Fat in the Diet and Mortality from Heart Disease: A Plagiaristic Note

Not too long ago I was a graduate student at the University of Washington where I was taking an advanced class on nutrition and metabolism and the entire class was caught plagiarizing! Let me explain…

We all had a professor for several quarters that was really intelligent and everyone liked him, but the trouble was that during the classes he would verbally expel so much dense information on a topic that it was nearly impossible to digest in one sitting (pardon the pun). Our professor knew this and so at the beginning of our very first class he suggested that we actually record his lectures so we could go back and listen to them one or more times to better absorb the material.

Most people in the class – including me – did end up recording his lectures. It got to where there were so many recording devices that it looked like a press conference. I had the largest recording device, too. I’m a bit of an audiophile so a dinky Tascam DR-08 would not work for me. I had a Zoom H4n that stuck out like crazy, and sometimes I would even attach a Shure SM-58 to it before class started just for kicks. But that’s not terribly relevant; what is relevant is that not only did the class record his lectures, but most of the class got wise and started actually transcribing the damn things to make searching for specific details during a lecture much easier. Now if you have ever tried to transcribe something you will know that for each hour of speech it takes at least two hours of listening and typing if not more, depending on how fast you type. Of course to be more efficient one person would volunteer to type it and then email the document to the rest of the class. Now I was absolutely not interested in transcribing a near two-hour lecture during my evenings, so I never volunteered to do it. I knew this meant not getting my hands on the transcripts, but that was perfectly fine with me.*

About halfway through the year our prof begins one class very soberly by saying that he is very disappointed in us. We have been essentially plagiarizing our assignments by simply copy-pasting text from the transcripts into our assignments. How did he know this? It wasn’t simply that we all gave strikingly similar answers to the questions. Perhaps some of that is to be expected if we are all given the same questions, have the same professor, and have the same textbooks. No, the real smoking gun in this case was that whomever transcribed one particular lecture had misspelled something and the rest of the class had misspelled the exact same word in the exact same way.

We were banned from transcribing and/or sharing transcripts after that point. I actually have a friend going through the same graduate program right now, and he says his class was told in no uncertain terms at the beginning of the quarter that the prof will not tolerate any transcribing of his lectures. All because of our class that was too lazy to just do our own research and put it into our own words. I am glad that the professor called us on it. He takes plagiarism seriously as he should. It’s clearly a serious offense in academia, but even if we’re not in the ivory tower plagiarism is basically fraud. Anyone that has been caught plagiarizing has not only lost me as an audience of their work, but they have also lost my respect.**

Which brings me to Gary Taubes. Wait! It’s not what you think. I have ragged on Taubes in the past, but I am actually advocating for Taubes here. Honest! I’m going to discuss a topic that I touched on in the past, but just so everyone reading this is on the same page let me go through some background before I get to Taubes.

The Facts

You may or may not have heard of a guy named Ancel Keys. He was a Harvard-trained physiologist and epidemiologist. He did some research on human starvation in the mid-20th century before moving on to study heart disease for which he is probably most famous. In 1953 he gave a scientific presentation at the Mt. Sinai Hospital in New York city. The meat-and-potatoes of this presentation was subsequently published in the Journal of Mount Sinai Hospital (now known as the Mount Sinai Journal of Medicine) with the title “Atherosclerosis: A Problem in Newer Public Health.”1 I don’t know what to make of the journal. It’s not really what I would consider a bona-fide journal, but it’s peer-reviewed and a couple tiers above a monthly newsletter. Anyway, it basically summarizes a lot of what’s known about cholesterol and heart disease of various countries at the time. It is not terribly newsworthy; the only thing in the article that is of any note is a Cartesian graph of the relationship between rate of death from heart disease and total fat intake (as a percentage of calories) in a few countries.

Keys1

Keys mentions that only a few countries are available for any kind of real comparison at the time of publishing. Some countries he leaves out of the graph because of major population shifts or poorly-maintained vital health statistics. He does mention that there are good quality health statistics available for many other European countries, but since WW2 had such an effect on diets (partially because Germany invaded, occupied, and rationed food) the food data of Nazi-occupied territories were left out. What is left appears to be a remarkable relationship between fat intake and death.

