Category Archives: Carbohydrate

August 7, 2010 · 2:00 AM

Low-Fat and Low-Carb Diets End Battle in Tie After Two Years, But…

Dieters on low-fat and low-carb diets both lost the same amount of weight after two years, according to a just-published article in Annals of Internal Medicine.  Both groups received intensive behavioral treatment, which may be the key to success for many.  Low-carb eating was clearly superior in terms of increased HDL cholesterol, which may help prevent heart disease and stroke.

The study was funded by the National Institutes of Health and was carried out in Denver, St. Louis, and Philadelphia.

How Was It Done?

Healthy adults aged 18-65 were randomly assigned to either a low-fat or low-carbohydrate diet.  Average age was 45.  Average body mass index was 36 (over 25 is overweight; over 30 is obese).  Of the 307 participants, two thirds were women.  People over 136 kg (299 lb) were excluded from the study—I guess because weight-loss through dieting is rarely successful at higher weights.  Diabetics were excluded. 

The low-carb diet:  Essentially the Atkins diet with a prolonged induction phase (12 weeks instead of two).  Started with maximum of 20 g carbs daily, as low-carb vegetables.  Increase carbs by 5 g per week thereafter as long as weight loss progressed as planned.  Fat and protein consumption were unlimited.  The primary behavioral goal was to limit carb consumption.

The low-fat diet:  Calories were limited to 1200-1500 /day (women) or 1500-1800 (men).  [Those levels in general are too low, in my opinion.]  Diet was to consist of about 55% of calories from carbs, 30% from fat, 15% from protein.  The primary behavioral goal was to limit overall energy (calorie) intake. 

Both groups received frequent, intensive in-person group therapy—lead by dietitians and psychologists—periodically over two years, covering such topics as self-monitoring, weight-loss tips, management of weight regain and noncompliance with assigned diet.  Regular walking was recommended.

Body composition was measured periodically with dual X-ray absorptiometry.

What Did They Find?

Both groups lost about 11% of initial body weight, but tended to regain so that after two years, both groups average losses were only 7% of initial weight.  Weight loss looked a little better at three months in the low-carb group, but it wasn’t statistically significant. 

The groups had no differences in bone density or body composition.

No serious cardiovascular illnesses were reported by participants.  During the first six months, the low-carb group reported more bad breath, hair loss, dry mouth, and constipation.  After six months, constipation in the low-carb group was the only symptom difference between the groups.

During the first six months, the low-fat group had greater decreases in LDL cholesterol (with potentially less risk of heart disease), but the difference did not persist for one or two years.

Increases in HDL cholesterol (potentially heart-healthy) persisted throughout the study for the low-carb group.  The increase was 20% above baseline.

About a third of participants in both groups dropped out of the study before the two years were up.  [Not unusual.]

My Comments

Contrary to several previous studies that suggested low-carb diets are more successful than low-fat, the study at hand indicates they are equivalent as long as dieters get intensive long-term group behavioral intervention. 

Low-carb critics warn that the diet will cause osteoporosis, a dangerous thinning of the bones that predisposes to fractures.  This study disproves that.

Contrary to widespread criticism that low-carb eating—with lots of fat and cholestrol— is bad for your heart, this study notes a sustained elevation in HDL cholesterol (“good cholesterol”) on the low-carb diet over two years.  This also suggests the low-carbers  followed the diet fairly well.  The investigators also note that low-carb eating tends to produce light, fluffy LDL cholesterol, which is felt to be less injurious to arteries compared to small, dense LDL cholesterol.

A major strength of the study is that it lasted two years, which is rare for weight-loss diet research.

A major weakness is that the investigators apparently didn’t do anything to document the participants’ degree of compliance with the assigned diet.  It’s well known that many people in this setting can follow a diet pretty well for two to four months.  After that, adherence typically drops off as people go back to their old habits.  The group therapy sessions probably improved compliance, but we don’t know since it wasn’t documented. 

How often do we hear “Diets don’t work.”  Well, that’s just wrong.

Overall, it’s an impressive study, and done well. 

Individuals wishing to lose weight on their own can’t replicate these study conditions because of the in-person behavioral intervention component.  There are lots of self-help calorie-restricted balanced diets (e.g., Sonoma Diet, The Zone,  Advanced Mediterranean Diet) and low-carb diets (e.g., Atkins Diet, Banting’s Letter on Corpulence, Low-Carb Mediterranean or Ketogenic Mediterranean Diets).  On-line support groups—e.g. Low Carb Friends and SparkPeople and 3 Fat Chicks on a Diet—could supply some necessary behavioral intervention strategies and support.  

Choosing a weight-loss program is not as easy as many think.  [Well, I’ll admit that choosing the wrong one is easy.]  I review the pertinent issues in my “Prepare for Weight Loss” page.

Steve Parker, M.D.

Reference: Foster, Gary, et al.  Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial. Annals of Internal Medicine, 153 (2010): 147-157   PMID: 20679559

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June 25, 2010 · 2:00 AM

Seminal Paper: Carbohydrate Restriction for Type 2 Diabetes and Metabolic Syndrome

Carbohydrate-restricted eating is slowly gaining mainstream acceptance as treatment for type 2 diabetes and metabolic syndrome.  I thought it would be useful to present one of the watershed reports that summarize the potential benefits.  The article is from 2008.  Among the co-authors are some of the brightest names in this field: Richard K. Bernstein, Annika Dahlqvist, Richard Feinman, Eugene J. Fine, Robert Lustig, Uffe Ravnskov, Jeff Volek, Eric Westman, and Mary C. Vernon.

