Monthly Archives: July 2012

Your Lifetime Risk of Cancer

I have good news and bad news.  Which would you like first?

The good news is that cancer death rates in the U.S. have dropped over the last 20 years.  The reduction is 18% for men and 10% for women.

The bad news is that the American Cancer Society projects around 600,000 yearly deaths from cancer in the U.S.

If we look at deaths of people under 85, cancer kills more people than heart disease.

In men, 25% of all invasive cancers will be prostate cancer.  In women, breast cancer is the leader, comprising 26% of all cancers.  (Common skin cancers are rarely invasive or fatal and are not included in these statistics.  Melanoma, on the other hand, is invasive and dangerous.)

The lifetime probability of an individual developing invasive cancer in the U.S. is about 4 in 10 (40%).  A little higher in men (45%), a little lower in women (38%).

Obesity is associated with higher risk for kidney and esophageal cancer in both sexes, prostate and colo-rectal cancer in men, and uterine, gallbladder, cervical, ovarian and breast cancer in women.  Excess body fat causes  14 to 20% of all cancer-related deaths in the U.S.  It’s reasonable to believe that reducing excess body fat will lower the risk of developing these cancers.

The traditional Mediterranean diet is associated with less risk of prostate, breast, colon, and uterus cancer.  And lower rates of cardiovascular disease.  Combine a Mediterranean diet with loss of excess body fat, and what’s not to love?

Steve Parker, M.D.

Reference:  Jemal, Ahmedin, et al.  Cancer Statistics, 2008.  CA Cancer Journal for Clinicians, 58 (2008): 71-96. 

Camp Raymond Experience

Not Camp Raymond, but you get the idea

My son and I recently returned from a week at the Boy Scouts of America’s Camp Raymond in northern Arizona.  Located in a Ponderosa pine forest at an elevation of 6,700 feet above sea level, it’s about a 45-minute drive west and south of Flagstaff.  160-acre Camp Raymond is on the edge of Sycamore Canyon Wilderness.

What Are Boy Scouts?

In case you’re not familiar with BSA, here’s their mission statement:

The mission of the Boy Scouts of America is to prepare young people to make ethical and moral choices over their lifetimes by instilling in them the values of the Scout Oath and Law.

The Scout Oath:

On my honor I will do my best
To do my duty to God and my country
and to obey the Scout Law;
To help other people at all times;
To keep myself physically strong,
mentally awake, and morally straight.

The Scout Law:

A Scout is trustworthy, loyal, helpful, friendly, courteous, kind obedient, cheerful, thrifty, brave, clean, and reverent.

I highly recommend Scouting for boys, who can join at age 11.  BSA is a great organization.

What Was It Like?

Ten scouts and six adults from Scottsdale, Arizona’s Troop 131 camped in tents for six nights.  The campsite had running water, a latrine, and no electricity.  Fires were forbidden due the the extreme risk of forest fires: there hasn’t been much rain lately.  Meals were prepared by professional staff and eaten in a dining hall.  Scouts and attending adults did nearly all the food serving and meal cleanup for 400 people on-site.  Our troop did KP duty (kitchen patrol) for two lunches, requiring two hours’ work each time.

Coyotes howling woke us up twice one night.  We saw a deer bouncing through the camp one morning.  I bet he’d been eating the lush grass growing on the septic tank field.  Smelled one skunk and saw another.

Temperatures were perfect, between 50 and 86° F.  No rain except a brief light sprinkle one night.  I had a little trouble falling asleep, I think because of the altitude.  Few bugs.

I’d heard stories about the infamous and pervasive Camp Raymond dust.  This was indeed the dustiest place I’d ever camped.  It’s not a problem, just…remarkable.  You can wash and dry your feet, then don sandals and walk 50 feet: you’re dirty again!

We were there over the Independence Day holiday, explaining why camp was only 60% full.  A side benefit is that the boys had much less waiting in line to use the popular facilities, such as the dining room and archery, rifle, and shotgun ranges.