Four years later in 1957 a couple of researchers named Jacob Yerushalmy and Herman Hilleboe published a paper titled “Fat in the Diet and Mortality from Heart Disease; A Methodologic Note” that was critical of the above graph.2 Apparently they found the graph overly simplistic and perhaps a bit misleading. So they instead decide to conduct their own statistical analysis of similar data. They don’t use the same exact data as Keys used for whatever reason; Keys used FAO & WHO data from 1948-1949 and Yerushalmy and Hilleboe use FAO & WHO data from 1951-1953. They don’t exclude any countries from the analysis either, for any reason, choosing instead to include all the countries for which the FAO & WHO had data, which happened to be 22 countries.

YH data

As you can see when 22 countries are included in the analysis the relationship between fat calories and heart disease mortality is not so striking. However, despite not being as pronounced as Keys’s graph, this one still clearly shows a relationship between fat and heart disease. You can still see an upward trend happening as the percent of fat calories increases.

Y&H also make the convincing case that comparing total fat to heart disease mortality is kinda lame. They argue that the types of fat (or in this case the sources of fat) are far more interesting. In the paper they actually do some comparisons with heart disease and animal fat vs. plant fat and animal protein vs. plant protein and find that fat from animals and protein from animals each has a much stronger association with heart disease than simply total fat. They go on to say that their analysis shows that plant fat and plant protein is actually negatively associated with heart disease mortality. In other words, fat and protein from plants might have some sort of protective effect against heart disease.

Both Keys and Y&H assemble what is called a cross-sectional analysis, which in terms of observational studies is one of the weakest – at least when it comes to trying to show any kind of cause-effect relationship. Both Keys and Y&H mention this and state that their results are merely an association and that more robust studies on the matter need to be conducted.

Indeed, Keys actually goes on to conduct such a robust study several years later, colloquially known as the Seven Countries Study. This was a very large longitudinal cohort study that lasted for several years. Quite a bit of knowledge was gained from this study, including important information on diet, exercise, smoking, obesity, serum cholesterol, and many diseases (dementia, diabetes, hypertension). In fact, data from the cohorts is still being published today. In terms of epidemiological studies, a large prospective cohort study like the Seven Countries Study is about as strong as it gets. Of course the results are not as definitive as a randomized controlled trial of the same scale and duration, but enrolling so many people into a randomized controlled trial of that size and time is effectively an impossibility. Plus with a RCT you can only examine one variable, but with super large cohorts like this many variables can be studied.

At any rate, the first of many Seven Countries Study reports is published in 1970, thirteen years after the Y&H paper and a full 17 years after Keys’s presentation at Mt. Sinai Hospital. It is this study that becomes wildly influential and puts Keys on the map as an elite epidemiologist.

The Mistake

In his whopper of a diet book Good Calories, Bad Calories Gary Taubes blatantly lies about makes a mistake when reporting the results of the Y&H paper. He claims that the link between fat and heart disease vanishes if no countries are excluded from the analysis.

Taubes on page 18:

Many researchers wouldn’t buy it. Jacob Yerushalmy, who ran the biostatistics department at the University of California, Berkeley, and Herman Hilleboe, the New York State commissioner of health, co-authored a critique of Keys’s hypothesis, noting that Keys had chosen only six countries for his comparison though data were available for twenty-two countries. When all twenty-two were included in the analysis, the apparent link between fat and heart disease vanished.

As we have seen the link between fat and heart disease does not vanish.

Moreover, Taubes then says “Keys had noted associations between heart-disease death rates and fat intake, Yerushalmy and Hilleboe pointed out, but they were just that. Associations do not imply cause and effect […]” What follows is purely a semantic argument, but I would argue that correlations can and often do imply cause and effect. In fact most researchers test hypotheses based off of observational studies that suggest some sort of relationship between two things. Of course correlations certainly do not prove causation, and no epidemiologist worth his/her salt would claim otherwise.

The Fraud

Here’s the crux of this whole post: many people have been ripping off Taubes’s work. They have been ripping him off without attribution and making money doing it. You know how I know they are ripping him off? It’s not just that their verbiage and syntax are eerily similar. Much like my old professor the clincher is that these journalists and bloggers and charlatans all make the exact same mistake Taubes made with respect to the Y&H paper. In fact, many of these authors make it painfully obvious that they haven’t read ANY of the papers that they are making claims about.

Now it’s one thing to blog about, say, toasters and misinform your readers, but when you are dispensing health advice and you have no idea what you talking about… well, that can impact people’s lives in a very real way. And a very negative way.

