Monthly Archives: February 2012

Type 2 Diabetes CAN Be Prevented

Not Paula Deen

Paula Deen’s recent announcement of her type 2 diabetes got me thinking about diabetes prevention again. If you’re at high risk of developing diabetes you can reduce your risk of full-blown type 2 diabetes by 58% with intensive lifestyle modification. Here’s how it was done in a 2002 study:

The goals for the participants assigned to the intensive lifestyle intervention were to achieve and maintain a weight reduction of at least 7 percent of initial body weight through a healthy low-calorie, low-fat diet and to engage in physical activity of moderate intensity, such as brisk walking, for at least 150 minutes per week. A 16-lesson curriculum covering diet, exercise, and behavior modification was designed to help the participants achieve these goals. The curriculum, taught by case managers on a one-to-one basis during the first 24 weeks after enrollment, was flexible, culturally sensitive, and individualized. Subsequent individual sessions (usually monthly) and group sessions with the case managers were designed to reinforce the behavioral changes.

Although the Diabetes Prevention Program encouraged a low-fat diet, another study from 2008 showed that a low-fat diet did nothing to prevent diabetes in postmenopausal women.

I don’t know Paula Deen. I’ve never watched one of her cooking shows. She looks overweight and I’d be surprised if she’s had a good exercise routine over the last decade. I’m sorry she’s part of the diabetes epidemic we have in the U.S. I wish her well. Amy Tenderich posted the transcript of her brief interview with Paula, who calculates her sweet tea habit gave her one-and-a-half cups of sugar daily).

  • Nearly 27% of American adults age 65 or older have diabetes (overwhelmingly type 2)
  • Half of Americans 65 and older have prediabetes
  • 11% of U.S. adults (nearly 26 million) have diabetes (overwhelmingly type 2)
  • 35% of adults (79 million) have prediabetes, and most of those affected don’t know it

I think excessive consumption of concentrated sugars and refined carbohydrates contribute to the diabetes epidemic. Probably more important are overweight, obesity, and physical inactivity.

The Mediterranean diet has also been linked to lower rates of diabetes (and here). Preliminary studies suggest the Paleo diet may also be preventative (and here).

Greatly reduce your risk of type 2 diabetes by eating right, keeping your weight reasonable, and exercising.

Steve Parker, M.D.

PS: Paula, if you’d like a copy of Conquer Diabetes and Prediabetes: The Low-Carb Mediterranean Diet, have your people contact my people.

Reference: Diabetes Prevention Program Research Group. Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin. New England Journal of Medicine, 346 (2002): 393-403.

The Inimitable Denise Minger on the “Cherry Picking” Ancel Keys

Keys lived his last years in Pioppi, Italy, not near the Tower of Pisa

Here’s her take on Ancel Keys, the father of cardiovascular epidemiology and the what we now consider the healthy Mediterranean diet.  She is funny. Warning: Her post is only for serious nutrition science geeks.

Too bad he’s not alive to defend himself.  He died young, almost reaching 101. Check out his New York Times obituary.

Steve Parker, M.D.

Are Saturated Fats Really All That Bad?

This is an epic post of mine from the old Advanced Mediterranean Diet blog, originally dated July 6, 2009.  That was a watershed year for me because of the ideas in this article.

I’ve been thinking a lot lately about saturated fats. Weird, huh?

No saturated fat in grapes

The American Heart Association recommends that Americans limit the amount of saturated fats they eat to less than 7 percent of total daily calories. If you eat 2,000 calories a day, no more than 140 of them should come from saturated fats. That’s about 16 grams of saturated fats.

In over two decades of clinical practice, I’ve never run across a patient willing to do that calculation. Not many physicians could tell you the “seven percent rule.”

One of the two major themes of Gary Taubes’ book, Good Calories, Bad Calories, is that dietary saturated fats are not particularly harmful to our health, if at all. From what I’ve been taught, this is sacrilegious. “Saturated fats are a major cause of heart disease and strokes,” I’ve heard and read over and over. In brief, this is the Diet-Heart Hypothesis or the “lipid hypothesis”: Dietary saturated fat, total fat, and cholesterol are directly related to coronary heart disease and other forms of atherosclerosis (aka hardening of the arteries).

