Category Archives: coronary heart disease

December 9, 2009 · 2:00 AM

Book Review: Good Calories, Bad Calories

Here’s my  review of good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease, by Gary Taubes, 2007.  I give it five stars on Amazon.com’s five-star system (“I love it”).

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This brilliant book deserves much wider currency among physicians, dietitians, nutritionists, and obesity researchers.  The epidemic of overweight and obesity over the last 30 years should make us question the reigning theories of obesity treatment and prevention.  Taubes questioned those theories and pursued answers wherever the evidence led.  He shares in GCBC his eye-opening, even radical, well-reasoned findings. 

Ultimately, this tome is an indictment of the reigning scientific community and public nutrition policy-makers of the last four decades.  That explains why, twoyears after publication, this serious, scholarly work has not been reviewed by the New England Journal of Medicine, the Journal of the American Medical Association, the American Journal of Clinical Nutrition , and the Journal of the American Dietetic Association (as of August, 2009).

In Part 1, Taubes examines the scientific evidence for what he calls the fat-cholesterol hypothesis.  More commonly known as the diet-heart hypothesis, it’s the idea that dietary fat (especially saturated fat) and cholesterol clog heart arteries, causing heart attacks.  Taubes finds the evidence unconvincing.  He’s probably right.

Part 2, The Carbohydrate Hypothesis, revives and older theory from the mid-twentieth cenury that is elsewhere called the Cleave-Yudkin carbohydrate theory of dental and chronic systemic disease.  In the carbohydrate theory,  high intake of sugary foods, starches, and refined carbhohyrates leads first to dental disease (cavities, gum inflammation, periodontal disease) then, later, to obesity and type 2 diabetes, coronary heart disease, perhaps even cancer and Alzheimer’s Disease.  These are, collectively, the “diseases of civilization.”

Part 3 tackles obesity and weight regulation.  Taubes writes that “…fattening and obesity are caused by an imbalance—a dysequilibirium—in the hormonal regulation of adipose [fat] tissue and fat metabolism.”  Think of the transformation of a skinny 10-year-old girl into a voluptuous young woman.  It’s not over-eating that leads to curvaceous fat deposits, growth of mammary tissue, and increase in height; it’s hormonal changes beyond her control. 

The primary hormonal regulator of fat storage is insulin, per Taubes.  Elevated insulin levels lead to storage of food energy as fat.  Carbohydrates stimulate insulin secretion and make us fat. 

Although it’s a brilliant book, by no means do I agree with all Taubes’ conclusions.  For instance, if carbohydrates cause heart disease, why is glycemic index only very weakly associated with coronary heart disease in men?  It’s way too early to blame cancer and Alzheimers on carbohydrates.  Primitive cultures may not exhibit many of the diseases of civilization because their members die too young.  Taubes is clearly an advocate of low-carb eating.  Why didn’t he directly address the evidence that fruits, vegetables, and whole grains in the right amounts are healthy?

I have to give Taubes credit for thinking “outside the box.”  His search for answers included reviews of esoteric literature and interviews with scientists in the fields of genetics, athropology, public policy, physiologic psychology, and paleontology, to name a few.

Towards the end of the book, Taubes describes a Mediterranean-style or “prudent” diet that is popular these days.  After five years of research for his book, he says that whether a very low-carb meat diet is healthier than a prudent diet “… is still anybody’s guess.”  It’s hard for me to put aside numerous observational studies associating health benefits with legumes, fruits, vegetables, and wholegrains.  So my “guess” is that the Mediterranean-style diet is healthier.  Perhaps the answer is different for each individual.  Heck, maybe the answer is low-carb Mediterranean.  Both Taubes and I are prepared to accept either result when we have proof-positive data.    

Taubes doesn’t base his opinions on late-breaking scientific results.  Instead, his research findings mostly span from 1930 to 1980, especially 1940-1960.  Once the fat-cholesterol (diet-heart) hypothesis took root around 1960 and blossomed in the 1970s, these data were ignored by the entrenched academics and policy-makers of the day. 

