Mediterranean Diet Prevents Sudden Cardiac Death in Women

A Mediterranean-style diet is one of four factors helping to greatly reduce the risk of sudden cardiac death in women, as reported by Reuters on June 5, 2011. The other factors reducing risk were maintainence of a healthy weight, regular exercise, and not smoking.

The study involved women only, so we don’t know if the research, reported in the Journal of the American Medical Association, applies to men.

This study confirms many earlier ones linking the Mediterranean diet with longevity and reduced rates of heart disease.

Steve Parker, M.D.

Target Heart Rate

To get the full health benefits of regular physical activity, you need to put some effort into it. A leisurely hour-long stroll in the mall while window-shopping doesn’t pass muster, although that’s better than nothing.

One rough way to gauge whether you are working hard enough during aerobic exercise is to monitor your heart rate, also known as pulse. Subtract your age from 220. The result is your theoretical maximum heart rate in beats per minute. Your heart rate goal, or target, during sustained aerobic exercise is a pulse that is 60 to 80 percent of your theoretical maximum pulse. For example: maximum heart rate for a 40-year-old is 180 (220 – 40 = 180), so the target heart rate zone during exercise is between 108 and 144 (60 to 80 percent of 180). Exceeding the upper end of the target zone is usually too uncomfortable to be sustainable. Exercise heart rates below the target zone suggest you’re not working hard enough to reap the full long-term benefits of aerobic exercise.

Here’s how to determine your pulse. After five or 10 minutes of exercise, stop moving and place the tips of your first two fingers lightly over the pulse spot inside your wrist just below the base of your thumb. Count the pulsations for 15 seconds and multiply the number by four. The result is your pulse or heart rate. It will take some practice to find those pulsations coming from your radial artery. If you can’t find it, ask a nurse or doctor for help.

Like all rules-of-thumb, this target heart rate zone isn’t always an accurate gauge of cardiovascular workout intensity. For instance, it is of very little use in people taking drugs called beta blockers, which keep a lid on heart rate.

As you become more fit, you’ll notice that you have to work harder to get your heart rate up to a certain level. This is a sure sign that your heart and muscles are responding to your challenge. You may also want to monitor your resting heart rate taken in the morning before you get out of bed. Unfit, sedentary people have resting pulses of 60 to 90. Athletes are more often in the 40s or low 50s. Their hearts have become more efficient and just don’t need to beat as often to get the job done.

As you become more fit, you’ll also notice that you have more energy overall and it’s easier to move about and handle physical workloads. You’ll feel more relaxed and have a sense of accomplishment. Expect these benefits eight to 12 weeks after starting a regular exercise program.

Steve Parker, M.D.

Nuts Improve Blood Sugar and Cholesterol in Diabetics

Eating nuts improves blood sugar control and cholesterol levels in type 2 diabetics, according to a research report in Diabetes Care.

Canadian researchers randomized 117 type 2 diabetics to eat their usual types of food, but also to be sure to eat either

  • mixed nuts (about 2 ounces a day)
  • muffins (I figure one a day)
  • or half portions of each.

They did this daily for three months. Compared to the muffin group, the full nut group ate quite a bit more monounsaturated fatty acids. (I don’t have full study details because I have access only to the article abstract.)

Results

Hemoglobin A1c, a reliable measure of blood sugar control, fell by 0.21% in the mixed nut group. That’s a move in the right direction. LDL cholesterol, the “bad cholesterol” linked to heart and vascular disease, also dropped significantly.

So What?

The investigators suggest that replacement of certain carbohydrates with 2 ounces of daily mixed nuts is good for people with type 2 diabetes.

I must mention that nuts are a mandatory component of the Ketogenic Mediterranean Diet and the Low-Carb Mediterranean Diet, and a recommended option on the Advanced Mediterranean Diet.

Steve Parker, M.D.

References: Jenkins, David J.A., et al. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care, June 29, 2011. doi: 10.2337/dc11-0338

PS: The lead author of this study is the same David Jenkins of glycemic index fame.

Mediterranean Diet Ranked No.2 Overall

US News and World Report last year ranked 20 popular diets for weight loss, overall healthfulness, and diabetes and heart disease management. Overall best diet was awarded to the DASH diet. Mediterranean came in No.2. The Mayo Clinic has free info on the DASH diet. Here’s my definition of the Mediterranean diet.

Click for my weight-loss version of the Mediterranean diet: The Advanced Mediterranean Diet (2nd Edition).

