While interesting this is a highly flawed study. It should be considered preliminary with more properly controlled followup studies.
1. No control group
You need to have a control group that continues eating a standard healthy diet that includes animal products. The 11% who were non-adherent could have been eating unhealthy diets which contributed to their instances of CAD. Without a control it could have just been eating a healthy diet that helped, not the exclusion of animal products.
2. No blinding
Of course a food consumption study is nearly impossible to double blind but at the very least the researchers could have been blinded. This also requires a control group.
3. Self-reported data
While it's very tough to get anything other than self-reported data for long term food consumption, it makes it far more likely that the participants will report inaccurate or incorrect data. Results tend to be biased because participants don't want to let researchers down and lie about adherence.
The most interesting item in the article, was this, "We referenced the plummeting death rates from strokes and heart attacks in Norway during World War II when the German occupying forces confiscated their livestock, limiting Norwegians to plant-based nutrition.15"
I didn't know about this. This might be the only reliable
evidence of the efficacy of plant based diets we have so far? I don't know the mindset of Norwegians back then
concerning health, so I don't think the Placebo Effect played much of a role in final statistics, and they must have been under a lot of stress. I couldn't find the footnote 15, but will look harder.
I don't remember the source, but I read an article a couple of years ago that linked that statistic of plummeting death rates in Norway during WW2 to high consumption of cod liver oil, which apparently was readily available. Take that as you will.
"This study had several limitations. First, it included self-selected, very deter- mined patients. Without a control group, it is challenging to establish causality and as- sess how much of the observed changes are specifically due to the diet. Only some of the observed beneficial outcomes may have been due to the diet. This study was not pro- spectively randomized. Nevertheless, this fact does not detract from proof of concept that major cardiovascular events occurred in probably <1% (and certainly <10%) of the entire adherent cohort, compared with 62% of the nonadherent cohort (TaBlE 2). These data convey a strong message of patients accepting empowerment to be the locus of control to arrest their disease and confirm that patients will adopt a significant lifestyle transition to plant-based nutrition to halt and regress what we believe is a largely food- borne illness.
The past several decades have witnessed a substantial and sustained reduction in CAD. Nevertheless, CAD remains the number one killer of women and men in this country. Thousands of stable patients having stents experience no reduction in major cardiac events.6 While drugs have some effects on disease initiation and progression, these in- terventions do not address disease causation. Not surprisingly, most patients experience disease progression, more drugs, more im- aging, repeat interventions, progressive dis- ability, and, too often, death from a disease of western malnutrition, the cause of which has been largely left untreated. We have in press several patient experiences that exemplify the repeated failure of present-day cardiac drugs and procedural interventions, and that confirm the capacity of whole-food plant- based nutrition to restore health in “there is nothing further we can do” situations.36
In summary, the present cardiovascular medicine approach tested beyond 40 years can neither cure the disease nor end the epi- demic and is financially unsustainable. The safety, diminished expense, and prompt, powerful, and persistent results in treating the cause of vascular disease by whole-food plant-based nutrition offer a paradigm shift from existing practice. We think the time is right for a controlled trial. But in the mean- time, the data are sound and strong enough that patients should be informed of this option."
> These data convey a strong message of patients accepting empowerment to be the locus of control to arrest their disease and confirm that patients will adopt a significant lifestyle transition to plant-based nutrition to halt and regress what we believe is a largely food- borne illness.
In other words, they conclude that diet can impact CAD and some people will be willing to change their diet. No surprise there. The fact that the study was for plant-based nutrition holds very little relevance since there was no control group. It could simply be that people transitioned to a healthy diet. We can't know for sure without proper controls.
I don't think the effectiveness of a whole foods plant based diet is really in question here. There are enough robust studies showing that it prevents and reverses CAD (look for Dr. Dean Ornish and Dr. Collin Campbell).
Knowing that CAD is the number one killer in several countries, I am all for studies like this being published, even with the lack of formal control group, after all, the numbers are pointing in one direction. If I had heart disease, I would have liked to know about this data.
Nearly 100% of participants who changed their diet had no additional cardiac events; some even had measurable disease reversal. These were all sick people. The hard question is "What is a healthy diet that includes animal products?" This study doesn't address that interesting question but does demonstrate that if you eat a particular healthy diet that happens to not include any animal products, you won't die from heart disease. That's a profound result for the participants, with profound public health implications.
I don't know if it's highly flawed, though it does have the flaws you mention. The numbers may be true, but they don't smell right to me. 90% adherence for a significant change in diet for the long-term of three and a half years? Even for people who've had close shaves with death and those who have 'every intention' of following through, this seems absurdly high.
