Easy way to learn to search the medical literature

I frequently mention in my posts that I find interesting papers by trolling through the medical literature. It dawned on me that maybe others would like to do the same, but really don’t know how to access or search the medical literature. I looked around on some academic sites and found an easy tutorial so that anyone interested can learn.

Before we get to the tutorial, let’s take a look at how I go through the literature. I have a number of journals that I look through every month (or every other month or weekly or however often they are published). Most of these journals are listed in alphabetical order on the Journals Page of our Protein Power website. By clicking on any of these journals you will be taken to the journal’s website and be able to read the abstracts of all the articles. Some of these journals make full text versions of their articles available after a time, usually a year. Most of these journals have an email service for their table of contents that you can sign up for, then you will receive an email listing the table of contents (or TOC, as they refer to it) whenever the newest issue of the journal goes online. If you keep up with these journals, you will be abreast of 90 percent of all the newest nutritional research.

I’m often sent links from articles in the mainstream press about new research. If you find an article you would like to know more about or see if the reported reported it correctly, you can use PubMed (a government-funded data base available free to anyone that contains all the medical literature) to get to the abstract from the journal. Here is an easy way to do it.

Within the last few days I’ve received links from readers about a recent study showing that a lifetime of carb abuse kills of the appetite-suppressing cells in the brain, leading to overeating with aging. (Here are a couple of links.) Usually the press reports have a statement from or somehow identify the lead author of the paper in question. In the case of these reports, the author is identified as Zack Andrews. PubMed can be searched by author. We put Andrews Z in the search line and hit ‘search’ and we come up with a list of papers that include Andrews Z as an author. In this case, the first paper listed is the paper in question. If you click on the highlighted authors’ names, you will be taken to an abstract of the paper. Since this is a recent paper in Nature, you won’t have access to the full text.

If you look at older journals, however, you often will have full text available to you. Here is the link for a famous paper published about 12 years ago that compares the Zone diet to the Protein Power diet. If you look in the upper right-hand corner, you will see a box that says ‘Full Text Free Links.’ Click there and you will be provided with the full-text pdf of this article. You should print this article for a couple of reasons. First, it’s a good article showing the difference between a low-calorie, higher-carb diet (Zone) and a low-calorie, low-carb diet (Protein Power) in terms of numerous parameters. The change that stands out the most is that the PP diet reduced insulin levels by about 50 percent whereas the Zone diet reduced insulin levels by about 8 percent. (I say this study represents the PP diet instead of the Atkins diet or a generic low-carb diet because the carb content is precisely what we recommended in PP.) The other interesting thing about this paper is its title: “Similar weight loss with low- or high-carbohydrate diets.” At the end of the study the weight loss differences were increasing but hadn’t reached statistical significance yet. But virtually every other parameter evaluated changed markedly for the better on the low-carb diet. So why the title? Why not ‘Low-carb diet markedly decreases fasting insulin’ or any of the other titles that would have been accurate. I suspect it’s because this is the title the peer reviewers wanted. Wouldn’t want the title to say anything positive about low-carb diets, now would we?

If you don’t have an author’s name or you don’t have a specific paper in mind, then you have to search PubMed the regular way. Here is a great little tutorial that shows you how to do it. Once you’ve gone through this, you’ll be able to find just about anything you need found in the scientific literature. In the audio sessions, when the woman speaking tells you to go to the Galen Homepage and select UCSF PubMed just go to PubMed and take it from there.

Once you’ve gone through this tutorial and learned how to find articles you want to find, you’ll be better able to keep me on my toes. We’ll both be the better for it.

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13 thoughts on “Easy way to learn to search the medical literature

  1. Excellent post Dr. Eades. Way to spread the wealth.

    I had to discover pubmed on my own awhile back to further my own studies as I keep my weight loss intact.

    Also I love recommending your site to others in the medical profession. Keep up the great work.

    Pete Thomas
    http://WinningMan.com

    Thanks, Pete. I’m glad you enjoyed it. Keep up the good work yourself.

    Cheers–

    MRE

  2. the problem is that, for me, most of these types of articles are written in such a way as to be unreadably obtuse. Scientific gobbledygook. My eyes just glaze over, even when it’s study I’m interested in.

    Unfortunately I can’t help you with that. But may be Mr. Jameson can. 🙂

    Cheers–

    MRE

  3. Dr. Eades – thanks so much for this post, I’ve been banging my head against the wall with Google Scholar. It’s a great tool, but I think this will help a lot more!

