Advanced Mediterranean Diet

I blogged about a study by Gu et al on April 30, 2010, that found significantly lower incidence of Alzheimer dementia in people in Manhattan who followed this dietary pattern:

• relatively high consumption of salad dressing, nuts, fish, tomatoes, fruits, dark green leafy vegetables, and cruciferous  vegetables
• relatively low consumption of poultry, red meat, butter, and high-fat dairy

About the same time, a National Institutes of Health expert panel pooh-poohed the possibility that diet had any effect one way or the other on Alzheimer’s. 

Why does this matter?  Five million U.S. adults have Alzheimer dementia already, and it’s going to get much worse over the coming decades.

A June, 2010, issue of Journal of the American Medical Association has a commentary by two doctors (Martha Morris, Sc.D., and Christine Tangney, Ph.D.), experts in the field of nutrition.  Here’s their explanation of the NIH panel’s negative findings:

Many of the inconsistencies among studies of dietary factors can be attributed to the complexity of nutrition science and the omission of nutrition expertise in the design and analysis of both epidemiological and randomized controlled trials.

Morris and Tangney think the findings of Gu et al are valid, confirming prior studies showing benefit to diets high in vitamin E (from food) and low in saturated fat from animals.  They point out that the animal foods may simply be displacing beneficial nutrients in other foods, rather than directly causing harm.

Until we have further data, anyone at risk for Alzhiemer’s may be better off following the dietary pattern above, or the Mediterranean diet.  The two are similar.

Steve Parker, M.D.

Disclaimer:  All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status.  Always consult your personal physican before making any dietary or exercise changes. 

Reference: Morris, M., & Tangney, C. (2010). Diet and Prevention of Alzheimer Disease JAMA: The Journal of the American Medical Association, 303 (24), 2519-2520 DOI: 10.1001/jama.2010.844

The Health on the Net Foundation is asking people to tell them how they use the Internet for health/disease information.  If you’re willing to participate in their survey, click on the the following logo:

You know there’s much misleading information on the Internet regarding health, and most everything else.  I appreciate the Health on the Net Foundation for attempting to certify reliable health information resources, such as this website.

Steve Parker, M.D.

Dr. Shock wrote yesterday about dark chocolate as a treatment for high blood pressure.  Doesn’t look too promising.

Steve Parker, M.D.

Compared to the low-fat American Heart Association diet, the traditional Mediterranean diet rich in olive oil has more capacity to counteract potentially harmful “free radicals” and “reactive oxygen species” in our bodies, according to researchers at the University of Navarra in Spain.

Our tissues normally contain free radicals and reactive oxygen species, which are intrinsic to cell metabolism.  They serve useful purposes.  In excessive amounts, however, many believe they cause ”oxidative damage” and thereby contribute to chronic degenerative conditions such as atherosclerosis, aging, dementia, and cancer.

Antioxidants are thought to neutralize free radicals and reactive oxygen species, which may lead to better health.

The PREDIMED study is an ongoing Spanish project testing the heart-protective effects of the Mediterranean diet in high-risk people over the course of four years.  The three intervention groups are 1) Medi diet plus supplemental virgin olive oil, 2) Medi diet plus extra tree nuts, and 3) low-fat American Heart Association diet.

After three years of follow-up, the researchers measured “total antioxidant capacity” in the bloodstream of a subset of the PREDIMED participants.

They found that the two Mediterranean diet groups had significantly greater total antioxidant capacity, about 50% more than the low-fat control group.  Within the Medi + olive oil group, the participants with the highest levels of antioxidant capacity actually tended to lose weight, an association not seen in the other groups.

The Researchers’ Conclusions

Mediterranean diet, especially rich in virgin olive oil, is associatied with higher levels of plasma antioxidant capactiy.  Plasma total antioxidant capacity is related to a reduction in body weight after three years of intervention in a high cardiovascular risk population with a Mediterranean-style diet rich in virgin olive oil.

In other words, the Mediterranean diet with virgin olive oil may help you keep your weight under control, and the antioxidant capacity may contribute to the well-documented health benefits of the diet.

Steve Parker, M.D.

PS:  It’s impossible to tell from this report just how much weight loss was seen in the high-TAC Medi+olive oil subjects.  I doubt it was much.  Baseline body mass index for all participants was around 29, so they were overweight and just a shade under obese.