Similarly the marked difference in effects between the groups - two thirds of the non-adherent group versus a single case in the 177 adherents, in terms of having another event? It's not like the benefits of vegetarianism all arrive the following day - I would have thought there'd likely be a few more in the adherents group that had an event while they were still 'in transition'.
It may all very well be true, but it does smell a little funny.
Control and double blind studies are more important when the placebo effect and subjective outcomes are at play. Not necessary here. Everyone that follows a different diet would like to complain about that. You should have compared it to the paleo diet, or low-carb diet, or whatever. Show studies that those diets have similar effects and then they merit comparison.
Self reporting is an issue, but this is not the only type of study on the issue. It has been supported by international studies, animal testing, and countless studies about the health benefits of more fruits/vegetables and less meat.
My friend, (a scientist) wants to develop a pill that "triggers" the placebo effect (lets face it, its as effective as many drugs). Could you test that?
Sure, but you would just be testing it against other placebos. There has been work in this area. For instance getting a pill from a doctor is stronger than getting the same pill from a stranger. The look/cost of the pill affects it's strength, etc.
This post needs to be higher. Note the weasel-words about this being an adjunct to normal cardiovascular care:
>These patients with established cardiovascular disease (CVD) were interested in transitioning to plant-based nutrition as an adjunct to usual cardiovascular care.
In other words, this study cannot establish that the statins these patients were already taking didn't account for their perceived health benefits.
0.6% recurrent event rate does not mean it was 99.4% effective. You need to know what the recurrent event rate would have been if everything else was the same and they hadn't followed the diet. Hint: if the normal recurrent event rate is 0.3% then they are worse off, not better (insert test of statistical significance here).
If the event you are testing for (recurrent CVA) is rare, then a large enough sample and proper statistical significance tests are even more important.
2. No control group
"Didn't follow the diet" is not a control group. They have, post-hoc, selected the subgroup consisting of "people unlikely to follow a lifestyle intervention". That group might also been the most likely to continue smoking, not take their medication, do no exercise, be too unwell to follow a rigorous diet, etc etc.
3. Subgroup analysis
Drawing a circle around a subgroup after your study and making inferences from them is an excellent way to get bogus results. (Classic example: Wimbledon winner prediction system. Email 2000 people at random with each player and ask them to bet $1 on that player. After you know the winner, get the subgroup of people who won, and ask them how accurate they think your winner prediction system is.)
I suspect that rather than what they ate, what they did not eat played a major role....
" Patients were also asked to avoid sugary foods
(sucrose, fructose, and drinks containing
them, refined carbohydrates, fruit juices, syrups, and molasses). Subsequently, we also
excluded caffeine and fructose."
That quote is from the article, yes. But they repeatedly summarize the diet as "plant-based", rather than sugar-free and plant-based. What if the fact that they cut meat had absolutely no effect or even a negative one? Would we be able to tell from this?
That's a fantastic question, and one that I really like to know the answer to, but not the question I replied to. It is indeed what they removed, which caused the problem. And the diet they ate was also "plant based". Now we just need more studies to nail down which of that large list is actually the culprit. Like yourself, I highly doubt that it's all of them.
This is a pretty ground-breaking study, and do hope it gets much wider coverage in mainstream media. I had earlier read the book by the lead author of this study Dr. Esselstyn, "Prevent and reverse heart disease", which describes the plant-based diet approach and research done earlier that was effective with a group of 22 patients with terminal heart disease. Also, recommend reading related work on diet-based approaches by Dean Ornish. Ornish's approach does allow the use of some diary, eggs, and some amount of oil.
The documentary "Forks over knives" - available on Netflix, describes this approach and has features interviews with Esselstyn as well.
So they cut sugar and they cut meat and dairy, and they blamed the improvements on cutting meat and dairy, or am I misreading this?
It seems like as if I wanted to prove that a television-free lifestyle improved health outcomes, so I studied a group that stopped watching television (and taking heroin.) I keep reading "plant-based" as characterizing the diet, including in the abstract, when the sugar they cut out was almost certainly plant-based too.
This was some years ago now, but I saw the PI of the Nurses's Health Study [0] (I don't remember if it was Speizer or Willett; probably Willet) give a talk at Harvard. This was just after I read The China Study [1] -- a book recommended by Prevent and Reverse Heart Disease, which was given to participants of this study. The recommendations of the NHS [2] seem to disagree with the more extreme diets of TCS and this study. I asked about this in the Q&A. The speaker dismissed TCS, saying that the their data did not in fact support their conclusions. It seems Willett and Campbell have had an ongoing exchange [3] in the literature.
