Tag Archives: Mediterranean Diet

Asian Strokes Are Not Same as Western

The higher the consumption of saturated fat, the lower the risk of death from stroke, according to Japanese researchers in a recent American Journal of Clinical Nutrition

Most physicians in the West would have predicted the opposite: saturated fats increase your risk of stroke.  Western physicians tend to think most strokes and heart attacks are caused by the same process, atherosclerosis, and would be aggravated by saturated fat consumption.  We’re learning that ain’t necessarily so.

Most strokes in the Western world are thought to be linked to atherosclerosis (hardening of the arteries) of relatively large arteries. In Japan, most strokes not caused by bleeding in the head are actually lacunar infarctions involving small arteries in the brain, not necessarily involving atherosclerosis

Another major difference between East and West is that saturated fat consumption in Japan is far lower than in the West.

Are you confused yet?

It seems to me that comparing strokes in Japan versus the West is comparing apples to oranges.  The take-away point to me is that we have to be quite wary of generalizing the research results applicable to one culture or ethnic group, to others.

By the way, stroke had been the third leading cause of death in the U.S. for the last 50 years.  It was recently demoted to fourth place by chronic lower respiratory disease.  The traditional Mediterranean diet is one way to reduce your risk of stroke, and the DASH diet works for women.  Keeping your blood pressure under 140/90 is another.  And don’t smoke.

Steve Parker, M.D.

Reference:  Yamagishi, Kazumasa, et al.  Dietary intake of saturated fatty acids and mortality from cardiovascular disease in Japanese: the Japan Collaborative Cohort Study for Evaluation of Cancer Risk Study.  American Journal of Clinical Nutrition, August 4, 2010.  doi: 10.3945/ajcn.2009.29146

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Mediterranean Diet Prevents Middle-Age Weight Gain? Yeah, Right…

Several mainstream media sources recently touted the Mediterranean diet as an effective method for prevention of the expected middle-age weight gain.  Reuters is one source, for example.  Men on the Mediterranean diet gained 2 lb (about a kilogram) less than other men over six years.  Mediterranean-dieting women gained weight too, but a whole 0.77 lb (0.35 kg) less than others.

Big whoop.

The media attention was based on a Spanish study of over 10,000 men and women university graduates over the course of six years.  Average baseline age was 38.  A Mediterranean diet score was calculated based on a food frequency questionnaire given only at the start of the study.  Adherence with a Mediterranean-style diet was judged for each individual as either low, medium, or high.

You’d think this research report would tell you how much weight these folks gained on average over six years, and how manypounds less if one followed the Mediterranean diet.  Think again.  No such luck, which reminds me of one of my favorite aphorisms: “eschew obfuscation.”

I had to do my own calculations based on Table 3.  And I still don’t know how much the average person in this cohort gained over six years.

I am a die-hard Mediterranean diet advocate.  It’s linked to myriad health benefits.  I’d love to believe it prevents middle-age weight gain.  But the results of this study are so modest as to be almost nonexistent.

Steve Parker, M.D.

Reference:  Beunza, J., et al.  Adherence to the Mediterranean diet, long-term weight change, and incident overweight  or obesity: The Seguimiento Universidad de Navarra (SUN) cohortAmerican Journal of Clinical Nutrition.  doi: 10.3945/ajcn.2010.29764

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Mediterranean Diet Prevents Diabetes – Again

Spanish researchers report that the Mediterranean diet reduced the risk of developing diabetes by 50% in middle-aged and older Spaniards, compared with a low-fat diet. 

Over 400 people participated in a trial comparing two Mediterranean diets and a low-fat diet.  Over the course of four years, 10 or 11% of the Mediterraneans developed type 2 diabetes, compared to 18% of the low-fatters.  One of the Mediterranean diets favored olive oil, the other promoted nut consumption.

We’ve seen previously that the Mediterranean diet prevents diabetes—not all cases, of course—in folks who have had a heart attack.  It also reduced the risk of diabetes in younger, generally healthy people in Spain.