Camp has a heated pool, which our troop didn’t use much.  Nor did we avail ourselves of the canoeing and rowing opportunities on the small lake.  We should have  taken a hike down into Sycamore canyon, but never got around to it.  We did a nighttime orienteering course.  Three other adults and I took a three-mile hike trying to find Lone Elk Point but lost the trail.

My personal trip highlights:

  • Skeet shooting with a 20 gauge shotgun.  I hadn’t fired a shotgun in over 40 years.  Somehow I hit 46 of 50 clay pigeons.
  • The Order of the Arrow call-out ceremony.  OA is an honor society for scouts; I was a member over 40 years ago.  The ceremony starts with a silent nocturnal single-file walk through the forest, involving about 200 individuals. Three of our troop’s scouts were called-out.
  • My son Paul was publicly recognized (with totems) by two of the Archery staffers as being the most polite scout they’d ever worked with.

The Scouts spent most of the day working on merit badges and, to a lesser extent, rank advancement.  Popular badges were environmental science, leatherwork, woodcarving, geology, archery, rifle (.22 caliber), shotgun, mammal study, basketry,  soil and water, and first aid.  The environmental science badge was particularly popular because it’s difficult to achieve in other settings and it’s required for Eagle rank, the pinnacle of the scouting experience.

No one got seriously hurt, and all had a splendid time!

-Steve

Notes:

We were in campsite 5a, a good one.  It’s close to all the activities, and has good tent sites.  Campsite 6a looks just as good.  Some of the campsites are as much as a half mile away from the dining hall.

Attending adults were Scott H, Gary F, Mark Z, Dave K, John U (from nearby Troop 15), and me.  Scott F came up for the final 24 hours.

The scouts were Christian R, Jacob M, Jacob F, Kyle K, Reid F, Nathan H, JD H, Matthew Z, John U (from Troop 15), and my son.

I was the “adult lead” for the trip while Scott H was the scoutmaster.  Adult leading was fairly easy, mainly involving paperwork, attending a few meetings, and being familiar with all aspects of the program.  I could have done a better job if I’d:

  • Had a parents/scouts meeting about a month prior to departure for camp.
  • Run across an online document called “merit badges at a glance.”  The merit badge program is somewhat confusing.  For example, 1) several scouts attended duplicate presentations for the same merit badge, a waste of time, and 2) working on one badge can easily conflict with work on another if you’re not careful.  The experienced scouts, especially Nathan H, were quite helpful explaining this to the newbies.

The online published document called Adult Leaders Packet was not entirely accurate.  For instance, I eventually saw three discordant schedules for the first evening’s activities.  The most accurate schedule was the pocket-sized Adult Leaders Handbook I was given soon after arrival.  All the adults and the lead scouts needed this.

Camp Raymond is well-organized and well-run.  Staff and progams exemplify the 12 points of the Scout Law.

Do Eggs Cause Heart Attacks and Premature Death?

At the beginning of my 30-year medical career, egg consumption was condemned as a cause of heart attacks.  Heart attacks can kill.  How did eggs kill?  It was thought to be related to the cholesterol content – 200 mg per egg – leading to higher serum cholesterol levels, which clogged arteries (atherosclerosis), leading to heart attacks.

Fifteen years ago the pendulum began to swing the other direction: Egg consumption didn’t seem to matter much, if at all.

The evidence is usually collected in observational, epidemiologic studies of large groups of people.  The groups are analyzed in terms of overall health, food intake (e.g., how many eggs per week), healthy lifestyle factors, etc.  Egg consumption of the group is broken down, for example, into those who never eat eggs, eat 1-4  eggs per week, eat 5-10 per week, or over 10 eggs weekly.  A group is followed and re-analyzed over 10-20 years and rates various diseases and causes of death are recorded.  Researchers don’t follow just 25 people like this over time.  You need thousands of participants to find statistically significant differences.