In his review of Taubes’ book, Dr. George Bray didn’t even address Taubes’ point about saturated fats, writing instead, “read and decide for yourself.”

That started me thinking either that the Diet-Heart Hypothesis is indefensible or that Dr. Bray is lazy. I don’t think he’s lazy. Dr. Bray is a Grand High Pooh-Bah in the fields of obesity and nutrition.

The American Heart Association in 1957 recommended that polyunsaturated fats replace saturated fats.

U.S. public health recommendations in 1977 were to reduce fat intake to 30% of total calories to lower the risk of coronary heart disease. Slowly, some fats were replaced mostly with carbohydrates, highly refined ones at that. This shift tends to raise triglycerides and lower HDL cholesterol levels, which may themselves contribute to atherosclerosis. Current recommendations are, essentially, to keep saturated fatty acids as low as possible.

One concern about substituting carbohydrates for fats is that blood sugar levels rise, leading to insulin release from the pancreas, in turn promoting growth of fat tissue and potentially leading to weight gain. Some believe that the public health recommendation to reduce total fat (which led to higher carbohydrate intake) is the reason for the dramatic rise in overweight and diabetes we’ve seen over the last 30 years.

Note that if intake of saturated fats is inadequate, our bodies can make the saturated fats it needs from carbohydrates. These are generally the same saturated fats that are present in dietary fats of animal origin. The only exceptions are the two essential fatty acids: alpha-linolenic acid and linoleic acid.

Why would saturated fats be harmful? Apparently because they raise blood levels of cholesterol (including LDL cholesterol – “bad cholesterol”), which is thought to be a cause of atherosclerosis, which increases the risk of coronary heart disease and stroke. I don’t recall seeing any mention of a direct toxic effect of saturated fats (or fatty acids) on arterial walls, where the rubber meets the road. (Saturated fats are broken down in the small intestine to glycerol and fatty acids.)

Dietary saturated fats also raise HDL cholesterol – “good cholesterol” – although not to the degree they raise LDL.

You needed a break

Let’s not forget many other factors that cause, contribute to, or predict coronary heart disease and atherosclerosis: smoking, family history, high blood pressure, obesity, diabetes, oxidative stress, homocysteine level, systemic inflammation, high-glycemic index diets, C-reactive protein, lack of exercise, and others. I discussed dietary factorsin my April 14, 2009, blog post.

Often overlooked in discussion of dietary fat effects is the great variability of response to fats among individuals. Response can depend on genetics, sex, fitness level, overweight or not, types of carbohydrates eaten, amount of total dietary fat, etc. And not all saturated fats affect cholesterol levels.

Many of the journal articles listed as references below support the idea that the link between dietary saturated fats and coronary heart disease is not strong, and may be nonexistent. Read them and you’ll find that:

  • Some studies show no association between dietary saturated fats and coronary heart disease.
  • Some studies associate lower rates of coronary heart disease with higher saturated fat intake.
  • Higher saturated fat intake was associated with less progression of coronary atherosclerosis in women.
  • Lowering saturated fat intake did not reduce total or coronary heart disease mortality.

“Read and decide for yourself,” indeed. I think you’ll begin to question the reigning dogma.

For example, here’s a conclusion from the Hooper article (from 2001):

In this review we have tried to separate out whether changes in individual fatty acid fractions are responsible for any benefits to health (using the technique of meta-regression). The answers are not definitive, the data being too sparse to be convincing. We are left with a suggestion that less total fat or less of any individual fatty acid fraction in the diet is beneficial.

And a conclusion of the J.B. German article:

At this time [2004], research on how specific saturated fatty acids contribute to coronary artery disease and on the role each specific saturated fatty acid play in other health outcomes is not sufficient to make global recommendations for all persons to remove saturated fats from their diet. No randomized clinical trials of low-fat diets or low-saturated fat diets of sufficient duration have been carried out; thus, there is a lack of knowledge of how low saturated fat intake can be without the risk of potentially deleterious health outcomes.

