Looking at the link between red meat, eggs, and heart disease

Two recent papers about heart disease from the Cleveland Clinic are making the rounds. The studies report that red meat and eggs cause heart disease because our gut bacteria converts carnitine and choline into Trimethylamine N-oxide (TMAO), a heart disease trigger.

At Huffington Post, Chris Kresser has questions about the papers:

[W]hile at first glance the papers from Dr. Hazen's group might appear to be the final nail in the coffin for the omnivorous among us, a closer inspection of their data reveals some troubling questions. First, a study back in 1999 found that seafood generates much higher levels of TMAO than red meat, eggs, or any of the other 46 foods tested. One species of fish, halibut, produced 107 times as much TMAO as beef, and 53 times as much TMAO as eggs. If high TMAO levels cause cardiovascular disease, and eating fish increases TMAO more than any other food, we'd expect to see high rates of heart disease in people who eat the most fish. Yet that is the opposite of what research shows. In fact, some studies have found eating more fish (particularly cold-water, fatty fish like salmon) reduces the risk of heart attack by a greater margin than statin drugs!
In fact, whole grains could play a role in elevating TMAO levels:
In their second paper, Dr. Hazen's team raises the possibility that the foods we eat aren't the primary driving force behind our TMAO levels, because most people are able to excrete excess TMAO that accumulates in the blood via the urine. This suggests that something else may be to blame for high TMAO. What could that be? One possibility, which the researchers themselves demonstrated in the first paper, is that differences in our gut bacteria could account for the higher TMAO levels observed in some people. They showed that those with greater amounts of a type of bacteria called Prevotella in their gut generated more TMAO after eating carnitine. And what might lead to a higher concentration of Prevotella in the gut? Ironically, previous research has shown that the people who eat large amounts of whole grains are the most likely to fit this pattern. This would suggest that a diet high in whole grains -- and not red meat or eggs -- could increase the risk of heart disease by elevating TMAO in the blood.
Red Meat and Eggs on Trial Again, But Jury Is Still Out


    1. Fruits too. At least, fruit juice, even fresh squeezed. You know how much sugar is in that?

      In their natural form, though, it’s pretty hard to OD on fruits and vegetables, though, true.

      1. Yes, about 10%, give or take.

        Ever try drinking so much fruit juice that you reach unhealthy amounts of sugar (fructose)? You’d throw up first.

          1. Yes, about 1/2 l of orange juice would be too much for me in one go. Also, the 50 g or so of sugar in it is hardly dangerous.

            Unless you are Doctorow and all sugar is evil.

            (Sorry I’m not familiar with the units you used. I *think* 1 pint is half a liter, close enough anyway.)

          2. If a glass of OJ has 25g of sugar, that’s a big percentage of the ~40g a day an adult can eat before being unhealthy.

            And I can certainly drink 3 or 4 glasses of OJ a day.

          3. @samfen:disqus So just how is it that a person who drinks 3-4 glasses of OJ (or apple juice) per day becomes “unhealthy”? 

            And surely there’s a big difference in healthiness between the sugar that’s in fresh fruit and refined white sugar or HFCS?

          4. @boingboing-2c4ab9b7954f1c0af3fab408b3290a86:disqus It’s still a huge amount of sugar. It doesn’t matter that it comes from fruit: pretty much all sugars come from fruits or vegetables. Somehow juice from oranges seem “natural and healthy” while corn syrup doesn’t, but that’s as much image as anything else.

            First hit on Google for “sugar oj”: http://blog.fooducate.com/2009/11/13/orange-juice-is-just-as-bad-as-cola-really/ : “It’s pretty much the same as sugar water” 

            If you consume 3 glasses of OJ a day, that’s around 75g of sugar. That really is a lot, even from something as iconic to our image of health as a glass of OJ is.

          5. @samfen:disqus But I’ve known people who eat fruit all day long, and they’re healthy as proverbial horses (anecdotal data isn’t data, I know I know). I just don’t get how eating a lot of fresh-fruit “sugar” can be bad for a person, and I’d love to see some studies showing ill effects from it (and not from high consumption of it combined with other factors, like a lack of exercise and high fat consumption). 

          6. Fructose isn’t magic. Corn, sugar cane and beets are all plants, too.

            Sugars may have somewhat different interactions in a human body, but a high proportion of any sugar makes for a bad diet. People chug the juice equivalent of ten oranges, getting all the sugar and hardly any of the fiber. That’s not healthy. And you can get the same vitamins and minerals from eating tomatoes, red peppers or arugula without loading yourself with sugars.

          7. Point granted in regards to juice.

            Eating fruit all day long is probably different from drinking fruit juice all day long; a lot of pieces of fruit go into each glass of juice. I’ll wait for convincing studies before I fear eating five or six or seven pieces or “servings” of fresh fruit on some days (especially in season, yuuuum.)