Let’s begin the plagiarism parade, shall we?

Nina Teicholz

http://www.nbcnews.com/id/22116724/ns/health-diet_and_nutrition/t/what-if-bad-fat-isnt-so-bad/

At the time, plenty of scientists were skeptical of Keys’s assertions. One such critic was Jacob Yerushalmy, Ph.D., founder of the biostatistics graduate program at the University of California at Berkeley. In a 1957 paper, Yerushalmy pointed out that while data from the six countries Keys examined seemed to support the diet-heart hypothesis, statistics were actually available for 22 countries. And when all 22 were analyzed, the apparent link between fat consumption and heart disease disappeared.

Ms. Teicholz also says prior to the above paragraph “The first scientific indictment of saturated fat came in 1953. That’s the year a physiologist named Ancel Keys, Ph.D., published a highly influential paper titled ‘Atherosclerosis, a Problem in Newer Public Health.’”

According to Google Scholar this “highly influential” paper that doesn’t even mention saturated fat has only been cited 247 times since its publication, which spans 61 years as of this writing. An average of four citations per year. It was cited merely 99 times from the time it was published to 1973, a full twenty years after its publication. Each report from the Seven Countries Study, however, has been cited several thousand times each. Perhaps that’s what Ms. Teicholz is referring to, although if that were true then she could not have trotted out the Yerushalmy paper. Or maybe she doesn’t know what she’s talking about and just plagiarized Taubes and changed some words.

Dustan Howell

http://www.inshapeathome.net/blog/2013/01/10/Clean-food-versus-Dirty-Foods.aspx

At the time, many scientists were skeptical of Key’s claims. Jacob Yerushalmy, Ph.D. (founder of the biostatistics graduate program at the University of California at Berkeley) pointed out that while the data from the six countries supported the diet-heart hypothesis, statistics were available from twenty-two countries. When those countries were analyzed the apparent link between fat intake and heart disease vanished.

Jonathan Bailor

https://thesmarterscienceofslim.com/a-brief-history-of-lipophobia-the-fear-of-fat/

http://thecaloriemythbook.com/fatfacts/

Keys examined diet and heart disease trends in twenty-two countries. He was apparently more interested in headlines than science because he then published a study that included data from only the six countries that showed a scary link between diet and heart disease. Keys garnered a massive amount of press and then went on tour preaching that eating fat is deadly.

Here are the facts: When the data from all twenty-two countries in Keys’ study is examined, they show no relationship between fat intake and heart disease deaths. Keys selectively picked data and designed a headline-worthy conclusion.

Talk about hyperbole! He “garnered a massive amount of press and then went on tour preaching that eating fat is deadly,” eh? I don’t think so. Maybe 20 years after it was published and for a separate reason. Furthermore, Keys’s presentation to the Mt. Sinai Hospital wasn’t a study. Even the published text could not be considered a study. You could maybe call it a review article or an editorial, but it definitely was not any kind of experiment with a hypothesis. I suppose you could technically call it a cross-sectional study, but it’s a real stretch considering the Keys paper is 22 pages long and the “study” only takes up three paragraphs and one figure in those twenty-two pages from data that is publicly available. It’s not much more than a footnote in the text. I have literally written more words bitching about Nina Teicholz and Jonathan Bailor than Keys wrote for his “highly influential study.”

PhotoCalorie

http://blog.photocalorie.com/data-driven-dining/saturated-fats/

This correlation provided a great basis for creating a hypothesis, however the relationship may have been misleading. A caveat to this apparent relationship, pointed out by biostatistician Dr. Jacob Yerushalmy, was the questionable choice of these specific countries, when data was available for 22. Dr. Yerushalmy showed that if all 22 countries are included, the correlation becomes much weaker. Other researchers later showed that this correlation is just as strong when compared with any characteristic of a developed nation, such as television and radio sales.

At least whoever wrote this piece doesn’t claim that the link vanished.

Georgia Ede

http://www.diagnosisdiet.com/food/fats/

The misguided belief that saturated fats cause heart disease is rooted in a famous study published in 1970 called “The Seven Countries Study”, in which renowned scientist Ancel Keys claimed that people in countries where more animal fat was eaten had more heart disease then people in countries where less animal fat was eaten. Not only was this study an epidemiological study, and therefore incapable of proving a causal link between any dietary factor and any disease, but the original study actually involved 22 countries, not 7; the data from the other 15 countries having been omitted for undisclosed reasons. When the data from all 22 countries were analyzed, no correlation between fat and heart disease was found (Yerushalmy and Hilleboe 1957).