ResearchBlogging.orgThese are not wild-eyed, bomb-throwing radicals.  They are on faculty at some of the best institutes of higher learning.  They note that while many of the national diabetes organizations downplay the benefits of carb restriction, we have enough evidence now to warrant careful reconsideration.

Here are some of their major points, all backed up by references (68) from the scientific literature:

  1. Glucose (blood sugar) is a “major control element,” whether directly or indirectly through insulin, in glycogen metabolism, production of new glucose molecules, and in formation and breakdown of fat.
  2. The potential adverse effects of dietary fat are typically seen with diets high in carbohydrate.
  3.  Carb restriction improves control of blood sugars, a major target of diet therapy.  Many of the supportive studies were done with overweight or obese people (85% of type 2 diabetics are overweight).  Very low-carb diets are often so effective that diabetic medications have to be reduced at the outset of the diet. 
  4. For weight loss, carb-restricted diets work at least as well as low-fat diets.  They are usually superior. 
  5. Carb-restricted diets usually replace carbs with fat, resulting in improve markers for cardiovascular disease (lower serum triglycerides and higher HDL cholesterol levels). Replacing dietary fat with carbohydrate—the goal of many expert nutrition panels over the last 40 years—tends to increase the amount of artery-damaging “small, dense LDL cholesterol” in most of the population. 
  6. Carbohydrate restriction improves all five components of the metabolic syndrome: obesity, low HDL cholesterol, high triglycerides, high blood pressure, elevated blood sugar.
  7. Beneficial effects of carbohydrate restriction seem to occur even without weight loss. 
  8. Still worried about excessive fat consumption?  Many low-carb dieters demonstrate a significant increase in the percentage of total calories from fat, but without an increase in the absolute amount of fat eaten.  That’s because they simply reduced their total calories by reducing carb consumption. 

This post was chosen as an Editor's Selection for ResearchBlogging.orgThe authors in 2008 called for a widespread reappraisal of carbohydrate restriction for type 2 diabetes and metabolic syndrome.  It’s been happening, and many patients are reaping the benefits.

Steve Parker, M.D.

Reference: Accurso A, Bernstein RK, Dahlqvist A, Draznin B, Feinman RD, Fine EJ, Gleed A, Jacobs DB, Larson G, Lustig RH, Manninen AH, McFarlane SI, Morrison K, Nielsen JV, Ravnskov U, Roth KS, Silvestre R, Sowers JR, Sundberg R, Volek JS, Westman EC, Wood RJ, Wortman J, & Vernon MC (2008). Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal. Nutrition & metabolism, 5 PMID: 18397522

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June 18, 2010 · 2:00 AM

Sugar-Sweetened Beverages: Bane of Mankind?

Over the last 30 years in the U.S., consumption of sugar-sweetened beverages (SSBs) has increased from3.9% of total calories to 9.2% (in 2001).  In that same time span, the percentage of overweight American adults increased from 47% to 66%.  The obesity percentage rose from15 to 33% of adults. 

[Did the beverages cause the weight gain, or are they just associated?] 

Those are just a few of the many facts shared by the authors of “Sugar-sweetened beverages, obesity, type 2 diabetes mellitus, and cardiovascular disease risk,” published recently in Circulation.  Sugar-sweetened beverages, by the way, include soft drinks, fruit drinks, energy drinks, and vitamin water drinks. 

ResearchBlogging.orgSounds like an interesting article, doesn’t it?  It’s written by some of the brightest lights in nutritional science, including George Bray and Frank Hu.  Unfortunately, the article is a little too boring and technical for most of my readers.  Here are a few tidbits I enjoyed:

  • Fructose (found in similar amounts in sucrose (table sugar) and high fructose corn syrup) may particularly predispose us to deposit fat in and around our internal abdominal organs (“visceral fat,” which some believe to be more unhealthy than fat  in our buttocks or thighs).
  • Fructose may also lead to fat deposits in cells other than fat cells, potentially interfering with cell function.
  • Fructose may adversely affect lipid metabolism (higher triglyceride levels and lower HDL levels, which could promote heart disease).
  • Fructose raises blood pressure and reduces insulin sensitivity.
  • In the liver, fructose is preferentially converted to lipid, causing high triglyceride levels (associated with heart disease and insulin resistance).  [The authors did not mention the common condition of “fatty liver” (aka hepatic steatosis) in this context.]

Some of the authors conclusions:

  • SSBs are the largest contributor to added-sugar intake in the U.S.
  • SSBs contribute to weight gain.
  • SSBs may cause type 2 diabetes and cardiovascular disease—separate from their effect on obesity—via high glycemic load and increased fructose metabolism, in turn leading to insulin resistance, inflammation, pancreas beta cell impairment, high blood pressure, visceral fat build-up, and adverse effects on blood lipids.

I especially like their final sentence:

For these reasons and because they have little nutritional value, intake of SSBs should be limited, and SSBs should be replaced by healthy alternatives such as water.

Steve Parker, M.D.

Reference: Malik, V., Popkin, B., Bray, G., Despres, J., & Hu, F. (2010). Sugar-Sweetened Beverages, Obesity, Type 2 Diabetes Mellitus, and Cardiovascular Disease Risk Circulation, 121 (11), 1356-1364 DOI: 10.1161/CIRCULATIONAHA.109.876185

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May 27, 2010 · 12:31 AM

Book Review: Diabetes Solution – The Complete Guide to Achieving Normal Blood Sugars

Here’s my review of Dr. Bernstein’s Diabetes Solution: The Complete Guide to Achieving Normal Blood Sugars, published in 2007.  Per Amazon.com’s rating scale, I give it five stars (I love it).  