[2] "A Mediterranean-type diet reduces risk of incident CHD and stroke. Fish intake reduces risk of stroke. Nut and wholegrain consumption reduces risk of CHD. Refined carbohydrates and trans fats increase risk.", see:
I'm surprised they excluded nuts, and avacados? I guess
they wanted a diet of zero fats? When I was younger I had
and extreme fear of my clogging up my arteries. I ate a
normal diet, but no processed food, and no sugar.(I was so
young I didn't know about fructose, etc.). I just really
vigilant about sugar. I got my cholesterol down to 120.
Yes, it's antidotal, but my doctor was surprised. I wish
I wish I stayed on that diet! One other antidotal story.
My best friend smoked three packs of cigarettes a day(12 to 70 years) and
at least a pot of coffee. Everyone told him his arteries
are probably partially occluded. Well he went in for extensive
tests, and he had no plaque build up. We were all surprised.
I think what saved him is he only ate one meal a day? He
died at 71 because of COPD, but he was functional up to 70.
I pass this along to the Smokers who can't stop. Everyday,
people told him he would get cancer, or heart disease--he got neither. I'm not condoning smoking, but in think calorie restriction might save your life if you just won't/can't quit? When he finally quit at 70, he said I was
much easier than he thought, and comparing it to quitting
Heroin was ridiculous. And I know--it's antidotal, and his
experience does not come close to a double blind study.
Seconded. We've changed the url to that from http://www.jfponline.com/articles/editor-s-pick/article/a-wa.... We've also reverted the title. The submitted title ("A 99.4% effective way to reverse Coronary Artery Disease (CAD).") seemed pretty editorialized.
Mea culpa. That was the original title I submitted. When no one had responded for a good while, I inserted the "99.4% effective" part. I should have at least wrapped it [in brackets]. I hadn't intended to drop the question mark.
Allow me to don my doctor hat and provide some comment here. I'll leave the statistical analysis to the mathematicians below.
1. The study was self-selected
- we don't know to what degree. Did they place flyers in vegetarian recruiting grounds?
2. They explicitly state that they are not including 8 patients that experienced thrombotic or embolic events or had progression, blaming them on other factors. That may be the case, but it is not ok to exclude patients on that basis and report your adverse event as 1% due to that.
3. There is no marker of cardiac function provided in the study / we have no idea if the groups had similar baseline function.
This is a critical point because amongst the 'non-adherent' group there is one patient who underwent a heart transplant.
A heart transplant is a very rare procedure and is only reserved for extremely severe heart failure. If a patient in a study eventually underwent a heart transplant, that patient very likely had horrific cardiac function at the beginning of the trial.
What is more telling is that such information could have been statistically provided very easily:
They could have chosen to provide a summary of number of patients who had experienced infarcts;
number of patients with aberrant ECG rhythms;
number of patients on spironolactone (a medication reserved for use for late in heart failure);
Left ventricular ejection fraction estimated from TTE;
The list goes on.
Instead they provide only the sexes, 'symptom reduction', and adverse events.
In my opinion this study provides little more than anecdote that patients should switch entirely to a plant based diet, and at this point I would certainly not recommend a patient of mine to switch. However it should be studied in greater detail and it would be interesting if stronger evidence emerged.
I'm surprised you didn't point out that the diet itself was flawed. The basis of the plant-based diet was vegetables and fruits, and yet they explicitly excluded fructose. You can't have any fruits then! Nearly every fruit contains fructose in some appreciable amount, among the lowest in concentrations are raspberries and strawberries. Even vegetables have significant amounts of fructose, such as asparagus and tomatoes (though technically a fruit as well). I feel like with a study that self reports from it's patients, especially of this size, a diet this restrictive is nearly impossible to keep 24/7.
Does anyone have access to the PowerPoint described in this study for the in depth 5 hour course they took? I would like to see what exact foods were suggested to both eat and stay away from.
This is a pretty poorly conducted study. First off, they make a causal claim that nutritional intervention induced reversal of CAD progression. This is an observational study so such a claim is inappropriate. This is also a very bold claim and yet this paper is published in a shit journal with an impact factor of < 1. That should be a huge red flag right off the bat.
Indeed, there are huge limitations in this study:
1. No control group
2. Self reported dietary adherence
3. Obvious possibility of the healthy adherer effect (people who voluntarily present for interventions and are adherent to dietary changes will probably also exhibit other healthy behaviors like exercise, mood control, better sleep etc which introduces confounders.