The debate about eggs was re-opened (although never really closed) by the publication in April, 2008, of an article in The American Journal of Clinical Nutrition.  Scientists of the Physicians’ Health Study suggest that consumption of seven or more eggs weekly is associated with significantly increased risk, over 20 years, of all-cause mortality.  Interestingly, this level of consumption did not cause heart attacks or strokes.  Study participants, by the way, were 21,327 Harvard-educated male physicians.  5,169 deaths occurred during 20 years of follow-up.  If you’re not a Harvard-educated male physician, the study results may not apply to you.

When physicians with diabetes  – type 2’s mostly, I assume –  were analyzed separately, consumption of even less than seven eggs per week was associated with higher all-cause mortality.

Several other observational studies looking at this same issue have found no association between egg consumption and cardiovascular disease, heart attacks, and all-cause mortality.

Bottom line?  If you worry about egg consumption, limit to 7 or less per week.  If you have type 2 diabetes, consider limiting to 4 or less per week.

I wouldn’t be surprised if a study were published next week saying “eat as many eggs as you want; they don’t have adverse health effects.”

Remember, all the cholesterol is in the yolk.  Try making an omelet using the whites only.  But in our lifetimes you’ll never see an observational study looking at egg white consumption and mortality rates.

I’m still not convinced egg consumption is worth losing sleep over.  “More studies are needed…”

Steve Parker, M.D.References:

Djousse, L. and Gaziano, J. M.  Egg consumption in relation to cardiovascular disease and mortality: the Physicians’ Health Study.  American Journal of Clinical Nutrition, 87 (2008): 964-969.

Dawber, T.R, et al.  Eggs, serum cholesterol, and coronary heart disease.  American Journal of Clinical Nutrition, 36 (1982): 617-625.

Nakamura, Y., et al.  Egg consumption, serum cholestrol, and cause-specific and all-cause mortality: the National Integrated Project for Prospective Observation of Non-communicable Disease and Its Trends in the Aged, 1980.  American Journal of Clinical Nutrition, 80 (2004): 58-63.

Is Exercise Important as Part of a Weight Management Plan?

While physical activity alone seldom results in significant and sustained weight loss, maintaining weight loss without physical activity is nearly impossible.

The quote above is from James Early, M.D., Clinical Associate Professor, Department of Preventive Medicine and Public Health, University of Kansas School of Medicine-Wichita (Wichita, Kansas), as printed in Clinical Cornerstone, 2007, volume 8, No. 3, page 69.

It’s a simple truth, one that bears repeating, as the truth too often is submerged in a roiling sea of misinformation and trivia.

Exercise is extremely important for the vast majority of people who want to lose weight and keep it off, but it’s encouraging to know that it is possible to be successful if you don’t want to or can’t exercise.

This second quote is from the first edition of Thin For Life: 10 Keys to Success From People Who Have Lost Weight and Kept It Off, by Anne Fletcher, page 20.  Out of the 160 “weight-control masters” studied by Anne, 70% exercised three or more times per week.  Nine percent told her they didn’t exercise at all.

For help with your exercise program, consider Physical Activity for Everyone and Shape Up America!

Steve Parker, M.D.

Mediterranean Diet Cuts Risk of Type 2 Diabetes

The traditional Mediterranean diet has long been associated with lower risk of developing cardiovascular disease, cancer, and dementia.  The diet is rich in olive oil, fruits, nuts, cereals, vegetables, and fish but relatively low in dairy products and meat.  Several studies suggest the Mediterranean diet may also help prevent type 2 diabetes.

Researchers at the University of Navarra in Spain followed 13,380 non-diabetic university graduates, many of them health professionals, over the course of 4.4 years.  Average age was 38.  I assume most of the study participants lived in Spain, if not elsewhere in Europe (the article doesn’t say).  Dietary habits were assessed at the start of the study with a food frequency questionnaire.  Food intake for each participant was scored by adherence to the traditional Mediterranean diet.  Participants were labelled as either low, moderate, or high in adherence.  Over an average follow-up of 4.4 years, 33 of the study participants developed type 2 diabetes.  Compared to the participants who scored low on adherence to the Mediterranean diet, those in the high adherence category had an 83% lower risk of developing diabetes.  The moderate adherence group also had diminished risk, 59% less.