So What?

The study at hand is not ground-breaking.  It enhances the body of evidence that the Mediterranean diet is one of the healthiest around.  I suppose another way to look at this study would be to say that the low-fat diet caused diabetes.

Learn how to move your diet in a Mediterranean direction at Oldways or the Advanced Mediterranean Diet website. 

Diabetics and prediabetics should consider the Low-Carb Mediterranean Diet; otherwise look into the Advanced Mediterranean Diet if you need to lose weight.

Steve Parker, M.D.

Reference:  Salas-Salvado, Jordi, et al.  Reduction in the incidence of type 2 diabetes with the Mediterranean diet: Results of the PREDIMED-Reus Nutrition Intervention Randomized Trial.  Diabetes Care, epub ahead of print, October 7, 2010.  doi: 10.2337/dc150-1288

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Filed under Causes of Diabetes, Health Benefits, Mediterranean Diet, Prevention of T2 Diabetes

Book Review: Why We Get Fat

Gary Taubes’s new book, Why We Get Fat: And What To Do About It, comes on the market later this month.  I give it five stars per Amazon.com’s ranking system (I love it).

♦   ♦   ♦

At the start of my medical career over two decades ago, many of my overweight patients were convinced they had a hormone problem causing it.  I carefully explained that’s rarely the case.  As it turns out, I may have been wrong.  And the hormone is insulin.

Mr. Taubes wrote this long-awaited book for two reasons: 1) to make the ideas in his 2007 masterpiece (Good Calories, Bad Calories) more accessible to the public, and 2) to speed up the process of changing conventional wisdom on overweight.  GCBC was the equivalent of a college-level course on nutrition, genetics, history, politics, science, physiology, and biochemistry. Many nutrition science geeks loved it while recognizing it was too difficult for the average person to digest.

Paradigm Shift

The author hopes to convince us that “We don’t get fat because we overeat; we overeat because we’re getting fat.”  We need to think of obesity as a disorder of excess fat accumulation, then ask why the fat tissue isn’t regulated properly.  A limited number of hormones and enzymes regulate fat storage; what’s the problem with them?

Mr. Taubes makes a great effort convince you the old “energy balance equation” doesn’t apply to fat storage.  You remember the equation: eat too many calories and you get fat, or fail to burn up enough calories with metabolism and exercise, and you get fat.  To lose fat, eat less and exercise more.  He prefers to call it the “calories-in/calories-out” theory.  He admits it has at least a little validity.  Problem is, the theory seems to have an awfully high failure rate when applied to weight management over the long run.  We’ve operated under that theory for the last half century, but keep getting fatter and fatter.  So the theory must be wrong on the face of it, right?  Is there a better one?

So, Why DO We Get Fat?

Here is Taubes’s explanation.  The hormone in charge of fat strorage is insulin; it works to make us fatter, building fat tissue.  If you’ve got too much fat, you must have too much insulin action.  And what drives insulin secretion from your pancreas?  Dietary carbohydrates, especially refined carbs such as sugars, flour, cereal grains, starchy vegetables (e.g., corn, beans, rice, potatoes), liquid carbs.  These are the “fattening carbs.”  Dozens of enzymes and hormones are at play either depositing fat into tissue, or mobilizing the fat to be used as energy.  It’s an active process going on continously.  Any regulatory derangement that favors fat accumulation will CAUSE gluttony (overeating) or sloth (inactivity).  So it’s not your fault. 

What To Do About It

Cut back on carb consumption to lower your fat-producing insulin levels, and you turn fat accumulation into fat mobilization.

Before you write off Taubes as a fly-by-night crackpot, be aware that he’s received three Science-in-Society Journalism Awards from the National Association of Science Writers.  He’s a respected, professional science writer.  Having read two of his books, it’s clear to me he’s very intelligent.  If he’s got a hidden agenda, it’s well hidden.

