July 24, 2011 · 2:00 AM

Research Round-Up

 

I have a stack of scientific articles I’ve been meaning to review in depth and blog about.  But I have to finally admit I don’t have the time.  Here they are.  Click through for details.

  1. Long-term calorie restriction in humans appears highly effective in reducing atherosclerosis risk factors (lab tests) and actual carotid artery atherosclerosis. Only 18 study subjects, however.
  2. A very-low-carbohydrate diet improved memory in older adults with mild cognitive impairment over six weeks.  Twenty-three subjects were randomized to either high-carb or very-low-carbohydrate diet.  The low-carbers improved verbal memory performance, lost weight, reduced fasting blood sugar and fasting insulin levels.  Ketone levels were positively correlated with memory performance.
  3. A high-fat diet impairs cognitive function and heart energy metabolism in young men.  Sixteen test subjects.  Crossover study design with a five-day high-fat diet deriving 75% of energy from fat, compared to a low-fat diet deriving 23% of energy from fat.  High-fat diet led to impaired attention, speed, and mood.  I’m sure low-carb bloggers have been all over this.  At first blush, it appears they were testing during “induction flu” phase of very-low-carb eating, between days 2 to 7 of a new ketogenic diet.  It takes several weeks to adapt metabolism to running almost entirely on fat rather than standard carbohydrates.  Suspect results would have been different if given time to adapt.
  4. Weight-loss with the laparoscopic gastric banding procedure has poor long-term outcome, according to Belgian surgeons reporting on 82 patients.  Four in 10 patients had major complications.  Nearly half of the 82 patients needed to have the bands removed, and six of every 10 required some kind of re-operation.
  5. Trust me, you DON’T want age-related macular degeneration.  Women, reduce your risk of ARMD with a healthy lifestyle, including regular exercise, avoidance of smoking,  and by eating abundant plant foods (vegetables [including orange and dark leafy green ones], fruits, and whole grains) and limit foods high in fat, refined starches, sugar, alcohol, and oils.  At least according to these researchers. 
  6. Leafy green vegetables and olive oil are linked to reduced heart disease (CHD) in Italian women.  Fruit consumption had no effect.  This is from a subset of the huge EPIC study, following 30,000 women over almost eight years.
  7. The Mediterranean diet protects against metabolic syndrome, reducing risk by about a third according to a huge meta-analysis from Greek and Italian investigators.  It works best in Mediterranean countries. 
  8. The Mediterranean diet was linked to slower rates of cognitive decline in Chicago residents over the course of almost eight years.  The comparison diet was the Healthy Eating Index-2005.  Of the 3,800 participants, about two-thirds were black.  A Manhattan population showed lower risk of dementia when eating Mediterranean-style.

There ya’ go.  This is better than letting the articles just sit in my briefcase for months on end, eventually to be thrown out.

Steve Parker, M.D.

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July 21, 2011 · 2:00 AM

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.

ResearchBlogging.orgVery-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

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July 18, 2011 · 2:17 AM

Waist-Hip Ratio: How to Determine, and What It Means

High WHR

A comment left under my recent 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.  The Journal of the American College of Cardiology two months ago reported that heart patients (coronary artery disease) with “central obesity” had a greater risk of death.  A high WHR is one measure of central obesity.

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 the
      measuring 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.

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July 11, 2011 · 2:00 AM

Healthy Weight Ranges

In the past it was pretty easy to find tables of recommended healthy body weights.  Not so much anymore.  Most of the experts want you calculate your body mass index, recommending the healthy BMI range as 18.5 to 24.9.  I just spent an hour putting together a healthy weight range based on BMIs.  Since I have many readers outside the U.S., I use both U.S. customary and metric numbers.

Metropolitan Life Insurance Company last published its ideal weight and height table in 1983.  The US Department of Agriculture abondoned its 1995 healthy weight table by the turn of the century recommending BMI calculation instead.  Of note is that the upper end of its weight ranges was a BMI of 25; the lower ends were all BMIs of 19. 

Body Mass Index (BMI) is your weight in kilograms divided by your height in meters squared (kg/m2).  A pound equals 2.2 kilograms. A pound equals about 454 grams (453.6 to be exact). An inch equals 2.54 centimeters.  There are 100 centimeters in one meter. Thus, a 5-foot, 4-inch woman (1.63 meters) weighing 200 pounds (91 kilograms) has a BMI of 34.2.  Perhaps you’re starting to understand why this weight standard isn’t too popular yet.