How could the Mediterranean diet protect against diabetes?  The authors note several potential mechanisms: high intake of fiber, low amounts of trans fats, moderate alcohol intake, high vegetable fat  intake, and high intake of monounsaturated fats relative to saturated fats.  Olive oil, loaded with monounsaturated fats, is the predominant fat in the Mediterranean diet.  In summary from the authors:

Diets rich in monounsaturated fatty acids improve lipid profiles and glycaemic control in people with diabetes, suggesting that a high intake improves insulin sensitivity.  Together these associations suggest the hypothesis that following an overall pattern of Mediterranean diet can protect against diabetes.  In addition to having a long tradition of use without evidence of harm, a Mediterranean diet is highly palatable, and people are likely to comply with it.

Please give serious consideration to the Mediterranean diet, especially if you are at risk for developing type 2 diabetes.  Major risk factors include sedentary lifestyle, overweight, and family history of diabetes.

Steve Parker, M.D.

Reference: 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).

Eat Slowly to Increase Meal Satisfaction and Reduce Consumption

Some weight-management gurus advocate a slow eating rate to reduce food intake when on a weight loss diet, but there has never been much proof that it works.  Now there is, at least in healthy normal-weight women.

The Journal of the American Dietetic Association in 2008 reported a study in which 30 women were told to eat as much at meals as they wanted, until they were satisfied.  The abstract of the article doesn’t specify, but I assume each participant was studied for several meals and was told to eat either slowly or quickly at different meals.

When eating quickly, the women ate 646 calories per meal.  Eating slowly resulted in 579 calories per meal.  Sixty-seven calories less per meal doesn’t sound like much, but would quickly add up over time to a substantial calorie deficit which could help with weight loss.  Additionally, satisfaction with the meal was higher under the slow eating condition.

So if you’re watching your weight, why not slow down and enjoy your meals?

Steve Parker, M.D.

Reference: Andrade, Ana M., Greene, Geoffrey W., and Melanson, Kathleen J.  Eating slowly led to decreases in energy intake within meals in healthy women.  Journal of the American Dietetic Association, 108 (2008): 1,186-1,191.

Eye-Popping Statistics

I often talk to people interested in improving their health or losing weight via lifestyle modification, mostly changes in diet and exercise.  Many of them are motivated by health-related facts.  Here is a smattering of facts I compiled in 2008 (so some are outdated), starting out worrisome and ending hopeful: 

  • 65% of U.S. adults are overweight or obese.  Half are overweight, half are obese. 

  • 12% of deaths in the U.S. are due to lack of regular physical activity – 250,000 deaths yearly.

  • 11% of U.S. adults have diabetes mellitus.

  • 24 million in the U.S. have diabetes.  Another 57 million have pre-diabetes, a condition that increases your risk for diabetes.

  • 23% of U.S. adults over 60 have diabetes. 

  • 85% of people with type 2 diabetes are overweight.

  • 200,000 yearly deaths in the U.S. are due to obesity.

  • Excess body fat causes 14 to 20% of all cancer-related deaths in the U.S.

  • 550,000 people die yearly of cancer in the U.S. 

  • Obesity-related cancers in men: prostate and colorectal.  Obesity-related cancers in women: endometrial (uterine), cervix, ovary, breast.  Both sexes: kidney, esophageal adenocarcinoma.

  • 20% of us in the U.S. will die of cancer.

  • Lifetime risk of developing invasive cancer in the U.S. is four in 10 (a little higher in men, a little lower in women).

  • At least one-half of high blood pressure cases are caused by excess body fat.  Every 20 pounds of excess fat increases blood pressure by two to three points.

  • Peak aerobic power (a measure of physical fitness) decreases by 50% between age 20 and 65.

  • Middle-aged and older people through regular exercise can increase their aerobic power by 15 to 20%, equivalent to a 10 or 20-year reduction in biological age. 