♦   ♦   ♦ 

Dr. Richard K. Bernstein gives away thousands of dollars’ worth of medical advice in this masterpiece, Diabetes Solution.  It’s a summation of his entire medical career and a gift to the diabetes community.  

The book starts off with some incredible testimonials: reversal of diabetic nerve damage, eye damage, and erectile dysfunction.  They’re a bit off-putting to a skeptic like me, like an infomercial.  Dr. Bernstein is either lying about these or he’s not; I believe him.  His strongest testimonial is his own.  He’s been a type 1 diabetic most of his life, having acquired the disease at a time when most type 1’s never saw 55 candles on a birthday cake.  He’s in his mid-70s now and still working vigorously.  

I only found one obvious error and assume it’s a misprint. He writes that 95% of people born today in the U.S. will eventually develop diabetes.  That’s preposterous.  The U.S. Centers for Disease Control predicts that one in three born in 2000 will be diagnosed.  

Dr. Bernstein delivers lots of facts that I can neither confirm nor refute.  He’s a full-time diabetologist; I am not.  

"Put down the bread and no one will get hurt!"

  

The central problem in type 1 diabetes is that, due to a lack of insulin,  ingested carbohydrates lead to spikes (elevations) in blood sugar.  The sugar elevations themselves are toxic.  The usual insulin injections are not good imitators of a healthy pancreas gland. So Dr. Bernstein is an advocate of low-carb eating (about 30 g daily compared to the usual American 250-300 g).  He says the available insulins CAN handle the glucose produced by a high-protein meal.  

Dr. B reminds us that insulin is the main fat-building hormone, which is one reason diabetics gain weight when they start insulin, and why type 2 diabetics with insulin resistance (and high blood insulin levels) are overweight and have trouble losing weight.  You can have resistance to insulin’s blood sugar lowering action yet no resistance to its fat-building (fat-storing) action.  Insulin also stimulates hunger, so insulin-resistant diabetics are often hungry.  

“Carbohydrate counting” is a popular method for determining a dose of injected insulin.  Dr. B says the gram counts on most foods are only a rough estimate—far too rough.  He minimizes the error by minimizing the input (ingested carbs).  From his days as an engineer, he notes “small inputs, small mistakes.”  

Dr. B also cites problems with the absorption of injected insulin.  Absorption is variable: the larger the dose, the greater the variability.  So don’t eat a lot of carbs that require a large insulin dose.  For adult type 1 diabetics, his recommended rapid-acting insulins doses are usually three to five units.  If a dose larger than seven units is needed, split it into different sites.  

He recommends diabetics aim for normal glucoses (90 mg/dl or less) almost all the time, and hemoglobin A1c of 5% or less.  This is extremely tight control, tighter than any expert panel recommends.  He says this is the best way to avoid the serious complications of diabetes.   

Here’s a smattering of “facts” in the book that made an impact on me, a physician practicing internal medicine for over two decades.  I want to remember them, incorporate into my practice, or research further to confirm:  

