Resources

  1. Public Health Nutrition: 14(12A), 2274–2284 doi:10.1017/S1368980011002515. Mediterranean diet pyramid today. Science and cultural Updates
  2. https://www.nejm.org/doi/10.1056/NEJMoa1800389 (recall and republication)
  3. https://www.nejm.org/doi/full/10.1056/NEJMoa1200303 (original recalled article) 

Transcript

Dr. Frank Domino:
Martin is a 50-year-old male who comes in for follow-up of his hyperlipidemia. He states, "Just when you think you have a good plan in place, you find out it's not good anymore. I heard on the radio that the Mediterranean diet doesn't work." You had suggested that he start eating the Mediterranean diet as a way to control his hyperlipidemia, cooking with olive oil, eating more nuts, and eating whole grain. His cholesterol seemed to benefit from this intervention and he actually lost some weight. He heard today on the radio that the research supporting the Mediterranean diet was recently called into question.

Hi, this is Dr. Frank Domino, Professor and family physician in the Department of Family Medicine and Community Health at the University of Massachusetts Medical School. And joining me today to discuss the changes recently broadcast about the Mediterranean diet is Susan Feeney, Assistant Professor and Coordinator of the Family Nurse Practitioner Program at the University of Massachusetts Medical School Graduate School of Nursing. Hi, Susan.

Susan Feeney:
Hi, Frank. 

Dr. Domino:

Well, the Mediterranean diet really hit the news this past week, and it seems to be providing a fair amount of misinformation. Can you briefly tell me what was the original study and what is the Mediterranean diet?

Susan Feeney:
Well, first, the traditional Mediterranean diet really looks at high intake of olive oil, like 4-5 tablespoons a day, tree nuts like almonds and walnuts, fruits and vegetables that are fresh, not processed, and high grain cereals or grains, moderate intake of fish and white meat or poultry, and low intake of dairy, red meat, and processed meats and sweets. And of course, they do say wine with moderation, especially with meal. So that's a traditional diet. The study that was done, it was critical landmark study in 2013 out of Spain looked at the Mediterranean diet with... They had three arms, they had a control which was a traditional low-fat diet that was low in all types of fat, high in grains, low in saturated fats, but high in dairy products.

And then they had two arms, they had additional arms, they had a Mediterranean diet that was extra olive oil but it was the extra virgin olive oil, and then one that had extra nuts. And what they found was, there was a difference in reduction of overall cardiovascular events in people who are high risk for atherosclerotic cardiovascular disease, and they found that that risk was reduced greater in the folks who had the Mediterranean diet with the olive oil. A little bit and not as good, but better with the extra nuts and both of them were superior to the low-fat diet. The low-fat diet wasn't terrible but they did find that the Mediterranean diet with the olive oil was the best.

Dr. Domino:

Great. Okay, so what changed? What happened this past week? And why did the authors retract this study and publish a new one?

Susan Feeney:
Well, what happened was, they on re-look up at their data, this was a multi-site study in Spain, and over those five years that they looked at folks, they found that one or two of their sites had not followed randomization the way that they had intended so it brought there the concept of randomization into doubt and that they were speculating it might have affected 20% of their participants. So they re-analyzed the data using methods that didn't solely depend on randomization. When they did that, they looked at the data and they really found no change, so what they did is voluntarily retracted their publication. You can't find it on PubMed, you have to go to the Internet. They retracted that and they resubmitted a new article with their mea culpa and their explanation of their data, and that was accepted by the New England Journal of Medicine.

Dr. Domino:
So it sounds like they were able to use statistical methods to overcome the challenges they identified.

Susan Feeney:

Right.

Dr. Domino:

And it sounds like from what you've said, there was no difference in outcomes, both types of Mediterranean diet still led to lower risk of adverse cardiac events in high-risk populations. 

Susan Feeney:
Right. Their endpoints were MI, stroke, and cardiovascular death. And they did find out that their original findings did hold, and what was interesting is when they really dug down into the diets of the folks who are on the Mediterranean diet, both the olive oil and the nuts, that it was really the fat that they were using, it was the low-fat diet, the fact that they didn't have those monounsaturated fats, and then the olive oil and not arms, that it was really the... It had nothing to do with calories or intake, it was really the use of those fats that seemed to be helpful and protective. And that what was very interesting is, neither of the Mediterranean arms, if you will, were calorie restricted. It was really based on, they could eat what they wanted as long as they kept it in those categories, and it still was beneficial.

Dr. Domino:

Okay, well, Martin's here and you've just dispelled his confusion about the Mediterranean diet. How do you incorporate this into practice? And how do you discuss this with patients?

Susan Feeney:
Well, it's not a one-size-fits-all. You have to really talk to people about, it's really about the choices that you're making and that the cleaner the food, the less processed, the less added sugar, no trans fats, those things are gonna be helpful. So what I do is I get a feel for what their likes are and if I talk about the Mediterranean diet, and that sounds like something that's interesting to them, then I would give them information on that because we've got some good data that seems to be holding up. If they're more comfortable with a low-fat diet, I would tell them what the benefits of the Mediterranean, see if they could add some olive oil in their cooking and use that as a substitute for any other type of oil they're using. But I think it's really all about the diet and a commitment to eating clean. The one thing they talk about too in all of it is trying to eat local foods that are not processed, that really eat foods that are in season, and that does seem to have a benefit as well.

Dr. Domino:
Alright, so when you look at the specifics of the Mediterranean diet, things that strike me are using primarily extra virgin oil oil, getting five servings of fruits and vegetables minimally a day, adding nuts and seeds. Really interesting was getting two or more servings of fish per week. I think that's something certainly in this country, we're a bit challenged to do and trying to limit your protein to things like legumes, eggs, and white proteins. And I don't think, despite the commercial, that pork is white. Any final thoughts on dealing with Martin and our future patients on the Mediterranean diet?

Susan Feeney: 
Well, it's like everything else, because our patients are so well-informed, many times they feel like they're getting good information and then they get something that will come across the news and they feel like they're always being that, "Gee, they gave me information and now that's not true." So just keeping them saying, look, we all have to be vigilant, that we know that all research can be flawed but it's important that they look at it again and that they stay, well... That we all need to be good consumers of research, and that always to feel comfortable to come in and discuss it with me.

Dr. Domino:
Well, thank you, Susan. This is great and I appreciate you bringing this forward.

Susan Feeney:

Thank you, Frank.

Dr. Domino:

Practice pointer. Despite the recent headlines in the news, the Mediterranean diet is still effective at lowering adverse cardiac risks. Join us next time when we discuss breastfeeding in the newborns and possible ways to improve outcomes. And for more timely relevant and practical medical education, check out pri-med.com.