Category Archives: carbohydrate

Great lecture videos available on line

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In January I attended the annual meeting of Physicians for Ancestral Health. There were great presentations on many topics related to lifestyle and health. Take a look at the website linked below to learn about many topics relating nutrition, exercise, and lifestyle to health.

Open Video Archives | Physicians for Ancestral Health

I presented a lecture titled “The Lipoprotein Retention Model, What’s Missing?” This discusses many factors (root causes) that contribute to the formation of plaque in arteries and what can be done to prevent this insidious process by adopting a “Paleo Lifestyle“.

Other videos include:

Paleopathology and the Origins of the Paleo Diet. Keynote speaker Michael Eades MD, author of several books and a well known website.

Medicine Without Evolution is like Engineering Without Physics– Randolph M Neese, MD Director of the Arizona State University Center for Evolution.

The Roles of Intermittent Fasting and Carbohydrates in Cancer Therapy– Dawn Lemanne, MD, MPH, integrative oncologist.

 23 and Me: Practical First Steps-Deborah Gordon MD, discusses a practical approach to utilizing information from this genetic test.

Histamine Intolerance-Why (food) Freshness Matters– Georgia Ede MD.

 

Mood and Memory: How Sugar Affects Brain Chemistry-Georgia Ede, MD.

Systems Analysis and Multiple Sclerosis– Tommy Wood MD, author, blogger and lecturer, frequently interviewed on topics related to exercise and nutrition.

Cholesterol OMG– Jeffry Gerber, MD “The Diet Doctor” in Denver Colorado

Bob Hansen MD

 

 

 

Still want a doughnut or cereal for breakfast?

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A recent study has demonstrated that brain deterioration detected by MRI scan seems to be linked to higher blood sugar levels even within the “normal range”.

Here are some important quotes from a Medscape discussion:

“Previous studies have shown that T2D (type 2 diabetes) is associated with brain atrophy, cognitive deficits, and increased risk for dementia. Elevated plasma glucose levels still within the normal range increase the risk for T2D.”

“Studies showed that in apparently healthy individuals, atrophy of the amygdala and hippocampus increased as FPG (fasting plasma glucose) within the normal range increased.”

“You start having abnormalities in the brain even at levels that are within the normal range. This is important because, should we be defining normal glucose levels for different purposes?”

Bottom line, as discussed by neurologist David Perlmutter in his book Grain Brain, even “normal” blood sugars as defined by measurements in our society many not be healthy. If a whole modern culture has higher blood sugars, higher blood pressures, fatter waistlines compared to our healthy hunter gatherer ancestors, then the “normal range” may not really be “normal”. If we define “normal” as individuals within 1 or 2 standard deviations of the mean, but a large portion of the population is unhealthy, is normal healthy?

Do you want to spend your last day in diapers drooling in a nursing home or do you want to go out hiking in the woods and enjoying grandchildren?

The choice is yours, but the next time you have a doughnut or cereal for breakfast, consider the long term consequences.

Live clean and prosper.

Bob Hansen MD

Here is the whole Medscape article for those interested in the nitty-gritty details.

White Matter Lesions Linked to Rising Plasma Glucose

SANTIAGO, Chile — Higher fasting plasma glucose (FPG) levels are associated with a higher burden of brain white matter hyperintensities (WMH), particularly in the frontal lobes.

The association is especially strong in individuals with type 2 diabetes (T2D), a new study shows.

Lead author Nicolas Cherbuin, PhD, and colleagues in the Centre for Research on Ageing, Health and Wellbeing of the Australian National University in Canberra used data from the Personality and Total Health (PATH) Through Life Project, a large, longitudinal, population-based study investigating the time course and determinants of cognitive aging and mental health.

The study findings were presented here at the XXII World Congress of Neurology (WCN).

The PATH Through Life Project aims to follow approximately 7500 randomly selected adults in the greater Australian capital area over 20 years.

From an older age cohort (60 to 64 years; n = 2551), 401 community-living individuals were available for analysis. All were free of neurologic disorders, stroke, and gross brain abnormalities and had a Mini-Mental State Examination (MMSE) score of 27 or greater.

Using linear regression analysis, the researchers tested the association between FPG and WMH volumes, controlling for covariates of age, sex, intracranial volume, education, smoking, hypertension, body mass index (BMI), diabetes, and interactions of diabetes and sex.

