Wednesday, September 5, 2012

How would you like your eggs: Reading nutrition related news critically

After fifteen years of counseling people on nutrition, I think one of the questions that I have a serious love/hate relationship with is the one that goes like this, “Last night on the news I saw that such and such is going to kill me,” or “Did you see this article about how this particular food will lead to the zombie apocalypse?”  OK, so I was exaggerating just a little, but it seems to be easy for people to get bent out of shape if they are not sure what to look for in these articles.  Fortunately, our friends over at Skeptical Raptor (Link) and Double X Science (Link) have already written fantastic articles on how to sort through the headlines, and the article itself, to help you help yourself to determine whether or not the information might be useful, merely of interest, or not useful at all.  I'm going to try to narrow the focus a little bit more to how to critically read articles relating to foods and food intake and use one of the articles I've been sent as an example.

1) Skip the headline.  Done. And if you have already clutched your pearls and fainted because you really like eggs, please pick yourself up off the floor.  I've also seen quite a few articles like this one where you probably want to ignore the first paragraph too.  The headline is there to grab your attention, that’s all.  Try not to take it personally, and make sure you keep reading if you think there might be something interesting.

2) What is the basis of the article? Sometimes the news article is kind enough to link to the actual study, sometimes (as is the case here) you can tell from the news article itself what kind of basis it has, and sometimes you have to start using search engines like Google Scholar, etc to figure out more about the basis.  In this news article, you don't have to do a whole lot of digging to figure out this one was original research, and that it was published in a journal.  I usually take the time to go look up the original article here even though technically I am jumping ahead a step.

3) What words does the article use?  In the linked news article they completely skipped over the words association, and link, and jumped directly to using the word "cause."  That should be a red flag right there, because the researchers themselves will typically use words like "association," which, as it says in the Double X post, describes a mathematical association, not a biological cause.  Now typically in my head I usually go "that's interesting, I wonder if there is going to be anymore research done on potential causes?" but I know that correlation does not equal causation.  I think another thing to keep in mind is that if the news article greatly simplifies a complex bodily process that should also be a red flag that you are not getting all the information.  It almost sounds like the cholesterol from the egg goes directly to your arterial wall, and it (fortunately) is not that simple or even accurate. 
4) Look at the original source of the information.  Sometimes you will only come up with an abstract, but in this case a Google search using the journal name and egg yolks (often helps to use the author's name too) provides us with a link to the full text of the article hereIn this case it looks like the original research was actually published in a journal which is a good thing.  And if you have access to the full text of the article, read the entire thing.  You will want to see what kinds of methods were used to do the research because the methods used might also tell you whether or not the information is reliable.

5) Remember that everyone involved has some sort of return they're seeking.  Sometimes I see a study is sponsored by a particular group, like the National Beef Council, etc and it's pretty easy to start pointing fingers at who has a stake (pun intended) in the research.    I am going to engage in some speculation here based on what I've read in the conclusions; they were likely trying to disprove some of the other diets out there that include regular consumption of eggs.  (***Warning, warning, warning!  SkepticRD is engaging in speculation based on the arguments she has seen in the scientific community!  I am not claiming any kind of conspiracy, just pointing out that people argue and that we all have to watch out for confirmation bias!)

6) Ask a scientist to clarify; we like to talk about science!  A lot of prominent researchers associated with Universities will have their bios on the website and you might be able to e-mail them directly from there.  If the authors are not readily contactable, someone else who writes about science on the internet could help clarify.  And I will add, you will want to try to find someone with knowledge relevant to the field at hand.  When it comes to nutrition, most of your general practice physicians, physician assistants, and nurse practitioners do not have the practical knowledge necessary to educate you on the specifics of eating certain foods to help.  Cardiologists and endocrinologists tend to have more experience when it comes to nutrition, but not always.  And if you are looking for someone who has “nutrition” floating around in their titles be careful here too.  If a person has "RD" behind their name like yours truly, it means this person has actually gone through an accredited program, an internship, and then taken an exam so they have legitimate credentials.  Anyone can hang out a sign that says "nutritionist" and it means…nothing.  And yes, yes, I know you went to an endocrinologist and she was grumpy or you went to a dietitian and he told you "follow this plan or else" and it didn't work for you, etc.  I know, I have worked with plenty of people who for whatever reason never learned critical thinking skills, forgot how to use them, or are so afraid to think for themselves that they can't stop giving advice even when it's bad.  Take some time to research the experts too.

Which way do I go to get off my soapbox again?  Ah, stage left.  So, one thing this "expert who loves to talk about nutrition" would like to point out is the problem with their data gathering methods.  They used the dreaded self reporting food frequency questionnaire.  Ok, so how many of you can remember what you ate yesterday?  Last week?  Last month?  For the past two years?  I thought so.  So the amount of eggs they reported eating, as well as other kinds of food were guesses at best.  Also, the researchers singled out one food out of whatever else they were eating meaning that lots of other variables were unaccounted for.  Do we know how much carbohydrate they were eating, or what type of other fats they were consuming, or how many vegetables they ate, or were they active, did they get enough sleep, etc?  It is so easy to want to point to one particular food as a problem, but in the case of a complex problem like atherosclerosis we just can’t do that.  It’s also worth it to point out that smoking also has a more direct impact on atherosclerosis; smoking causes the arterial walls to be inflamed, the body produces more cholesterol to serve as a “band-aid” on the inflammation, and the resulting “band-aid” is what is known as the plaque build-up.  As I said in a previous post about inflammation, usually there are multiple dietary factors that play a role in inflammation.
So this expert once again says, "well, that study is interesting in as far as you might have something there later to do a double-blind study if you ever get the time and money to do so, but I can't actually advise people to change based on unreliable information."  

I also found it interesting that the researchers themselves would not mention the flaws in their research methods, which should be another red flag.  I also find it interesting that in their conclusions they mention Ancel Keys who has also been vilified for "cherry picking data" when it comes to diet and heart disease as summarized in this little clip.

Just as an aside, I’ve had to stop “liking” certain articles that I read because it shows up on my social networking sites like Facebook.  Suddenly my “huh, that was interesting, I hope they do more research on that” results in people, who don’t read articles like I do, assuming that I thought the tiny little research study was pivotal instead of just “I hope they do more with that” and I find myself discussing things not worth discussing.  

I think it’s time for an omelet.

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