular disease (ApoE-knockouts) develop atherosclerosis at twice the normal rate when exposed to TMAO in the diet and/or serum. That’s all that they’ve established. Humans with the right (wrong?) gut flora composition also generate serum TMAO in response to dietary carnitine, but increased atherosclerosis has not been shown. And, contrary to their assumptions, a relationship between red meat (not processed meat) and cardiovascular disease has not been established in the literature. Quite the contrary: recent epidemiological evidence seems to exonerate the fresher, redder stuff.

If anything, this serves to underline (not undermine) the basic gist of the Primal eating philosophy. Eat a variety of foods. Don’t just eat steak. Eat fish, and eggs, and chicken liver, and pork chops. Don’t just eat meat. Eat vegetables. Eat probiotic-rich foods (probiotics have already been used to lower TMAO levels, while kimchi consumption was said to account for the inter-individual differences in TMAO production in another study). Eat prebiotic-rich foods, so as to provide food for your gut and diversify the population.

That last bit is key. We have to realize that it’s the gut flora modulating the effects of carnitine and TMAO – not the carnitine (or red meat) itself. It may be that we Primal eaters (as if you could categorize us so easily) have the absolute worst kind of gut flora, the kind that produces TMA by the truckload to be carted off to the liver for conversion into TMAO, and we’re about to start dropping off like flies. But I doubt it. I think the way we eat is more likely to diversify our guts and give us a floral profile associated with better health, rather than worse. But we’ll see. We still have a lot to learn about what lurks – and lives – inside us.

I’m sure you’ll be inundated with other writers giving their thoughts today and in the near future, but these are my initial ones. Hope it helps!

Subscribe to the Newsletter

If you'd like to add an avatar to all of your comments click here!

Leave a Reply

154 Comments on "Does Red Meat Clog Your Arteries After All?"

avatar

Sort by:   newest | oldest
Nick
Nick
3 years 7 months ago

So… I should be supplementing with daily antibiotics to lower my dangerous TMAO levels? Seems legit.

Jake Dickenson
Jake Dickenson
3 years 7 months ago

Yep…time to replace your daily probiotic with a daily antibiotic! Imagine what they could do for the Pharmaceutical Industry!

Erin
Erin
3 years 7 months ago

IV pennicilin, here I come! hahah…. Who would volunteer to wipe out their gut flora, that’s what I’m wondering. There had better be lifetime compensation involved.

Jake Dickenson
Jake Dickenson
3 years 7 months ago

I currently supplement Acetyl L-Carnetine, so now I am wondering if I there is any cause for concern. Is there any reason to believe that I could be causing myself harm?

Josh Diesel
3 years 7 months ago

It depends on how much Acetyl L-Carnitine you are taking and for how long. I usually don’t take it for much longer than 10 days at a time, in order to help reduce excess bodyfat prior to competition.

Too much and it seems to dry out my muscles.

Cherice
Cherice
3 years 7 months ago

I would assume that if you’re eating meat and seafood on a regular basis, than the carnitine supplement isn’t necessary.

I think this falls in line again with the “get your nutrients from whole food sources” mindset since supplementation is often at levels beyond what we’d naturally get from a food source.

Wenchypoo
Wenchypoo
3 years 7 months ago

Thank you, Mark, for addressing my concerns so quickly.

Nick
Nick
3 years 7 months ago

LMAO at the study.

D
D
3 years 7 months ago

Why would you laugh at the study? It is what it is. The media may have interpreted it in whatever fashion it chose to do, but I doubt you’re qualified to “LMAO” at the study.

Harry Mossman
3 years 7 months ago

+1 Do most people actually bother to read Mark’s posts before firing off broadsides? Mark certainly did not LHAO at the study.

Nick
Nick
3 years 7 months ago

LMAO/TMAO. It’s a play on words. Lighten up.

Andy
Andy
3 years 7 months ago

Um… I think you missed it. TMAO LMAO…

Nocona
Nocona
3 years 7 months ago

Yes Harry, on here I doubt anyone is actually reading Mark’s post on it, (tongue planted firmly in cheek).

Dana
Dana
3 years 7 months ago

T. Colin Campbell. China Study.

Just because someone’s “qualified” doesn’t mean they’re right.

Though it might be more appropriate to LAAO (laugh anyone’s ass off) at the study *conclusion.* That’s pure opinion, not pure data.