I think this is an example of what happens when you don’t plagiarize from the source and instead plagiarize the plagiarizers. The errors start to compound in on each other. Evidently Yerushalmy and Hilleboe are seers and wrote a critique in 1957 of a study in that would not be published for another thirteen years. There are actually so many errors in that one paragraph I don’t even want to bother writing more.

Nathane Jackson

http://www.nathanejackson.com/blog/heart-healthy-tips/

Up until recently, much of today’s science was based on researcher, Ancel Keys, 22 country heart disease and dietary fat study, or at least this is where it all started. Key’s has been accused of cherry picking the six countries that would support his hypothesis of saturated fat causing heart disease. However, as it turns out, one could have picked six entirely different countries and shown the complete opposite, in that eating dietary fat had very little connection with the risk of dying from heart disease.

Clearly English is not Mr. Jackson’s native tongue.

Three Sixty Personal Training

http://threesixtypersonaltraining.co.uk/free-stuff/articles-videos/the-whole-fat-story/

The trouble is that Keys selectively picked his data to match his hypothesis. In 1957, a biostatistician named Jacob Yerushalmy, along with Herman Hilleboe, published a paper noting that while data from the six countries analysed supported Keys’ hypothesis, Keys had actually collected data from 22 countries, and that when the data from all 22 countries was analysed, the apparent link between fat intake and heart disease was not found.

Chris Masterjohn

http://www.cholesterol-and-health.com/The-Cholesterol-Myths.html

Ancel Keys first argued this theory by charting heart disease mortality against fat availability for six countries, showing the more dietary fat available, the higher the rate of mortality. There was just one pesky problem: data was available for 22 countries at the time. Include the other 16, and the association falls apart.

Also Chris Masterjohn

http://blog.cholesterol-and-health.com/2011/04/let-us-honor-ancel-keys-our-patron-as.html

Keys had presented data from six countries, purporting to show a clear linear relationship between the amount of fat consumed in a country and its incidence of heart disease. This graph is shown on the left below. The one problem was that data was available for 22 countries at the time, and including that data demolished the relationship.

Keys

This graph actually appears in many of these posts. The right one is overlayed incorrectly because #13 is Japan, #12 is Italy, #22 is USA, etc.

Brendan Coburn

http://thehealthycow.blogspot.com/2011/03/historical-context-part-3-ancel-keys.html

The six countries he reported on (United States, Canada, Australia, UK, Italy, and Japan), showed a very strong association between fat intake and heart disease. Now, of course, this is only an observational study and no cause and effect can be determined. But the biggest problem with his study is that he left out the data from the 16 other countries for which data was available. When all 22 countries are considered, his perfect correlation turns into a much weaker one.

Paleo Leap

http://paleoleap.com/fear-of-saturated-fat-and-cholesterol/

Cherry picking data is the dishonest situation where a scientist wants to prove an hypothesis so bad that he chooses only the data that fits with it and ignores the conflicting data. In the case of Ancel Keys’s 7 country study, data for 22 countries was available to him, but he only picked 7. […] In this new graph you can see that no correlation whatsoever can apparently be made between heart disease and saturated fat consumption.

Do I really need to point out the hypocrisy of accusing Keys of being dishonest while at the very same time plagiarizing AND misrepresenting journal articles that you never read?

Craving Fresh

http://www.cravingfresh.com/2012/01/fresh-reviews-great-cholesterol-con-by.html

Keys hand-picked data from six countries that showed a clear link between heart disease and the dietary intake of fat. He actually had data from 22 countries available to him, but left out the rest as they told a completely different story. He was a man on a mission to prove that dietary intake of saturated fat causes heart disease, and he wasn’t going to let mere facts get in his way.

Keys’s “hand-picked data” was not about saturated fat – it was about total fat. But I guess Craving Fresh isn’t letting mere facts get in their way.