  • Regular aerobic exercise reduces blood pressure by 8 to 11 points.  

  • Have you already had a heart attack?  If so, regular exercise reduces the odds of fatal recurrence by 25% and adds two to three years to life.

  • The Mediterranean diet is associated with lower incidence of cancer (colon, breast, prostate, uterus), cardiovascular disease (e.g., heart attacks), and dementia (both Alzheimers and vascular types). 

  • High fruit and vegetable consumption protects against cancer of the lung, stomach, colon, rectum, oral cavity, and esophagus.  The protective “dose” is five servings a day.

  • Coronary artery disease is the cause of heart attacks and many cases of sudden cardiac death.  Legume consumption lowers the risk of coronary artery disease.  The protective dose is four servings of legumes a week. 

  • Whole grain consumption is associated with reduced risk of coronary artery disease (e.g., heart attacks), lower risk of death, lower incidence of type 2 diabetes and several cancers.  The protective dose is three servings a day. 

The good news is that we can significantly reduce our risk of premature death and common illnesses such as high blood pressure, cancer, diabetes, coronary artery disease, and dementia.  How?  Weight management, diet modification, and physical activity.     

Steve Parker, M.D.

Mediterranean Diet Reduces Cancer Risk

In 2008, the British Journal of Cancer published a report linking the traditional Mediterranean diet “…with markedly and significantly reduced overall cancer….”

Researchers from the University of Athens, the International Agency for Research on Cancer, and the Harvard School of Public Health looked at 25,623 participants of the Greek portion of the European Prospective Investigation into Cancer and nutrition (the EPIC study).  Adherence to the Mediterranean diet was assessed with a food-frequency questionnaire.

Cancer developed in 851 participants over an average follow up of 7.9 years.  Non-melanoma skin cancers were not included since they are usually not serious or life-threatening.  The common cancers in men involved the lung, prostate, colon, and stomach.  For women, common cancers were breast, colon, ovary, and uterus.

Participants’ conformity to the Mediterranean diet was graded on a 10-point scale based on consumption of vegetables, legumes, fruits and nuts, cereals, fish, meat and meat products, dairy products, ethanol (alcohol), and the monounsaturated to saturated lipid ratio.  A score of zero indicated minimal adherence; maximal adherence scored a nine.

Every two-point increase in adherence was associated with a 12% reduction in the incidence of overall cancer.  So those participants with greatest conformity to the traditional Mediterranean diet had a dramatically reduced incidence of cancer compared to those with minimal adherence.

The researchers cite three independent studies that found a similar association between the Mediterranean diet and cancer.  The study at hand was not sufficiently powered to determine reliably which specific cancers were reduced with the Mediterranean diet.  Other studies indicate that the reduced cancers are prostate, breast, colon, and uterus.

The researchers surmise that the cancer-reducing benefit of the Mediterranean diet relates to the whole diet rather than to individual components.

To move your way of eating in a Mediterranean direction, review the diet here.

Steve Parker, M.D.

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

DIRECT Trial Compares Mediterranean, Low-Fat, and Low-Carb Eating for Weight Loss

Today’s post is a reprint of my 2008 analysis of the DIRECT trial.

In 2008, the New England Journal of Medicine published a well-done study comparing the Mediterranean, low-carb, and low-fat weight-loss diets in an Israeli population over the course of two years.  The researchers conclude that “Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets.  The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.”

How was the study set up?

Moderately obese participants (322) were randomly assigned to one of the three diets: 1) low-fat, calorie-restricted, 2) Mediterranean, calorie-restricted, or 3) low-carbohydrate, non-restricted.  Calories in the low-fat and Mediterranean diets were “restricted” to 1800 per day for the men, 1500 for the women.  Average age of participants was 52, and average body mass index was 31.  [A 5-foot, 10-inch man weighing 216 pounds (98.2 kg) has a BMI of 31.]  Nearly all participants – 277 or 86% of the total – were men.  So there were only 45 women.  Forty-six participants had type 2 diabetes.