Eric R
3 years 7 months ago

These “studies” that continue to vilify red meat, fat, & cholesterol are getting out of control. Once again, data that shows association, not causation.

Shary
Shary
3 years 7 months ago

Right. Red meat is what eggs were a few years ago. Most such studies are flawed for one reason or another and shouldn’t be blindly taken as gospel. If researchers want to legitimately demonize something, why aren’t they taking a closer look at sugars and grains? Why are those always such a sacred cow?

Kev
Kev
3 years 7 months ago

It is just big Pharma and Agra trying to secure their future. There are more people waking up to the truth about sugars and grains every year. It is their life blood, they cannot afford to loose it.

RenegadeRN
RenegadeRN
3 years 7 months ago

+1

zack
zack
3 years 7 months ago

So they tested the TMAO levels in the urine. Doesn’t that mean the body is flushing it out? It makes me think of your Gout article http://www.marksdailyapple.com/gout-primal-paleo-diet/#axzz2Q4hb9QV2

Thoughts?

GHEE
GHEE
3 years 7 months ago

+1

Izzy
Izzy
3 years 7 months ago

+2

Sunny
Sunny
3 years 7 months ago

+1

Josh S
Josh S
3 years 7 months ago

Every scientific research study that concerns red meat should be required to classify the source of their meat. Grass/grain/GMO fed is a variable known to make a difference in the scientific community.

These studies just seem to be getting more ridiculous, as if they are digging for new reasons to stop people from eating meat…

Sean
Sean
3 years 7 months ago

+1

It seems as if their aim is to vilify meat, red meat in particular.

Nocona
Nocona
3 years 7 months ago

Grass fed, grass fed, grass fed…once and for all. Can we please get studies that demarcate between the crap and the good stuff? We intuitively know that there is a difference!

RenegadeRN
RenegadeRN
3 years 7 months ago

Agreed!
This is how I feel about studies vilifying hormone replacement therapy ( when appropriate) that do not differentiate between bioidentical hormones and such shite as Premarin. Progestin is NOT progesterone! Etc.

Kevin
Kevin
3 years 7 months ago

Lets be clear,

Their aim is to get results that help them get more funding for further research.

paleo-leo
3 years 7 months ago

+1

Ann
Ann
3 years 7 months ago

Except that the researchers trying to vilify meat don’t care what kind of meat it is – they don’t want us eating any.

Gwen
3 years 7 months ago

What Eric (and Mark) said. Yeesh.

Austin
Austin
3 years 7 months ago

Also, do we know who funded this study? Who are the key players behind this and what are their affiliations? Not that it isn’t already dubious enough on its own, of course.

anabelle
anabelle
3 years 7 months ago
This paper made it into a high-impact (Nature) journal because it is a rigorous big study on a topic that has a lot of public health interest and relevance. We do, in fact, know who funded the work. You can look at the link above; it was published in Nature Medicine. Most of the contributing authors are at legitimate major research centers (The Cleveland Clinic, UCLA, etc). The funding is primarily from federal (NIH) grants, some from the American Heart Association. You can actually ready the paper yourself if you wish. This is not a BAD study. The authors do… Read more »
Nocona
Nocona
3 years 7 months ago

Come on anabelle, legitimate research centers? They can’t even use real meat that’s grass fed! Just more conventional wisdom poppycock!

Harry Mossman
3 years 7 months ago

Mark constantly says to eat grass fed meat if you can but that conventional meat is still very good for you.

Nocona
Nocona
3 years 7 months ago

Yes Harry, but if you do, don’t eat the fatty part!

Mark A
Mark A
3 years 7 months ago

Whether you’re eating grass-fed or grain-fed beef, you’re stilling ingesting the same amount of carnitine. And really, since the majority of America eats grain-fed beef, it really makes more sense if they did in fact use grain-fed beef in the studies. And it would also make more sense for readers to then worry about their consumption of beef. If you eat only grass-fed beef and you believe this study does not apply to grass-fed beef, then you have nothing to worry about.

anabelle
anabelle
3 years 7 months ago

What I meant by “legitimate research centers” is that this study was performed by actual scientists rather than researchers at the “Vegan Center Performing Studies To Stop People From Eating Animals.” (which I made up. I hope that doesn’t exist)