Innate Fitness

http://innatebodybootcamp.com/myths-about-saturated-fat/

Keys’ most famous study (the one still cited today) was called the 7 Countries Study. Keys plotted the rate of heart disease against the percentage of calories consumed as fat for Japan, Italy, England, Wales, Australia, Canada, and the United States. Looking at this graph you would definitely think that dietary fat intake was linked to increased heart disease risk. What most people don’t know (and what doctors their doctors don’t tell them) is that the study actually gathered data from 22 countries. When all the countries were added to the graph it looked like “buckshot hitting a page instead of a straight line,” in the words of one of Keys’s fellow researchers. While there is a significant relationship between fat intake and heart disease (at least as presented), the graph GREATLY over-exaggerates it’s importance.

At least the author of this post doesn’t claim the link vanished. Yet like many other bloggers here doesn’t understand the difference between the 1953 paper and the Seven Countries Study. Plus I think that quote is bogus. I think it goes without saying that it is unattributed, but I found a book that published the same quote and claims it is from David Kritchevsky. I still don’t buy it because there’s no source of the quote.

Kristopher Cleary

http://realconstipationremedies.com/eating-fat-can-help-my-constipation-are-you-kidding/

There were countries he turned a blind (or denial) eye to which devoured a diet high in fat and also showed a surprisingly very low rate of cardiovascular disease. Whilst on the other side of the table there were countries that demonstrated a high level of cardiovascular disease eating a little fat at all. In reflection, the study was not phenomenal. It was flawed. The Seven Countries study should have really comprised of ‘twenty-two’ countries. If this had of transpired then there would have been a very clear message out of it: ‘there is no relationship between fat intake and heart attacks’.

Colin E. Champ

http://www.cavemandoctor.com/2011/12/20/why-your-doctor-recommends-a-low-fat-diet-and-what-it-has-to-do-with-a-rabbit-and-a-little-lie/

Keys then performed a big “study” where he looked at the fat intake and death from heart disease in 7 countries (Japan, Italy, England, Wales, Australia, Canada, and the USA), appropriately calling it the 7 Countries Study. He found that the more fat citizens in these countries ate, the more they got heart disease and died. In 1956 the American Heart Association used this data to inform the public that consuming animal fat causes heart disease. […]

However, there is one little issue with Keys’ experiment – he actually looked at 22 countries and then picked 7 that showed an association between heart disease and fat intake. He ignored the rest and pretended he never saw them. Ok, fair enough, it’s a big issue. This was pointed out by Yerushalmey [sic] and Hilleboe who showed the graphs he used before he cherry-picked his countries.

For someone who claims to be a doctor he sure gets a bunch of things wrong. In fact pretty much everything. Every single sentence he writes is wrong. Dr. Champ can’t even spell the authors correctly.

Donald W. Miller, Jr

http://archive.lewrockwell.com/miller/miller38.1.html

Evidence against fat wilts upon close scrutiny. In his Six Country Study, Ancel Keys ignored data available from 16 other countries that did not fall in line with his desired graph. If he had chosen these six other countries, or even more strikingly, these six countries he could have shown that increasing the percent of calories from fat in the diet reduces the number of deaths from coronary heart disease.

If Keys had included all 22 countries in his study, the result would have been a clutter of dots like this.[graph] In fact, it turns out that people who have highest percentage of saturated fat in their diets have the lowest risk of heart disease.

Rebecca A. Malamed

http://www.drrebecca.com/2012/02/myth-of-cholesterol-and-heart-disease.html

Dr. Keys released a convincing diagram in 1953 which showed a very neat correlation between the levels of dietary fat in six countries and the rates of coronary heart disease in those countries. It was part of a very famous document called “The Seven Countries Study”, which has since been roundly refuted and shown to be poorly done science. This diagram appeared to show what can only be described as a perfect match between the level of calories from dietary fat and rates of coronary heart disease, making his theory appear to be perfectly correct. To this day, the concept of a low-fat diet is preached by many as essential to preventing heart disease.

Ignoring, for a moment, a well established mantra of science (“correlation does not imply causation”), there are a number of fundamental flaws with the data that Ancel Keys presented.

While the data points he used were technically correct, he only used data from 7 countries when, at the time, data was available for 22 countries. If those other 16 countries are added into the diagram, the neat line matching fat intake to coronary heart disease loses virtually all meaning.

Literally every sentence there is wrong, except for one: low-fat diets are preached by many, for better or worse.

Bryan Mayo

http://mayosmind.blogspot.com/2013/04/saturated-fat-and-heart-disease-folly.html

Unfortunately for Keys and his Diet-Heart Hypothesis, his study actually collected data on 22 countries. Because the data from these remaining 15 countries didn’t support his theory very well, he simply threw them out. If you put the data from all 22 countries back together, then the earlier clear line between fat intake and heart disease becomes non-existent.