To be fair, I’ve got to mention this is not light reading.  A majority of people never read another book after they graduate high school.  Of those who do, many (like me) will have to look up the definition of “tautology,” “solecism,” etc. 

I was taught in medical school years ago that “a calorie is a calorie is a calorie.”  Meaning: if you want to lose excess weight, it doesn’t matter if you cut calories from fat, protein, or carbohydrates.  I really wonder about that now.

Steve Parker, M.D 

Additional Reading

Bray, George A.  Viewpoint: Good Calories, Bad Calories by Gary Taubes.  Obesity Reviews, 9 (2008): 251-263.

Taubes, Gary.  Letter to Editor: Response to Dr. George Bray’s review of Good Calories, Bad Calories.  Obesity Reviews, 10 (2008): 96-98.

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November 27, 2009 · 12:00 AM

Modern Heart Disease Found in Ancient Egyptian Mummies

HeartWire on November 23, 2009, reported the discovery of atherosclerosis (hardening-of-the-arteries) in Egyptian mummies 3000 years old. 

So it appears that atherosclerosis in not just a disease of modern civilization, as suggested by some.

Steve Parker, M.D.

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November 24, 2009 · 2:00 AM

Are Vegetarian Diets Any Good For Diabetes?

Plant-based diets may offer special benefits to people with diabetes, according to a recent review article by U.S. researchers who reviewed the pertinent English language literature published since 1966.  They found 116 potentially relevant articles, 10 of which were directly related to diabetes management and glucose control.

The authors failed to define “vegetarian” early on.  Some vegetarians eat eggs, some eat cheese, some drink milk.  I assume vegans eat no animal products whatsoever.  On the last page of the review the authors write that a vegetarian “does not eat meat, fish, or poultry” although it’s not clear if that applies throughout the review.  There are many references to “low-fat vegetarian” diets, with little or no mention of moderate- or high-fat vegetarian diets.

The authors often refer to vegetarian diets as “plant-based.”  No doubt, they are.  But even the healthy Mediterranean diet is considered plant-based, while clearly not vegetarian.

It’s also unclear whether they focused on type 1 or type 2 diabetes.  My sense is, probably type 2.

Here are the major points: 

  1. Are vegetarians less likely to develop diabetes?  Observational studies have found a lower prevalence of diabetes among vegetarians compared to non-vegetarians, especially among Seventh Day Adventists.  In other studies, meat consumption is linked to higher risk of diabetes among women. 
  2. Do vegetarian diets help control diabetes?  Several small studies showed that low-fat near-vegetarian and vegan diets improved glucose control and insulin sensitivity and reduced diabetes medication use, compared with a traditional diabetes diet – which is typically low-fat and high-carb.  I’m not sure, but I assume that the intervention diets were not heavy in refined, processed carbohydrates, but instead consisted of natural whole plant foods.  “Weight loss accounts for much although not all, of the effect of plant-based diets on glycemic control,” they write.
  3. Heart disease is quite common in older diabetics.  Do vegetarian diets offer any cardiac benefits?  They cite Dr. Ornish’s Lifestyle Heart Trial of a low-fat vegetarian diet and intensive lifestyle intervention: smoking cessation, stress management (meditation?), mild exercise, and group meetings.  Dr. Ornish’s program reduced LDL cholesterol by 37%, reversed heart artery blockages in 82% of participants, and found 60% lower risk of cardiac events compared to the control group. Dr. Ornish’s Multisite Lifestyle Cardiac Intervention Program also documented impressive cardiac results at 12 weeks, but had no control group.  Dr. Caldwell Esselstyne is also mentioned in this context.
  4. Vegetarian diets are linked to lower blood pressure, which may help prolong life and prevent heart attacks and strokes.
  5. Antioxidant-rich foods like fruits and vegetables—common in the Mediterranean diet and vegetarian diets—may lower cardiovascular disease risk. 
  6. People with diabetes are at risk for impaired kidney funtion.  In women with impaired baseline kidney funtion, high animal protein intake is associated with continued kidney deterioration. 
  7. A small study showed dramatic improvement in type 2 diabetics with painful neuropathy over 25 days on a low-fat vegan diet and a daily 30-minute walk.  Many participants were able to reduce diabetes drug dosages.
  8. Do any diabetes advocacy associations endorse vegetarian diets for people with diabetes?  The American Dietetic Association deems that vegetarian and vegan diets, if well-planned, are nutritionally adequate. I don’t know the position of the American Diabetes Association.  Vegetarians need planning to get adequate vitamin D, B12, and calcium.
  9. “Low-fat vegetarian and vegan diets do not require individuals to limit energy or carbohydrate intake….”  If true (and these guys should know), that might broaden the diet’s appeal.
  10. I saw no mention of decreased overall mortality in vegetarians.