Dana
Dana
3 years 7 months ago
I eat CAFO meat fat, thank you. Someone broke down the fatty acid composition, I think it might have been Kresser, and the biggest difference between CAFO and grass-fed meat is the CAFO has lost its omega-3. You can make that up by eating whole fish, or using cod liver oil. One of the selling points of grass-fed meat is its leanness, because we kill our ruminant animals too young now for maximum profits, and instead of letting the cattle get older before slaughter, they kill them at the same age the CAFO-finishing ranchers do. The grain-finishing, in fact, was… Read more »
D
D
3 years 7 months ago

Clearly your wisdom is lost on most of the people here who are obviously highly qualified to make judgments on the validity of the research. Don’t forget, it’s acceptable in modern times to view science in a manner identical to religion. It’s belief based… (i.e. I don’t “believe” in global warming and my “belief” is just as valid as scientific research).

Harry Mossman
3 years 7 months ago

+1

Kev
Kev
3 years 7 months ago

+1

JMH
JMH
3 years 7 months ago

+1 I said something similar. Honestly people, most of the time it’s not the researchers being the pricks, it’s how it’s being reported which is an entirely different problem.

Harry Mossman
3 years 7 months ago

+1

Jim
Jim
3 years 7 months ago

Well done Annabelle. Two types on here…1) they type to objectively consider new information…2) “defenders” who drank the kool-aid and lost their objectivity. Everything isn’t black and white and there will much more to this story, be patient and follow along objectively, and don’t…jump…to conclusions (although it would make a cool mat).

Nocona
Nocona
3 years 7 months ago

I think the Kool-aid may be what you are drinking. What do you think when you see red meat? How broad a statement can you get? Where did the red meat come from? What was it fed? I hope they do keep up all the research, the more legitimate the better,but when the testers use terms like red meat…they already lose me.

F Jeff
F Jeff
3 years 7 months ago
There is plenty of obvious bias in this article, Annabelle. The title alone shows bias. L-carnitine, available in many foods, and gut flora are the focal points of this study, but the title of it singles out red meat. The obvious bias of the researchers shows in the last sentence of the abstract: “Intestinal microbiota may thus contribute to the well-established link between high levels of red meat consumption and CVD risk.” What “well-established” link? The only place I know of that this “well established link” exists is in the well-debunked book “The China Study” by T. Colin Campbell, also… Read more »
Jim
Jim
3 years 7 months ago

SAD gut may be different from Primal gut, Nocona, let it play out, you may get what you want in the end. These are some pretty bright people working on this, and there’s always more to do.

Nocona
Nocona
3 years 7 months ago

+1 Jim

anabelle
anabelle
3 years 7 months ago
They chose this project to study red meat. If you read the first paragraph of the introduction, you will see that they were trying to suss out why red meat has been associated with CVD (and you can see their citations for that information), as previous work has shown that the fat and cholesterol are maybe not the cause (citations for that, too), which surprised the world of CW (not us) and has therefore launched further research. The title singles out red meat because the broad question is about red meat, although the specific finding is about carnitine + microbiome.… Read more »
Dana
Dana
3 years 7 months ago
Seriously. If red meat made people sicker than grain does, I shouldn’t have started feeling better when I cut back the grain and ate more of the meat. If these “everybody knows” statements they trot out were in any way valid, there shouldn’t be any exceptions to the rule on the scale of normal variation. They say “red meat increases CVD risk” the way they would say “liquid cyanide above X quantity is always a poison to humans” or “you die in X number of minutes without oxygen”. The two statements are not even on the same *planet* in terms… Read more »
Dr Jason
3 years 7 months ago

Actually, if you read the interview in NYT by the lead researcher, he directly says he loves meat, but that he is dropping his personal consumption based on this work (his own), because it is SO absolute. 🙂 So they do assume meat is bad for you in public related to the study.

Julie
Julie
3 years 7 months ago

+1 annabelle. Well said.