Zarraga and Schwartz (2006) conclude:

Numerous studies have been conducted to help provide dietary recommendations for optimal cardiovascular health. The most compelling data appear to come from trials that tested diets rich in fruits, vegetables, MUFAs [monounsaturated fatty acids], and PUFAs [polyunsaturated fatty acids], particularly the n-3 PUFAs. In addition, some degree of balance among various food groups appears to be a more sustainable behavioral practice than extreme restriction of a particular food group.

Here’s another of my favorite quotes on this topic, from the J.B. German article:

If saturated fatty acids were of no value or were harmful to humans, evolution would probably not have established within the mammary gland the means to produce saturated fatty acids . . . that provide a source of nourishment to ensure the growth , development, and survival of mammalian offspring.

Take-Home Points

The connection between dietary saturated fat and coronary heart disease is weak.

I may be excommunicated from the medical community for uttering this. You won’t hear it from most physicians or dietitians. They don’t have time to spend 80 hours on this topic, so they stick with the party line. And maybe I’m wrong anyway.

The scientific community is slowly moving away from the original Diet-Heart/Lipid Hypothesis. It is being replaced with stronger anti-atherosclerosis theories that promote:

  • fruit and vegetable intake
  • whole grain intake
  • low-glycemic index eating
  • increased consumption of plant oils and fish
  • moderate intake of nuts
  • ? moderate intake of low-fat diary (e.g., DASH diet) (less consensus on this point)

So, saturated fats and dietary cholesterol are being crowded out of the picture, or ignored. In many cases, saturated fats have literally been replaced by poly- and monounsaturated fats (plant oils). Several clinical studies indicate that’s a healthy change, but it may be related more to the healthfulness of the plant oils than to detrimental effects of saturated fats.

The original Diet-Heart Hypothesis won’t die until the American Heart Association and U.S. public health agencies put a gun to its head and pull the trigger. That will take another 10 years or more.

If you want to hedge your bets, go ahead and limit your saturated fat intake. It probably won’t hurt you. It might help a wee bit. By the same token, I’m not going on an all-meat and cheese, ultra-high-saturated fat diet; I don’t want to miss out on the healthy effects of fruits, vegetables, whole grains, fish, nuts, and low-glycemic index carbohydrates. Some would throw red wine into the mix. This “prudent diet” reflects what I hereby christen The 21st Century Diet-Heart Hypothesis.

If you’re worried about coronary heart disease and atherosclerosis, spend less time counting saturated fat grams, and more time on other risk-reducing factors: diet modification as above, get regular exercise, control your blood pressure, achieve a healthy weight, and don’t smoke. More bang for the buck.

What do you think?

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.

Selected References Contradicting or Questioning the Diet-Heart Hypothesis (updated December 17, 2014):

Puaschitz, Nathalie, et al. Dietary Intake of Saturated Fat Is Not Associated With Risk of Coronary Events Or Mortality In Patients With Established Coronary Artery Disease. Journal of Nutrition, Feb. 1, 2015. First published online Dec. 10, 2014. doi: 10.3945/jn.114203505. The title of the article says it all. A strong majority (81%) of the 2412 study participants were men, so I’m not sure the results apply to women.

Chowdhury, Rajiv, et al. Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysisAnnals of Internal Medicine 2014;160(6):398-406-406. doi:10.7326/M13-1788  The conclusion of this meta-analysis: “Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.”

Ramsden, Christopher, et al.  Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis.  British Medical Journal 2013; 346 doi: http://dx.doi.org/10.1136/bmj.e8707 (Published 5 February 2013). Cite this as: BMJ 2013;346:e8707  (Almost 500 middle-aged men with a recent coronary event were followed over time.  Those who substituted saturated fat with omega-6 fatty acid (polyunsaturated fatty acid, mostly linoleic acid) had higher death rates (cardiac and overall deaths) than those who continued their habitual diet.)  Also see editorial by Philip Calder in the same issue.