    Thanks also for the Zone v. PP article, I was just discussing Zone v. “Low-Carb” last night with some of our athletes. This helps a ton.

    -Brian

  4. Off topic with regard to this post, but relevant to the blog, see this story in the Independent:
    http://www.independent.co.uk/life-style/health-and-wellbeing/features/why-ill-never-eat-a-fryup-again-908395.html

    The good doctors recently commented on their appreciation of the Great English Breakfast, which this misinformed party seems to have missed. I’m flabbergasted that even today the culprit is the saturated fat and not the great gobs of bread and rice, etc., that would have been eaten by poor Ahmed.

    What a totally misinformed article.

  5. If you want to stay on top of the literature than you could create your own page at Pubmed.There you can create your personal interests which will be mailed to you as easy links to Pubmed each week for instance 🙂 Goto :
    http://www.ncbi.nlm.nih.gov/sites/entrez

    In the upper right hand corner is a small Sign In/Register link for accessing your page.The manual is here :
    http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=helpmyncbi.chapter.MyNCBI

    I’ve not done this myself, but it sounds like a good idea.

  6. I have always admired those who can go through the med literature and come up with good ,applicable stuff. I can find good articles but was statistically challenged in school. I leave the epidemiology stuff to someone much better and figuring it out like you or Dr. Dean Edell ;-). Thanks for doing this for us. How about Google Scholar? Someone mentioned about the fact that they include journals which Medline doesn’t.

    The link above made me think of this article…

    http://www.metametrix.com/resources/content/LearningCenter/Articles/IM-1(1)38-44.pdf

    I guess when you understand biochemistry and realize that everyone’s starting to recommend fish oils plus the media’s scorn of vitamin E and the ever present PUFA’s in our SAD diets, I can see why you have started to recommend krill oil. I can see the others above creating the perfect storm (with a little elevated insulin levels added in for flavor). And definitely stay away from that “vegetable ghee”! What the Hades is that? Poor Ahmed giving up his steaks to kneel at the pagan altar of Ornishites.

    I’ve never been real happy with Google Scholar. I’ve found the full-text version of a couple of papers there that I couldn’t get access to through my university affiliation, but for the most part, I’ve found it less than optimal.

    PubMed should contain ALL the papers in the medical scientific literature.

    Cheers–

    MRE

  7. I could probably use Mr. Jameson’s help, but most of the folks who write these articles need to get some help from Mr. Strunk and Mr. White.

    True dat. (Sorry, I’ve been watching too much of The Wire.)

  8. Mike, I found the article from 1996 interesting but somehow not very convincing when I read the conclusions. I’m not sure either that we could safely say that the comparison was between Protein Power and The Zone. Maybe I’m being too purist! When I think of Protein Power, which I’ve followed for years, I think not only in the low-carbohydrate part (which does fall between 12-15% carbohydrate intake), but also in the ‘adequate protein intake’ as well. By adequate, and strictly adhering to Protein Power, I mean a protein intake that is calculated based on lean body mass and level of physical activity. The article set the protein intake to whatever it fell after carbohydrate and fat intake were decided. True, the article did want to keep the amount of calories at 1000, which doesn’t make much sense as weight loss is expected anyway at that low caloric level. So, it is unclear if the authors wanted to really compare the effect of carbohydrate intake knowing that there could be benefits just by reducing caloric intake. At least they were wise enough to also measure insulin, triglycerides, HDL and glucose, even if they fell to recognize that a lower carbohydrate intake brings about more benefit than a higher carb intake.

    The conclusion that it is caloric intake what did the trick and not dietary composition, at least in my opinion, is not water-tight. However, I have to concede that we know more about the effect of protien now than back then. Protein is not even mentioned there, probably because protein intake wasn’t at all that different.