Txomin
Txomin
3 years 7 months ago

+1

J Money
J Money
3 years 7 months ago
I don’t find the American Heart Association a good source for science. Any study that hits the mass media is going to be misinformation, we’ve seen that time and time again. When are we going to stop allowing these people to cloud our minds? Long term data solidifying primal/paleo… try hundres of thousand (probably even millions, see book “Hidden History of the Human Race”) of years of existence. Not to mention grass fed was never even addressed. Reminds me of the Monsanto study on their rats… Monsanto conveniently stopped their findings at 3 months, and an independent study found that… Read more »
ylla fucilla
ylla fucilla
2 years 11 months ago

+1

Cindy C
Cindy C
3 years 7 months ago
There has been studies of epigenetics. A diet change can change how our genes are expressed(turned on or off). It does the same to the bacteria in our bodies. They change /adapt rapidly to a diet change as well. Bacteria are literally a part of our mitochondria, and serious consequences occur if they are killed off. A diet change can be beneficial to a person, and the bacteria adapt to help the person in a different way. E Coli deprived of sugar will adapt to a stain that ferments glutamate(handy if too much glutamate in the brain). If a diet… Read more »
JMH
JMH
3 years 7 months ago
It behooves us to differentiate between bad science, and bad science reporting. The study seems pretty solid. It’s not making any connections that aren’t there, and is useful for ideas for other research. It’s how it’s being touted in the newspapers that’s the problem, and it’s a recurring one. Half the studies used to demonize meat aren’t actually saying that, and the researchers can get pretty pissy about how their work gets misused, justifiably so. We look at the study, see what it actually says. Sometimes the researchers are pushing an agenda, sometimes they’re not. This time, they’re really not.… Read more »
F Jeff
F Jeff
3 years 7 months ago

EXCEPT in the title of their study……why point out the connection to red meat, when l-carnitine is in so many other foods?

Kate
Kate
3 years 7 months ago

Just curious… under ‘red meat’ does the study mean only beef? Or would it also include other red meats, like lamb, buffalo, venison, etc.?

Adriane
Adriane
3 years 7 months ago

Breathing oxygen causes heart disease! Oxidative stress leads to damage of the endothelium, which leads to atheroma, and then to heart disease, therefore OXYGEN is the cause of heart disease! So all we need to do is stop breathing and then we won’t die of heart disease (just asphyxiation.)

Shary
Shary
3 years 7 months ago

Hmm… Could it be that we were not (gasp!) meant to live forever?

Andrew
Andrew
3 years 7 months ago

My main issue with this study would be the supplementation of the carnitine tablets. That introduces a variable to the study right there. No human is ingesting tablets of the stuff, we get it from food. The study should have been done solely with the meat to test levels. But that would require people to consume ~1.25 lbs of red meat and if the meat was consumed in a single sitting would make the study damn near impossible.

mars
mars
3 years 7 months ago

+1 I too was wondering why they supplemented with carnitine

Harry Mossman
3 years 7 months ago

Ummm, excuse me. Many people do take carnitine supplements.

Shary
Shary
3 years 7 months ago

Yes they do, but do they also eat red meat every day? Probably some do both, but at the price of halfway decent red meat, I would guess that most of us don’t.

I agree with the others who thought the study would have more credibility if they had omitted the carnitine supplements. As it is, it looks more like they were just try to beef up their case (no pun intended) against red meat.

Nocona
Nocona
3 years 7 months ago

And eat rice and beans and corn…

Andrew
Andrew
3 years 7 months ago
Are the supplements the same type as the compound found in the meat? Genuine question since I don’t know about carnitine but iron in meat for example can have a different molecular composition than an iron supplement. If they are the same, does the body process them the same? Since the meat has other compounds that may hinder/help the body to utilize the carnitine. Questions like this are usually why I’m skeptical of nutritional science. Scientific studies strive to eliminate all variables other than the one being testing but to do so with food, you have to eliminate the other… Read more »
Dana
Dana
3 years 7 months ago

Same for choline. Supplemental choline increases TMAO; choline from lecithin (which you find in egg yolk and probably liver) does not. As Chris Masterjohn pointed out.

Nocona
Nocona
3 years 7 months ago

Does anybody know if the carnitine profile is different with CAFO and Grass Fed beef? It may be the same amount of carnitine, but what of the molecular composition?

Bob C
Bob C
3 years 7 months ago

Once again Mark, your pragmatic approach (as opposed to the knee-jerk, gloom and doom of traditional media) is refreshing and very much appreciated.

BrynsterD
BrynsterD
3 years 7 months ago

I’m still having my Fish Tacos with Citrus Dressing tonight.

mars
mars
3 years 7 months ago

Thanks for addressing this Mark!