Plasma glucose was measured after an overnight fast and was categorized as normal, defined as less than 5.6 mmol/L (<100.8 mg/dL), impaired (5.6 to 7 mmol/L [100.8 to 126 mg/dL]), or T2D (≥7 mmol/L [≥126 mg/dL] or self-report of T2D).

Patient groups with normal FPG (n = 276), impaired FPG (n = 86), or T2D (n = 39) were similar in age (approximately 63 years), education (14 years), and MMSE scores (29.26 to 29.45). BMI was higher in the impaired FPG and T2D groups than in the normal FPG group. There was also more hypertension in the T2D group.

WMH Mostly in Frontal and Temporal Lobes

Dr Cherbuin reported that among the entire cohort, higher FPG was associated with a higher burden of WMH in the right hemisphere (P = .02) but not in the left hemisphere. The effect was most prominent in the frontal and temporal lobes.

These findings were largely attributable to participants with impaired FPG or T2D, and the effect was most pronounced for participants with T2D.

Table. WMH Volumes per FPG Level

Location Normal FPG (n = 276) Impaired FPG (n = 86) T2D (n = 39)
Left hemisphere WMH (mm3) 2343.68 ± 2311.72 2331.07 ± 2528.34 2800.62 ± 2152.87
Right hemisphere WMH (mm3) 2379.59 ± 2645.19 2414.98 ± 2609.72 3199.79 ± 4031.47
Values are expressed as mean ± standard deviation.

 

Previous studies have shown that T2D is associated with brain atrophy, cognitive deficits, and increased risk for dementia. Elevated plasma glucose levels still within the normal range increase the risk for T2D.

Studies showed that in apparently healthy individuals, atrophy of the amygdala and hippocampus increased as FPG within the normal range increased. Striatum volumes decreased several years later in line with higher FPG or occult T2D. Functionally, poorer performance of fine motor skills is evident with higher FPG.

Session chairman Samuel Wiebe, MD, professor of neurology at the University of Calgary, Alberta, Canada, commented to Medscape Medical News that the present study intrigued him because it addresses the fact that the definition of normal glucose “maybe doesn’t apply to everything…. You start having abnormalities in the brain even at levels that are within the normal range. This is important because, should we be defining normal glucose levels for different purposes?”

Higher levels of glucose even within the normal range may affect facets that are just beginning to be understood, such as white matter changes. “That’s just one aspect. There could be other areas,” he said. “So I think that that’s an intriguing finding that deserves further study.”

Dr Wiebe said the greater effect of elevated glucose seen in the frontal lobes may be related to some degree to their sheer size or to blood flow. “I think that the truth is that it is a spectrum. It begins to have an impact at a range of values that are lower than the cutoff” for traditional interventions, he said.

He feels it would be interesting to follow up this study with assessments that go beyond WMH volume measurements, such as tractography or connectivity studies that look at brain function.

There was no commercial funding for the study. Dr Cherbuin and Dr Wiebe have disclosed no relevant financial relationships.

XXII World Congress of Neurology (WCN). Abstract 434. Presented November, 2, 2015.

Carbohydrate Restriction for Diabetes I and II

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A great review article challenging the current low fat dogma has been published. This should be required reading for all physicians. It brings clarity, data, and perspective to the discussion.

Here is the abstract:

Abstract

“The inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines.”

Here are the opening paragraphs.

“The benefits of carbohydrate restriction in diabetes are immediate and well-documented. Concerns about the efficacy and safety are long-term and conjectural rather than data-driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss) and leads to the reduction or elimination of medication and has never shown side effects comparable to those seen in many drugs.

Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term random-controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed.

“At the end of our clinic day, we go home thinking, ‘The clinical improvements are so large and obvious, why don’t other doctors understand?’ Carbohydrate restriction is easily grasped by patients: because carbohydrates in the diet raise the blood glucose, and as diabetes is defined by high blood glucose, it makes sense to lower the carbohydrate in the diet. By reducing the carbohydrate in the diet, we have been able to taper patients off as much as 150 units of insulin per day in eight days, with marked improvement in glycemic control – even normalization of glycemic parameters.”

— Eric Westman, MD, MHS [1].