  • Hemoglobin A1c of 5% equals an average blood sugar of 100 mg/dl (5.56 mmol/l).  For each one % higher, average glucose is 40 mg/dl (2.22  mmol/l) higher.
  • He’s against any drugs that overstimulate (“burn out”) the remaining pancreas function in type 2 diabetics: sulfonylureas, meglitinides, “phenylalanine derivatives”.  Pancreas-provoking agents cause hypoglycemia and destroy beta cell function.
  • The insulin sensitizers are metformin and thiazolidinediones.  He likes these.
  • Blood sugar normalization in type 2 diabetes and early-stage type 1 can help restore beta cell function.
  • He often speaks of preserving beta cell function.
  • He believes in “insulin-mimetic agents” like alpha lipoic acid (especially R-ALA, and take biotin with either form) and evening primrose oil.  These  are no substitute for insulin injections but allow for lower insulin doses.  ALA and evening primrose oil don’t promote fat storage like insulin does.
  • He says many cardiologists take ALA for its antioxidant properties [news to me]
  • He says rosiglitazone works within two hours [news to me] but later admits it may take 12 weeks to see maximal benefit
  • One of his goals is to preserve beta cell function if at all possible
  • He prefers rosiglitazone over pioglitazone due to fewer drug interactions
  • “Americans are fat largely because of sugar, starches, and other high-carbohydrate foods.”
  • He’s convinced that people who crave carbohydrates have inherited the problem, which also predisposes to insulin resistance and type 2 diabetes.  Low-carb diets decrease the cravings for many, in his experience.
  • In small amounts, alcohol is relatively harmless: dry wine, beer, spirits.  Very few doctors have the courage to say this.
  • If you’re in a restaurant, you can use urine sugar test strips and saliva to test for presence of sugar or flour in food
  • A rule of thumb: one gram of carbohydrate will raise blood sugar about 5 mg/dl (0.28  mmol/l) or less for most diabetic adults weighing 140 lb (64  kg) and about 2.5 mg/dl (0.139 mmol/l) in a 280-pounder (127  kg).  This must refer to type 1 diabetics or a type 2 with little residual pancreas beta cell function; variable degrees of insulin resistance and beta cell reserve in many type 2s would make this formula unreliable.
  • Be wary of maltodextrin in Splenda: it does raise blood sugar.
  • Much new to me in his section on artificial sweeteners.  Be wary of them.
  • He avoids all grains, breads, crackers, barley, oats, rice, and pasta.
  • Most diet sodas are OK.
  • Coffees with 1-2 tsp milk is OK.  Cream is OK.
  • He eats NO fruit and recommends against it.
  • He avoids beets, corn, potatoes, and beans. A slice of tomato in one cup of salad is OK.  A small amount of onion is OK.
  • String beans and snow peas are OK.
  • Cooked vegetables tend to raise blood sugar more rapidly than raw.
  • Use “Equal” aspartame tabs as a sweetener.  Don’t use “powdered” Splenda.
  • Avoid nuts: too easy to overeat.
  • For desert: sugar-free Jell-O Brand Gelatin.
  • Yogurt?  Plain, whole milk, unsweetened.  Flavor with cinnamon, Da Vinci syrups, baking flavor extracts, stevia or Equal.
  • Avoid balsamic vinegar.
  • Need fiber?  Bran crackers or soybean products.
  • “Ideally, your blood sugar should be the same after eating as it was before.”  85 mg/dl (4.72  mmol/l) is his usual goal.  If blood sugar rises by more than 10 mg/dl (0.56 mmol/l) after a meal, either the meal has to be changed or medication changed.
  • Protein is a source of glucose: keep protein amounts at meals constant from day to day, especially if taking glucose-lowering drugs.
  • The lowest-carb meal of the day should be breakafast.  Why?  Dawn phenomenon.
  • He promotes strenuous, prolonged exercise, especially weight training (extensive discussion and instruction in book).
  • Many diabetics on insulin need dose adjustments in 1/2 and 1/4 unit increments [news to me: if I ordered 4 and 1/4 units of insulin at the hospital, the nurses would laugh].
  • Typical rapid-acting insulin doses for his adult type 1 patients are 3-5 units.  The “industrial doses” of insulin seen or recommended by many physicians reflect diets too high in carbohydrate.
  • He says Lantus only acts for nine hours (nighttime injection) or 18 hours (AM injection).
  • He doesn’t like mixed insulins (e.g., 70/30).
  • Humalog and Novolog are more potent than regular insulin, so the dose is about 2/3 of the regular insulin dose
  • “Only a few of the 20 available [home glucose monitoring] machines are suitably accurate for our purposes.”  “None are suitably accurate or precise above 200 mg/dl [11.11 mmol/l].”
  • Vitamin C in doses over 250 mg interferes with fingertip glucose monitors.  Later he says doses over 500 mg cause falsely low readings.
  • He prefers regular insulin (45 minutes before meal) over Novolog and Humalog, because of its five-hour duration of action.
  • Insulin users need to check glucose levels hourly while driving.
  • His personal basal insulin is 3 units Lantus twice daily.
  • He urges use of glucose (e.g., Dextrotabs) to correct hypoglycemia.
  • He says hypoglycemia is rare on his regimen.
  • He has an entire chapter on gastroparesis.

Dr. Bernstein’s recommended eating program in a nutshell:  

  • Some similarities to the Atkins diet, which he never mentions.
  • No simple sugars or “fast-acting” carbs like bread and potatoes, because even type 2s have impaired or nonexistent phase 1 insulin response.
  • Limit carbs to an amount that will work with your injected insulin or your remaining phase 2 insulin response, if any.
  • “Stop eating when you no longer feel hungry, not when you’re stuffed.”
  • Follow a predetermined meal plan (each meal: same grams of carb and ounces of protein)
  • Six g (or less) of carbs at breakfast, 12 g (or less) at lunch and evening meal.  So his patients count carb grams and protein ounces.
  • Supplements are not required IF glucoses are controlled and eating a variety of veggies.  Otherwise you may need B-complex or multivitamin/multimineral supplement.
  • Recipes are provided.

His has four basic drug treatment plans, tailored to the individual.  They are outlined in the book.  Dr. B provides detailed notes on what he does with his personal patients.  

Overall impressions:  

  • Too complicated for most, and they won’t give up higher carb consumption.  It requires a high degree of committment and discipline.  In fact, I’ve never had a patient tell me they were on the Bernstein program.
  • If I had type 1 diabetes, I might well follow his plan or the Low-Carb Mediterranean Diet, NOT the high-carb diet recommended by the ADA and many dietitians.
  • And if I had type 2 diabetes?  Low-Carb Mediterranean Diet first, Diabetes Solution as second choice.
  • If one can get his hemoglobins A1c down to 5% with other methods, would that be just as good?  Dr. B would argue that all other methods have blood sugar swings that are too wide.
  • Many new ideas and techniques here, at least to me.
  • He pretty much reveals his entire program here, which is priceless.
  • I’m not sure this plan will work unless the patient’s treating physician is on-board.
  • His personal testimony and breadth of knowledge are very persuasive. 

Steve Parker, M.D.  

Disclosure:  I was given nothing of value by Dr. Bernstein or his publisher in return for this review.

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May 19, 2010 · 2:00 AM

Has Low-Carb Eating Been Good for YOU?

Just add steamed broccoli and a spinach salad!

Just add steamed broccoli and a spinach salad!

Low-carb or carbohydrate-restricted eating has been very beneficial to many people with type 2 diabetes, judging by what I hear from my patients and read on the Internet.  By “beneficial,” I mean has this eating style helped you to control your glucose levels, lower your hemoglobin A1c, ameliorated complications, helped you lose weight,  energized you, or just plain made you feel better?

I would love to hear about your experiences with carb-restricted eating, both good and bad.  How much did you restrict your carb intake?  How did you go about it?  Did you go “full Atkins,” and restrict carbs to 20 or less grams a day?   Or were you more moderate, restricting carbs to 30% of total calories, as in The Zone Diet?  [The typical American diet derives 55-60% of all calories from carbohdrates.]  If you don’t care to share with the world, please send me an email to steveparkermd (at) gmail (dot) com.  I’ll keep all all personal responses to my email address private and confidential.