PPS:  Both the Ketogenic Mediterranean and Diabetic Mediterranean Diets mandate minimal amounts of olive oil consumption, with no upper limit.

Reference: Razquin, C., Martinez, J., Martinez-Gonzalez, M., Mitjavila, M., Estruch, R., & Marti, A. (2009). A 3 years follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain European Journal of Clinical Nutrition, 63 (12), 1387-1393 DOI: 10.1038/ejcn.2009.106

ORIGINS

It all starts with Ancel  Keys.

Keys was the leader of the team who put together the Seven Countries Study, which seemed to demonstrate lower rates of coronary heart disease in countries consuming less saturated fat.  [Coronary heart disease is the leading cause of death in Western cultures.]  He also found that cardiovascular disease rates rose in tandem with blood cholesterol  levels.  The two countries particularly illustrative of these connections were Italy and Greece, both Mediterranean countries.

The other countries he analyzed in “Seven Countries” were the United States, Yugoslavia, Japan, Finland, and the Netherlands.

Keys and his wife Margaret, a biochemist, drilled deeper in to the “Mediterranean diet” that was characteristic of Italy, Greece, and other countries on or near the Mediterranean Sea in the 1950s and 1960s.  [“Diet” in this context refers to the usual  food and drink of a person, not a weight-loss program.]  Their efforts culminated in the publication of several best-selling Mediterranean diet books in the 1970s, and Keys’ photo on the cover of Time magazine in 1961.

Thus began the still-popular Mediterranean diet.

Oldways Preservation Trust re-invigorated the Mediterranean diet around 1990, helping the public incorporate Mediterranean diet principals into everyday life.  Oldways founder, K. Dun Gifford, passed away just recently.

DEFINITION

There is no monolithic, immutable, traditional Mediterranean diet.  But there are similarities among many of the regional countries that tend to unite them, gastronomically speaking.  Greece and southern Italy are particularly influential in this context.

So here are the characteristics of the traditional, healthy Mediterranean diet  of the mid-20^th century:

•It maximizes natural whole foods and minimizes highly processed ones

•Small amounts of red meat

•Less than four eggs per week

•Low to moderate amounts of poultry and fish

•Daily fresh fruit

•Seasonal locally grown foods with minimal processing

•Concentrated sugars only a few times per week

•Wine in low to moderate amounts, and usually taken at mealtimes

•Milk products (mainly cheese and yogurt) in low to moderate amounts

•Olive oil as the predominant fat

•Abundance of foods from plants: vegetables, fruits, beans, potatoes, nuts, seeds, breads and other whole grain products

•Naturally low in saturated fat, trans fats, and cholesterol

•Naturally high in fiber, phytonutrients, vitamins (e.g., folate), antioxidants, and minerals (especially when compared with concentrated, refined starches and sugars in a modern Western diet)

•Naturally high in monounsaturated and polyunsaturated fats, particularly as a replacement for saturated fats

CONTROVERSIES

Keys has been criticized for “cherry-picking” the data that linked saturated fat consumption with increased heart disease.  Subsequent studies indicate a weak link, if any.  A list of the pertinent studies de-linking heart disease and saturated fat is at the Advanced Mediterranean Diet Blog.

The Seven Countries Study included only men.  It’s practical implications, therefore, may not apply to women.

The traditional Mediterranean diet is increasingly a thing of the past as Mediterranean countries adopt the Western diet characterized by “fast food” and highly processed foods.

FUN FACTS FOR FOOD GEEKS

Ever heard of K rations used by the U.S. military in World War II?  Keys invented them.  He earned Ph.D.s in biology and physiology.  Keys lived to age 100 and was said to be intellectually active through his 97^th year.

Steve Parker, M.D.

References:

Keys, Ancel (1970). Coronary heart disease in seven countries. Circulation, 41

Keys, Ancel.  Coronary heart disease in seven countries.  Circulation, 41, (1970) supplement I: I-1 through I-211.

Keys, Ancel.  Seven Countries:  A Multivariate Analysis of Death and Coronary Artery Disease.  Harvard University Press, 1980.

Oldways website.

For years I’ve been recommending measures to help prevent mental the decline and dementia associated with advanced age.  Measures immediately coming to mind are the Mediterranean diet, exercise, not smoking, avoiding obesity, eating cold-water fatty fish regularly (for the omega-3 fatty acids), and keeping the mind active.