My Comments

Have you heard of the Physicians Committee for Responsible Medicine?  Their president is Neal Barnard, the lead author of the study at hand.  He has a new book on reversal of diabetes with a low-fat vegetarian diet.

The authors cite a journal article (reference #16) in support of plant-based diets, but the article doesn’t mention a vegetarian or vegan diet—it’s high-carb, high-fiber diet.  I didn’t review all 92 of their references to see if any others were misleading.

“Plant-based diets” must be a euphemism for vegetarian diets.  Too many people shut down when you talk to them about vegetarian diets.

I won’t rule out the possibility that vegetarian/vegan diets may be helpful in management of diabetes.  Such diets are, of course, 180 degrees different from the very low-carb diets I’ve reviewed favorably in these pages!  Both models, ideally, move away from the over-processed, concentrated carbohydrates so prevalent in Western culture.  Perhaps that’s the unifying healthy theme, if there is one. 

Or different sub-types of diabetes respond better to particular diets.

I heartily agree with the authors that larger clinical trials of vegetarian diets in diabetics are needed.  I’d love to see a long-term randomized controlled trial comparing a very low-carb diet diet with a low-fat vegetarian diet.  That’s the best way to settle which is better for diabetics: vegetarian or low-carb.

It’ll never be done.

Has a vegetarian diet helped control your diabetes?

Steve Parker, M.D.

Reference:  Barnard, Neal, et al.  Vegetarian and vegan diets in type 2 diabetes management.  Nutrition Reviews, 67(2009): 255-263.   doi: 10.1111/j.1753-4887.2009.00198.x

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November 9, 2009 · 2:00 AM

Walnuts: More Evidence in Favor of Health Benefits

MPj03095770000[1]Nuts are a time-honored component of the Mediterranean diet and may contribute to the lower risk of cardiovascular disease  associated with the diet. 

Regular nut consumption lowers total cholesterol and LDL (“bad cholesterol”) by 5 to 15%, which would tend to lower heart disease risk.  Walnuts are particularly high in alpha-linolenic acid, an omega-3 fatty acid.

Bix over at Fanatic Cook links to three scientific studies showing that walnuts:

  • improved arterial function in people with type 2 diabetes
  • improved arterial function in people with high cholesterol eating a Mediterranean diet
  • decreased fasting insulin levels in people with type 2 diabetes
  • decreased LDL cholesterol in people with type 2 diabetes who were on a low-fat diet

The “dose” of walnuts in these studies was 1–2 ounces (28–56 g) daily.

For good reason, nuts have a prominent role in both the Advanced Mediterranean Diet and Ketogenic Mediterranean Diet. 

I don’t know Bix, but he or she seems to base many of his/her nutrition opinions on scientific principles, which I appreciate.

Steve Parker, M.D.

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September 7, 2009 · 2:08 AM

Do Grape Products Other Than Wine Affect Heart Disease Risk?