The low-fat diet was based on the American Heart Association guidelines of 2000: 30% of calories from fat [this isn’t very low], 10% of calories from saturated fat, cholesterol limited to 300 mg/day.  [The AHA revised their guidelines in 2006.]  Low-fat dieters “were counseled to consume low-fat grains, vegetables, fruits, and legumes and to limit their consumption of additional fats, sweets, and high-fat snacks.”

The Mediterranean diet was based on the recommendations of Walter Willett and P.J. Skerrett as in their book, Eat, Drink, and be Healthy: The Harvard Medical School Guide to Health Eating.  Mediterranean dieters ate 2 fish meals per week, a handful of nuts daily, 30-45 grams of extra virgin olive oil per day, etc.  [One tablespoon of olive oil is 14 grams.]  The AHA states that “this diet reflects the current recommendations from the American Heart Association.”  There were no specific recommendations regarding alcohol in any of the diets.

The low-carb diet was based on  Atkins’ New Diet Revolution of 2002.  The goal was to provide 20 grams of carbohydrate per day for the 2-month induction phase, with a gradual increase to a maximum of 120 grams daily to maintain weight loss.  Total calories, protein, and fat were not limited.  “Participants were counseled to choose vegetarian sources of fat and protein….”

Whole grains were recommended for the low-fat and Mediterranean cohorts.

All participants worked at the same nuclear research facility in Dimona, Israel.  They were given careful instructions, initially and periodically, regarding the diet to which they were assigned.  Lunch is the main meal of the day in Israel, and they all ate lunch at the facility’s self-service cafeteria, which prompted them to choose the proper food items.  I assume they were told to maintain the diet when off-duty.  Adherence to the diets was assessed by a food-frequency questionnaire.

Findings

  • After 24 months, how many participants were still involved?  90% in the low-fat group, 85% in the Mediterranean, 78% in the low-carb.
  • There was little change in the usage of medications, and no significant differences among the groups.
  • Daily energy intake (calories or kcal) decreased from baseline levels significantly – about 450 calories – in all groups at 6, 12, and 24 months compared with baseline, with no significant differences among the groups in the amount of decrease.
  • All groups started with 51% of energy intake (calories) from carbohydrate.
  • At 24 months, the low-carb dieters were getting 40% of their daily calories as carbohydrates.  The other two groups were eating 50% of energy intake from carbs. [This still seems like a lot of carbs on the Atkins diet.  A gram of carbs has 4 calories.  The stated carbohydrate goal was a maximum of 120 grams of carbs daily, on a diet of 1800 calories.  So 120 grams of carbohydrate should be 27% of total daily calories.  At no point did the low-carb group reduce their average percentage of calories from carbohydrates under 40%.  OK, maybe be in the first two weeks but those data are not reported.  On an 1800 calorie diet, 40% of calories from carbs would be 180 grams.]
  • At 24 months, the low-carb dieters were getting 39% of their daily calories as fat.  The other two groups were in the 30-33% range.
  • Baseline fat intake for all groups was 31-32% of total calories, with saturated fat being 10% of the fat calories.
  • The low-fat cohort dropped their fat calories from 31 to 30% of total calories, which is essentially no change from baseline percentage.
  • At 24 months, the low-carbers were getting 22% of their daily calories from protein.  The other groups were at 19%.  [The low-carb Atkins diet is often criticized as having too much protein.]
  • Only the low-carb group made major changes in macronutrient composition of their diet.  Macronutrients are protein, fat, and carbohydrates.  This Atkins group increased saturated fat from 10 to 12% of total calories, reduced carbs from 51 to 40% of calories, increased protein from 19 to 22% of calories, and increased total fat from 32% to 39% or total calories.
  • All cohorts lost weight, but losses were greater in the low-carb and Mediterranean groups.  For the 272 participants who completed the full 24 months of intervention, the losses averaged 3.3 kg (7.3 lb) for the low-fat group, 4.6 kg (10.1 lb) for the Mediterraneans, and 5.5 kg (12.1 lb) for the low-carb group.
  • Among the 45 women, the low-fat group lost only 0.1 kg (0.22 lb), the Mediterraneans lost 6.2 kg (13.6 lb), and the low-carbers lost 2.4 kg (5.3 lb).  There were only 15, 20, and 10 women in these groups, respectively.
  • All groups had significant blood pressure reductions: about 4 mmHg systolic and 1 mmHg diastolic.
  • HDL cholesterol (the “good cholesterol”) increased in all groups, 8.4 mg/dl in the low-carb group, about 6.3 in the others.
  • LDL cholesterol (the “bad cholesterol”) fell 5.6 mg/dl in the Mediterraneans, 3.0 mg/dl in the low-carbers, and none in the low-fat group.  But these were not statistically significant differences between the groups.
  • The ratio of total to HDL cholesterol decreased for all groups, but the relative 20% decrease in the low-carb group was statistically significant compared to the 12% relative decrease in the low-fat group.  The ratio fell 16% in the Mediterranean group.  [The total/HDL ratio is thought to reflect risk of developing atherosclerotic complications.  You want it under 5 to 1, and 3.5 to 1 may be ideal.]
  • The level of high-sensitivity C-reactive protein decreased significantly only in the Mediterranean and low-carb cohorts.  [C-reactive protein is felt to be a marker of the systemic inflammation that has a role in atherosclerosis or hardening of the arteries.]
  • Thirty-six of the diabetics had adequate lab studies for analysis – about 12 in each diet group.  Only those in the Mediterranean group had a significant decrease in fasting glucose – 33 mg/dl.  The low-fat group had an increase.  Glycated hemoglobin decreased in all three groups although to a significant degree (0.9%) only in the low-carb group.  [High glycated hemoglobin levels reflect poor control of blood sugar levels in diabetics.]
  • Insulin levels decreased significantly in all three groups, diabetic or not.  [Abnormally high insulin levels are felt to have adverse health effects.]