 To learn your own BMI but skip the math, use an online calculator.

 To see if your BMI is in the healthy range of 18.5 to 24.9, find your height in the table below, then look to the healhy weight ranges to the right.  Measure your height without shoes and weight without clothes.

Table of Healthy Weight Ranges Based On Body Mass Index: 18.5 to 24.9

       Height               Weight in lb        Weight in kg

5’0” or 152 cm             95 – 128             43.0 – 58.0

5’1” or 155 cm             98 – 132             44.4 – 59.8

5’2” or 157 cm           101 – 137            45.8 – 62.1

5’3” or 160 cm           105 – 141             47.6 – 63.9

5’4” or 163 cm           108 – 146             48.9 – 66.2

5’5” or 165 mc           111 – 150             50.3 – 68.0

5’6” or 168 cm           115 – 155             52.0 – 70.3

5’7” or 170 cm           118 – 160             53.5 – 72.5

5’8” or 173 cm           122 – 164             55.3 – 74.3

5’9” or 175 cm           125 – 169             51.7 – 76.6

5’10” or 178 cm         129 – 174             58.5 – 78.9

5’11” or 180 cm         133 – 179             60.3 – 81.8

6’0”  or 183 cm          137 – 184             62.1 – 83.4

6’1” or 185 cm           140 – 189              63.5 – 85.7

6’2” or 188 cm           144 – 195             65.3 – 88.4

6’3” or 191 cm           148 – 200             67.1 – 90.7

6’4” or 193 cm           152 – 205             68.9 – 92.9

BMIs between 25 and 29.9 designate “overweight” and accurately describe about 35 percent of the United States population.

A BMI of 30 or higher defines “obesity” and indicates high risk for poor health. About 30 percent of us are obese. At a BMI of 35 and above, incidence of death and disease increases sharply.

The BMI concept is helpful to researchers and obesity clinicians, but the number doesn’t mean much yet to the average person on the street and to many physicians. It should be used more widely. (I know, I know: it’s not perfect.  Do you have a better, cheap, widely applicable alternative?)  Know your BMI. If it’s under 25, any excess fat you carry is unlikely to affect your health and longevity; your efforts to lose weight would be purely cosmetic.

Steve Parker, M.D.

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July 9, 2011 · 10:42 AM

Dr. Jay Wortman Chooses Ketogenic Diet for His Type 2 Diabetes

 The Low Carb Diabetic blog posted a video of Dr. Jay Wortman discussing treatment of his own type 2 diabetes with a very-low-carb ketogenic diet.  Well worth a listen if you’re skeptical about whether it works.

Steve Parker, M.D.

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July 8, 2011 · 2:00 AM

Quote of the Day

White flour is better suited to glue for kindergarten art projects than to nutrition.

    —Drs. Westman, Phinney, and Volek in The New Atkins for a New You

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July 5, 2011 · 2:00 AM

Book Review: The Art and Science of Low Carbohydrate Living

I just finished reading The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable, by Stephen Phinney, M.D., Ph.D., and Jeff Volek, Ph.D. published this year.  I give it four stars per Amazon.com’s rating system ( I like it).

♦    ♦    ♦

The authors medicalize overweight and obesity by naming the cause of most cases to be “carbohydrate intolerance,” along the lines of lactose intolerance and gluten intolerance.  Given the myriad illnesses and shortened lifespan associated with obesity, medicalizing it isreasonable.  Ask Gary Taubes why we get fat, and he’ll say it’s excessive consumption of carbohydrates, especially sugars and refined flours.  Ask Phinney and Volek, and they’ll say “carbohdyrate intolerance.”  For them, the “treatment” is avoidance of carbs.

If a patient asks me why he’s fat, I guess I’d prefer to say “you have carbohydrate intolerance,” rather than “you eat too many carbs.”  It’s less confrontational and doesn’t blame the patient.

So how many of us in the U.S. have carbohydrate intolerance?  The authors estimate a hundred million or more – about a third of the total poplulation, or more, who could directly benefit from carbohydrate restriction.  I agree.