4. No monitoring of medication adherence. Perhaps these people simply started taking their medications more regularly while in this program. Medication adherence among patients with CAD is notoriously terrible.
5. Possibility of sick stopper effect in their non-adherers (sickest people also most likely not to take their meds, precipitating worse outcomes).
6. They note that on average their patients lost 18 lbs; perhaps weight loss alone was responsible for their improvements
7. They exclude some of their sickest patients
8. They report symptom relief in adherent patients but don't mention what that means. Do they report less angina? Did they see plaque size reduction? If the former, you have introduced potential for placebo effect.
Nope, and no blinding either. This should be considered a preliminary study at best. The quantity of participants doesn't make much of a difference without proper scientific controls.
I'm not trying to quibble, but am genuinely curious: What would a control group consist of? There were plenty of patients who didn't receive the trial program, at large in the general population. And it couldn't have been a blind study, because the patients knew what they were eating.
A control group goes through the same amount of attention and procedure as the experimental group, controlling for as many independent variables as possible. "Someone in a lab coat is watching my diet" all by itself is probably a pretty strong motivator for change, and one that the general public does not have. What people eat when they think someone's watching can be markedly different to what they'd eat in private.
It would be an equivalent population who weren't asked to change their diets.
There are multiple reasons the patients in this study might not be comparable to participants in other studies or to the general population. Age, gender, average disease severity all need to be controlled for. And if nothing else the simple fact the patient knows they're being monitored could have an impact on all sorts of behaviors.
Yeah, these are interesting results, but without a control group you can't say for certain what is causing an effect or, actually, if an effect exists.
> It would be an equivalent population who weren't asked to change their diets.
Which is actually an ethical quandary when you think about it. A doctor's ethics are really tested when he has to say to some patients "sure, I think you should change your diet and you'll probably die if you don't, but you're part of the control group!"
One more ethical (and still statistically somewhat interesting) way of administering such a study would be to bring in doctors advocating different sorts of diets. The Cleveland Clinic hasn't done such a thing but they probably could: they've got a group that advocates the rigid vegan diet and another that advocates the Mediterranean diet. Not as good as having a control group that continues to subsist on cheeseburgers and coke but it actually can test a few specific ideas, like the vegan claim.
> Which is actually an ethical quandary when you think about it.
You're right, of course. But whether a study is scientifically valid and whether it is ethical are two orthogonal questions.
Similar concerns are why most cancer therapy trials end up looking more like A/B testing than classic experimental/control experiments. The point I was trying to make, though, is that you need at least two groups which differ only by a small set of (ideally one) known variables to draw any real conclusions
Is that not standard advice when you have a heart attack. Give up smoking, eat healthier, do a bit of exercise. It's going to be difficult to find a willing and valid control group under the circumstances.
Not exactly a control group, but among the group of 22 patients who did not follow the diet, 13 or 62% had some sort of adverse event (stroke/heart-attack etc), compared with just 1 out of the group of 177 (0.6%) who did follow the diet. That seems to be pretty compelling evidence that the approach is effective.
One immediate issue is that conscientiousness, e.g. the ability to maintain a difficult diet for an extensive period of time, is quite correlated with longevity.
This is a very commonly known effect, which makes me more than a bit suspicious of this particular study.
This is also why a control group with random assignment is necessary, particularly in the social sciences. There are simply too many confounding factors to make epidemiology useful in basically any way.
A good portion of people who come to the Esselstyn way of eating, do so to hopefully "reverse" their cardiovascular disease. The name of this study is "A Way to Reverse CAD"
We are told that 39 participants (22%) had documented reversal of CAD. But we are given zero data or information about those patients. What was the average reversal?
How many of those patient were on statins as well as the diet?
We don't have even the most basic definition of how "reversal" is defined for that 22%.
My gosh, the name of the study is about "reversal"
Yet we are given no data at all similar to that seen in both the Ornish studies. At least Ornish gave precise percentage reversals in the arteries with blockages. Average reversal for tertiles of aherence in percentage terms.
Something we could analyze in terms of effectiveness.
Something that could be measured.
In this study all we are told is that there was reversal in 22%, with no further information. Not even a clear definition of the word "reversal".
Something is very wrong with that. Many Esselstyn followers are in it for the long haul. Sure, its nice to know there were less cardiac events over the 3.7 years, but we're looking for a process lasting 20 or more years into the future.
What the heck does reversal mean if you don't define it and don't give any data about those who got reversal.