Alexandra something-or-other from High on Fat

http://www.highonfat.com/3/post/2014/03/the-low-fat-fallacy.html

While the lipid hypothesis, or cholesterol theory can be dated back over 100 years ago, it was Ansel Keys’ [sic] famous “Seven Countries Study” in 1958 that can be credited for the fat phobia that plagues us today.

Based on his published findings, Keys claimed that there was a direct link between heart disease related death and the amount of fat in the diet. Therefore, if saturated fat raises cholesterol, and cholesterol causes heart disease, we should stop consuming saturated fat in order to reduce the risk of heart disease in our world.

Seems logical at first. However, there were two problems:1. Correlation does not equal causation 2. The “Seven Countries Study” actually consisted of 22 countries. Keys simply left out the data of all the countries that did not align with his theory. Tisk tisk…

Tisk tisk, indeed.

Diana Rodgers

http://www.radiancenutrition.com/2012/12/06/are-you-fat-phobic/

One of the biggest detriments to our thinking about fats came in the mid 1950’s, when a guy named Ancel Keys published a paper which served as an early kick off for the cholesterol campaign. Although he had data from 22 different countries, he cherry picked seven to show in his paper. What he showed was a correlation (note, this is different from cause, just an association) between increased fat intake and death.

She also highly recommends you check out a “smart, in-depth blog post” by Denise Minger that actually argues the opposite of what Diana Rodgers is arguing.

Dylan Klein

http://nutridylan.com/2013/07/15/the-great-cholesterol-consensus/

Researchers skeptical of Keys’ “study” pointed out that relevant data was available for 22 countries at the time and that Keys did nothing more than cherry-pick his data set to include the countries which supported his preconceived hypothesis of diet and heart disease. Indeed, when data from all 22 countries are incorporated into the analysis, the perfect relationship between fat and heart disease disappears.

Dana Carpender

http://holdthetoast.com/content/ancel_keys

Keys faked his data. Oh, it’s absolutely true that he had a lovely graph showing seven countries with their rates of saturated fat consumption paralleling their rates of heart disease. However, Keys had data from 22 countries. And when you look at the data for all 22 countries, the tidy rising line vanishes.

Joseph Mercola

http://articles.mercola.com/sites/articles/archive/2011/10/22/debunking-the-science-behind-lowering-cholesterol-levels.aspx

In 1953, Dr. Ancel Keys published a seminal paper that serves as the basis for nearly all of the initial scientific support for the Cholesterol Theory. The study is known as the Seven Countries Study, that linked the consumption of dietary fat to coronary heart disease. What you may not know is that when Keys published his analysis that claimed to prove the link between dietary fats and coronary heart disease (CHD), he selectively analyzed information from only seven countries to prove his correlation, rather than comparing all the data available at the time — from 22 countries.

As you might suspect, the studies he excluded were those that did not fit with his hypothesis, namely those that showed a low percentage fat in their diet and a high incidence of death from CHD as well as those with a high-fat diet and low incidence of CHD. If all 22 countries had been analyzed, there would have been no correlation found whatsoever; it should have been called the 22 Countries Study!

Even Tom Naughton from the awful documentary Fat Head gets in on the plagiarism.

In Conclusion

The hypocsrisy here cannot be overstated. These authors are all accusing Keys of academic dishonesty while plagiarizing Taubes (or someone else who stole his work) and claiming to have knowledge of academic journal articles that they have almost certainly never read. Additionally, many of the blogs or articles mentioned here advocate pro-meat and pro-saturated fat diets yet the central study they invoke as evidence against Keys also happens to make the case against eating animal fat or animal protein.

In case anyone wants to actually read the texts in question I have linked to them in the endnotes. Enjoy.

cloud

*As it turned out I was almost always emailed the transcripts anyway. (Thanks y’all for supporting this bum that never took one for the team.) It didn’t really matter, though, because I rarely used them anyway. I much preferred listening back to the lectures over reading them. I can’t recall if this incident was one of those rare times or not. It could be the case that I was a party in this debacle.