DanielS
DanielS
3 years 7 months ago
Carnitine supplements are readily available at health food stores and in energy drinks. The study looked at multiple facets of carnitine metabolism in multiple species. Although it was not a human intervention using cardiovascular disease/atherogenesis as an outcome, it is a strong study. It would be a shame to dismiss it without looking into it as many here are doing. The lead author of the study was quoted in the mainstream write ups as being a lover of a good steak. I don’t think he was setting out to condemn meat consumption. Analysis of a study should be done first… Read more »
Harry Mossman
3 years 7 months ago

+1

BrynsterD
BrynsterD
3 years 7 months ago

How many ‘Fred Flintstones’ dropped dead at the Bedrock Quarry from clogged arteries? I’m thinking not many.

According to this study, Mr. Slate would have been out of business long ago.

TL
TL
3 years 7 months ago

It is hard to come to the conclusion they did about red meat when they made them supplement the carnitine. If they had just eaten the meat, maybe. To me, it seems they forced them to eat more carnitine than one would usually get in any meal.

D
D
3 years 7 months ago

Their conclusion relates to carnitine, not read meat, no?

Sean
Sean
3 years 7 months ago
So the things that increase TMAO: Carbohydrates, red meat, choline (eggs, meat, dairy, and offal). Clearly there is a “mediator” variable accounting for this. The primary problem I see with these studies is that they compare “health conscious vegetarians” against any old person that also eats meat (smokers, dunkin donought aficionados, carbaholics and maybe a few primal “outliers” they likely removed from analysis). There is 0% effort to compare “health conscious vegetarians” against “health conscious fat/meat eaters”, until this is done I’m going to continue to assume that “process carbs are bad and make ANY diet worse”. Until researchers (like… Read more »
Nocona
Nocona
3 years 7 months ago

+1. I agree. Knock knock, who’s there? NOBODY!

Meg
Meg
3 years 7 months ago

Yes, this!!!!!!

Erin
Erin
3 years 7 months ago

AGREED!!!

Joanne - The Real Food Mama
3 years 7 months ago

Anyone have a headache now.

Note to self: keep eating a variety of clean meat, veggies & fruit. Done and done. 🙂

Sean
Sean
3 years 7 months ago

+1

anabelle
anabelle
3 years 7 months ago

Keep calm and eat real food.

Tim
Tim
3 years 7 months ago

Nice, Anabelle!

Pam
3 years 7 months ago

+1

Karen
Karen
3 years 7 months ago

+1

Finnegans Wake
Finnegans Wake
3 years 7 months ago

Timely and thorough. Thank you, Mark.

Groktimus Primal
3 years 7 months ago

Just another time wasting smoke screen by big agra, the government and the vegans. It’s time they learn we no longer listen to their agenda driven BS. We listen to commonsense and our bodies (how we look feel and perform).

Sam Grant
Sam Grant
3 years 7 months ago

Examine (found them via you) also had a post on it: http://examine.com/blog/media-sensationalism:-meat-is-bad-for-your-heart/

luke
luke
3 years 7 months ago

“It’s complicated”

Reading that sums it up pretty well… It’s amazing how we take isolated ideas/studies (which are cool that we do them) and attempt to make such broad assumptions in something as complex as the human body/experience.

It never fails to amaze me.

Jasmine
Jasmine
3 years 7 months ago

A good response to the media misinterpretations of an otherwise interesting but not Earth-shattering research paper. It’s too bad many studies are blown out of proportion and publicised by journalists who don’t understand the basic aims of the study they are reporting on, let alone the conclusions.

Thank you Mark for taking a more level-headed look at it. (And for breaking down the trickier sciencese for the rest of us :D)

Ted
Ted
3 years 7 months ago

What about all those animal studies suggesting that supplements combining l-carnitine with alpha lipoic acid reduce age-related damage?

Stan
Stan
3 years 7 months ago

the thin red line – red meat is bad
maybe the study is fine but they just accumulate “material” against red meat
all they do is scare people until we stop eating altogether

Jane
Jane
3 years 7 months ago

Another really good example of why you have to read and understand the study and not just the headline.

GiGi
3 years 7 months ago

And with that, I am off to eat a burger – lol!