Turns out there’s not much good evidence ( but there’s some) in support of that advice, according to a study commissioned by the National Institutes of Health and published this month in Annals of Internal Medicine.

The investigators did a literature review of the best-designed studies looking for associations between about 45 factors and the risk of cognitive decline in later life.  It’s a little unclear, but this report seems to focus on mild cognitive impairment rather than dementia such as Alzheimer disease.  Mild cognitive impairment is often a precursor to dementia such as Alzheimer disease.  The review included 127 observational studies, 22 randomized controlled trials, and 16 systematic reviews.

The list of cognitive decline risk factors (and protective factors) included the apoliprotein E epsilon-4 gene, smoking, diabetes, physical activity, alcohol consumption, obesity, Mediterranean diet, omega-3 intake, and many others.

For all of the factors, the investigators found insufficient evidence from which to draw firm conclusions.  They are fairly confident that statin drugs and aspirin are not associated with cognitive decline.

They found high-quality evidence for only one factor that protects against cognitive decline: cognitive training (involving memory, reasoning, and speed).

They noted that overall quality of the scientific evidence is low [so there’s hope they missed some protective effects?].

Another report in the same issue of Annals focused on Alzheimer disease and was similarly disappointing in terms of action we can take now to prevent cognitive decline and Alzheimer dementia.  Beaucoup experts and thousands of man-hours were devoted to this report.  Here’s a depressing line:

Currently, firm conclusions cannot be drawn about the association of any modifiable risk factor with cognitive decline or Alzheimer disease.

Now What?

Enjoy life while you can, and plan ahead for possible cognitive decline.

Hope and pray the researchers come up with some solutions soon.  There’s a tsunami of dementia in our future.

I still think the Mediterranean diet (and perhaps some of the other factors analyzed) may be brain-protective, and here’s why.  Note that the reviewers of these studies point out we have “no high-quality studies upon which to base firm conclusions.”  The reviewers gave most credence to randomized controlled trials.  And with good reason: such studies are probably the best way to prove that a medical or dietary intervention is effective.  Observational studies, on the other hand, can point to associations, which may have nothing to do with cause and effect.

Here’s how you do a randomized controlled trial to see if the Mediterranan diet has a long-term effect on cognitive function.  Take 5,000 adults aged 3o to 50 and make half of them eat the Mediterranean diet and the other half eat a specific standard diet.  Keep all other variables the same for both groups.  Over the course of 30-40 years, monitor the changes in cognition in all individuals and compare the two groups.  That study has the potential to yield high-quality data and proof.

Problem is, it’ll probably never be done because it’s close to impossible.  It’s hard enough to get a free-living 40-year-old to follow a new way of eating for 12 weeks, much less 30 years.  That’s why so much population-wide nutrition research is observational.  Most, but not all, of the studies supporting the brain-protective properties of the Mediterranean diet are observational.  I’m not aware of a single randomized controlled study on the long-term cognitive effects of the Mediterranean diet.

And one more thing . . .

The NIH reports at hand didn’t look at the synergy among factors that individually may have only tiny positive effects.  For instance, what if you combine the Mediterranean diet with physical activity, non-smoking, mind-stimulating activities, and avoidance of diabetes and obesity?  Could have a winning combo there! 

Sounds like I’m grasping at straws, doesn’t it?

I’m not prepared yet to abandon idea of the brain-protective Mediterranean diet.

Steve Parker, M.D.

References:

Brenda L. Plassman, PhD; John W. Williams Jr., MD, MHSc; James R. Burke, MD, PhD; Tracey Holsinger, MD; and Sophiya Benjamin, MD (2010). Systematic review: NIH state-of-the-science conference: Factors associated with risk for and possible prevention of cognitive decline in later life.

Annals of Internal Medicine, 152

Daviglus ML, Bell CC, Berrettini W, Bowen PE, Connolly ES Jr, Cox NJ, Dunbar-Jacob JM, Granieri EC, Hunt G, McGarry K, Patel D, Potosky AL, Sanders-Bush E, Silberberg D, & Trevisan M (2010). National Institutes of Health State-of-the-Science Conference Statement: Preventing Alzheimer Disease and Cognitive Decline. Annals of internal medicine PMID: 20547888

“The Declaration of Independence—the “father of all moral principle” in our politics, as Lincoln called it—defines the purpose of government in distinctly limited terms: “To secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed.”  The rights in question are the natural ones to life, liberty, and the pursuit of happiness.  That the Declaration speaks of the pursuit of happiness rather than happiness itself as a right is an important indication of the Founders’ commitment to limited government.  A government that is responsible for sustaining the conditions in which we can pursue happiness is a limited one.  But is is difficult to say what the limits are on a government that is responsible for our happiness iteslf.”