One example  illustrates how hormones control growth of tissues, including fat tissue.  Consider the transformation of a skinny 11-year-old girl into a voluptuous woman of 18. Various hormones make her grow and accumulate fat in the places we now see curves.  The hormones make her eat more, and they control the final product.  The girl has no choice.  Same with our adult fat tissue, but with different hormones. If some derangement is making us grow fatter, it’s going to make us more sedentary (so more energy can be diverted to fat tissue) or make us overeat, or both.  We can’t fight it.  At not least very well, as you can readily appreciate if look at the people around you at any American shopping mall.

This’N’That

Taubes’s writing is clear and persuasive.  He doesn’t beat you over the head with his conclusions. He lays out a logical series of facts and potential connections and explanations, helping you eventually see things his way.  If insulin controls fat storage by building and maintaining fat tissue, and if carboydrates drive insulin secretion, then the way to reduce overweight and obesity is carbohydrate-restricted eating, especially avoiding the fattening carbohydrates.  I’m sure that’s true for many folks, perhaps even a majority.

If you’re overweight and skeptical about this approach, you could try out a very-low-carb diet for a couple weeks or a month at little expense and risk (but not zero risk).  If Mr. Taubes and I are right, there’s a good chance you’ll lose weight.  At the back of the book is a university-affiliated low-carb eating plan.

If cutting carb consumption is so critical for long-term weight control, why is it that so many different diets—with no focus on carb restriction—seem to work, if only for the short run?  Taubes suggests it’s because nearly all diets reduce carb consumption to some degree, including the fattening carbs.  If you reduce your total daily calories by 500, for example, many of those calories will be from carbs.  Simply deciding to “eat healthy” works for some people: stopping soda pop, candy bars, cookies, desserts, beer, etc.  That cuts a lot of fattening carbs right there.

Losing excess weight or controlling weight by avoiding carbohydrates was the conventional wisdom prior to 1960, as documented by Mr. Taubes.  Low-carb diets for obesity date back almost 200 years.  The author attributes many of his ideas to German internist Gustav von Bergmann (1908).   

Taubes discusses the Paleolithic diet, mentioning that the average paleo diet derived about a third of total calories from carbohdyrates (compared to the standard American diet’s 55% of calories from carb).  My prior literature review  found 40-45% of paleo diet calories from carbohydrate.  I’m not sure who’s right.

Minor Bone of Contention RE: Coronary Heart Disease

Mr. Taubes provides numerous scientific references to back his assertions.  I checked out one in particular because it didn’t sound right.  Some background first. 

Reducing our total fat and saturated fat consumption over the last 40 years was supposed to lower our LDL cholesterol, thereby reducing the burden of coronary heart disease, which causes heart attacks.  Instead, we’ve experienced the obesity epidemic as those fats were replaced by carbohydrates.  Taubes mentions a 2009 medical journal article by Kuklina et al, in which Taubes says Kuklina points out the number of heart attacks has not decreased as we’ve made these diet changes.  Kuklina et al don’t say that.  In fact, age-standardized heart attack rates have decreased in the U.S. during the last decade. 

Furthermore, autopsy data document a reduced prevalence of anatomic coronary heart disease in people aged 20-59 from 1979 to 1994, but no change in prevalence for those over 60. The incidence of coronary heart disease decreased in the U.S. from 1971 to 1998 (the latest reliable data).  Death rates from heart disease and stroke have been decreasing steadily over the last 40 years in the U.S.; coronary heart disease death rates are down by 50%.  I do agree with Taubes that we shouldn’t credit those improvements to reduced total and saturated fat consumption.  [Reduced trans fat consumption may play a role, but that’s off-topic.] 

I think Mr. Taubes would like to believe that coronary artery disease is either more severe or unchanged in the last few decades because of low-fat, high-carb eating.  That would fit nicely with some of his theories, but it’s not the case.  Coronary artery disease is better now thanks to a variety of factors, but probably not diet (setting aside the trans-fat issue).