Limitations of the study

  • Relatively few women, making it difficult to reliably generalize results to women.
  • Relatively few people with diabetes, making it difficult to reliably generalize results to people with diabetes.
  • Israeli gene pool?  Results not applicable to others?
  • No change in physical activity recommended to participants.  Increased exercise should enhance weight loss.

Take-Home Points

  • Caloric restriction leads to weight loss.
  • Mild degrees of weight loss reduce blood pressure.
  • In this study, the low-carb/Atkins and Mediterranean diets were more effective than the “low-fat” diet.
  • Atkins dieters can lose weight without counting calories, by limiting carbohydrate intake.
  • You gotta wonder if the low-carb group would have been even more successful if they had actually limited carbs to 120 grams daily, or less.
  • It’s possible a lower-fat diet may have been more efficacious than the one utilized here.
  • This study did not enroll enough women to prove that a calorie-restricted Mediterranean diet is superior to low-fat and Atkins diets.  The greater weight loss – 13.6 pounds for Mediterranean versus 5.3 with Atkins – is suggestive and requires further study.
  • The average amounts of weight loss are not much when you think about the effort expended over 24 months of intervention.
  • These dieters reportedly reduced their daily caloric intake from baseline levels by about 450 calories, over the course of two years.  Yet they lost relatively little weight.  The numbers do not jive.  Most likely there is a problem with the methodology.  I doubt the average daily calorie deficit was as high as 450.
  • The Mediterranean diet seems to have been better for the people with diabetes.  Confirmatory studies are imperative.  Insulin resistance is an important factor in type 2 diabetes.  Monounsaturated fats, which are prominent in olive oil and the Mediterranean diet, are linked to improvement in insulin resistance in other studies.
  • For people who need to lose excess fat yet refuse to consciously restrict overall caloric  intake, the low-carb Atkins diet is a reasonable option.
  • The traditional Mediterranean diet has demonstrable long-term health benefits: longer lifespan, less cancer (colon, prostate, breast, uterus), reduction of cardiovascular disease, less dementia, and prevention of type 2 diabetes.  The Atkins diet cannot make those claims in 2008.