Thank you Mark for clarifying everything. Honestly though, considering how long I have enjoyed grass-fed red meat and how healthy I feel, I don’t feel like any study is going to make me stop eating it!

DanielS
DanielS
3 years 7 months ago
The carnitine supplementation was necessary so they could identify that it was the carnitine being metabolized into TMAO. Theoretically, there should be no difference in the TMAO levels resulting from Grass fed vs. conventionally raised beef, or any other red meat. It could, perhaps, even be higher in elk, venison, etc. due to higher metabolic demands of active tissue (increased carnitine). Red meat makes up the majority of Carnitine consumption for pretty much everyone. Dismissing good research will do more to push your views to the fringe than anything else. Great points above, Mark, and thanks for not dismissing this!
Nocona
Nocona
3 years 7 months ago

It may all have to do with the gut flora in the end. Hope they do better syudies in the future. I like your ideas on elk, venison, etc. maybe having higher carnitine levels and what that might mean. Why would you theoretically say there should be no TMAO difference in grass fed vs. conventionally raised beef? I would think the whole profile would be different. Feed on GMO corn and soy, or grass fed and finished like they were meant to eat, and I know which one I would choose.

DanielS
DanielS
3 years 7 months ago

I know which one I choose as well. And we can probably modify our heart disease risk based on the types of fats we are consuming (omega-3/6 balance) But in this study we are looking at a nutrient, L-Carnitine, which is necessary for muscle function. Both grass fed beef and conventionally raised beef need muscle function. There is little to none TMAO in either type of beef. Just the ‘pre-cursor’ which is turned into TMAO in the presence of certain intestinal bacteria.

I don’t see any reason why grass-fed would have less of the L-carnitine which allows their muscle’s to function.

Mark A
Mark A
3 years 7 months ago

Probably because the carnitine is the same regardless of what the cows ate.

Richad
Richad
3 years 7 months ago
The primary difference between grass-fed and conventionally fed beef is in the ratio of fatty acids (e.g., more omega-3 fats in grass fed beef) and increased levels of some of the vitamins associated with grass (beta-carotene, vitamin E, volatile fat-soluble compounds that contribute to flavor, etc.). Carnitine does not fall into this category, but rather is synthesized from amino acids lysine and methionine. Carnitine is required for very very important metabolic processes, and because it is both acquired through diet and biocynthesized, I would heavily suspect that levels are the same intra-species. Nevertheless, I cannot be sure that there is… Read more »
Harry Mossman
3 years 7 months ago

+1

DanielS
DanielS
3 years 7 months ago

Perfect.

Mark A
Mark A
3 years 7 months ago
Well said. It doesn’t do anyone any good to simply become parroting apostles without understanding the reasons for choosing to eat or live a certain way. Even the tried-and-true “I feel better so I must be doing the right thing” should be questioned. Things like high blood pressure and atherosclerosis can’t be “felt.” Whether red meat causes heart disease or not, it’s at least a good idea to attempt to understand metabolic processes. Think about this: we’re one of only a handful of countries in the world where beef is a primary protein source. We’ve also perfected factory-based agriculture to… Read more »
Kristin
Kristin
3 years 7 months ago

I’m relieved to hear your comments, Mark. But lots of people do take carnitine supplements. My ten year-old, for example, has been taking carnitine for the last seven years and we were told he would need it for the rest of his life. He has a mitochondrial disorder, and needs the carnitine supplement to help his processing of fatty acids. I am concerned about this study. The field of genetic medicine and those who specialize in metabolic disorders are scrambling now to reevaluate the children taking carnitine long term.

pup
pup
3 years 7 months ago

Doesn’t any study involving mice and heart disease these days need to pass through this filter first?

http://www.pnas.org/content/early/2013/02/07/1222878110

Heather
Heather
3 years 7 months ago

The fact that the same people that have said for the last 60 years that sat fat in meat causes heart disease are all of a sudden saying “We were wrong. It’s not the sat fat its the carnitine”…hmmmm….I’m I bit inclined NOT to believe them. I heard this on the radio the other day. They actually used the word CAUSE. I just don’t get it anymore.