Going Forward

Low-carb dieting was vilified over the last half century partly out of concern that the accompanying high fat consumption would cause premature heart attacks, strokes, and death.  We know now that total dietary fat and saturated fat have little to do with coronary heart disease and atherosclerosis (hardening of the arteries), which sets the stage for a resurgence of low-carb eating.  

I advocate Mediterranean-style eating as the healthiest, in general.  It’s linked with prolonged life and lower risk of heart disease, stroke, dementia, diabetes, and cancer.  On the other hand, obesity is a strong risk factor for premature death and development of heart disease, stroke, diabetes, and cancer.  If consistent low-carb eating cures the obesity, is it healthier than the Mediterranean diet?  Maybe so.  Would a combination of low-carb and Mediterranean be better?  Maybe so.  I’m certain Mr. Taubes would welcome a decades-long interventional study comparing low-carb with the Mediterranean diet.  But that’s probably not going to happen in our lifetimes. 

Gary Taubes rejects the calories-in/calories-out theory of overweight that hasn’t done a very good job for us over the last 40 years.  Taubes’s alternative ideas deserve serious consideration.

Steve Parker, M.D.

Update December 18, 2010: I found Mr. Taubes’s reference for stating that Paleolithic diets provide about a third of calories from carbohydrate (22-40%), based on modern hunter-gatherer societies).  See References below.   

References:
Coronary heart disease autopsy data:  American Journal of Medicine, 110 (2001): 267-273.
Reduced heart attacks:  Circulation, 12 (2010): 1,322-1,328.
Reduced incidence of coronary heart disease:  www.UpToDate.com, topic: “Epidemiology of Coronary Heart Disease,” accessed December 11, 2010.
Death rates for coronary heart disease:  Journal of the American Medical Association, 294 (2005): 1,255-1,259.

Cordain, L., et al.  Plant-animal subsistance ratios and macronutrient energy estimations in worldwide hunter-gatherer dietsAmerican Journal of Clinical Nutrition, 71 (2000): 682-692.

Disclosure:  I don’t know Gary Taubes.  I requested from the publisher and received a free advance review copy of the book.  Otherwise I received nothing of value for this review.

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 physician before making any dietary or exercise changes.

Update April 22, 2013

As mentioned above, WWGF was based on Taubes’ 2007 book, Good Calories, Bad Calories. You may be interested in a highly critical review of GCBC by Seth at The Science of Nutrition.

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Filed under Book Reviews, coronary heart disease, Fat in Diet, Mediterranean Diet

Heart Patients, Listen Up: Mediterranean Diet to the Rescue

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., et al.  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 eventAmerican Journal of Clinical Nutrition, May 10, 2010.  doi:10.3945/ajcn.2009.28982

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Health Benefits of the Mediterranean Diet

The enduring popularity of the Mediterranean diet is attributable to three things:

1.       Taste

2.       Variety

3.       Health benefits

For our purposes today, I use “diet” to refer to the usual food and drink of a person, not a weight-loss program.

The scientist most responsible for the popularity of the diet, Ancel Keys, thought the heart-healthy aspects of the diet related to low saturated fat consumption.  He also thought the lower blood cholesterol levels in Mediterranean populations (at least Italy and Greece) had something to do with it, too.  Dietary saturated fat does tend to raise cholesterol levels.

Even if Keys was wrong about saturated fat and cholesterol levels being positively associated with heart disease, numerous studies (involving eight countries on three continents) strongly suggest that the Mediterranean diet is one of the healthiest around.  See References below for the most recent studies.