  1. This is what happens when you try and connect nothing with nothing.

    TS Eliot tried to warn us…

    1. my neighbor’s step-aunt makes $72 every hour on the laptop. She has been fired from work for 9 months but last month her payment was $12762 just working on the laptop for a few hours. Read more on  Zap22.c­om

    1. Mark had to find a source that agreed with his predecided bias towards the paleo diet. When someone agrees with what you already believe, it doesn’t matter how reputable they are.

      This kind of innate bias is almost impossible to shake, no matter how good a thinker you are.

      1.  Agreed. Eggs have been mostly cleared from the “eggs are evil” scare from the 80s. And the HuffPo’s dubious reputation (vis à vis their strong support of woo, among other problems), makes them instantly unreliable in my book.

      2. You are right (except for the part where you said I’m a “good thinker.” — but thanks!)

        It’s hard for me to see outside my reality tunnel, even on the rare days when I realize I’m inside one. Before my paleo-esque regimen I was 30 pounds heavier and got sick much more often than I do know, and that’s something that’s hard to discount.

        1. I know, it sounds like it worked for you, and can probably work for a lot of people.

          It just means that you shouldn’t immediately jump on studies that show that there might be problems with a high-meat diet. For example, everyone could lose 30 lbs and still have a higher chance of dying of heart disease later down the road because of things like TMAO.

           You’re taking both with a grain of salt, which is good (depending on your diet, of course!), but my guess is that you’re more inclined to side with those arguments that match your expectations… as we all do.

          1. If we’re all inclined to do it then why bring it up? Rather, why not address the counter argument in Kresser’s response and see what sticks? Wouldn’t that move the conversation forward rather than stagnating it confirming someone’s opinion that you already know?

          2. “Since many people have the same cognitive bias then why bring it up at all?” I don’t even understand this line of thinking. What are you trying to say, that it’s not important to understand our biases?

            The whole point of a cognitive bias is that it’s not rational, so it’s important to recognize them so we can understand when we’re not being rational.

            In this case, we have some scientific evidence on the one hand, and then a person with an innate bias against this evidence saying to himself “this doesn’t sound right” and he so cherry-picks a blog that disagrees with the evidence.

            Either side could be right, of course, but it’s important to recognize that the only reason this other blogger is being held to the same level as the original research is because of the cognitive bias. If, instead, it had been interesting new research about global warming, and some blogger on HuffPo said “this doesn’t sound right,” Mark wouldn’t necessarily have felt that the two views had the same weight.

            Again, none of this is to disrespect Mark or his diet, but I think talking about the meta-precesses that underlie our thinking and our arguments are just as important as the arguments themselves. Especially since, unless we’re dietary scientists, we’re really not all that qualified to “move the conversation” much further and instead we’re all just spouting our gut feelings.

  2. This one annoyed me only slightly less thatn popsci.com reposting an “11 health foods that will KILL you” article from “a medical student’s” blog that attacked whole grains, gluten, and then gluten free, fruit juice, etc… plenty of footnotes, but when you followed through the conclusions in the articles did not even start to match the abstracts of the papers, to say nothing of the strength of the papers themselves… 

    All this only months after popsci’s “Every health article you read is wrong” rant about how shaky and sensational health and nutritional articles are

      1. Rereading my comment, *I* annoyed myself more than the OP. All my snark is much more directed at popsci than BB here, but BB bore the brunt, mostly because nobody reads the comments sections of that particular blog. The presentation here was a hell of a lot more informative, balanced and cautious than in other places.

        I think it is worth noting, though, that there is good reason to react to health and dietetic reporting in non-scientific publications with immediate and strong skepticism,  even if the knee doesn’t need to jerk *quite* so hard as mine did here. Not being firmly skeptical of new science wouldn’t be very scientific, and certainly not being skeptical of headlines, pull-quotes and summaries would be a disservice as well. A lot of reporting does tend to be sensationalized and link-bait-y, and health and dietetics are such complex topics, but people are so susceptible to panic and rapid shifts.

        In previous comments you’ve left the sentiment that making these rapid shifts in lifestyle based on new science makes sense because “*something* we’re doing isn’t working” but that makes me wonder if, like born-agains who suddenly take control of their lives and ascribe the positive change to Jesus, is it the act of “taking control” that has the inspirational effect, or the specific nature of the cure? If it’s the former, then “change something, ANYTHING” does seem to make sense.

        Of course, some of the science will be solid, and sadly, some science (don’t eat twinkies and drink sugar-water all day) haven’t cracked through on all fronts, and maybe vocal skepticism about new science gets confused in some people’s minds as a justification for poopooing ANY dietetic advice. End of the day, thatnks for the gut-check.