Here is the link to the whole article.

Dietary Carbohydrate restriction as the first approach in diabetes management. Critical review and evidence base

Peace and good health.

Bob Hansen MD

Amputations, Gangrene and Carbohydrates

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As an anesthesiologist I have spent more than 60,000 hours in the operating room and cared for over 30,000 patients. I often observe the end-results of bad dietary advice. I am referring to the liberal carbohydrate allowance that the American Diabetes Association and other agencies offer diabetics.

Today was a particularly poignant day as I cared for two diabetics who required amputations for complications of diabetes type II. These complications could have likely been avoided if our supermarkets were not stocked with high carb nutritionally deplete “food” AND if the ADA, physicians and nutritionists counseled diabetics to significantly reduce their carbohydrate intake. Instead, the low fat narrative has so predominated our culture, that we have taken our eyes off of the major dietary threats during the past 40 years, excessive carbohydrates and especially refined carbohydrates.

The leading cause of amputations in modern society are the complications of diabetes including peripheral arterial disease (atherosclerosis in the arteries to our limbs) and peripheral neuropathy (loss of sensation in the feet and hands). The combination of these two, or just one alone can lead to non-healing wounds and ulcers in the feet, then chronic infections and ultimately gangrene. Futile efforts to restore circulation to the legs with vascular bypass surgeries or arterial stents usually just briefly delay the inevitable series of amputations that start in the toes and progress up the leg, step by step until only a stump is left above the level once occupied by the knee.

Gangrene is an ugly thing. During the Civil War the major cause was trauma. Today the major cause is diabetes and indirectly, excess carbohydrate consumption.

The visual experience of gangrene results in a visceral reaction, even after more than 30 years of observation. The knowledge that most of these complications could be avoided by simply eating whole fresh foods instead of crap in a bag or crap in a box is frustrating. The human suffering and economic costs (lost wages, disability, medical expenses) are staggering. Diabetes type II is largely a disease of lifestyle. The lifestyle elements involved include poor dietary habits, lack of exercise, inadequate sleep, and stress. All of these contribute and all are modifiable and avoidable.

Type II diabetes is arguably reversible early in the disease process. As it progresses a patient reaches an irreversible point of no return where the pancreas has been exhausted and the insulin producing cells are no longer efficient and effective. Equally important,  the cells in the rest of the body do not respond in a normal fashion to what little insulin is produced. But even at this stage carbohydrate restriction can mitigate complications if only healthy fresh whole-foods are consumed and modest exercise is practiced on a daily basis.

Other complications of diabetes including blindness, painful neuropathy, kidney failure requiring dialysis, heart attack and stroke all are arguably avoidable with a whole foods paleolithic carbohydrate restricted diet and modest amounts of regular exercise.

What a pity, what a shame, what a waste.

Below are some links and research articles to back up my statements.

Peace, health, and harmony.

BOB

1. Type 2 Diabetes

2. American Diabetes Association Embraces Low-Carbohydrate Diets. Can You Believe It? | Richard David Feinman

3. Nutrition Science on Pinterest

4. Low-Carb for You: Low-Carb versus Low-Fat

And Many More:

Jenkins DJ, Kendall CW, McKeown-Eyssen G, Josse RG, Silverberg J, Booth GL, Vidgen E, Josse AR, Nguyen TH, Corrigan S et al: Effect of a low-glycemic index or a high-cereal fiber diet on type 2 diabetes: a randomized trial. JAMA 2008, 300(23):2742-2753.

Westman EC, Yancy WS, Mavropoulos JC, Marquart M, McDuffie JR: The Effect of a Low-Carbohydrate, Ketogenic Diet Versus a Low-Glycemic Index Diet on Glycemic Control in Type 2 Diabetes Mellitus. Nutr Metab (Lond) 2008, 5(36).

Gannon MC, Hoover H, Nuttall FQ: Further decrease in glycated hemoglobin following ingestion of a LoBAG30 diet for 10 weeks compared to 5 weeks in people with untreated type 2 diabetes. Nutr Metab (Lond) 2010, 7:64.

Gannon MC, Nuttall FQ: Control of blood glucose in type 2 diabetes without weight loss by modification of diet composition. Nutr Metab (Lond) 2006, 3:16.