Relatively strong evidence supports the Mediterranean diet’s association with:

■ increased lifespan

■ lower rates of cardiovascular disease such as heart attacks and strokes

■ lower rates of cancer (prostate, breast, uterus, colon)

■ lower rates of dementia

■ lower incidence of type 2 diabetes

Weaker supporting evidence links the Mediterranean diet with:

■ slowed progression of dementia

■ prevention of cutaneous melanoma

■ lower severity of type 2 diabetes, as judged by diabetic drug usage and fasting blood sugars

■ less risk of developing obesity

■ better blood pressure control in the elderly

■ improved weight loss and weight control in type 2 diabetics

■ improved control of asthma

■  reduced risk of developing diabetes after a heart attack

■ reduced risk of mild cognitive impairment

■  prolonged life of Alzheimer disease patients

■ lower rates and severity of chronic obstructive pulmonary disease

■ lower risk of gastric (stomach) cancer

■ less risk of macular degeneration

■ less Parkinsons disease

■ increased chance of pregnancy in women undergoing fertility treatment

■  reduced prevalence of metabolic syndrome (when supplemented with nuts)

■ lower incidence of asthma and allergy-like symptoms in children of women who followed the Mediterranean diet while pregnant

Did you notice that I used the word “association” in relating the Mediterranean diet to health outcomes?  Association, of course, is not causation. 

The way to prove that a particular diet is healthier is to take 20,000 similar young adults, randomize the individuals in an interventional study to eat one of two test diets for the next 60 years, monitoring them for the development of various diseases and death.  Make sure they stay on the assigned test diet.  Then you’d have an answer for that population and those two diets.  Then you have to compare the winning diet to yet other diets.  And a study done in Caucasians would not necessarily apply to Asians, Native Americans, Blacks, or Hispanics.

Now you begin to see why scientists tend to rely on observational  rather than interventional diet studies.

I became quite interested in nutrition around the turn of the century as my patients asked me for dietary advice to help them lose weight and control or prevent various diseases.  At that time, the Atkins diet, Mediterranean diet, and Dr. Dean Ornish’s vegetarian program for heart patients were all popular.  And you couldn’t pick three programs with more differences!  So I had my work cut out for me. 

After much scientific literature review, I find the Mediterranean diet to be the healthiest for the general population.  People with particular medical problems or ethnicities may do better on another diet.  People with diabetes or prediabetes are probably better off with a carbohydrate-restricted diet, such as the Low-Carb Mediterranean Diet

Dan Buettner makes a good argument for plant-based diets in his longevity book, The Blue Zones.  The Mediterranean diet qualifies as plant-based.

What do you consider the overall healthiest diet, and why?

Steve Parker, M.D.

References:

Sofi, Francesco, et al.  Accruing evidence about benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysisAmerican Journal of Clinical Nutrition, ePub ahead of print, September 1, 2010.  doi: 10.3945/ajcn.2010.29673

Buckland, Genevieve, et al.  Adherence to a Mediterranean diet and risk of gastric adenocarcinoma within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort studyAmerican Journal of Clinical Nutrition, December 9, 2009, epub ahead of print.  doi: 10.3945/ajcn.2009.28209

Fortes, C., et al.  A protective effect of the Mediterraenan diet for cutaneous melanoma.  International Journal of Epidmiology, 37 (2008): 1,018-1,029.

Sofi, Francesco, et al.  Adherence to Mediterranean diet and health status: Meta-analysis.  British Medical Journal, 337; a1344.  Published online September 11, 2008.  doi:10.1136/bmj.a1344

Benetou, V., et al.  Conformity to traditional Mediterranean diet and cancer incidence: the Greek EPIC cohort.  British Journal of Cancer, 99 (2008): 191-195.

Mitrou, Panagiota N., et al.  Mediterranean Dietary Pattern and Prediction of All-Cause Mortality in a US Population,  Archives of Internal Medicine, 167 (2007): 2461-2468.

Feart, Catherine, et al.  Adherence to a Mediterranean diet, cognitive decline, and risk of dementia.  Journal of the American Medical Association, 302 (2009): 638-648.