-Steve Parker, M.D.

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

Additional information and critical analysis:

Dr. Dean Ornish’s analysis in Newsweek online   Dr. Ornish is a leading low-fat diet advocate.

American Heart Association comments on the study in a July 19, 2008, news release

Update on August 23, 2008:

The Mediterranean diet used in this study is based on Walter Willett’s 2001 book, Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating.  From the author:

I wrote this book to show you where the USDA Pyramid is wrong and why it is wrong.  I wanted to offer a new healthy eating guide based of the best scientific evidence, a guide that fixed the fundamental flaws of the USDA Pyramid and helps you make better choices about what you eat.  I also wanted to give you the latest information on new discoveries that shuould have profound effects on our eating patterns. 

Dr. Willett made a conscious decision not to call his new eating plan a Mediterranean diet.  Elsewhere in the book he notes that the Mediterranean diet pyramid promoted by Oldways Preservation and Exchange Trust is a good, evidence-based guide for healthy eating.  The entire book promotes Harvard’s Healthy Eating Pyramid, not the Mediterranean diet per se.

Harvard’s Healthy Eating Pyramid:

Harvard's Healthy Eating Pyramid

So were the Mediterranean dieters in the study at hand even following the Mediterranean diet?  The most glaring difference is Harvard’s lack of emphasis on olive oil.  Of lesser note is Harvard’s recommendation to eat white rice, white bread, potatoes, and refined-flour pasta only sparingly.  However, the researchers for this study directed Mediterranean diet participants to ingest 30-45 grams of olive oil per day.  After comparing the Harvard pyramid with the Oldways Mediterranean pyramid and other Mediterranean diet descriptions, it is fair to say the dieters here were indeed instructed on a Mediterranean diet.  In fact, the Mediterranean diet in this study is quite similar to the Advanced Mediterranean Diet.

Traditional healthy Mediterranean diet pyramid of Oldways Preservation and Exchange Trust:

Traditional healthy Mediterranean diet pyramid of Oldways Preservation and Exchange Trust

Mediterraneans Fatter After Abandoning the Traditional Mediterranean Diet

In 2008, the United Nation’s Food and Agriculture Organisation reported rates of overweight and obesity in various countries in the European Union.

Greece won honors as the fattest EU country – 75% of adult Greeks are overweight or obese. Way to go, Greece!  Over the 40 years preceeding 2002, the Greeks increased their average caloric intake by 30%, compared to a 20% increase in the rest of the EU.  And I’d bet they’re expending fewer calories in physical activity than did the Greeks of 40 years ago.

Although outdone by the Greeks, over half of the adult populations in Italy, Spain, and Portugal are overweight, too.

The authors of the UN report suggest reasons for Greece’s decisive capture of first place:

  • more sedentary lifestyles
  • less home cooking
  • supermarkets and fast-food restaurants offering convenient, processed foods high in sugar, animal fat, and salt.  [Salt should have nothing to do with weight gain.]
  • less fruit and vegetable consumption

In other words, they’ve been moving away from the traditional Mediterranean diet and lifestyle of the mid-20th century.  Recent observational studies in Greece and Spain showed less obesity in current residents who had higher adherence to the traditional Mediterranean diet.

How do North American adult overweight and obesity rates compare?

  • United States – 67%
  • Mexico – 63%
  • Canada – 59%

If the Mediterraneans have forgotten their dietary heritage, I can help.

Steve Parker, M.D.

References:

Mendez, M.A., et al.  Adherence to a Mediterranean diet is associated with reduced 3-year incidence of obesity.  Journal of Nutrition, vol. 136 (2006): 2,934-2,938.

Panagiotakos, D.B., et al.  Association between the prevalence of obesity and adherence to the Mediterranean diet: the ATTICA study.  Nutrition, vol 22 (2006): 449-456.