A new study condemning eggs has the dietary world all atwitter. Unfortunately, I am in the midst of a “career change” so I don’t have the time to get the full paper and do a proper critique. I’ll explain what the career change entails a bit later, after the dust settles on the mechanics of departing a large organization where one has worked for over 22 years. In the meantime, my somewhat desultory blogging habits will likely be even more so, at least until I reach my new equilibrium, probably a few months from now.
This newest egg study is from the group at U of Toronto where the glycemic index was invented by Jenkins who is a co-author on this paper. Jenkins has collaborated in the past with Dr Neil Barnard, the PETA-affiliated vegan evangelist, who runs the Physicians Committee for Responsible Medicine, a thinly disguised vegan advocacy group. Dr Barnard has the distinction of having been sanctioned by the American Medical Association more than once for the use of guerrilla tactics to advance the animal rights, vegan agenda. I am beginning to view these UofT folks as cut from the same cloth as T. Colin Campbell whose “China Study” has served as a paean to the virtues of veganism and validation for everyone who has that inclination while actually relying on science of the flimsiest kind to build the case (see Denise Minger’s excellent critique at http://rawfoodsos.com/the-china-study/).
Okay, enough ad hominem character assassination, what about the merits of the study? Just from the abstract, here are some major problems. Firstly, it is an observational study. As you know, you can establish correlations from this kind of data but not causation. Secondly, it relies on food recall questionnaires. These are notoriously flawed and may return accurate information at a rate as low as 15%. The findings have huge overlapping confidence intervals and yet achieve statistical significance. How does that happen? (recall what Dr Mike Eades said: if you torture the data enough you can get it to tell you anything you want) And finally, the data showed an increase in plaque area of only 5.6%. In an observational study, you don’t have to overlook much of a confounder to get that kind of variation. Recall the hormone replacement therapy cock-up where the observational data showed a 50% reduction in CVD risk and when the clinical trial was done the result was actually a 30% increase, instead. That’s an 80% spread because of overlooked confounders. A 5.6% effect, given the inherent problems with this type of data – why is this even being published?
For a critique from somebody who has actually read the study, I recommend you have a look at what Zoe Harcombe has to say: http://www.zoeharcombe.com/blog/
There has been, predictably, much coverage of this study in the mainstream media, as well. This is the only article that I have seen that puts the issue into proper perspective: http://news.nationalpost.com/2012/08/15/yolks-as-bad-as-smokes-we-try-to-unscramble-the-truth-about-eggs/
What does it all mean? Well, as I write this I am finishing my usual breakfast of frittata (with eggs, cream, mushrooms, onion, cheese and, oh the humanity – bacon!). And I will continue to tell anyone who will listen that an egg is a perfect food since it contains all the ingredients needed to make a baby chicken.
“an egg is a perfect food since it contains all the ingredients needed to make a baby chicken”
Agree 100%! Plus it is convenient, economical, and above all versatile. If we add some veggies for vitamin C, say peppers, we are pretty much covered.
Thank you for a heads-up about this study and good luck with your new career! Change is always hard work but it is worth it as it drags us out of our comfort zone and makes us learn more and so much faster.
Looking forward to your future posts.
Dr Jay’s Reply:
Most of the time we don’t welcome big changes in our lives, especially when they are thrust upon us. I tend to look at them as opportunities more than anything. Sometimes change is for the better. I’ll keep you posted.
When you first see that a study is “observational,” simply quit reading. The only other piece of information you need is who paid for it. If you are actually reading an observational “study,” you are wasting time that could have been used for more valuable things.
Dr Jay’s Reply:
Yet, a lot of the nutritional guidance we get is based on the results of observational studies. It’s a crazy world out there!
Thanks for this. Just last night I read the Science Daily summary of this article, which included statements like “It has been known for a long time that a high cholesterol intake increases the risk of cardiovascular events” whereas dietary cholesterol has relatively little impact on serum cholesterol.
I thought I really should slog through it and blog about it, pointing out its limitations, but then I said no. I’m tired of the studies that associate some food (on the basis of food questionnaires) with some outcome and magnify its importance. I’m more interested in the mechanics: Why does some nutrient affect some outcome?
So I threw the article in the trash.
Dr Jay’s Reply:
Bravo!
Zoe Harcombe does a nice analysis of the data. What disappoints me is how the poor the coverage has been in media such as the Globe & Mail. The papers now don’t even purport to have professional science reporters, much less reporters with some science education. This egg “study” was in the “Hot Blog Button” section which is written by superficial chat specialists. They don’t even read the studies and simply rehash the press release from the authors of the paper. One of the “editors” of the Globe wrote a weekend piece on the artificial butter “flavour” (flavouring, actually) in movie and microwave popcorn being linked to Alzheimer’s. There were several comments on how poor the article was. I find now that usually only the critical comments online are worth reading–the articles (written by airheads) are mere context for the comments. The editor who wrote the popcorn article confessed in a subsequent article (about a book on dogs) that she was a “science newbie.” That about sums up the quality of science reporting these days. Unfortunately they are useful idiots for agenda-driven propaganda science. Considered responses take a day or two and by then the articles are buried by the next days sensations.
I’m happy to see that this “study” is taking a beating over at that font of dietary nonsense, Huffington Post. Ever the optimist, I take this as a hopeful sign that more and more people actually recognize cr@p “science” when they see it.
Dr Jay’s Reply:
The commenters at HuffPo seem to be getting it more so than the writers. I live in hope!
Hi Jay!
I’ve got the paper. You’re not missing anything. One thing conspicuously missing from this new one is the Conflict of Interest statement. Here’s the one from this group’s 2010 anti-egg paper:
Dietary cholesterol and egg yolks: Not for patients at risk of vascular disease
Can J Cardiol 2010
Conflict of Interest
Dr. Spence and Dr. Davignon have received honoraria and speaker’s fees from several pharmaceutical companies manufacturing lipid-lowering drugs, and Dr. Davignon has received support from Pfizer Canada for an annual atherosclerosis symposium: his reasearch has been funded in part by Pfizer Canada, AstraZeneca Canada Inc. and Merck Frosst Canada Ltd.
Given the strong conflict of interest and the poor study design, this is a study to ignore. Let’s stick to examining real science with rigorous study design and execution.
Be well,
Ben
Dr Jay’s Reply:
I have seen the paper now and agree. Thanks.
Consider it ignored. I came across a reference to this paper somewhere–I think it was mentioned in a talk that some vegan commenter on a Huff Po article linked when I asked for evidence of some claim she made. I had the same reaction you did. No one, and I mean no one, is going to convince me that eggs are anything but super food, especially not on the basis of some observational study using food questionnaires. And I told the lady as much.