Scarmeas, Nikolaos, et al.  Physical activity, diet, and risk of Alzheimer Disease.  Journal of the American Medical Association, 302 (2009): 627-637.

Scarmeas, Nikolaos, et al.  Mediterranean Diet and Mild Cognitive Impairment.  Archives of Neurology, 66 (2009): 216-225.

Scarmeas, N., et al.  Mediterranean diet and Alzheimer disease mortality.  Neurology, 69 (2007):1,084-1,093.

Fung, Teresa, et al.  Mediterranean diet and incidence of and mortality from coronary heart disease and stroke in women.  Circulation, 119 (2009): 1,093-1,100.

Mente, Andrew, et al.  A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart DiseaseArchives of Internal Medicine, 169 (2009): 659-669.

Salas-Salvado, Jordi, et al.  Effect of a Mediterranean Diet Supplemented With Nuts on Metabolic Syndrome Status: One-Year Results of the PREDIMED Randomized Trial.  Archives of Internal Medicine, 168 (2008): 2,449-2,458.

Mozaffarian, Dariush, et al.  Incidence of new-onset diabetes and impaired fasting glucose in patients with recent myocardial infarction and the effect of clinical and lifestyle risk factors.  Lancet, 370 (2007) 667-675.

Esposito, Katherine, et al.  Effects of a Mediterranean-style diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetesAnnals of Internal Medicine, 151 (2009): 306-314.

Shai, Iris, et al.  Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet.  New England Journal of Medicine, 359 (2008): 229-241.

Martinez-Gonzalez, M.A., et al.  Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study.  British Medical Journal, BMJ,doi:10.1136/bmj.39561.501007.BE (published online May 29, 2008).

Trichopoulou, Antonia, et al.  Anatomy of health effects of the Mediterranean diet: Greek EPIC prospective cohort studyBritish Medical Journal, 338 (2009): b2337.  DOI: 10.1136/bmj.b2337.

Barros, R., et al.  Adherence to the Mediterranean diet and fresh fruit intake are associated with improved asthma control.  Allergy, vol. 63 (2008): 917-923.

Varraso, Raphaelle, et al.  Prospective study of dietary patterns and chronic obstructive pulmonary disease among US men.  Thorax, vol. 62, (2007): 786-791

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THIS Is Why I Love the Mediterranean Diet

Italian researchers reviewed the medical/nutrition literature of the last three years and confirmed that the Mediterranean diet 1) reduces the risk of death, 2) reduces  heart disease illness and death, 3) cuts the risk of getting or dying from cancer, and 4) diminishes the odds of developing dementia, Parkinsons disease, stroke, and mild cognitive impairment.

These same investigators published a similar meta-analysis in 2008, looking at 12 studies.  Over the ensuing three years (as of June, 2010), seven new prospective cohort studies looked at the health benefits of the Mediterranean diet.  The report at hand is a combination of all 19 studies, covering over 2,000,000 participants followed for four to 20 years.  Nine of the 19 Mediterranean diet studies were done in Europe.

The newer studies, in particular, firmed up the diet’s protective effect against stroke, and added protection against mild cognitive impairment.

So What?

The Mediterranean diet: No other way of eating has so much scientific evidence that it’s healthy and worthy of adoption by the general population.  Not the DASH diet, not the “prudent diet,” not the American Heart Association diet, not vegetarian diets, not vegan diets, not raw-food diets, not Esselstyne’s diet, not Ornish’s diet, not Atkins diet, not Oprah’s latest diet, not the Standard American Diet, not the  . . . you name it. 

Not even the Low-Carb Mediterranean Diet.

Just as important, the research shows you don’t have to go full-bore Mediterranean to gain a health and longevity benefit.  Adopting  just a couple Mediterranean diet features yeilds a modest but sigificant gain.  For a list of Mediterranean diet components, visit Oldways or the Advanced Mediterranean Diet website. 

Steve Parker, M.D.