Gannon MC, Nuttall FQ: Effect of a high-protein, low-carbohydrate diet on blood glucose control in people with type 2 diabetes. Diabetes 2004, 53(9):2375-2382.

Forsythe CE, Phinney SD, Feinman RD, Volk BM, Freidenreich D, Quann E, Ballard K, Puglisi MJ, Maresh CM, Kraemer WJ et al: Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet. Lipids 2010, 45(10):947-962.

Jakobsen MU, Overvad K, Dyerberg J, Schroll M, Heitmann BL: Dietary fat and risk of coronary heart disease: possible effect modification by gender and age. Am J Epidemiol 2004, 160(2):141-149.

Siri-Tarino PW, Sun Q, Hu FB, Krauss RM: Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr 2010, 91(3):502-509.

Int J Cardiol. 2006 Jun 16;110(2):212-6. Epub 2005 Nov 16. Effect of a low-carbohydrate, ketogenic diet program compared to a low-fat diet on fasting lipoprotein subclasses. Westman EC, Yancy WS Jr, Olsen MK, Dudley T, Guyton JR.

Mol Cell Biochem. 2007 Aug;302(1-2):249-56. Epub 2007 Apr 20.Beneficial effects of ketogenic diet in obese diabetic subjects. Dashti HM, Mathew TC, Khadada M, Al-Mousawi M, Talib H, Asfar SK, Behbahani AI, Al-Zaid NS.

 

 

Not all calories are the same.

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The old school teaching about obesity went like this. Consume more calories than you burn and you gain weight. Consume less calories than you burn and you lose weight. Obesity is just a problem of self control. All calories are the same.

This way of thinking has been dis proven but still pervades many discussions.

Ample evidence supports the following facts that should be considered in choosing foods and mitigating the obesity epidemic.

  • High glycemic high carbohydrate foods and beverages such as bread, pasta, potatoes, crackers, chips, granola bars, breakfast cereal, soda, energy drinks produce a rapid rise in blood sugar and insulin levels, stimulate hunger, enhance further carbohydrate cravings, and drive people to overeat. Thus, what kind of food you eat affects how much you eat. (1,2)
  • High carbohydrate diets  result in decreased calorie burning (decreased metabolic rate) compared to high fat high protein diets. Thus, a diet with carbohydrate restriction not only limits hunger (improves satiety) but also results in burning more calories for the same level of activity and at rest. I have previously discussed weight loss studies that consistently demonstrate that carbohydrate restriction results in spontaneous reduction in caloric consumption. At the same time this approach results in burning more calories while you watch TV or go for a walk. (3)
  • The human body does not absorb all of the calories present in food. A higher % of the calories present in highly processed refined foods (which represent 70% of the American diet) are absorbed compared to whole unprocessed foods such as tree nuts. (4)
  • Whole foods, especially non-starchy vegetables, provide much more satiety producing fiber (non-starchy vegetables have five to seven times as much fiber compared to whole grain bread on a per calorie basis)
  • Food choices produce different effects on the gut flora. A diet consisting of whole hunter-gatherer type foods (grass fed meat, free range poultry and eggs, wild seafood, fresh fruits, vegetables and nuts) enhance and support the development of “good bacteria” in the gut. As discussed before , the gut flora have a major impact on the risk of obesity and other diseases.
  • High carbohydrate diets produce higher insulin levels.  Insulin results in conversion of carbohydrate into fat and storage of fat. Insulin inhibits the burning of fat. Carbohydrate restriction results in burning fat for energy.
  • The process of protein digestion consumes more calories compared to the digestion of carbohydrate. Protein has a higher  thermogenic effect compared to carbohydrate.

THE BOTTOM LINE: not all calories are the same. The quality of the food we consume affects our metabolic rate, our absorption of calories, how quickly we feel full and therefore how many calories we consume, and the mix of good bacteria and bad bacteria that live in our GI tract.