** In case I am coming off as too much of a righteous plagiarism crusader… I am guilty of it. The one time I knowingly plagiarized something was in high school. I was given an assignment to write a review of some book that I never read. I don’t recall what book it was, but it was some 19th century British romantic novel that did not interest me at all. Rather than doing the assignment I grabbed some review someone else had already written online and turned that in. I was ultimately caught, and had to re-do the assignment. (Who knew that teachers could use the internet, too?) I regret the act and wish I would not have been such a lazy asshole and just done the damn homework.

Lipids, Inflammation, and Atherosclerosis

[Lipids, Inflammation, and Atherosclerosis mp3]

Today’s guest is the venerable Dr. Michael Rosenfeld, cardiovascular disease researcher and college professor extraordinaire. Most of his studies focus on atherosclerosis and the myriad factors that influence it.

Aside from being a pain-in-the-ass to pronounce, what exactly is atherosclerosis?

Before discussing the etiology of the disease it is important to have an understanding of how lipids are transported by the body. This is actually a more complex issue than one might suppose. Think about it: the human body is essentially an aquatic environment, and we all know that lipids are insoluble in water and will aggregate with other lipids in polar environments. So how would you be able to reliably and consistently transport dietary fat from your intestines to your liver and other organs and tissues as needed? You also need to consider that while some blood vessels are large in diameter others are quite small. Organisms like us have evolved a system to transport fats using what are called lipoproteins. They are basically tiny balls of triglycerides and cholesterol with a surface coat of various proteins and phospholipids that allow them to move about and interact in the polar environment of human plasma. There are essentially four kinds of lipoproteins: chylomicrons, very-low density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). I won’t go into great detail about all of them right now, but each contains varying amounts of triglycerides and cholesterol and have slightly different proteins on their surfaces.

What do lipoproteins have to do with atherosclerosis? I’ll tell you. LDL particles are like the hot dog vendors at baseball games. They swim around the blood saying “Hiyoooo! Who needs cholesterol?? Get your cholesterol here! Use it for all kinds of things: bile salts, vitamin D, lipids rafts, testosterone… you name it! I got some fresh hot cholesterol just for you.” If a cell needs some cholesterol then it manufactures an LDL receptor, sticks it onto the cell membrane, and grabs any available circulating LDL. The LDL particle gets endocytosed and the cell can then use the delicious, gooey cholesterol for whatever it needs.

So what’s the problem? The problem is that LDL has a tendency to migrate through the endothelial cell layer of blood vessel walls and become trapped in the intima where it becomes oxidized or modified in some way. The oxidized/modified LDL particles trigger an immune response which ultimately leads to macrophages – informally known as scavengers or sometimes even garbage collectors – coming in and engulfing the oxidized/modified LDL. Now one of two things can happen here: 1) The cholesterol from macrophages can be handed off to HDL particles. The HDL can then take up this cholesterol and transport the it back to the liver to be recycled. The HDL could also give it to other lipoproteins in the blood. This process is known as reverse cholesterol transport. Or 2) The macrophage can hang out in the intima and continue to gobble-up incoming modified/oxidized LDL particles. This will lead to the formation of foam cells.1, 2


To make a long story short one or two or five foam cells within the vessel wall is no big deal, but over time, if the conditions are right, foam cells can accumulate within the vessel walls leading to a host of things you don’t want to happen with your arteries such as: narrowing of the blood vessel, chronic inflammation, recruitment of more macrophages, rupturing foam cells leading to all the oxidized LDL spilling out all over the place, migrating smooth muscle cells into the intima to wall-off the lesion, formation of a necrotic core filled with dead cells and cholesterol, and eventually rupture of the vessel wall (called a thrombosis) when all the contents spill out and can slow or stop the flow of blood. Platelets are then mobilized to repair the damage, but this probably only exacerbates the problem. If the thrombosis occurs in a coronary artery this can be deadly.


Inside an artery with advanced atherosclerosis

So what does this have to do with nutrition? There are several risk factors for atherosclerosis that can be manipulated via the diet. The following are risk factors that are considered to be “definitely modifiable” in the scientific and medical literature:

  • Cholesterol
  • HDL
  • Triglycerides
  • Blood Pressure
  • Cigarettes
  • Diabetes
  • Obesity
  • Sedentary Lifestyle
  • Alcohol

The following risk factors are classified as “potentially modifiable”