Jennifer
Jennifer
3 years 7 months ago

I’m just hoping that all these silly meat-hating articles lead to a decrease in demand and price for red meat leaving more for me and my Primal friends. Is that wrong? 😉

Nocona
Nocona
3 years 7 months ago

Wow, love the thought! Let’s keep these anti-red meat articles flowing…

freerangepiglings
freerangepiglings
3 years 7 months ago

But then I worry about my lovely lovely butcher at my favourite farm shop going out of business. He’s already had to half his days open because of drop in business due to austerity. These unscientific reporters with their fear-mongering headlines must be really terrible for hard-working, conscientious small-scale farmers who are endeavouring to produce healthy, well-butchered meat at affordable prices.

Mark P
3 years 7 months ago

I just saw this study on the news the other day. I continued to eat my pork sausage, one heart-attack-laden bite at a time. *sarcasm*.

George
George
3 years 7 months ago

As a vegetarian who eats lots of eggs and consumes whey protein drinks and has embraced most all of the other (non-meat) aspects of the primal diet … and have learned a great deal from Mark, I suspect he is right on about this. If you eat a variety of food including a lot of veggies and leafy greens and ingest probiotics, eating some grass fed beef once or twice a week should not be a big deal IMHO. I like Mark’s quip about the vegetarian test subjects that “were somehow about to get the steak down” LOL.

George
George
3 years 7 months ago

Somehow *able* to get the steak down, sorry about that, oh for an edit button. 🙂

AlexAlive&Kickin
AlexAlive&Kickin
3 years 7 months ago
In an unusual turn of events, I read about this study before seeing your take on it on MDA! I knew you would get to it soon enough… I’m pleased to see that my own interpretation was very similar to yours (score 2 points of validation for me!). I was left with the questions of “what intestinal flora (or should that be fauna) composition would be optimal?” and “does my primal diet help me keep a diverse collection or result in a narrow representation of different flora/fauna?” I was disturbed by the implied goal of future research of learning which… Read more »
Rokzane
Rokzane
3 years 7 months ago
What irks me about studies like this is that the researches don’t really bother to take into account other aspects of their test subjects diet. For instance: vegetarians who ate the steaks did not have higher levels of TMAO, while the omnivores did….so what’s REAL difference here? Vegetarians tend to eat much more fresh produce and fiber than the typical American SAD omnivore. Without enough fresh produce and fiber, your body cannot eliminate unneeded cholesterol. Cholesterol serves a purpose to a point in the body (injury repair and hormone production), when the body is optimally healthy and getting the proper… Read more »
Nocona
Nocona
3 years 7 months ago

Well Mr. Mossman, I lean this way, you can have your CAFO!

Pharmagirl
Pharmagirl
3 years 7 months ago

So now I’m confused. I have to take a statin (genetic form of high cholesterol; nothing else works and I eat primally for the most part). I supplement with 100 mg coq 10 to fight against its depletion and recently added l carnitine 330 mg daily. I eat red meat about two times a week. I also supplement with magnesium, b complex, fish oil and am adding in a high potency antioxidant. Should I stop the l carnitine?

Rokzane
Rokzane
3 years 7 months ago
Did your doctor advise you take the L-cardnitine? Just because you have high cholesterol doesn’t mean you HAVE to take a statin drug. Have you been officially diagnosed w/ heart disease or did your doctor just push it onto w/ fear mongering about having a heart attack? Statin drugs should be used for the most severe cases of heart disease, otherwise they’ve been shown to do more harm than good. Have you had your cholesterol analyzed for composition? Is your LDL the large, fluffy kind (which is actually protective and the most desirable), or the small, dense particle kind? These… Read more »
Pharmagirl
Pharmagirl
3 years 7 months ago
Rokzane, thanks for this info. I have a strong family history of heart disease (strokes, heart attacks) and diet has no impact. My tests are always for LDL, total cholesterol, HDL, triglycerides and lipoproteins a and b. i have elevated total cholesterol and triglycerides with good hdl levels. With regards to the type of LDL or is there another test to determine the type of LDL I have other than lipoprotein a or b? Fyi, i have elevated lipoprotein a and normal b. I understand that the elevated a puts me at increased risk for coronary heart disease. I have… Read more »
Rokzane
Rokzane
3 years 7 months ago
There’s a specific test that’s used for determining particle size, and you have to specifically ask for it, but an educated guess can be made based on your current tests. If your triglycerides are elevated and your HDL is low, then you most likely have small dense particle LDL. However, your HDL is in the high range, so you may be borderline in this area. The best way to bring your TG levels down is to get really strict w/ your carb intake: no added sugar, restrict fruit intake to 2 servings/day, no potatoes, no pasta, no bread, no refined… Read more »
Peggy Holloway
Peggy Holloway
3 years 7 months ago

The conclusion I got from this “study:” Don’t feed your mice steak.