Thanks!

Steve Parker, M.D.

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May 17, 2010 · 12:22 AM

Low-Carb Mediterranean Diet Improves Glucose Control and Heart Risk Factors in Overweight Diabetics

In overweight type 2 diabetics, a low-carbohydrate Mediterranean diet improved HDL cholesterol levels and glucose control better than either the standard Mediterranean diet or American Diabetes Association diet, according to Israeli researchers reporting earlier this year.

Background

Prior studies suggest that diets rich in monounsaturated fatty acids (olive oil, for example) elevate HDL cholesterol and reduce LDL cholestrol and triglycerides in type 2 diabetics.

Low-carb diets improve blood sugar levels and reduce excess body weight in type 2 diabetics, leading to the ADA’s allowance in 2008 of a low-carbohydrate diet as an alternative to standard diabetic diets.

Many—probably most—type 2 diabetics have insulin resistance:  the body’s cells that can remove sugar from the bloodstream are not very sensitive to the effect of insulin driving sugar into those cells.  They “resist” insulin’s effect.  Consumption of monounsaturated fatty acids  improves insulin sensitivity.  In other words, insulin is better able to push blood sugar into cells, removing it from the bloodstream.

Previous studies have shown that both low-carb diets and the Mediterranean diet reduce after-meal elevations in blood sugar, which likely lowers levels of triglycerides and LDL cholesterol.

How Was the Study Done?

The goal was to compare effects of three diets in overweight type 2 diabetics in Israel over the course of one year.  Study participants totalled 259.  Average age was 56, average weight 86 kg (189 lb), average hemoglobin A1c 8.3%, and average fasting plasma glucose (sugar) was 10.3 mmol/L (185 mg/dl).  [Many diabetics in the U.S. fit this profile.]  People taking insulin were excluded from the study, as were those with proliferative diabetic retinopathy—no reasons given. 

Participants were randomly assigned to one of three diets, so there were about 85 in each group.  [Over the course of one year, people dropped out of the study for various reasons, leaving each group with about 60 subjects.] 

Here are the diets:

  • 2003 ADA (American Diabetes Association) diet:  50-55% of total caloric intake from carbohydrate (mixed glycemic index carbs), 30%  from fat, 20% from protein
  • Traditional Mediterranean (TM):  50-55% low-glycemic-index carbs, 30% fat—high in monounsaturated fat, 15-20% protein
  • Low-carb Mediterranean (LCM) :  35% low-glycemic-index carbs, 45% fat—high in monounsaturated fat, 15-20% protein

Patients were followed-up by the same dietitian every two weeks for one year.  All were advised to do aerobic exercise for 30-45 minutes at least three days a week.

Olive oil is traditionally the predominant form of fat in the Mediterranean diet and is a particularly rich source of monounsaturated fat.  At no point in this report was olive oil mentioned, nor any other source of monounsaturated fat.  Until I hear otherwise, I will assume that olive oil was the major source of monounsaturated fat in the TM and LCM diets. 

 All diets were designed to provide 20 calories per kilogram of body weight. 

In all three diets, saturated fat provided 7% of total calories.  Monounsaturated fatty acids provided 23% of total calories in the LCM, and  10% in the other two diets.  Polyunsaturated fatty acids provided 15% of calories in the LCM, and 12% in the other two diets.  The ADA diet provided 15 grams of fiber, the TM had 30 g, and the LCM had 45 g.

Adherence to the assigned diet was assessed with a “food frequency questionnaire” administered at six months.

What Did the Researchers Find?

Average reported energy intake was similar in all three groups: 2,222 calories per day.

Monounsaturated fat intake differences were statistically significant: 14.6, 12.8, and 12.6% for the LCM, TM, and ADA diets, respectively.  Polyunsaturated fat intake differences were statistically significant: 12.9, 11.5, and 11.2% for the LCM, TM, and ADA diets, respectively.

Percentage of energy from carbs was highest for the ADA diet (45.4%), intermediate for the TM diet (45.2%), and lowest for the LCM diet (41.9%).

At the end of 12 months, all three groups lost about the same amount of weight (8-9 kg or 18-20 lb), body mass index, and waist circumference.

Hemoglobin A1c fell in all three groups, but was significantly greater for the LCM group than for the ADA diet (6.3% absolute value vs 6.7%).

Triglycerides fell in all three groups, but was significantly greater for the LCM diet compared to the ADA diet.

The LCM group achieved a significant increase (12%) in HDL cholesterol compared to the ADA diet, but not different from the TM group.

LDL cholesterol fell in all three groups, and the LCM group’s drop (25%) was clearly superior to that of the ADA diet (14%) but about the same as the TM diet (21%).

Conclusions of the Investigators

We found that an intensive community-based dietary intervention reduced cardiovascular risk factors in overweight patients with [type 2 diabetes] for all three diets.  The LCM group had improved cardiovascular risk factors compared to either the ADA or the TM groups.

Only the LCM improved HDL levels and was superior to both the ADA and TM in improving glycaemic control.

It would appear that the low carbohydrate Mediterranean diet should be recommended for overweight diabetic patients.

My Comments

There’s no way the average diabetic could replicate this low-carb Mediterranean diet without working closely with a dietitian or nutritionist.

Any superiority of this low-carb Mediterranean diet may have as much to do with the increased monounsaturated fat intake as with the reduced carb consumption.  Monounsaturated fatty acid consumption is thought to improve insulin sensitivity. 