Reference:  Sofi, Francesco, et al.  Accruing evidence about benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis.  American Journal of Clinical Nutrition, ePub ahead of print, September 1, 2010.  doi: 10.3945/ajcn.2010.29673

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Paleo Diet for Heart Patients With Diabetes and Prediabetes

A Paleolithic diet lowered blood sugar levels better than a control diet in coronary heart disease patients with elevated blood sugars, according to Swedish researchers reporting in 2007.

About half of patients with coronary heart disease have abnormal glucose (blood sugar) metabolism.  Lindeberg and associates wondered if a Paleolithic diet (aka “Old Stone Age,” “caveman,” or ancestral human diet) would lead to improved blood sugar levels in heart patients, compared to healthy, Mediterranean-style, Western diet.

Methodology

Investigators at the University of Lund found enrolled 38 male heart patients—average age 61—patients and randomized them to either a paleo diet or a “consensus” (Mediterranean-like) diet to be followed for 12 weeks.  Average weight was 94 kg.  Nine participants dropped out before completing the study, so results are based on 29 participants.  All subjects had either prediabetes or type 2 diabetes (the majority) but none were taking medications to lower blood sugar.  Baseline hemoglobin A1c’s were around 4.8%.  Average fasting blood sugar was 125 mg/dl (6.9 mmol/l); average sugar two hours after 75 g of oral glucose was 160 mg/dl (8.9 mmol/l).

The paleo diet was based on lean meat, fish, fruits, leafy and cruciferous vegetables, root vegetables (potatoes limited to two or fewer medium-sized per day), eggs, and nuts (no grains, rice, dairy products, salt, or refined fats and sugar). 

The Mediterranean-like diet focused on low-fat dairy, whole grains, vegetables, fruits, potatoes, fatty fish, oils and margarines rich in monounsaturated fatty acids and alpha-linolenic acid. 

Both groups were allowed up to one glass of wine daily.

No effort was made to restrict total caloric intake with a goal of weight loss.

Results

Absolute carbohydrate consumption was 43% lower in the paleo group (134 g versus 231 g), and 23% lower in terms of total calorie consumption (40% versus 52%).  Glycemic load was 47% lower in the paleo group (65 versus 122), mostly reflecting lack of cereal grains.

The paleo group ate significantly more nuts, fruit, and vegetables.  The Mediterranean group ate significantly more cereal grains,oil, margarine, and dairy products.

Glucose control improved by 26% in the paleo group compared to 7% in the consensus group.  The improvement was statisically significant only in the paleo group.  The researchers believe the improvement was independent of energy consumption, glycemic load, and dietary carb/protein/fat percentages.

High fruit consumption inthe paleo group (493 g versus 252 g daily) didn’t seem to impair glucose tolerance. 

Hemoglobin A1c’s did not change or differ significantly between the groups.

Neither group showed a change in insulin sensitivity (HOMA-IR method).

Comments

The authors’ bottom line:

In conclusion, we found marked improvement of glucose tolerance in ischemic heart disease patients with increased blood glucose or diabetes after advice to follow a Palaeolithic [sic] diet compared with a healthy Western diet.  The larger improvement of glucose tolerance in the Palaeolithic group was independent of energy intake and macronutrient composition, which suggests that avoiding Western foods is more important than counting calories, fat, carbohydrate or protein.  The study adds to the notion that healthy diets based on whole-grain cereals and low-fat dairy products are only the second best choice in the prevention and treatment of type 2 diabetes.

This was a small study; I consider it a promising pilot.  Results apply to men only, and perhaps only to Swedish men.  I have no reason to think they wouldn’t apply to women, too.  Who knows about other ethnic groups?

This study and the one I mention below are the only two studies I’ve seen that look at the paleo diet as applied to human diabetics.  If you know of others, please mention in the Comments section. 