    When I read old studies, I sometimes go through the exercise of thinking how would I do the same study today with what we know today. First, I would really compare Protein Power as described, regardless of the final amount of calories. The reason? the calorie rule doesn’t necessarily apply when the menus are truly ala-PP. When carbohydrates are that low (around 15%), one cannot think of the calorie rule in the same way because oxygen consumption is different as more fat is being used for fuel. This changes the respiratory quotient and caloric intake determined by the standard calorie rule may overestimate the amount of calories really needed under low-carb consumption (when fat is used more than carbohydrate, the respiratory quotient decreases by 25%). Second, I would not set the caloric intake and I would carefully record what is the actual consumption of calories. As many studies have shown, caloric intake is not likely to increase but to decrease. I speculate that it is because of the effect of the protein in the diet but that, precisely, is what I would try to find out in such a study. More recent studies (well, maybe not that recent but a couple of years old, maybe three…), suggest that fat oxidation is increased when there is more protein in the diet, which could also explain why protein-rich diets in which there is no effort in restricting fat intake, bring about so much benefit in terms of weight loss (of course when carbohydrates are kept low as well but regardless of energy intake).

    To me what the article shows is that enough reduction of carbohdyrates improves the ‘invisible parameters’ as I like to call them (plasma glucose, insulin, cholesterol and triglycerides). The conclusion that it is caloric intake is not convincing to me because the caloric level is too low anyway… sort of saying that ‘when you kill something you can always show that it dies…” Setting caloric intake ‘loose’ would really say something about dietary composition. Had not been for the inpatient setting, I doubt that people could have stayed in a 1000-cal/day diet for too long.

    What I like about the study, nonetheless, is that everything was done under rigorous supervision (the dietitians were present during meal consumption!) and in an environment as controlled as they could have it, in an inpatient setting as opposed to letting patients to figure out how to follow their assigned diets. I also like that it was done 12 years ago! Which once again shows that what we talk about here is anything but new, but these results have somehow been ignored and not refuted with evidence. This study could be the basis for another, better designed one, that could really show if it is caloric intake, rather than dietary composition, what matters in terms of weight loss WITH improvement in those ‘invisible parameters’, not just weight loss per se.

    Hey Gabe–

    The reason I like this study is that naysayers can’t blame it all on a reduction in calories. So many times low-carb diets bring about all kinds of positive changes, but people say it’s only because of the reduction in calories. In this case the calories were exactly the same, yet the low-carb diet brought about significant changes in all lab parameters.

    Cheers–

    Mike

  9. I’ll pipe in that sometimes when searching it’s less effective for results to use layman terms – instead of “high blood sugar” it’s easier to search for “hyperglycemia”….instead of “fat” use “lipids”…..instead of “high blood pressure” use “hypertension – since many of the journals are targeting medical and scientific readers used to the medicalese.

    Another nice feature of PubMed is that you can click on the tab “Limits” and refine your search to include only human studies, particular age groups, gender specific, etc. – the “limit” function definitely helps when you are searching for something with thousands of hits and you really only want to cull through certain types of studies.

    Good points, Regina. Thanks. You’re always welcome to pipe in.

    Cheers–

    Mike

  10. For searching free on-line papers from most relevant medical journals, the best search engine currently available is HIGHWIRE (from Stanford University). Please visit and bookmark this essential link: http://www.highwire.org

    “A division of the Stanford University Libraries, HighWire Press hosts the largest repository of high impact, peer-reviewed content, with 1170 journals and 4,832,584 full text articles from over 140 scholarly publishers. HighWire-hosted publishers have collectively made 1,921,363 articles free. With our partner publishers we produce 71 of the 200 most-frequently-cited journals”.

    These are my suggested links regarding medical and sports scientific papers:

    In english:
    http://www.highwire.org (HighWire Press, Stanford University Libraries)
    http://books.google.com (Google Books)
    http://www.ncbi.nlm.nih.gov/sites/entrez?db=pmc (Pub Med Central)

    In portuguese:
    http://www.bvs.br (Biblioteca Virtual em Saúde)
    http://www.scielo.br (Brazilian scientific journals)
    http://www.scielo.oces.mctes.pt (Scielo Portugal)
    http://www.arquivosonline.com.br (Arquivos Brasileiros de Cardiologia)
    http://www.ibpefex.com.br (Revista Brasileira de Nutrição Esportiva)
    http://www.actamedicaportuguesa.com (Ordem dos Médicos de Portugal)

    In spanish:
    http://www.nexusediciones.com/buscador.asp (Publicaciones Nexus Ediciones, S.L.)

    Thanks for the links. The link to HighWire press (which I use often) is the Protein Power Journals page as well.

  11. I like pubMed. I am glad you recommend it and if there is ever anything doubtful, or if there is anything worth discussing, I know where to come.