NutritionData’s Nutrient Search Tool can give you a list of foods high in monounsaturated fat.

The Mediterranean diet and low-carb diets independently have been shown to lower after-meal glucose levels, which probably lowers LDL cholesterol and triglycerides.

I’m disappointed the dietitians were not able to achieve a lower level of carbohydrate consumption in the low-carb Mediterranean diet group.  I suspect if they had, improvements in glucose control and lipids would have been even better.  But proof awaits another day.

We saw last year an article in the Annals of Internal Medicine that showed a dramatic reduction in the need for glucose-lowering drugs in type 2 diabetics following a different low-carb Mediterranean diet over four years, compared to a low-fat American Heart Association diet.  These two studies convince me a low-carb Mediterranean diet has real life-preserving and life-enhancing potential. 

Diabetics looking for a low-carb Mediterranean diet today have several options:

If you’re aware of any other low-carb, explicitly Mediterranean-style diets, please share in the Comments section.

Steve Parker, M.D. 

References: 

Elhayany, A., Lustman, A., Abel, R., Attal-Singer, J., and Vinker, S.  A low carbohydrate Mediterranean diet improves cardiovascular risk factors and diabetes control among overweight patients with type 2 dabetes mellitus:  a 1-year prospective randomized intervention study.  Diabetes, Obesity and Metabolism, 12 (2010): 204-209.

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

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April 28, 2010 · 9:18 PM

Individual Response to Weight-Loss Diet May Depend on Genes

Dieters with particular genetic make-up respond better or worse to specific types of weight-loss diets, suggest researchers who presented data at the 2010 Cardiovascular Disease Epidemiology and Prevention /Nutrition, Physical Activity, and Metabolism conference.  Findings are preliminary, but may explain the common phenomenon of two people going on the same diet, but only one achieving good results. 

I’ll bet you can imagine several other explanations.

Several years ago, the “A to Z” study compared the weight loss of 311 overweight women on one of four diets:  Atkins (low-carb), Ornish (very low fat, vegetarian), Learn (low-fat), and Zone (moderate carb restriction, high protein, moderate fat).  Atkins was a bit better than the other diets, in terms of long-term (one year) weight loss.  But within each diet group, some women lost 40–50 pounds (18–23 kg), whereas others gained over 10 pounds (4.5 kg).

Stanford University researchers obtained DNA from 138 of the 311 women and noted the occurence of three genes—ABP2, ADRB2, and PPAR-gamma—that had previously been shown to predict weight loss via diet-gene interactions.  For example, a particular mix of these genes predict better weight loss with a low-fat diet; a different mix predicts more loss with a low-carb diet.

Women who had been randomly assigned to one of the A to Z diets tended to lose much more weight if they happened to have the gene mix appropriate for that diet (compared to those on the same diet with the wrong gene mix).  The difference, for example, might be loss of 12 pounds versus two pounds.

The lead researcher, Dr. Mindy P. Nelson, told TheHeart.Org that the proportion in the general population genetically predisposed to the low-fat versus low-carb approach is about 50:50.

Take-Home Points

These results, again, are preliminary; additional testing is necessary for confirmation.  If they had been able to test the DNA of the other 178 women in the A to Z study, the results could have been either stronger or shown no diet-gene interaction.  The study hasn’t even been published in a peer-reviewed journal yet.

Men may or may not be subject to similar diet-gene interaction.

If a genetic test is ever clinically available to tell a dieter which type of weight-loss diet would be more successful, it will likely be cheaper to just try a particular diet first and see if it works over 4–6 weeks.  Successful long-term weight loss is like smoking cessation—most smokers try 5–7 different times or methods before hitting on one that works for them.

This potential diet-gene interaction could be a major finding that will stop the arguing about which is the single best way to lose excess fat.  Many paths may lead to the mountaintop. 

Steve Parker, M.D.

Reference:  O’Riordan, Michael.  Dieting by DNA?  Popular diets work best by genotype, reseach shows.  HeartWire by TheHeart.Org, March 8, 2010.

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April 24, 2010 · 8:21 AM

Whole Grains Reduce Heart Attacks and Strokes

Whole grain consumption is associated with a 21% reduction in cardiovascular disease when compared to minimal whole grain intake, according to a 2008 review article in Nutrition, Metabolism, and Cardiovascular Disease.   

Coronary heart disease is the No. 1 killer in the developed world.  Stroke is No. 3.  The term “cardiovascular disease” lumps together heart attacks, strokes, high blood pressure,  and generalized atherosclerosis (hardening of the arteries). 

Investigators at Wake Forest University reviewed seven pertinent studies looking at whole grains and cardiovascular disease.  The studies looked at groups of people, determining their baseline food consumption via questionnaire, and noted disease development over time.  These are called “prospective cohort studies.” 

None of these cohorts was composed purely of diabetics.

The people eating greater amounts of whole grain (average of 2.5 servings a day) had 21% lower risk of cardiovascular disease events compared to those who ate an average of 0.2 servings a day.  Disease events included heart disease, strokes, and fatal cardiovascular disease.  The lower risk was similar in degree whether the focus was on heart disease, stroke, or cardiovascular death.

Note that refined grain consumption was not associated with cardiovascular disease events. 

Why does this matter?

The traditional Mediterranean diet is rich in whole grains, which may help explain why the diet is associated with lower rates of cardiovascular disease.  If we look simply at longevity, however, a recent study found no benefit to the cereal grain component of the Mediterranean diet.  Go figure . . . doesn’t add up. 