Good health, peace and tranquility to all

BOB

1. Fed Up Asks, Are All Calories Equal? – NYTimes.com

2. Changes in diet and lifestyle and long-term wei… [N Engl J Med. 2011] – PubMed – NCBI

3. Effects of Dietary Composition During Weight Loss Maintenance: A Controlled Feeding Study

4. Impact of Peanuts and Tree Nuts on Body Weight and Healthy Weight Loss in Adults

Fat consumption, Fat circulating in your blood, Heart Disease

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Another nail has been driven into the coffin of the diet-heart hypothesis. The Annals of Internal Medicine (the official journal for the American College of Physicians) just published a review article that considered three kinds of studies related to fat and heart disease. (1)

  1. Studies that evaluated the association between dietary consumption of different kinds of fat and cardiovascular disease (heart attack and stroke)
  2. Studies that evaluated the association between levels of different kinds of fat circulating in the blood and cardiovascular disease
  3. Studies that evaluated supplementation with various kinds of fat and cardiovascular disease.

Most importantly, the authors found no statistical association between consumption of saturated fat and cardiovascular disease. I have previously discussed another large meta-analysis published in 2010 with the same finding. (2)

I have discussed the unscientific demonization of saturated fat many times (3,4,5).

This is important because it again speaks against the dietary advice promulgated by the AHA and the USDA to reduce consumption of saturated fat. The low-fat advice has resulted in a proliferation of low-fat high-sugar and high-carbohydrate food products which arguably have contributed to the epidemics of obesity and diabetes in the US.

Similarly, recent studies have correlated dementia with high carbohydrate consumption. (6) If you reduce fat in the diet you must replace it with something else and unfortunately in the US that something else has been sugar and other refined carbohydrates.

Other statistically significant findings in the Annals of Internal Medicine study were an inverse relationship between circulating blood levels of the omega three fats found in seafood (EPA and DHA) and cardiovascular events. The authors pointed out that although higher blood levels of EPA and DHA were significantly associated with lower cardiovascular risk, supplementation with EPA and DHA have had mixed results  with many studies showing positive results but some showing no protective effects. My comments on the omega three supplement studies are

  1. supplementation with fish oil (omega three fats) will not benefit most individuals unless excess pro-inflammatory omega six fats (found in refined vegetable oils) are reduced/eliminated and that side of the equation has not been addressed in any of the published studies. In other words, the studies did not reduce omega 6 fats, they just supplemented with omega 3 fat. If an individual is consuming 30-60 grams of omega six fats per day, trying to balance that with 2-3 grams per day of fish oil will not achieve a healthy ratio.
  2. many of the fish oil (omega three) supplement studies used very low amounts of fish oil, well below the amounts used in the studies that demonstrated benefit.

I am not suggesting that everyone should take fish oil supplements. Instead, I support eating a whole foods paleolithic diet based on grass-fed meat, free range poultry, free range eggs, fresh wild seafood, fresh vegetables, fresh fruits and nuts.

Finally, the data on trans-fat consumption demonstrated statistically significant correlation with cardiovascular disease. The biochemistry and physiology of manufactured trans-fats demonstrate a disruptive role of these man-made fats and the elimination of these harmful fats from our food supply will likely provide great health benefits.

The authors comment on the complex relationship between fat consumption and circulating levels of specific fats in the blood as demonstrated by Forsythe et al. (6,7) I will discuss this in future posts. For now consider the paradox that high-fat carbohydrate restricted diets result in lower circulating levels of saturated fat compared to high carbohydrate diets. (6,7), Explanation: excess carbohydrates are immediately converted to fat and stored as saturated fat by humans.

1. Annals of Internal Medicine | Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis

2. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. 2010; 91:535-46.
PubMed

3. https://practical-evolutionary-health.com/2014/02/16/can-goose-liver-grass-fed-meat-aged-hard-cheese-free-range-eggs-and-cod-liver-oil-prevent-a-heart-attack/

4. https://practical-evolutionary-health.com/2013/11/03/saturated-fat-vs-sugar/

5. https://practical-evolutionary-health.com/2013/11/01/saturated-fat-does-it-matter/

6. Relative intake of macronutrients impacts risk of mild cognitive impairment or dementia. Journal of Alzheimers Dis. 2012;32(2):329-39. doi: 10.3233/JAD-2012-120862.