Bjarni
Bjarni
3 years 7 months ago

Don’t base your life on mice studies would be my take-home message from this study.

Rose
3 years 7 months ago
Mark, within your 3rd & 4th paragraphs, I thought, how is this silly study relevant? What threw me was the supplementation of 250 mg carnitine in addition to actually eating a steak PLUS administering of antibiotics. Long before I had ever heard of eating primal, I knew all too well how detrimental antibiotics are to our gut flora. Mess with the flora = mess of troubles in the body. But as you said, we’re fine as long as we eat red meat (grass fed & hormone free) in moderation and also a variety of other good foods. Too much of… Read more »
Greg
Greg
3 years 7 months ago

I’m thinking yet again, confounding variable(s). Every time we try to laser in on a really bad or really good thing, there’s always more to the story.

Sadly, I don’t see Veggie | Paleo | SAD control groups coming to a rigorous study any time soon, so we’re left to our own devices and this does give us a bit to think about.

As usual, we need to approach the system, not the constituent parts and as usual, Mark is doling out pragmatic, practical advice.

Eric
Eric
3 years 7 months ago

So… any scientific study showing the dangers of sugar or carbs is the gospel truth, but a study showing a correlation between red meat and heart disease warrants a LMAO? The lack of objectivity and critical thinking on this forum is laughable.

Kathleen
Kathleen
3 years 7 months ago
I remember getting my test results back from my doctor after eating low carb/clean protein (grass-fed/finished beef, lamb, pork, chicken), clean veggies/fruits (organic/local grown) and having the occasional goody (dark chocolate or other) if I wanted it. No “exercise” regime as we have a farm and I can walk up and down some steep inclines, haul feed bags, etc. I ate this way for about 6 months before the blood work tests. Her note to me? “Whatever you are doing, keep it up! These numbers are PERFECT! And you’ve lost 25 lbs.” The proof for me is in my own… Read more »
Craig
Craig
3 years 7 months ago
One of the concerns about the lead author was that many energy drinks contain carnitine as a supplement, and that many teenagers drink a lot of that crap. Might be useful to know if this is a bad idea for developing children. Also, the NY Times write up indicated that the association between TMAO levels and CVD risk had previously been established by a study which had examined blood from 10,000 people who had come though the Cleveland Clinic system. They were then followed for several years to monitor the subsequent development CVD. The point was to look for associations… Read more »
Leevin Sheftin
Leevin Sheftin
3 years 7 months ago

I think you do not have to be so careful if you are eating a small plate only and well balanced with many types of food. Too much of anything is a bad thing of course!

Margit
Margit
3 years 7 months ago

Another useless study, that doesn’t contribute any insights into the broad picture.

Barnaby
3 years 7 months ago
As well as the ‘quality’ of the mice used for testing, the ‘quality’ of the human would be just as critical. Its like saying ‘meat is bad for you’, because in many trials vegetarians have lower levels of cancer/cardiovascular disease. This in no way implies that meat is bad for you. Perhaps the vegetarians eat far more vegetables, or predominantly eat organically, and are avoiding pollutant-rich processed meats. The cause is not so discernible. In this case, the carnivores chosen for the test may have had poor gut flora balances or a host of other digestive disorders, and are therefore… Read more »
Ariel
Ariel
3 years 7 months ago

What bothers me in this study is, that 69% of participants were smokers and all were suffering from some kind of cardiac disease. 70% were men age 54-71. Their blood carnitine levels correlated with smoking, male gender, triglycerides as well as use of ACE-inhibitors (hypertension med). Correlation of these were in the same ballpark as ingested carnitine. So, makes one wonder, if high levels of carnitine in blood are result of deficient metabolism due to those other correlating factors?

Ariel
Ariel
3 years 7 months ago

The table I’m referring to can be found on page 3 of this document:
http://www.nature.com/nm/journal/vaop/ncurrent/extref/nm.3145-S1.pdf

wpDiscuz