Totally disappointed in the details, apparently chosen to be omitted. As though the reader, the patient, will just blindly accept the "22% reversal" claim with no data given.
Does anyone have knowledge of if that data will ever be released, or a definition of "reversal" given?
I started following this diet three years ago after receiving a coronary stent. People always tell me they could never eat like I do, giving up all their favorite meats and dairy. This study shows that motivated people really can do like I did, which is something doctors like the doc in a hat two days ago don't apparently believe. As to the criticisms based on statistical merits, I'll defer to this passage from the report, "The Cleveland Clinic Institutional Review Board determined that these were acceptable outcome measurements to evaluate the nutrition program." If it's good enough for the Cleveland Clinic, it's good enough for me. If you folks want a controlled study, do one yourselves.
There are 2 things which influence CAD: omega 6 intake and stress.
Arterial plaque is formed not as a result of a high fat diet (even animal fat) but as a result of inflammation which kickstarts the plaque building process.
The myth that high cholesterol or high fat is the culprit of CAD is difficult to kill, even when study after study shows no correlation whatsoever between them and CAD.
The correlation though does exist between high stress combined with poor diet: high omega 6, processed foods, high sugar, high starch/carb intake coupled with stress which is the precursor to inflammation.
Inflammation is in fact the #1 cause of disease in humans. But like cancer, it is a slipper sonofabitch to nail down.
>>The myth that high cholesterol or high fat is the culprit of CAD is difficult to kill, even when study after study shows no correlation whatsoever between them and CAD.
It's hard to kill because it's not a myth. Despite of all the blogs and books the paleo-opportunists are selling you, the best science available today shows a very strong correlation between cholesterol and CAD. Even the all mighty cattle industry will have a hard time convincing real scientists that the lipid hypothesis is a conspiracy theory.
>the best science available today shows a very strong correlation between cholesterol and CAD.
True, but can you show me a study that shows that reduction or increase in cholesterol levels is correlated with improvement or escalation of CAD?
There's a correlation between having a penis and baldness, but it doesn't necessarily follow that castrating yourself will cause your hair to grow back.
As I am sure you're aware, correlation is not causation. But you didn't say it. Plenty of studies suggest that it's how the cholesterol is carried in the blood that matters and this isn't just a matter of HDL and LDL; the type of LDL matters too as do triglycerides. Another important factor is inflammation i.e., high c-reactive protein levels need checking out. And of course other factors may be significant as well.
To put it politely, pertinent questions remain regarding the data which Ancel Keys picked to support his high fat = heart disease hypothesis.
Yea, it's scary. I took an introductory Psychology
course at COM, by a teacher who did landscaping during the
summer breaks. He spent a huge amount of time on the protocols of a good scientific study, and the Placebo Effect. I used to assume most published studies followed
the basic requirements he taught us; I and the FDA have
been duped--conned--and lied too! It's pathetic, and I
don't see anyone reprimanding these entities. I'm not
upset about this study, but I'm beyond disappointed with
Drug companies!
"Results: Of the 198 patients with CVD, 177 (89%) were adherent. Major cardiac events judged to be recurrent disease totaled one stroke in the adherent cardiovascular participants—a recurrent event rate of .6%, significantly less than reported by other studies of plant-based nutrition therapy. Thirteen of 21 (62%) nonadherent participants experienced adverse events."
"Methods: We followed 198 consecutive patients counseled in plant-based nutrition. These patients with established cardiovascular disease (CVD) were interested in transitioning to plant-based nutrition as an adjunct to usual cardiovascular care. We considered participants adherent if they eliminated dairy, fish, and meat, and added oil."
I emailed asking for the slides. I got this reply:
My husband’s book, Prevent and Reverse Heart Disease is widely available.
‘
On his web site, dresselstyn.com you will find his counseling DVD for purchase
Or you may come to the Cleveland Clinic Wellness Institute for his monthly counseling seminar. Details available through his secretary Jackie at 216-448-8556.
1. No control group
You need to have a control group that continues eating a standard healthy diet that includes animal products. The 11% who were non-adherent could have been eating unhealthy diets which contributed to their instances of CAD. Without a control it could have just been eating a healthy diet that helped, not the exclusion of animal products.
2. No blinding
Of course a food consumption study is nearly impossible to double blind but at the very least the researchers could have been blinded. This also requires a control group.
3. Self-reported data
While it's very tough to get anything other than self-reported data for long term food consumption, it makes it far more likely that the participants will report inaccurate or incorrect data. Results tend to be biased because participants don't want to let researchers down and lie about adherence.