                                          —Matthew J. Franck, professor and chairman of political science at Radford University, writing in National Review, May 17, 2010

Losing excess weight is easier than keeping it off.

Neither is exactly a walk in the park.

Prevention of weight regain is the most problematic area in the field of weight management.  You may have heard that “diets don’t work,” but they do.  Many different weight loss programs work short-term, if “work” is defined as loss of five, 10, or more pounds while you adhere to the program for several weeks or months.  The problem is that the lost pounds usually return.

Why?  You get bored with the diet, or your willpower flags, or the diet simply stops working, or the transition from weight loss to maintenance is unclear, or you just feel too bad to go on, or you lose your commitment, or you take a job as a taste tester for Baskin-Robbins Ice Cream, or whatever. 

Most diets ultimately fail in the long run because people go back to their old habits. 

Read on for the secret to prevention of weight regain.  They apply to a majority of weight-loss methods, although many programs ignore this problem because the cure is a hard pill to swallow. 

Moving Ahead

For purposes of further discussion, I will assume that you have already lost excess weight down to your goal and now we must focus on staying thereabouts from here on out.  Finally down to your goal!  A grand accomplishment!  You’ve got a new wardrobe, or the old clothes fit again.  You have more energy and feel younger.  Maybe you cured or improved some health problems.  Perhaps you’re getting more attention from the opposite sex (ooh la la!). 

Our species’ scientific name is Homo sapiens.  It is from the Latin sapere, which means “to be wise.”  Wisdom is the ability to make correct judgments and decisions.  Undoubtedly, your success at weight loss required correct judgments and decisions.  You are not done yet.  You will need sustained wisdom to avoid weight regain.

Be wise about this especially: you can never again eat all you want, whenever you want, over sustained periods of time.  

Now that you have reached your goal weight, you must restrain yourself on a daily basis.  Think about it.  You became overweight because you didn’t watch what you ate and didn’t exercise enough.  You can’t go back to your old ways.  Reject this advice, and you have a 100 percent chance of regaining your lost weight. 

Have you heard of the Energy Balance Equation?

Calorie Intake minus Calories Burned

         =  Change in Body Fat

You have been able to lose fat weight because you ate less energy (calories) than your body required for metabolism and physical activity.  Your body remedied the energy deficit by converting fat into energy.  A pound of fat contains 3,500 calories of energy.  If you lost a pound per week, your body on average converted 500 calories of fat daily into energy (7 days x 500 calories = 3,500 calories = 1 pound of fat). 

Now that you are at your goal weight and want to stay there, you need to add 500 calories per day back into the equation.  Add the calories by eating more food, exercising less, or a combination of the two. But if you add back more than 500, you will regain weight.

The true measure of a successful weight management program is not simply how much weight is lost, but whether the lost weight stays lost over the long run.  What distinguishes weight losers who keep the weight off from those who gain it back?  Two factors, mostly:

          1.  Restrained eating
          2.  Regular physical activity.

“Successful losers” apply self-restraint on an almost daily basis, avoiding food that they know will lead to weight regain.  They limit how much they eat.  They consciously choose not to return to their old eating habits, despite urges to the contrary.  The other glaring difference is that, compared to regainers, the successful losers remain physically active.  They exercised while losing weight, and continue to exercise in the maintenance phase of their program.  This is true in at least eight out of 10 cases.  It’s clear that regular exercise is not always needed, but it dramatically increases your chances of long-term success. 

In a nutshell, my maintenance phase prescription for you is: Keep exercising, and eat a little more.  Keep exercising, and eat a little more.

Go out of your way to be physically active for 30 to 45 minutes on at least four days per week, if not all days.  Walking is fine.  The more you exercise, the more you can eat without getting fat again. 

At the end of your weight-loss phase and the beginning of the maintenance phase, it is surprisingly easy to start overeating.  Forewarned is forearmed.  Avoid this landmine any way you can.  It helps to continue monitoring food consumption and exercise on your food diary while eating an additional 200–500 calories per day.  Continue weighing daily.  Keep exercising.  After a month or two of this regimen, you’ll have an intuitive sense of what and how much you should be eating without regaining weight.  Then stop the daily log routine. 