Steve Parker, M.D.

Spanish Ketogenic Mediterranean Diet Cures Metabolic Syndrome

The very-low-carb Spanish Ketogenic Mediterranean Diet cures metabolic syndrome, according to investigators at the University of Córdoba in Spain. The metabolic syndrome is a collection of clinical factors that are linked to high risk of developing type 2 diabetes and heart disease. Individual components of the syndrome include elevated blood sugar, high trigylcerides, low HDL cholesterol, high blood pressure, and abdominal fat accumulation.

Spanish researchers put 26 people with metabolic syndrome on the Spanish Ketogenic Mediterranean Diet for twelve weeks and monitored what happened. At baseline, average age was 41 and average body mass index was 36.6. Investigators didn’t say how many diabetics or prediabetics were included. No participant was taking medication.

What’s the Spanish Ketogenic Mediterranean Diet?

Calories are unlimited, but dieters are encouraged to keep carbohydrate consumption under 30 grams day. They eat fish, lean meat, eggs, chicken, cheese, green vegetables and salad, at least 30 ml (2 tbsp) daily of virgin olive oil, and 200-400 ml of red wine daily ( a cup or 8 fluid ounces equals 240 ml). On at least four days of the week, the primary protein food is fish. On those four days, you don’t eat meat, chicken, eggs, or cheese. On up to three days a week, you could eat non-fish protein foods but no fish on those days.

How’s this different from my Ketogenic Mediterranean Diet? The major differences are that mine includes one ounce (28 g) of nuts daily, less fish overall, and you can mix fish and non-fish protein foods every day.

Regular exercisers were excluded from participation, and my sense is that exercise during the diet trial was discouraged.

What Were the Results?

Metabolic syndrome resolved in all participants.

Three of the original 26 participants were dropped from analysis because they weren’t compliant with the diet. Another one was lost to follow-up. Final analysis was based on the 22 who completed the study.

Eight of the 22 participants had adverse effects. These were considered slight and mostly appeared and disappeared during the first week. Effects included weakness, headache, constipation, “sickness”, diarrhea, and insomnia.

Average weight dropped from 106 kg (233 lb) to 92 kg (202 lb).

Body mass index fell from 36.6 to 32.

Average fasting blood sugar fell from 119 mg/dl (6.6 mmol/l) to 92 mg/dl (5.1 mmol/l).

Triglycerides fell from 225 mg/dl to 110 mg/dl.

Average systolic blood pressure fell from 142 mmHg to 124.

Average diastolic blood pressure fell from 89 to 76.

So What?

A majority of people labeled with metabolic sydrome continue in metabolic sydrome for years. That’s because they don’t do anything effective to counteract it. These researchers show that it can be cured in 12 weeks, at least temporarily, with the Spanish Ketogenic Mediterranean Diet.

Very-low-carb diets are especially good at lowering trigylcerides, lowering blood sugar, and raising HDL cholesterol. Overweight dieters tend to lose more weight, and more quickly, than on other diets. Very-low-carb diets, therefore, should be particularly effective as an approach to metabolic syndrome. It’s quite possible that other very-low-carb diets, such as Atkins Induction Phase, would have performed just as well as the Spanish Ketogenic Mediterranean Diet. In fact, most effective reduced-calorie weight-loss diets would tend to improve metabolic syndrome, even curing some cases, regardless of carb content.

Most physicians recommend that people with metabolic syndrome either start or intensify an exercise program. The program at hand worked without exercise. I recommend regular exercise for postponing death and other reasons.

Will the dieters of this study still be cured of metabolic syndrome a year later? Unlikely. Most will go back to their old ways of eating, regaining the weight, and moving their blood sugars, triglycerides, and HDL cholesterols in the wrong direction.

Steve Parker, M.D.

Reference: Pérez-Guisado J, & Muñoz-Serrano A (2011). A Pilot Study of the Spanish Ketogenic Mediterranean Diet: An Effective Therapy for the Metabolic Syndrome. Journal of medicinal food PMID: 21612461

Quote of the Day

Success is the sum of small efforts, repeated day in and day out…

—Robert Collier

Waist-Hip Ratio: What Is It, and What’s Yours?

A comment left under my recent Diabetic Mediterranean Diet blog post on healthy weight ranges reminded me about the waist-hip ratio.