Astrup, A., et al (including Ronald Krause, Frank Hu, and Walter Willett). The role of reducing intakes of saturated fat in the prevention of cardiovascular disease: where does the evidence stand in 2010. American Journal of Clinical Nutrition, 93 (2011): 684-688.  (The authors believe that replacing saturated fats with polyunsaturated fats (but not carbohydrates) can reduce the risk of coronary heart disease (CHD). For the last four decades, low-fat diets replaced fat with carbohydates. So they believe saturated fatty acids cause CHD or polyunsaturated fatty acids prevent it. I see no mention of total fat intake in this article written by major names in nutritional epidemiology and lipid metabolism. “In countries following a Western diet, replacing 1% of energy intake from saturated fatty acids with polyunsaturated fatty acids has been associated with a 2–3% reduction in the incidence of CHD.” “Furthermore, the effect of particular foods on CHD cannot be predicted solely by their content of total saturated fatty acids because individual saturated fatty acids may have different cardiovascular effects and major saturated fatty acid food sources contain other constituents that could influence coronary heart disease risk.”)  A Feb. 19, 2012, press release from the Harvard School of Public Health covered much of the same ground. It’s titled “Time to Stop Talking About Low-Fat, say HSPH Nutrition Experts.”

Siri-Tarino, Patty, et al. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. American Journal of Clinical Nutrition, January 13, 2010. doi:10.3945/ajcn.2009.27725

Skeaff, C. Murray and Miller, Jody. Dietary fat and coronary heart disease: Summary of evidence from prospective cohort and randomised controlled trials. Annals of Nutrition and Metabolism, 55 (2009): 173-201.

Halton, Thomas, et al. Low-carbohydrate-diet score and the risk of coronary heart disease in women. New England Journal of Medicine, 355 (2006): 1,991-2,002.

German, J. Bruce, and Dillard, Cora J. Saturated fats: What dietary intake? American Journal of Clinical Nutrition, 80 (2004): 550-559.

Ravnskov, U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease. Journal of Clinical Epidemiology, 51 (1998): 443-460.

Ravsnskov, U. Hypothesis out-of-date. The diet-heart idea. Journal of Clinical Epidemiology, 55 (2002): 1,057-1,063.

Ravnskov, U, et al. Studies of dietary fat and heart disease. Science, 295 (2002): 1,464-1,465.

Taubes, G. The soft science of dietary fat. Science, 291 (2001): 2535-2541.

Zarraga, Ignatius, and Schwartz, Ernst. Impact of dietary patterns and interventions on cardiovascular health. Circulation, 114 (2006): 961-973.

Mente, Andrew, et al. A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease. Archives of Internal Medicine, 169 (2009): 659-669.

Parikh, Parin, et al. Diets and cardiovascular disease: an evidence-based assessment. Journal of the American College of Cardiology, 45 (2005): 1,379-1,387.

Bray, G.A. Review of Good Calories, Bad Calories. Obesity Reviews, 9 (2008): 251-263. Reproduced at the Protein Power website of Drs. Michael and Mary Dan Eades.

Hooper, L., et al. Dietary fat intake and prevention of cardiovascular disease: systematic review. British Medical Journal, 322 (2001): 757-763.

Weinberg, W.C. The Diet-Heart Hypothesis: a critique. Journal of the American College of Cardiology, 43 (2004): 731-733.

Mozaffarian, Darius, et al. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. American Journal of Clinical Nutrition, 80 (2004): 1,175-1,184.

Related editorial: Knopp, Robert and Retzlaff, Barbara. Saturated fat prevents coronary artery disease? An American paradox. American Journal of Clinical Nutrition, 80 (2004): 1.102-1.103.

Yusuf, S., et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet, 364 (2004): 937-952. (ApoB/ApoA1 ratio was a risk factor for heart attack, so dietary saturated fat may play a role if it affects this ratio.)

Hu, Frank. Diet and cardiovascular disease prevention: The need for a paradigm shift. Journal of the American College of Cardiology, 50 (2007): 22-24.  (Dr. Hu de-emphasizes the original diet-heart hypothesis, noting instead that “. . . reducing dietary GL [glycemic load] should be made a top public health priority.:)

Oh, K., et al. Dietary fat intake and risk of coronary heart disease in women: 20 years of follow-up of the Nurses’ Health Study. American Journal of Epidemiology, 161 (2005): 672-679.