Another option for transition to the maintenance phase: if you have been exercising regularly but loathe it, you could stop exercising and stay on your current calorie level diet.  In other words, don’t start eating more.  See what happens with your weight.  Perhaps you could later eat an extra 100 to 200 daily calories without gaining weight.  Continue recording your daily intake and weight for a couple months.  

Weigh yourself daily during the first two months of your maintenance-of-weight-loss phase. After that, weigh weekly.  Daily weights will remind you how hard you worked to achieve your goal.  When you look now at a brownie, candy bar, or piece of pie, you ask yourself, “Do I really want to walk an extra hour or jog an extra three miles today to burn off those calories?” If so, enjoy. Otherwise, forego the unneeded calories. 

Be aware that you might regain five or 10 pounds of fat now and then.  You probably will.  It’s not the end of the world.  It’s human nature.  You’re not a failure; you’re human.  

But draw the line and get back on your old weight-loss program for one or two months.  Analyze and learn from the episode.  Why did it happen?  Slipping back into your old ways? Slacking off on exercise?  Too many special occasion feasts?  Allowing junk food back into the house?  Learn which food item is your nemesis—the food that consistently torpedoes your resolve to eat right.  For example, I have two—candy, and sweet baked goods such as cookies and muffins.  If I just look at them I add a pound.  Remember an old ad campaign for a potato chip: “Betcha can’t eat just one!”?  Well, I can’t eat just one cookie.  So I don’t get started.  I might eat one if it’s the last one available.  Or I satisfy my sweet craving with fresh fruit or a diet soda.  Just as a recovering alcoholic can’t drink any alcohol, perhaps you should totally abstain from…?  You know your own personal gastronomic Achilles heel.  Or heels.  Experiment with various strategies for vanquishing your nemesis. 

It’s OK to overindulge in food infrequently (10–12 times per year), on special occasions such as birthdays, wedding anniversaries, holidays.  But you must counteract the extra calories by cutting down intake or by exercising more, either before or after the feast.  No big deal.

Click to read additional ideas on prevention of weight regain.

Steve Parker, M.D.

We have a guest post today, from Matthew Papaconstantinou, Ph.D.  Dr. P was born and raised in Greece.  As a biologist and native of the Mediterranean basin, he closely follows the latest research on the health benefits of the Mediterranean Diet and its use as part of a behavioral weight loss program.  He has a blog at his website, WeightLossTriumph.com.

**********

As a result of the rapid rise in obesity during the last decade, it is now estimated that one-half of all US adults are overweight or obese [1].  These statistics reflect in the number of gastric bypass surgeries, which skyrocketed from 20,000 in 1995 to 171,000 in 2005.

Although surgical and pharmacological interventions have been successful in treating obesity and preventing its commorbidities, behavioral weight loss approaches that focus on diet and exercise are considered the most effective treatments for obese people.

Behavioral weight loss programs aim at helping participants modify their eating and exercise habits through a number of educative sessions with nutritionists, exercise physiologists and behavioral therapists. However, for the treatments to be effective, the patients must complete the program.  Attrition is one of the major problems of behavioral programs as the number of people who drop out can be as high as 80%.

Using The Mediterranean Diet (MD) as Part of Behavioral Weight Loss Treatment

A recent study by Corbalan et al. evaluated the effectiveness of a behavioral therapy program that was based on the principles of the MD for treatment of obesity [2]. The purpose of this study was to assess whether this program can help participants lose weight and to determine the main obstacles to weight loss.

Why The MD?

Why did they choose the MD as part of this behavioral program? Well, an extensive body of scientific research has shown that the MD is related to lower occurrence of obesity.

MD Promotes Weight Loss

The ATTICA study is a good example [3].  This study, conducted in 2006, evaluated the nutritional habits of 3042 inhabitants of the province of Attica (Athens, Greece), by means of a diet score that incorporated the inherent characteristics of this diet. An inverse correlation between Body Mass Index (BMI) and adherence to the MD was observed—the higher the MD score, the lower the prevalence of overweight, obesity, and central adiposity was.

Of course, it has been suggested that it is not the MD that protects people from obesity, but other aspects of the MD lifestyle (i.e, engagement in outdoor activities, less stress, etc) that may lower BMI levels. Interestingly, the Attica study found that the inverse association between MD adherence and obesity holds true even after adjusting for potential confounders, such as physical activity status. This is a great indication that the Mediterranean diet alone protects against obesity.