The higher fruit consumption of the paleo group didn’t adversely affect glucose control, which is surprising.  Fruit is supposed to raise blood sugar.  At 493 grams a day, men in the paleo group ate almost seven times the average fruit intake of Swedish men (75 g/day).  Perhaps lack of adverse effect on glucose control here reflects that these diabetics and prediabetics were mild cases early in the course of the condition—diabetes tends to worsen over time.

ResearchBlogging.orgPresent day paleo and low-carb advocates share a degree of simpatico, mostly because of carbohydrate restriction—at least to some degree—by paleo dieters.  Both groups favor natural, relatively unprocessed foods.  Note that the average American eats 250-300 g of carbohydrates a day.  Total carb intake in the paleo group was 134 g (40% of calories) versus 231 g (55% of calories) in the Mediterranean-style diet.  Other versions of the paleo diet will yield different numbers, as will individual choices for various fruits and vegetables.  Forty percent of total energy consumption from carbs barely qualifies as low-carb. 

Study participants were mild, diet-controlled diabetics or prediabetics, not representative of the overall diabetic population, most of whom take drugs for it and have much higher hemoglobin A1c’s.

Lindeberg and associates in 2009 published results of a paleo diet versus standard diabetic diet trial in 13 diabetics.  Although a small trial (13 subjects, crossover design), it suggested advantages to the paleo diet in terms of heart disease risk factors and improved hemoglobin A1c.  Most participants were on glucose lowering drugs; none were on insulin.  Glucose levels were under fairly good control at the outset.  Compared to the standard diabetic diet, the Paleo diet yielded lower hemoglobin A1c’s (0.4% lower—absolute difference), lower trigylcerides, lower diastolic blood pressure, lower weight, lower body mass index, lower waist circumference, lower total energy (caloric) intake, and higher HDL cholesterol.  Glucose tolerance was the same for both diets.  Fasting blood sugars tended to decrease more on the Paleo diet, but did not reach statistical significance (p=0.08).

The paleo diet shows promise as a treatment or preventative for prediabetes and type 2 diabetes.  Only time will tell if it’s better than a low-carb Mediterranean diet or other low-carb diets. 

Steve Parker, M.D.

Reference: Lindeberg, S., Jönsson, T., Granfeldt, Y., Borgstrand, E., Soffman, J., Sjöström, K., & Ahrén, B. (2007). A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease Diabetologia, 50 (9), 1795-1807 DOI: 10.1007/s00125-007-0716-y

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Filed under Carbohydrate, coronary heart disease, Dairy Products, Fruits, Glycemic Index and Load, Grains, Mediterranean Diet, nuts

Mediterranean Diet Lowers Risk of Breast Cancer

A study in the current issue of the American Journal of Clinical Nutrition associates the Mediterranean diet with lower risk of breast cancer in postmenopausal women.

The data derive from the Greek portion of the massive EPIC study: European Prospective Investigation Into Cancer and nutrition.  Investigators followed almost 15,000 women for 10 years.  No protective effect was seen for premenopausal women eating Mediterranean-style.  The study at hand adds to prior evidence that the Mediterranean diet seems to protect against cancer of the breast, prostate, uterus, and colon/rectum.

Steve Parker, M.D.

Reference:  Trichopoulou, Antonia, et al.  Conformity to traditional Mediterranean diet and breast cancer risk in the Greek EPIC (European Prospective Investigation into Cancer and nutrition) cohortAmerican Journal of Clinical Nutrition, published July 14, 2010.  doi: 10.3945/ajcn.2010.29619

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Filed under cancer, Health Benefits, Mediterranean Diet

Diabetes Consumes 7% of the UK’s Drug Budget

The BBC reports that drugs for diabetes account for 7% of the United Kingdom’s National Health Service’s prescription drug budget. 

They would spend less on diabetic drugs if more diabetics adhered to low-carb eating or the Mediterranean diet.  Better yet, combine both eating styles as in the Low-Carb Mediterranean Diet.

Steve Parker, M.D.

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Filed under Drugs for Diabetes