The risk of heart and vascular disease is more closely linked to distribution of excess fat than with degree of obesity as measured by overall weight or body mass index. Waist-hip ratio (WHR) is a measure of abdominal or central obesity, the type of fat distribution associated with coronary artery disease. A high ratio indicates the android body habitus. To determine your waist-hip ratio:

  1. While standing, relax your stomach—don’t pull it in. Measure around your waist mid-way between the bottom of the rib cage and the top of your pelvis bone. Usually this is at the level of your belly button, or an inch higher. Don’t go above the rib cage. Keep themeasuring tape horizontal to the ground and don’t compress your skin.
  2. Then measure around your hips at the widest part of your buttocks. Keep the tape horizontal to the ground and don’t compress your skin.
  3. Divide the waist by the hip measurement.The result is your waist-hip ratio.

For example, if your waist is 44 inches (112 cm) and hips are 48 inches (122 cm): 44 divided by 48 is 0.92, which is your waist-hip ratio.

Scientists haven’t yet determined the ideal WHR, but it is probably around 0.85 or less for women, and 0.95 or less for men. Ratios above 1.0 are clearly associated with risk of cardiovascular disease such as heart attacks. The higher the ratio, the higher the risk. Compared with body mass index, WHR is a much stronger predictor of coronary artery disease. Several of the other obesity-related illnesses are also correlated with WHR, but the relationship between WHR and cardiovascular disease is particularly strong.

Steve Parker, M.D.

Starting Hillfit

Today I started Chris Highcock’s Hillfit exercise program.  It’s basically four exercises I can probably finish in 40 minutes a week, split into two sessions.

In addition I’ll be doing twice-weekly interval training on a treadmill:

  1. 3-minute warm-up at 5.3 mph, then
  2. 12 minutes of 1-minute fast runs (7-8 mph) alternating with 1-minute slow jogging (5.3 mph), then
  3. 3-minute cool-down by walking 2.5-3 mph

I’ll dial a 1% grade into the treadmill to simulate wind resistance I’d get if outdoors.

After six or eight weeks I’ll switch to another program, such as Jonathan Bailor’s Smarter Science of Slim, which also promises reasonable fitness with relatively little time and equipment investment.

If you hope to exercise regularly, you’ll need to be motivated.  I’ve recorded my motivations.  What’re yours? 

Steve Parker, M.D.

Does Diminished Work Activity Explain Our 50-Year Overweight Trend?

Daily work-related energy expenditure over the last half-century in the U.S. has decreased by over 100 calories. This may well explain the increase in body weights we’ve seen, according to a 2011 article in PLoS ONE.

I sorta hate to open this can o’ worms, but it’s important. As a population, are we fat because we eat too much or because we burn too few calories in physical activity? Or is it a combination? The correct answer may help us learn how to reverse the trend.

Methodology

Authors of the study at hand estimated the amount of energy (calories) necessary to perform various jobs, then noted changes in numbers of people employed in those jobs over time. In the early 196os, for example, nearly half of U.S. jobs required at least moderate intensity physical activity, compared to less than 20% demanding that degree of energy now. The authors note the dramatic shift from manufacturing to service-type jobs over the last 50 years. Service jobs, like mine, often entail a lot of sitting and standing around.

They chose to ignore how much energy we expend in exercise, figuring what we do in a 40-hour work week overwhelms the 1-2 hours of exercise we may do.

Researchers’ Findings and Conclusions

They found that work-related daily energy expenditure has decreased by over 100 calories over the last half-century, which (in the authors’ view) would account for a significant portion of the increased body weight we’ve seen. Since physically demanding jobs are unlikely to see a resurgence, the authors advocate physically active lifestyles away from workplace.

Discussion

Surveys indicate that only one in four of us fulfill the federal physical activity guidelines: 150 minutes a week of moderate intensity activity or 75 minutes a week of vigorous intensity activity. When activity is actually measured with an accelerometer, only one in 20 achieve that lofty goal. We over-estimate how much we exercise, and under-estimate how much we eat.

The researchers cite studies showing significantly increased average per capita calorie consumption in the U.S. over the last several decades. Some experts estimate the caloric increase is in the range of 500 a day for adults; the authors here think that’s too high but don’t offer a specific alternative. Looking at one of their references (Hall et al), they must think the increase is closer to 200 calories a day, comparing 2005 to 1975.

Several studies suggest that average daily energy expenditure has not decreased in developed countries, at least from the 1980s to the present. A strength of the current study at hand is that it spans about 50 years, up to 2008.