Parker, Steve. Time to abandon the diet-heart hypothesis? Advanced Mediterranean Diet Blog, May 1, 2009.

Parker, Steve. New study confirms the heart-healthy Mediterranean diet. Advanced Mediterranean Diet Blog, April 14, 2009. (Examination of the Mente study listed above.)

Selected References Supporting the Diet-Heart Hypothesis (by no means exhaustive)

Ascherio, A. Epidemiologic studies on dietary fats and coronary heart disease. American Journal of Medicine, 113 (supplement) (2002): 9S-12S.

Griel, Amy and Kris-Etherton, Penny. Beyond saturated fat: The importance of the dietary fatty acid profile on cardiovascular disease. Nutrition Reviews, 64 (2006): 257-262.  (Primarily a response to the Mozaffarian article above.)

Erkkila, Arja, et al. Dietary fatty acids and cardiovascular disease: An epidemiological approach. Progress in Lipid Research, 47 (2008): 172-187.

Is That “Annual Physical” Worthwhile?

Dr. Harriet Hall at Science-Based Medicine provides one suprising answer.

-Steve

Does Cutting Out Sugary Drinks Help With Weight Loss?

Are you obese, love sugary drinks, and want to easily lose four pounds (1.8 kg) over the next six months? Simply cut a couple of sugary drinks out of your daily diet, replace them with water or diet soda, and you may lose the pounds.  Or so say University of North Carolina researchers.

Down 4 pounds in 6 months. I'll take it!

In the U.S., our consumption of calories from sugar-sweetened beverages (SSBs) almost doubled between 1965 and 2002, now comprising 21% of our total calories.  (I’ve seen lower estimates, too, such as all added sugars accounting for 17% of total calories.)  Remember that our overweight and obesity rates started rising around 1970.  Any connection there?

Some have speculated that cutting back on SSB consumption would lead to loss of some excess weight.  But it’s never really been tested until now.

By the way, your typical sugary carbonated beverage has 145 calories of pure carbohydrate, most often high fructose corn syrup.  That’s equivalent to 10 tsp (50 ml) of table sugar.  Soft drinks are liquid candy.

Methodology

UNC investigators recruited  about 300 overweight and obese folks (average BMI 36, average weight 100 kg (220 lb), 84% female, 54% black) who drank at least 280 calories daily of caloric beverages (sugar-sweetened beverages, juice, juice drinks, sweetened coffee and tea, sweetened milk, sports drinks, and alcohol).  In other words, they all drank at least two soft drinks or the equivalent daily.  Participants agreed to make a dietary substitution for six months.

The participants were randomly assigned to one of three study groups with a hundred participants per group. For the next six months…

  • Group WA substituted at least two of their SSBs daily with water (WA), any type as long as it was calorie-free.  Bottled water was provided.  This reduced sugary drink calories by 230/day.
  • Group DB substituted at least two of their SSBs daily with calorie-free diet beverages (DB).  Beverages were provided.  This reduced sugary drink calories by 230/day.
  • Group AC (attention controls) made no changes in baseline beverage consumption.  Investigators made a point not to talk to them about beverages.

All three groups had monthly group meetings.  WA and DB group meetings were focused on adherence to the beverage substitution guidelines.
The AC group meetings will involved a weigh-in and general weight loss information (e.g., read food labels, increase vegetable consumption, portion control, and increase physical exercise).

“All … groups had access to a group-specific …website, where they recorded the beverages (water and DB only) they consumed, reported their weekly weight, received feedback on progress, viewed tips, and linked to group-specific resources.”

Results

All three groups lost statistically significant amounts of weight, but there was no difference in amount of weight lost among the groups.  In other words, the folks who substituted water or diet beverages for  sweet drinks didn’t do any better than the AC (attentive control) group.

Average amounts of weight lost were in the range of 1.8 to 2.5% of total body weight.  For example, if you weigh 200 lb (91 kg) and lose 2% of your weight, that’s a 4-lb loss (1.8 kg). 

