Science In Support of the Mediterranean Diet

Atherosclerosis is the formal term for “hardening of the arteries.”  Who cares how hard they are, as long as the arteries deliver blood to our organs, right?

Atherosclerosis in the arteries that supply blood to the heart – essentially a hollow muscle that pumps blood – is called coronary heart disease disease (CHD) or coronary artery disease (CAD).

LDL cholesterol is the “bad cholesterol” that is associated with atherosclerosis.  Generally, the higher the LDL, the worse the atherosclerotic complications: plaque build-up leads to poor circulation to vital organs, arterial blood clots, even death of tissue due to blocked arteries.  Oxidation of LDL cholesterol facilitates atherosclerosis.

People at high risk for coronary heart disease include type 2 diabetics, smokers, people with high blood pressure or cholesterol abnormalities, and people with a family history of coronary heart disease.  Advanced age is another strong risk factor.

The ongoing PREDIMED Study is designed to test the the effects of the traditional Mediterranean diet in primary prevention of coronary heart disease in a high risk population.  9000 study participants will be assigned to one of three diets:  1) low-fat, 2) Mediterranean plus extra olive oil, or 3) Mediterranean plus extra nuts.  The Mediterranean diet is moderate in percentage of calories derived from fat, and the main source of fat is olive oil.  Virgin olive oil has a particularly high content of antioxidant phenolic compounds.  Nuts are also a rich source of antioxidant phytochemicals.  These antioxidants can prevent the harmful transmogrification of plain LDL into oxidized LDL.

A group of 372 early study enrollees were randomly assigned to one of the three diet groups.  In both of the Mediterranean diet groups, researchers found reduced oxidized LDL, reduced blood pressures, lower total cholesterol, and lower total-HDL cholesterol ratios, more than in the low-fat diet group.

These observed changes would tend to reduce the incidence and severity of atherosclerotic complications.  When PREDIMED is completed, we’ll know whether the traditional Mediterranean diet, compared with a low-fat diet, is better at preventing death and disease from coronary heart disease.  That’s where the rubber meets the road.

Steve Parker, M.D.

References:

Montserrat, Fito, et al.  Effect of a Traditional Mediterranean Diet on Lipoprotein Oxidation: A Randomized Controlled Trial.  Archives of Internal Medicine, 167 (2007): 1,195-1,203.

Prevencion con Dieta Mediterranea Study (PREDIMED)  http://www.predimed.org

Potential Health Benefits of Alcohol

For centuries, the healthier populations in the Mediterranean region have enjoyed wine in light to moderate amounts, usually with meals. Epidemiologic studies there and in other parts of the world have associated reasonable alcohol consumption with prolonged lifespan, reduced coronary artery disease, diminished Alzheimer’s and other dementias, and possibly fewer strokes.

Alcohol tends to increase HDL cholesterol (the good stuff), have an antiplatelet effect, and may reduce C-reactive protein, a marker of arterial inflammation. These effects would tend to reduce cardiovascular disease. Wine taken with meals provides antioxidant phytochemicals (polyphenols, procyanidins) which may protect against atherosclerosis and some cancers.

What’s a “reasonable” amount of alcohol? An old medical school joke is that a “heavy drinker” is anyone who drinks more than the doctor does. Light to moderate alcohol consumption is generally considered to be one or fewer drinks per day for a woman, two or fewer drinks per day for a man. One drink is 5 ounces of wine, 12 ounces of beer, or 1.5 ounces of 80 proof distilled spirits (e.g., vodka, whiskey, gin). The optimal health-promoting type of alcohol is unclear. I tend to favor wine, a time-honored component of the Mediterranean diet. Red wine in particular is a rich source of resveratrol, which is thought to be a major contributor to the cardioprotective benefits associated with light to moderate alcohol consumption. Grape juice may be just as good—it’s too soon to tell.

Steve Parker, M.D.

References:

Standridge, John B., et al.  Alcohol consumption: An overview of benefits and risks.  Southern Medical Journal, 97 (2004): 664-672.

Luchsinger, Jose A., et al.  Alcohol intake and risk of dementia.  Journal of the American Geriatrics Society, 52 (2004): 540-546.

Adverse Effects of Alcohol

I’ve discussed frequently in these pages the potential benefits of judicious alcohol consumption on longevity, coronary artery disease, and dementia.

I have no intention of overselling the benefits of alcohol. If you are considering habitual alcohol as a food, be aware that the health benefits are still somewhat debatable. Consumption of three or more alcoholic drinks per day is clearly associated with a higher risk of breast cancer in women. Even one or two drinks daily may slightly increase the risk. Folic acid supplementation might mitigate the risk. If you are a woman and breast cancer runs in your family, strongly consider abstinence. Be cautious if there are alcoholics in your family; you may have inherited the predisposition. If you take any medications or have chronic medical conditions, check with your personal physician first.

For those drinking above light to moderate levels, alcohol is clearly perilous. Higher dosages can cause hypertension, liver disease, heart failure, certain cancers, and other medical problems. And psychosocial problems. And legal problems. And death. Heavy drinkers have higher rates of violent and accidental death. Alcoholism is often fatal. You should not drink alcohol if you:

  • have a history of alcohol abuse or alcoholism
  • have liver or pancreas disease
  • are pregnant or trying to become pregnant
  • may have the need to operate dangerous equipment or machinery, such as an automobile, while under the influence of alcohol
  • have a demonstrated inability to limit yourself to acceptable intake levels
  • have personal prohibitions due to religious, ethical, or other reasons

Steve Parker, M.D.

References: Lieber, Charles S.  Alcohol and health: A drink a day won’t keep the doctor away.  Cleveland Clinic Journal of Medicine, 70 (2003): 945-953.

What Is the Traditional Mediterranean Diet?

Some of my casual readers may have misconceptions as to the definition of the traditional Mediterranean diet.  I use the word “diet” here not as a weight-loss program, but “the usual food and drink of a person or animal.”  Twenty-one countries have a coastline of the Mediterranean sea, and additional countries are in the Mediterranean region.  “Traditional” refers to the mid-20th century.  Observational studies around that time associated the Mediterranean diet with longer life spans, reduced rates of chronic disease (less cardiovascular disease and dementia), and fewer cancers of the colon, breast, prostate, and uterus.

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 characteristcs of the traditional, healthy Mediterranean diet:

  • 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

Be aware that the documented health benefits may be related to a physically active lifestyle and other social and cultural issues.  For example, traditional Mediterranean mealtimes were leisurely family affairs, not a MacDonald’s Happy Meal eaten off your lap on your drive home from work.

Steve Parker, M.D.

Reference:  Oldways Preservation Trust

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.