It is interesting to note here that, for the majority of the Mediterranean basin inhabitants, the dietary intake is nowadays far from the MD dietary recommendations. This explains why 27% of males and 39% of females living today in the Greek Mediterranean islands are obese [4]. Forty years ago, farmers from the island of Crete had one of the healthiest lifestyles compared to other participants of the “Seven Countries Study” [5]. Today, mean weight has increased by 44lb, placing more than 80% of Cretan farmers in either the obese or overweight category [6].

The Study

But lets continue on the objective of the Corbalan study. Can an MD-based cognitive behavioral therapy be used for the treatment of obesity? What are the main obstacles to weight loss in a Mediterranean population?

This study recruited 1406 Spanish people who were all overweight or obese, aged 20-65 years old. The program lasted for 34 weeks and consisted of 4 components.

• Behavioral techniques—keeping dietary records and change the immediate environment in a way that is conducive to weight loss
• Physical activity—30 minute moderate intensity activity, 3 times a week (10,000 steps a day)
• Nutritional education—basic concepts in nutrition
• Diet—the Mediterranean Diet

Participants consumed 1351 calories per day. This was 67% of their normal daily energy intake, before the program began.  The macronutrient components of the MD were 30-35% fat, 50% carbs, and 15-20% protein and the participants were instructed to use olive oil as the only source of cooking fat. The subjects were also advised to consume at least 300 g of fruits and unrestricted amount of vegetables.

The Results

At the end of the treatment, participants lost on average 17.2 lb. The attrition was as low as 4%, which shows that the participation and adherence was far superior than that observed for other cognitive-behavioral techniques.

Based on a questionnaire that the subjects completed, a “Barriers to Weight Loss” score was calculated, which allowed the investigators to identify which were the main barriers to losing weight. “Loss of motivation”, “stress-related eating” and “eating when bored” were the most common obstacles experienced by those who did not achieve their weight loss goal.

On the other hand, those who succeeded by losing at least 10% of their initial weight, adopted the habit of “writing down absolutely everything”. This allowed them to be aware of what they were eating, control their behavior and monitor their progress.

Conclusion

The study concluded that “behavioral therapy, accompanied by food habit control, caloric reduction, and balanced nutrient distribution based on the Mediterranean diet is useful for weight loss and the improvement of certain alterations associated with obesity.”

This is the first study to show that a dietary/behavioral treatment based on the MD is effective and can be used in clinical practice.

References

1. Flegal KM, Carroll MD, Kuczmarski RJ, Johnson CL: Overweight and obesity in the United States: prevalence and trends, 1960-1994. Int J Obes 22:39-47, 1998.
2. Effectiveness of cognitive-behavioral therapy based on the Mediterranean diet for the treatment of obesity. Corbalán MD, Morales EM, Canteras M, Espallardo A, Hernández T, Garaulet M. Nutrition. 2009 Jul-Aug;25(7-8):861-9.
3. Association between the prevalence of obesity and adherence to the Mediterranean diet: the ATTICA study. Panagiotakos DB, Chrysohoou C, Pitsavos C, Stefanadis C. Nutrition. 2006 May;22(5):449-56. Epub 2006 Feb 2.
4. Nutrient intake in relation to central and overall obesity status among elderly people living in the Mediterranean islands: The MEDIS study. Tyrovolas S, Psaltopoulou T, Pounis G, Papairakleous N, Bountziouka V, Zeimbekis A, Gotsis E, Antonopoulou M, Metallinos G, Polychronopoulos E, Lionis C, Panagiotakos DB.
5. Keys A, Blackburn H, Menotti A, Buzina R, Mohacek I, Karvonen MJ, et al. Coronary heart disease in seven countries. Circulation 1970;41(Suppl. 1):1e211.
6. Prevalence of obesity and physical inactivity among farmers from Crete (Greece), four decades after the Seven Countries Study.Vardavas CI, Linardakis MK, Hatzis CM, Saris WH, Kafatos AG.

The Mediterranean diet preserves heart muscle performance and reduces future heart disease events, according to Greek researchers reporting in the American Journal of Clinical Nutrition, May 19, 2010.

Reuters and other news services have covered the story.