Before reading this book, I was convinced that carbohydrates are indeed major contributors to overweight and obesity, especially concentrated sugars and refined grains.  The authors cite much of the pertinent scientific/medical literature. 

Gary Taubes made the same case in his brilliant book, Good Calories, Bad Calories.  Dr. Robert Atkins argued the same in Dr. Atkins New Diet Revolution.  The problem is that many healthcare providers such as physicians and dietitians are biased against those sources.  Physicians resist a non-physician such as Taubes giving them advice about the practice of medicine.  And most physicians over 45 still labor under the misconception that dietary cholesterol and total and saturated fat are major-league killers, so they’ve already dismissed Dr. Atkins and don’t have time to get caught up to date on the recent research.

Phinney and Volek have wisely targeted this work towards healthcare providers such as physicians, so it’s somewhat technical and clinical.  Both have Ph.D.s and Phinney is also an M.D.  The authors are respected researchers who thoroughly review the science behind low-carb eating.  They explain how high blood pressure, metabolic syndrome, type 2 diabetes, and other conditions are related to carb consumption.

I rate the book four stars instead of five only because it’s a little pricey at $29 (US).

Smart nutrition- and fitness-minded folks will also benefit from a reading.  For a more consumer-oriented book, I recommend the authors’ The New Atkins for a New You or Taubes’ Why We Get Fat.

Steve Parker, M.D.

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July 2, 2011 · 10:13 PM

Nutty Treatment for Diabetes

Mixed Nuts Improve Diabetes

Eating nuts improves blood sugar control and cholesterol levels in type 2 diabetics, according to a recent 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.

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June 27, 2011 · 5:20 AM

Exercise, Part 11: 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.

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June 24, 2011 · 2:00 AM

Finally Settled: Alcohol Consumption Linked to Lower Rates of Death and Heart Attack

Canadian and U.S. researchers report that moderate alcohol consumption seems to reduce 1) the incidence of coronary heart disease, 2) deaths from coronary heart disease, and 3) deaths from all causes.  Reduction of death from all causes is a good counter-argument to those who say alcohol is too dangerous because of deaths from drunk driving, alcoholic cirrhosis, and alcohol-related cancers such as many in the esophagus. 

Remember, we’re talking here about low to moderate consumption: one drink a day or less for women, two drinks or less a day for men.  That’s a max of 12.5 grams of alcohol for women, 25 g for men.  No doubt, alcohol can be extremely dangerous, even lethal.  I deal with that in my patients almost every day.  Some people should never drink alcohol.

The recent meta-analysis in the British Medical Journal, which the authors say is the most comprehensive ever done, reviewed all pertinent studies done between 1950 and 2009, finally including 84 of the best studies on this issue.  Thirty-one of these looked at deaths from all causes.

Compared with non-drinkers, drinkers had a 25% lower risk of developing coronary heart disease (CHD) and death from CHD.  CHD is the leading cause of death in develop societies.

Stroke is also considered a cardiovascular disease.  Overall, alcohol is not linked to stroke incidence or death from stroke.  The researchers did see strong trends toward fewer ischemic strokes  and more hemorrhagic strokes (bleeding in the brain) in the drinkers.  So the net effect was zero. 

Compared with non-drinkers, the lowest risk of death from any cause was seen in those consuming 2.5 to 14.9 g per day (one drink or less per day), whose risk was 17% lower.  On the other hand, heavy drinkers (>60 g/day) had 30% higher risk of death. 

In case you’re wondering, the authors didn’t try to compare the effects of beer versus wine versus distilled spirits. 

On a related note, scientists at the Medical University of South Carolina found that middle-aged people who took up the alcohol habit had a lower risk of stroke and heart attack.  Wine seemed to be more effective than other alcohol types.  They found no differences in overall death rates between new drinkers persistent non-drinkers, perhaps because the study lasted only four years and they were following only 442 new drinkers.  

This doesn’t prove that judicious alcohol consumption prevents heart attacks, cardiac deaths, and overall deaths.  But it’s kinda lookin’ that way.

Steve Parker, M.D.

 References:  Ronksley, Paul, et al.  Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis.  British Medical Journal, 2011;342:d671    doi: 10.1136/bmj.d671

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