  3. I actually love this research and am following it quite closely.   Whether fish, eggs, red meat or grains cause TMAO to spike is still in doubt.  Whether these foods cause TMAO to be cleared or turned into a toxin is in doubt.  Whether the gut bacteria play a direct or indirect role is in doubt. 

    But what is not in doubt is previous research which shows that consumption of very little animal fats is directly linked to lower rates of disease.  And that type II diabetes can be controlled by diet alone, with diligence.  By whatever means you get there: bump up vegetables, trim down carbs, protein and fats, & reduce portion size overall.  Increase activity level.  Don’t smoke.  Pretty basic, when you get right down to it.

    1. “But what is not in doubt is previous research which shows that consumption of very little animal fats is directly linked to lower rates of disease.”
      I assume you’re referring to the supposed connection between saturated fat and cardiovascular disease.  If so, this might pique your interest: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824152/

        1. What really bugs me about all of this is that thanks to Keys it’s become “common sense” that saturated fat causes heart disease.  For my liking common sense is simply any assertion for which people no longer question the underlying assumptions, and from where I stand Keys’ assumptions appear faulty.

          1. “The studies that showed beneficial effects of diets reduced in saturated fat replaced saturated fat with polyunsaturated fat, with the implication that the CVD benefit observed could have been due to an increase in polyunsaturated fat or in the ratio of polyunsaturated fat to saturated fat (P:S), a hypothesis supported by a recent pooling analysis conducted by Jakobsen et al (24).” 

            Even this meta agrees that there is an effect, just not how to measure it, or even how to set it up for proper measurement.

  4. Seems to me the intersection between those-who-eat-significant-amounts-of-red-meat and those-who-eat-significant-amounts-of-whole-grains isn’t likely to be a large subset of people.  Should be pretty easy to see which of those two groups has the greater TMAO issue.

    Finally, the long-sought-after cage match between vegans and paleos.

    1. You are implying that someone can’t love oatmeal and steak….alright, perhaps not at the same time but that could easily be breakfast and dinner for me.  Not to mention the whole grain fad most companies are on now, so every breakfast cereal is full of those whole grains.

      1.  Not “can’t”…more like, usually doesn’t.

        But your point about breakfast cereals (etc.) is a good one.

  5. dosis facit venenum.   bacon falls between kale and polonium.   someone who eats bacon with the right genes will still die after someone who eats no bacon.  eliminating the bad things from our diets is certainly worthy, but it’s two factors down in significance from genes …and bacon tastes good  (next week:  kale’ll kill ye!)

  6. So then with all these different studies and papers what are we suppose to believe? I KNOW! I am damned if I do and I am damned if I don’t do why bother? lol

    1. And a pack of ciggies. And a fifth of Jack! What the fuck, eh? Caution to the wind! And only damn fools care about the effects their actions have on others.

      I don’t give others a hard time in person about their consumption choices, and it bugs the shit out of me when others give me a hard time about mine, and about the thought I’ve put into mine.

      1. Agree.  It’s the same argument over and over: people take any statement about diet to the EXTREME.  If I mention reducing animal fats, then people freak out thinking that I mean *CONSUME NO ANIMAL FATS!*  When I never said such a thing.  It’s ridiculous. 

        All things in moderation.  Get exercise.  Deal with your stress.  Don’t be an asshole on the Internet or in person. Get some fresh air.  Don’t smoke.  Eat lots of veggies and limit the calorie-dense foods, alcohol and sweets; keep those for every once-in-a-while.  Enjoy a glass of wine or a beer now and then, but not every day or on a binge.

        This doesn’t mean NEVER EAT A STEAK.  It doesn’t mean have steak every day.  It means to live cleanly, however that plays out for you.

          1. You’re probably right.  The body has an uncanny ability to adapt to different conditions and to clear out toxins, when it’s actively supported.  Stress is like the arterial plaque- it stops everything up mentally and keeps you from being able to adapt and clear.

  7. We should research, of course. But at some point. we just need to sit back, relax, and face the fact that there will never be a perfect diet, or the perfect diet will be so annoying that it won’t be worth the few extra years you’ll get. I am a light vegetarian by the way. I do eat fish, but wonder when the mercury is going to start taking its toll.

    1. Probably never.  It’s babies and kids, whose neurons are still developing, who see the worst effects of mercury.

  8. I was able to lower my cholesterol from 280 to 170 in 3 months by cutting grains and sugar from my diet. I was actually following Tim Ferris’s 4 Hour Body Slow Carb diet, so I was binging on Sundays.

    In fact, after reading some of the links at http://eatingacademy.com/category/cholesterol-2, I have come to believe that it is mainly grains, fructose and glucose that have the most affect on your blood chemistry, not dietary cholesterol. It appears that most of the double-blind studies that have sought to control cholesterol levels have actually had a worse affect than the control groups.

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