"Grapes may be just as healthful as wine"

"Grapes may be just as healthful as wine"

Grape products favorably affect four risk factors for heart disease, according to a scientific review published last year.

The “French Paradox” refers to the fact that certain regions of France have low levels of heart disease despite high consumption of saturated fats that supposedly cause heart disease.  Some have explained away the paradox by noting high consumption of red wine in those areas, which could counteract the adverse effects of saturated fats.  Others have used the paradox to indict the Diet-Heart Hypothesis itself. 

Wine, especially red wine, is an integral part of the Ketogenic Mediterranean Diet.  However, many people just don’t like wine, and others shouldn’t be drinking it.  So, I’ve been wondering if grape products other than wine might have the healthy effects of wine.

The reference article below reviewed grape product trials published over the previous 13 years: 34 studies in animals, 41 in humans.  In addition to wine, grape products included grape juice, grape seed, grape skin, grape pomace, and polyphenol-rich extracts.  The authors conclude that grape products have the following beneficial effects on cardiovascular risk factors:

  • lower blood pressure, mainly due to release of nitric oxide from cells lining the arteries
  • reduced levels of total cholesterol, LDL cholesterol (“bad cholesterol”), and trigylcerides, especially if these values are high at baseline
  • reduced development of early-stage atherosclerosis (less LDL oxidation and plaque formation)
  • improved antioxidant status

Here are some grape product “fun facts” from the article:

  • healthy effects are primarily attributed to polyphenols, which are strong antioxidants that disable free radicals and chelate metals
  • major grape polyphenols are anthocyanins in red grapes, flavon-3-ols in white grapes
  • red grapes have more total polyphenols than white grapes
  • the main polyphenols in wine are resveratrol, tannins, flavan-3-ols, flavan-3,4-diols, anthocyanins, flavonols, flavones, anthocyanins, and anthocyanidins
  • red wine has a much higher phenolic content than white wine

Unfortunately, the authors never make any specific recommendations for people wanting to substitute alcohol-free grape products for wine.  

But I bet if you went down to your local vitamin or health food store, you could find some grape extracts or other grape products to try.  Anyone on a very low-carb diet would want to be sure the grape product wouldn’t supply more than 3-4 grams of digestible carbohydrate per day.  For those not on such a diet, purple grape juice like Welch’s—4 to 8 fl oz a day—is a good alternative to wine.  Welch’s has 42 g of carbohydrate per 8 fl oz. 

Steve Parker, M.D.

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:  Perez-Jimenez, Jara and Saura-Calixto, Fulgencio.  Grape products and cardiovascular disease risk factors.  Nutrition Research Reviews, 21 (2008): 158-173.

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August 22, 2009 · 11:19 AM

Estimate Your Risk of Type 2 Diabetes, Heart Disease, and Stroke

"Who's next?"

"Who's next?"

The American Diabetes Association has just unveiled an online calculator that estimates your risk of developing type 2 diabetes, heart disease, or stroke over the next 30 years.  It’s at My Health Advisor.  Anyone can use it.

You use the calculator anonymously, although I assume they will capture the IP address of your computer.  You don’t have to know the following data about yourself, but the ADA says the results will be more accurate if you provide more information [certainly makes sense]:

  • cholesterol levels: total, HDL, LDL
  • most recent fasting plasma glucose level
  • recent blood pressure
  • results of oral glucose tolerance test
  • hemoglobin A1c result
  • estimate of average glucose levels

I have no idea of the accuracy of this calculator.  But I rather doubt the ADA would offer it without substantial validation.

I’m always trying to figure out how to motivate people to take better care of themselves.  This calculator could help.  The print-out of your results suggests ways you might reduce your risk. 

Remember that the Mediterranean diet has been shown to reduce risk of type 2 diabetes, heart attack, and stroke.

Steve Parker, M.D.