Readers here know that over the last four months I’ve been reviewing the nutritional science literature that supports the disease-suppression claims for consumption of fruits, vegetables, and legumes.  I’ve been disappointed.  Fruit and vegetable consumption does not lower risk of cancer overall, nor does it prevent heart disease.  I haven’t found any strong evidence that legumes prevent or treat any disease, or have an effect on longevity.  Why all the literature review?  I’ve been deciding which healthy carbohydrates diabetics and prediabetics should add back into their diets after 8–12 weeks of the Ketogenic Mediterranean Diet.

The study at hand is fairly persuasive that whole grain consumption suppresses heart attacks and strokes and cardiovascular death.  [The paleo diet advocates and anti-gluten folks must be disappointed.]  I nominate whole grains as additional healthy carbs, perhaps the healthiest.

But . . .

. . .  for diabetics, there’s a fly in the ointment: the high carbohydrate content of grains often lead to high spikes in blood sugar.  It’s a pity, since diabetics are prone to develop cardiovascular disease and whole grains could counteract that.  We need a prospective cohort study of whole grain consumption in diabetics.  It’ll be done eventually, but I’m not holding my breath.

[Update June 12, 2010: The aforementioned study has been done in white women with type 2 diabetes.  Whole grain and bran consumption do seem to protect them against overall death and cardiovascular death.  The effect is not strong.]

What’s a guy or gal to do with this information now?

Non-diabetics:  Aim to incorporate two or three servings of whole grain daily into your diet if you want to lower your risk of heart disease and stroke. 

Diabetics:  Several options come to mind:

  1. Eat whatever you want and forget about it [not recommended].
  2. Does coronary heart disease runs in your family?  If so, try to incorporate one or two servings of whole grains daily, noting and addressing effects on your blood sugar one and two hours after consumption.  Eating whole grains alone will generally spike blood sugars higher than if you eat them with fats and protein.  Review acceptable blood sugar levels here.
  3. Regardless of family history, try to eat one or two servings of whole grains a day, noting and addressing effects on your blood sugar.  Then decide if it’s worth it.  Do you have to increase your diabetic drug dosages or add a new drug?  Are you tolerating the drugs?  Can you afford them?    
  4. Assess all your risk factors for developing heart disease: smoking, sedentary lifestyle, high blood pressure, age, high LDL cholesterol, family history, etc.  If you have multiple risk factors, see Option #3.  And modify the risk factors under your control.   
  5. Get your personal physician’s advice.    

Steve Parker, M.D.

Extra Credit:  The study authors suggest a number of reasons—and cite pertinent scientific references—how whole grains might reduce heart disease:

  • improved glucose homeostasis (protection against insulin resistance, less rise in blood sugar after ingestion [compared to refined grains], improved insulin sensitivity or beta-cell function)
  • advantageous blood lipid effects (soluble fiber from whole grains [especially oats] reduces LDL cholesterol, lower amounts of the small LDL particles thought to be particularly damaging to arteries, tendency to raise HDL cholesterol and trigylcerides [seen with insulin resistance in the metabolic syndrome])
  • improved function of the endothelial cells lining the arteries (improved vascular reactivity)

Disclaimer:  All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status.  Always consult your personal physician before making any dietary or exercise changes.

Reference: Mellen, P.B, Walsh, T.F., and Herrington, D.M.  Whole grain intake and cardiovascular disease: a meta-analysis.  Nutrition, Metabolism and Cardiovascular Disease, 18 (2008): 283-290.

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March 7, 2010 · 2:58 PM

Book Review: The New Atkins for a New You

Here’s my review of The New Atkins for  a New You, a weight-loss book by Dr. Eric Westman, Dr. Stephen Phinney, and Dr. Jeff Volek released a week ago.  The copyright holder is Atkins Nutritionals, Inc.  Under Amazon.com’s five-star rating system, I give it four stars (“I like it”).  

♦   ♦   ♦ 

The most exciting nutritional medicine development in recent memory is the fact that saturated fat consumption is not a significant cause of heart disease and premature death. The same goes for for total fat and cholesterol.  When enough physicians, nutritionists, and dietitians learn this, low-carb eating will take off like a rocket.

For those unfamiliar with the Atkins diet, it is designed for weight loss via high fat consumption and major carbohydrate restriction.  Protein intake is a bit higher than average.  As long as carbohydrates (carbs) are kept low, other foods are mostly unlimited.  Atkins has four phases.  As you graduate from one phase tothe next, more carbs are allowed, adding some carb sources before others (the Carb Ladder). 

Atkins has been around for years.  It’s not just a weight-loss diet; it’s a lifetime way of eating.

Doctors Westman, Phinney, and Volek are leaders in low-carb nutritional science.  The last time Atkins peaked (2003), we didn’t have the scientific studies backing up safety of the diet.  Now we do, in large part thanks to these guys. 

Physicians see beaucoup patients with overweight-related medical conditions.  We’re not going to recommend a diet that causes heart attacks, strokes, and other major medical complications.  Published research over the last eight years has established the relative safety of very low-carb diets, particularly Atkins.  Low-carb diets may even be healthier than the low-fat, high-carb diet that has been recommended by U.S. public health authorities for the last forty years.  Come to think of it, our current obesity and diabetes epidemics started around that same time.

The book covers nutrition basics, day-to-day practical application of Atkins eating, recipes and detailed meal plans, and the science behind the program.    

What’s New Since Dr. Atkins’ 2002 Book?