  • Lipoprotein(a)
  • Oxidized Lipids
  • Glucose Intolerance
  • Homocysteine

And there are some factors you just can’t do anything about

  • Age
  • Sex
  • Genetics

Now one might think that levels of cholesterol in the blood are directly related to the amount of cholesterol ingested in the diet. It appears to make logical sense, right? As it turns out dietary cholesterol doesn’t have a huge effect on circulating cholesterol. Most of us only absorb roughly 50% of dietary cholesterol. Even if you do ingest quite a bit of cholesterol from your diet your cells can compensate somewhat by down-regulating things like endogenous cholesterol synthesis. There is even a remarkable case study about a farmer that ate approximately 25 eggs a day (which adds up to an enormous amount of dietary cholesterol) and still had more or less normal serum cholesterol levels. The author claims that farmer was able to maintain cholesterol homeostasis by producing a ton of bile acids (made from cholesterol) and probably excreting most of it in the stool. Bear in mind, however, that this guy was probably an outlier as many case-studies are.

 

Okay, if dietary cholesterol doesn’t have a huge influence on serum cholesterol, then just what the hell does? Surprisingly saturated fat intake has a much larger effect on LDL than actual cholesterol intake. What do I mean by this? Well many studies have shown that if you subsist on a diet where your main source of fat is of the saturated kind, then it is likely that your LDL levels are high, but if you switched to fats consisting of mainly mono- and polyunsaturated fatty acids then your LDL levels are likely to drop significantly. Good news, right? Sure, olive oil all around! Oh, and with the caveat that your HDL levels could also decrease. Bummer. The good news is that LDL levels will decrease much more than the HDL. And just to further complicate matters the short and medium-chain saturated fatty acids commonly found in plant-based fats like coconut oil and palm oil don’t have the effect that other saturated fatty acids do when it comes to increasing serum cholesterol. This is because short-chain fatty acids (SCFA) and medium-chain fatty acids (MCFA) are processed differently by the body; they are not packaged into lipoproteins like other fats are but instead hitch a ride on serum albumin to get to their destinations. Think of the long-chain fatty acids (LCFA) as having to get on an enormous and crowded bus to get anywhere, whereas the SCFAs and the MCFAs are small and fit and can get on a bike to go where they need. That’s kinda where the metaphor stops, though.3

What else can you do to reduce your risk of atherosclerosis? They are all in the list.

  • If you’re obese you should lose weight, not just because of the reduced risk of atherosclerosis but also the substantial decreased risk in a legion of diseases, cancers, and what-have-you.
  • If you’re still smoking then I assume you are well aware of the above risks but choose to ignore them.
  • Get your blood pressure under control if you’re hypertensive.
  • Exercise regularly or at least semi-regularly.
  • Try not to get old. If you figure out how to do this let me know.
  • If you have Type 2 diabetes and you can’t shake it then at least learn to manage your glucose levels.
  • If you have hyperhomocysteinemia then you may have a B vitamin deficiency. Potentially an easy fix.
  • There are some gene therapies being studied right now if you have a genetic disorder that causes hypercholesterolemia.
  • There is also a large and growing body of evidence on phytochemicals and their antioxidant and protective effects.
  • There is also a substantial amount of evidence regarding omega-3 fatty acids and their role in modulating inflammation. Take this into account please.
  • If all else fails or you just want to keep eating steak and ice cream then talk to your doctor about statins.

This is all boilerplate stuff, of course. If you are reading this blog then I assume you are at least marginally interested in nutrition and already heed most of these recommendations. I didn’t get too much into inflammation in this post, but Dr. Rosenfeld and I talk about it more in the podcast. Inflammation truly deserves one or more posts on its own.

  1. Word on the street is that when the blokes that were first researching atherosclerosis were dissecting and examining diseased blood vessels they came upon a type of cell that looked like beer foam, and that’s how the foam cells got their name.
  2. It’s actually more complicated than that as you can probably imagine. It seems that if a macrophage ingests unmodified LDL then it can maintain normal cholesterol homeostasis, and get rid of the excess via reverse cholesterol transport. If the macrophage ingests a lot of oxidized LDL then it will become a foam cell.
  3. Wait… lemme try to extend it… So these buses sometimes get stuck on the highway and then the macrophage troll that hides underground comes and gobbles up the bus. If there are a bunch of buses then the troll will gobble those up as well and if he eats enough LDL buses then he morphs into the foam troll. Then foam troll can use his new powers of chemotaxis to silently call other trolls like a dog whistle and if enough buses and trolls show up then you have a traffic jam and everybody dies. Got it?

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