Compared to the AC group, the WA group showed a statistically significant decrease in fasting blood sugar (down 3 mg/dl).  BTW, none of the participants were diabetic.

Sugar cane

Take-Home Points

Would the substituters have lost weight if they had simply cut out two sugary drinks a day, skipping the monthy meetings and website?  Don’t know.  But I bet that’s how the mainstream press will spin this. 

If I were obese and had a sugary drink habit, I’d start substituting water.  Yesterday.

Substituting water for a couple sugary drinks a day could reduce risk of developing diabetes.

I was hoping to see a significantly greater weight loss in the water and diet drink substituters compared to the AC (Attention Control) group.  Presumably all of these AC folks would have stayed at their baseline weights if they hadn’t done any of this.  The substitution groups apparently didn’t receive the general weight-loss information given to the AC group.

One caveat: All groups had monthly meetings for six months.  What were the substitution groups  talking about other than adherence to the protocol?  Your guess is as good as mine since the researchers don’t say.  Perhaps something about those meetings led to the weight loss, not the act of substituting water or diet drinks for sugar.

So they lost an average of 4–5 lb (2 kg).  Big deal, right?  But remember this was just a six-month study.  Could that 4 lb turn into 12 lb (5.5 kg) over 18 months?  Maybe, but we don’t know. 

Here’s the thing about averages.  Some of these people I’m sure lost closer to 5% of body weight, and some didn’t lose any, or gained.  Which group would you be in?  Only one way to find out. 

Remember that many medical conditions linked to overweight and obesity improve with loss of just 5% of body weight.

The substituters cut out 230 calories a day of sugary drinks.  All other things being equal, they should have lost 12 lb (5.5 kg).  Problem is, all other things aren’t equal.  Numerous other factors are at play, such as activity levels, replacement of sugary drink calories with other calories, measurement errors, reporting errors, etc.

This was a female-heavy study.  Would this strategy work for men?  Even better in men?  We don’t know.  Why not try it yourself?

Steve Parker, M.D.

PS: I did a sugar-free and wheat-free experiment on myself earlier this year.  Lost some weight, too.

Reference: Tate, Deborah, et al.  Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Conscioulsly Everday (CHOICE) randomized clinical trialAmerican Journal of Clinical Nutrition, February 1, 2012, Epub ahead of print.  doi: 10.3945/ajcn.111.026278

Sources of Calories in U.S. Diet Over Last Four Decades

Italian seaside totally unrelated to this post

Do you ever wonder how many of your total calories come from added sugars?  Grains? Dairy products?  Added fats?

You’d have to do some detailed nutrient analysis to get your personal numbers, but if you’d like U.S. averages, see this cool infographic at Civil Eats.

The graph also shows how many calories are or were available for consumption per capita over time (without accounting for wastage in restaurants).  It’s based on U.S. Department of Agriculture data.

A superficial glance suggests that U.S. per capita daily calorie consumption has increased by about 600 from the 1970s until now.  But remember, these numbers don’t discount for restaurant wastage.  Nor do I see an adjustment for children versus adults.  I’ve seen other calculations of and extra daily 150 calories (women) to 300 calories (men).  Even the lower numbers could explain our explosion of overweight and obesity.

The infographic suggests that U.S. average daily calorie consumption is 2,673.  Based on NHANES data, it’s probably closer to 2,250.

Steve Parker, M.D.

Is Your Strength Training Regimen Out-Of-Date?

Not Chris Highcock

You do have a strength training program, don’t you?

I recently finished reading Hillfit: Strength, an ebook by Chris Highcock of Conditioning Research. One of the scientific review articles he cites in support of his exercise recommendations is an eye-opener. Evidence-Based Resistance Training Recommendations is available free online. It’s published in Medicina Sportiva, which I’m not familiar with. I’ll confess I’ve read little of the hard-core literature on the science of strength training. It’s one of my more recent interests.

The review article has already got me questioning some of my notions, such as how often to work out, number of reps moving a weight, speed of moving a weight, and whether I should stick with free weights. Why not see if your dogma is supported? Worth a look.

Steve Parker, M.D.