  • adaptations for vegetarians and vegans
  • adaptations for Latinos
  • coffee is now OK
  • introduction of the term “foundation vegetables” and almost doubling the amount of vegetables allowed in Phase 1: “approximately six cups of salad and up to two cups of cooked vegetables, depending upon the ones you select”
  • more flexility, such as the option to skip Phase 1 (induction)
  • focus on adequate protein intake, based on your height
  • emphasis on getting enough omega-3 fatty acids
  • no emphasis on supplements and low-carb products sold by Atkins Nutritionals,Inc.
  • diet journals—a personal record of your weight-loss journey—are recommended
  • eliminate or minimize “induction flu” and constipation (in Phase 1) by eating at least 1/2 teaspoon of salt daily [I’m skeptical.]
  • discussion of the trendy omega-6/omega-3 fatty acid ratio
  • favor monounsaturated fatty acids (e.g., olive oil, canola oil) over certain polyunsaturated fats, as in oils from corn, soybeans, sunflower, cottonseed, and peanuts
  • no mention of testing urine for ketosis
  • more discussion of psychological aspects of weight

The lack of ads for Atkins Nutritionals products is welcome and refreshing.  Too many of the official Atkins books read like infomercials, which diminishes credibility.

A vegetarian or vegan “Atkins diet” is just not something I can visualize.

What Could Have Been Done Better?

  • no specific amounts given for these recommended supplements: calcium, vitamin D, omega-3 fats, multivitamin, magnesium and other minerals (except “no iron”).  [Is the idea to encourage a visit the official Atkins website?]
  • little guidance for physicians who are to advise diabetics doing Atkins.  Few physicians are familiar enough with the program to make the necessary changes in particular diabetic medications.
  • little discussion of the constipation and leg cramps that often accompany very low-carb diets
  • the hype on the cover: “How would you like to LOSE UP TO 15 POUNDS IN TWO WEEKS!”  [To their credit, the authors note that such results are not typical.]
  • nearly all the measurements are U.S. Customary.  Metric users are out of luck.
  • four phases seem a bit much.  The beauty of Atkins Phase 1 is its simplicity. 

My favorite sentence: “White flour is better suited to glue for kindergarten art projects than to nutrition.”

My least favorite sentence: “We can’t stress strongly enough that the best diet for you is one composed of foods you love.”  I love apple pie and Cinnabon cinnamon rolls, but they won’t help me manage my weight.

The only error I found worth mentioning is minor.  The authors state that the American Heart Association recommends consumption of fish three times a week. The official policy is still “at least twice weekly.”

The book is very practical and easily understood by average people.  Most will skip the science chapters at the end.  I know the basic Atkins program works at least short-term; many of my patients have done it.

In summary, the book has nearly everything you need to be successful with the Atkins diet. 

As far as I know, there are no comprehensive long-term studies (e.g., 10+ years) regarding health outcomes of Atkins-style eating.  In other words, does Atkins have any effect on longevity, cancer, heart attacks, strokes, etc.?  But very few of the popular diets have these data either.  The best researched ways of eating in this respect are the Mediterranean diet and vegetarian diets.

Steve Parker, M.D.

Disclosure:  I was given nothing of value for this review by the authors, publisher, or Atkins Nutritionals, Inc.  I wrote it for the benefit of my patients and readers.

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February 8, 2010 · 2:00 AM

You Know About Insulin. And Now, the REST of the Story . . .

When we digest carbohydrates, blood sugar rises.  If it goes too high it causes problems.  Everybody knows that insulin lowers blood sugar levels, right?  Less well-known is that regulation of blood sugar is the result of complex interactions of multiple hormones, not just insulin.

[As is my habit, I will use “sugar” and “glucose” interchangeably in this post.] 

Allow me to review the main hormones involved in blood glucose regulation:

1. Insulin is made and stored in pancreas beta cells.  As a meal is digested, blood sugar rises; the pancreas releases insulin to bring blood sugar back down by driving it into cells.

2. Amylin is also made and stored in pancreas beta cells and works to reduce blood sugar levels.  Blood levels of amylin rise and fall in concert with insulin levels.  Amylin slows emptying of the stomach, reduces food consumption, and regulates another hormone—glucagon—after meals.

3. Glucagon is from pancreas alpha cells.  It works to raise blood sugar by promoting the liver’s breakdown of glycogen into glucose, and by promoting the liver’s manufacture of new glucose molecules.

4. Glucagon-like peptide -1 (GLP-1) is produced in small intestine cells and it’s main action is to promote insulin secretion by the pancreas beta cells after absorption of food, which lowers blood sugar levels.  GLP-1 (like amylin) also inhibits emptying of the stomach, inhibits glucagon release, and inhibits appetite, all of which would tend to keep a lid on blood sugar levels. 

5. Gastric inhibitory polypeptide (GIP) promotes secretion of insulin following absorption of food.  GIP is also known as glucose-dependent insulinotropic polypeptide.

You can see that some hormonal mechanisms raise glucose levels; others lower glucose levels.  Homeostasis is all about reaching a happy medium between the two, without wild swings one way or the other.  In healthy people, eating food leads to release of gastrointestinal peptides (GLP-1 and GIP), insulin, and amylin.  The interaction among them keeps blood sugar levels in a fairly level low range.  In diabetes, one or more malfunctions in the system leads to abnormally high blood sugars.

The good news is that scientists have used this knowledge to devise new, effective treatments for diabetes.  Examples are GLP-1 analogues and DPP-4 inhibitors.

Steve Parker, M.D.

PS:   In lab animals, GLP-1 stimulates formation of new pancreas beta cells, so it hold promise in halting the progressive beta cell failure characteristic of type 2 diabetes.

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