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August 5, 2009 · 4:45 AM

Dental Problems and Systemic Chronic Disease: A Carbohydrate Connection?

Perfect health on a carnivorous, low-carb diet

Perfect health on a carnivorous, low-carb diet

Dentists are considering a return to an old theory that dietary carbohydrates first cause dental diseases, then certain systemic chronic diseases, according to a review in the June 1, 2009, Journal of Dental Research. 

We’ve known for years that some dental and systemic diseases are associated with each other, both for individuals and populations.  For example, gingivitis and periodontal disease are associated with type 2 diabetes and coronary heart disease.  The exact nature of that association is not clear.  In the 1990s it seemed that infections – chlamydia, for example – might be the unifying link, but this has not been supported by subsequent research.     

The article is written by Dr. Philippe P. Hujoel, who has been active in dental research for decades and is affiliated with the University of Washington (Seattle).  He is no bomb-throwing, crazed, radical. 

The “old theory” to which I referred is the Cleave-Yudkin idea from the 1960s and ’70s that excessive intake of fermentable carbohydrates, in the absence of good dental care, leads both to certain dental diseases – caries (cavities), periodontal disease, certain oral cancers, and leukoplakia – and to some common systemic chronic non-communicable diseases such as coronary heart disease, type 2 diabetes, some cancers, and dementia.  In other words, dietary carbohydrates cause both dental and systemic diseases – not all cases of those diseases, of course, but some.   

Dr. Hujoel does not define “fermentable” carbohydrates in the article.  My American Heritage Dictionary defines fermentation as:

  1. the anaerobic conversion of sugar to carbon dioxide and alcohol by yeast
  2. any of a group of chemical reactions induced by living or nonliving ferments that split complex organic compunds into relatively simple substances

As reported in David Mendosa’s blog at MyDiabetesCentral.com, Dr. Hujoel said, “Non-fermentable carbohydrates are fibers.”  Dr. Hujoel also shared some personal tidbits there. 

In the context of excessive carbohydrate intake, the article frequently mentions sugar, refined carbs, and high-glycemic-index carbs.  Dental effects of excessive carb intake can appear within weeks or months, whereas the sysemtic effects may take decades. 

Hujoel compares and contrasts Ancel Keys’ Diet-Heart/Lipid Hypothesis with the Cleave-Yudkin Carbohydrate Theory.  In Dr. Hujoel’s view, the latest research data favor the Carbohydrate Theory as an explanation of many cases of the aforementioned dental and systemic chronic diseases.  If correct, the theory has important implications for prevention of dental and systemic diseases: namely, dietary carbohydrate restriction.

Adherents of the paleo diet and low-carb diets will love this article; it supports their choices.

I agree with Dr. Hujoel that we need a long-term prospective trial of serious low-carb eating versus the standard American high-carb diet.  Take 20,000 people, randomize them to one of the two diets, follow their dental and systemic health over 15-30 years, then compare the two groups.  Problem is, I’m not sure it can be done.  It’s hard enough for most people to follow a low-carb diet for four months.  And I’m asking for 30 years?!   

Dr. Hujoel writes:

Possibly, when it comes to fermentable carbohydrates, teeth would then become to the medical and dental professionals what they have always been for paleoanthropologists: “extremely informative about age, sex, diet, health.”

Dr. Hujoel mentioned a review of six studies that showed a 30% reduction in gingivitis score by following a diet moderately reduced in carbs.  He mentions the aphorism: “no carbohydrates, no caries.”  Anyone prone to dental caries or ongoing periodontal disease should do further research to see if switching to low-carb eating might improve the situation. 

Don’t be surprised if your dentist isn’t very familiar with the concept.  Has he ever mentioned it to you?

Steve Parker, M.D.,

Author of The Advanced Mediterranean Diet

Reference:  Hujoel, P.  Dietary carbohydrates and dental-systemic diseases.  Journal of Dental Research, 88 (2009): 490-502.