My sense is that both calorie consumption (too much) and physical activity (too little) contribute to our overweight problem that started 40 or 50 years ago. Excessive consumption is the predominant factor. To “exercise off” the calories in a Snickers candy bar, you’d have to jog for an hour. If you’re watching your weight, you’ll have more success if you just skip the Snickers.

In case you couldn’t tell, I still believe in the “calories in/calories out” model of overweight and obesity, aka “the energy balance equation.” At the same time, I believe certain calories are more fattening than others: concentrated sugars and refined starches.

Steve Parker, M.D.

References:

Church, T., Thomas, D., Tudor-Locke, C., Katzmarzyk, P., Earnest, C., Rodarte, R., Martin, C., Blair, S., & Bouchard, C. (2011). Trends over 5 Decades in U.S. Occupation-Related Physical Activity and Their Associations with Obesity PLoS ONE, 6 (5) DOI: 10.1371/journal.pone.0019657

Swinburn, B., et al. Increased food energy supply is more than sufficient to explain the U.S. epidemic of obesity. American Journal of Clinical Nutrition, 2009 (90): 1,453-1,456.

Hall, K.D., et al. The progressive increase of food waste in America and its environmental impact. PLoS ONE, 2009, 4(11): e7940. doi: 10.1371/journal.pone.0007940

Does Loss of Excess Weight Improve Longevity?

Intentional weight loss didn’t have any effect either way on risk of death, according to research out of Baltimore. Surprising, huh?

Obesity tends to shorten lifespan, mostly due to higher rates of cancer and cardiovascular disease like heart attacks and strokes. Doctors and dietitians recommend loss of excess weight all day long, figuring it will reduce the risk of obesity-related death and disease. That’s not necessarily the case, however. It’s called the “obesity paradox“: some types of overweight and obese patients actually seem to do better (e.g., live longer) if they’re above the so-called healthy body mass index of 18.5 to 24.9. For instance: those with heart failure, coronary artery disease, and advanced kidney disease.

It’s never really been clear whether the average obese person (body mass index over 30) improves his longevity by losing some excess weight. That’s what the study at hand is about.

Methodology

Baltimore-based investigators followed the health status of 585 overweight or obese older adults over the course of 12 years. Half of them were randomized to an intentional weight loss intervention. All of them had a high blood pressure diagnosis. Average age was 66. Average body mass index was 31. Details of the weight-loss intervention are unclear, but it was probably along the lines of “eat less, exercise more.”

What Did They Find?

The weight-loss group lost and maintained an average of 4.4 kg (9.7 lb) over the 12 years of the study. This is about 5% of initial body weight, the minimal amount thought to be helpful for improvement in weight-related medical problems. Most of the weight loss was over the first three years.

The men assigned to the weight-loss program had about half the risk of dying over the course of the study, compared to the men not assigned to weight loss. The authors don’t seem to put much stock in it, however, stating that “…no significant difference overall was found in all-cause mortality between older overweight and obese adults who were randomly assigned to an intentional weight-loss intervention and those who were not.”

Comments

With regards to the men losing weight, we’re only talking about 100-150 test subjects, a relatively small number. So I understand why the researchers didn’t make a big deal of the lower mortality: it may not be reproducible.

This same research group did a similar study of 318 arthritis patients and intentional weight loss, finding a 50% lower death rate over eight years.

The authors reviewed many similar studies done by other teams, noting increased death rates from weight loss in some studies, and lesser death rates in others.

When the studies are all over the place like this, it usually means there’s no strong association either way. Nearly all the pertinent studies were done on relatively healthy, middle-aged and older folks. The most reliable thing you can say about the issue is that loss of excess fat weight doesn’t increase your odds of premature death.

Remember that patients with coronary heart disease, congestive heart failure, or advanced kidney disease tend to live longer if they’re overweight or at least mildly obese. It’s the obesity paradox. Will they live longer or die earlier if they go on a weight-loss program? We don’t know.

We do know that intentional weight loss helps:

  • prevent type 2 diabetes
  • maintain reasonable blood pressures (avoiding high blood pressure)
  • improves lower limb functional ability

Maybe that’s enough.

Steve Parker, M.D.

Reference: Shea MK, Nicklas BJ, Houston DK, Miller ME, Davis CC, Kitzman DW, Espeland MA, Appel LJ, & Kritchevsky SB (2011). The effect of intentional weight loss on all-cause mortality in older adults: results of a randomized controlled weight-loss trial. The American journal of clinical nutrition, 94 (3), 839-46 PMID: 21775558