The Mediterranean diet is well-established as an eating pattern that reduces the risk of death or illness related to cardiovascular disease—mostly heart attacks and strokes.  Most of the studies in support of the heart-healthy diet looked at development of disease in general populations.  The study at hand examined whether the diet had any effect on patients with known heart disease, which has not been studied much.

How Was the Study Done? 

 The study population was 1,000 consecutive patients admitted with heart disease to a Greek hospital between 2006 and 2009.  In this context, heart disease refers to a first or recurrent heart attack (70-80% of participants) or unstable angina pectoris.  Acute heart attacks and unstable angina are “acute coronary syndromes.”  Average age was 64.  Sixty percent had a prior diagnosis of cardiovascular disease (coronary heart disease or stroke).  Thirty percent had diabetes.  At the time of hospitalization, half had diminished function of the main heart pumping chamber (the left ventricle), half had normal pump function.  Men totalled 788; women 212.

On the third hospital day, participants were given a 75-item food frequency questionnaire asking about consumption over the prior year.  If a potential enrollee died in the first two hospital days, he was not included in the study.  A Mediterranean diet score was calculated to determine adherence to the Mediterranean diet.  Mediterranean diet items were nonrefined cereals and products, fruits, nuts, vegetables, potatoes, dairy products, fish and seafood, poultry, red meats and meat products, olive oil, and alcohol. 

Left ventricle function was determined by echocardiogram (ultrasound) at the time of study entry, at the time of hospital discharge, and three months after discharge.  Systolic dysfunction was defined as an ejection fraction of under 40%.  [Normal is 65%: when the left ventricle is full of blood, and then squeezes on that blood to pump it into the aorta, 65% of the blood squirts out.]

Participants were then divided into two groups: preserved (normal) systolic left ventricular function, or diminished left ventricular function. 

They were followed over the next two years, with attention to cardiovascular disease events (not clearly defined in the article, but I assume including heart attacks, strokes, unstable angina, coronary revascularization, heart failure, arrhythmia, and death from heart disease or stroke.

Results

• Four percent of participants died during the initial hospitalization.
• At the three month follow-up visit, those with greater adherence to the Mediterranean diet (a high Mediterranean diet score) had higher left ventricular performance (P=0.02).
• At the time of hospital admission, higher ejection fractions were associated with greater adherence to the Mediterranean diet (P<0.001).
• Those who developed diminished left ventricular dysfunction had a lower Mediterranean diet score (P<0.001)
• During the hospital stay, those in the highest third of Mediterranean diet score had lower in-hospital deaths (compared with the lower third scores) (P=0.009).
• Among those who survived the initial hospitalization, there was no differences in fatal cardiovascular outcomes based on Mediterranean diet score.
• Food-specific analysis tended to favor better cardiovascular health (at two-year follow-up) for those with higher “vegetable and salad”  and nut consumption.  No significant effect was found for other components of the Mediterranean diet score.
• Of those in the highest third of Mediterranean adherence, 75% had avoided additional fatal and nonfatal cardiovasclar disease events as measured at two years.  Of those in the lowest third of Mediterranean diet score, only 53% avoided additional cardiovascular disease events.   

The Authors’ Conclusion

Greater adherence to the Mediterranean diet seems to preserve left ventricular systolic function and is associated with better long-term prognosis of patients who have had an acute coronary syndrome.

My Comments

I agree with the authors’ conclusion.

We’re assuming these patients didn’t change their way of eating after the initial hospitalization.  We don’t know that.  No information is given regarding dietary instruction of these patients while they were hospitalized.  In the U.S., such instruction is usually given, and it varies quite a bit.

In this study, lower risk of cardiovascular death was linked to the Mediterranean diet only during the initial hospital stay.  Most experts on the Mediterranean diet would have predicted lower cardiovascular death rates over the subsequent two years.  Mysteriously, the authors don’t bother to discuss this finding.

For those who don’t enjoy red wine or other alcoholic beverages, this study suggests that the Mediterranean diet may be just as heart-healthy without  alcohol.  A 2009 study by Trichopoulou et al suggests otherwise.

Steve Parker, M.D.

Reference:
Chrysohoou, C., Panagiotakos, D., Aggelopoulos, P., Kastorini, C., Kehagia, I., Pitsavos, C., & Stefanadis, C. (2010). The Mediterranean diet contributes to the preservation of left ventricular systolic function and to the long-term favorable prognosis of patients who have had an acute coronary event American Journal of Clinical Nutrition DOI: 10.3945/ajcn.2009.28982