Mendosa, David.  Our dental alarm bell.  MyDiabetesCentral.com, July 12, 2009.

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June 25, 2009 · 2:00 AM

Mediterranean Diet Cuts Risk of Diabetes After Heart Attack

In a blog post last year I discussed how the Mediterranean diet reduces the incidence of type 2 diabetes in healthy people.  I found another scientific journal article that examined the effect of various lifestyle factors that might influence the onset of type 2 diabetes in a different population: people who have had a recent heart attack.

Dariush Mozaffarian and colleauges studied 8291 Italians who had suffered a heart attack within the previous three months, but who did not have diabetes at the time of the heart attack.  Each study participant was followed for an average of 3.2 years to see if diabetes developed.  The researchers devised a Mediterranean diet score (range 0-15) incorporating consumption of cooked and raw vegetables, fruit, fish  and olive oil.  They also looked at consumption of butter, oils other than olive oil, cheese, wine, and coffee.  Participants’ dietary habits were assessed and scored three times over 1.5 years.  A number of other demographic, clinical, and lifestyle risk-factors were assessed.

The study did not survey other components of the Mediterranean diet, such as legumes, nuts, and grains.  This is a weakness of the study.  I suspect it relates to the fact they were using information from the GISSI-Prevenzione study, which was designed to evaluate fish oil and vitamin E in people who had had a heart attack, and researchers did not want to burden outpatient cardiology offices with full-scale questionnaires.

Over the three years of the study, 12% of participants developed new-onset diabetes, or 3.7% per year.  If not for the recent heart attack, the expected incidence rate for development of diabetes would be roughly 1.2% per year.  An even larger percentage, over 25%, of participants developed impaired fasting glucose, a kind of prediabetes that often develops into full-blown diabetes over time.

Was there anything about the people who developed diabetes that distinguished them from those who did not?  Yes – they tended to have older age, higher body mass index, high blood pressure, and they smoked.  Current smoking was associated with a 60% higher risk.  Every unit of higher body mass index, e.g, going from BMI 26 to 27, increased the risk by 9%.  High blood pressure increased the risk by 22%.

What about Mediterranean diet score?  The higher Mediterranean diet scores – score of 11-15 compared to 0-5 – were associated with 35% lower risk of diabetes.  A reduction in onset of impaired fasting glucose was similar.

The authors cite another study of 2499 patients with stable angina pectoris or remote heart attack (over 6 months perviously).  Twenty-two percent of them (one in five) developed diabetes or impaired fasting glucose over six years of follow-up, a rate of 4.1% per year.

The researchers write:

The lower risk associated with a Mediterranean-type diet suggests that diet could help reduce incidence of prediabetes and diabetes after a myodcardial infarction.  Many, though not all, trials have indicated that a Mediterranean-type diet lowers risk factors linked to insulin resistance and diabetes, including serum triglycerides, HDL cholesterol, systemic inflammation, endothelial function, and insulin sensitivity.  These physiological effects in short-term randomized trials provide biological plausibility for the inverse association between consumption of a Mediterranean-type diet and incidence of [impaired fasting glucose] and diabetes in this study.

What are the take-home points of this study for people – Italians, at least – who have had a recent heart attack?

  1. A recent heart attack is a risk factor for development of diabetes and prediabetes.
  2. The risk of developing diabetes and prediabetes may be significantly reduced by smoking cessation, prevention of weight gain, and consumption of typical Mediterranean foods.

Patients with both heart attacks and diabetes  have significantly worse outcomes  than people with only one of these conditions.  Since we can prevent many cases heart attack and diabetes through diet modification, why not?

Steve Parker, M.D.

Reference:  Mozaffarian, Dariush, et al.  Incidence of new-onset diabetes and impaired fasting glucose in patients with recent myocardial infarction and the effect of clinical and lifestyle risk factors.  Lancet, 370 (2007) 667-675.

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