7. Forsythe CE, Phinney SD, Feinman RD, Volk BM, Freidenreich D, Quann E, et al. Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet. Lipids. 2010; 45:947-62. PubMed

8. Forsythe CE, Phinney SD, Fernandez ML, Quann EE, Wood RJ, Bibus DM, et al. Comparison of low fat and low carbohydrate diets on circulating fatty acid composition and markers of inflammation. Lipids. 2008; 43:65-77. PubMed

Peace,

Bob Hansen MD

Lose weight, control blood sugar, reduce inflammation

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The Duke University Lifestyle Medicine Clinic prescribes a nutritional program based upon a very simple concept, limit carbohydrate intake and multiple problems improve. This approach is so powerful in controlling blood sugar that diabetic patients must reduce their medication  before adopting the nutritional program in order to avoid very low blood sugars.

Compared to a low-fat diet weight loss approach, it is better or equal on every measurement studied. Here is what happens on the carbohydrate restricted program when compared to a low fat diet (American Heart Association diet). The carbohydrate restricted diet results in

  • Greater reduction in weight and body fat
  • Greater reduction in fasting blood sugar
  • Reduction in the amount of saturated fat circulating in the blood despite a higher intake than a low fat diet
  • Greater reduction in insulin with improved insulin sensitivity
  • Reduction in small LDL (low fat diets increase small LDL which is considered to be associated with more heart attacks and strokes)
  • Increase in HDL (low fat diets decrease HDL, decreased HDL is associated with increased risk of heart attack and stroke)
  • Greater reduction in Triglycerides
  • Reduction in the ApoB/ApoA-1 ratio (low fat diets do the opposite, and the opposite is considered to increase risk of heart attack and stroke).
  • Reduction in multiple markers of inflammation
  • Spontaneous reduction in caloric consumption without counting or restricting calories (people automatically eat less as a result of restricting carbohydrates, low-fat diets require counting and restricting calories in order to lose weight)
  • Increased consumption of non-starchy vegetables

All of these beneficial effects are accepted by the medical community as reducing cardiovascular risk .

The improved metabolic outcome can occur even without weight loss simply by substituting fat for carbohydrate.

“The key principle is that carbohydrate, directly or indirectly through the effect of insulin, controls the disposition of excess dietary nutrients. Dietary carbohydrate modulates lipolysis, lipoprotein assembly and processing and affects the relation between dietary intake of saturated fat intake and circulating levels.” see here

Yet despite these proven effects, the proponents of low-fat diets refer to the carbohydrate restriction approach as a “fad diet”. In his excellent discussion of this term, Richard Feinman points out that historically, a carbohydrate restriction approach is actually the longest standing and proven approach to the treatment of obesity compared to a low-fat diet which is a relative newcomer. He describes how a low-fat diet more closely meets the dictionary’s definition of a “fad”.

Multiple Studies have compared carbohydrate restriction to low fat diet approaches and the results are consistent. In addition to the advantages cited above, carbohydrate restricted approaches when compared to low-fat diets reveal that symptoms of  “negative affect and hunger improved to a greater degree” compared with those following a low fat diet”. (see here)

When one analyzes the carbohydrate restricted diet (CRD) approach employed by many centers, including the Duke Interventional Medicine Clinic, one finds great similarity to a paleolithic diet.

They both eliminate or dramatically reduce

  • sugar-sweetened foods and beverages,
  • grains, flour foods and cereal foods
  • legumes (paleo completely, CRD to a large extent)
  • processed-refined vegetable oils
  • dairy (paleo completely, CRD to a large extent)

Fruits under a CRD are limited to small amounts of berries initially and this is liberalized over time as weight loss is achieved and metabolic parameters are improved. This is consistent with a paleolithic approach that recognizes that fruits and vegetables grown today have been bred to provide much higher sugar and starch content compared to the pre-agricultural  fruits and vegetables that early hominids consumed for hundreds of thousands of years.

A carbohydrate restricted nutritional approach to treat obesity, diabetes, or metabolic syndrome appears to be a valid and arguably superior remedy to a growing problem in the developed world. Yet despite this strong and convincing scientific data, dietary fat-phobia has impaired the utilization of this proven therapeutic modality.

Peace,

Bob Hansen M.D.

Saturated fat, does it matter?

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Recommendations to reduce saturated fat consumption have pervaded our media since the AHA published its first dietary guidelines for the American public in 1961. The AMA at first opposed the recommendations but the AHA pushed on. The guidelines encouraged substitution of polyunsaturates for saturated fat. The guidelines were presented in a two page report with 1/2 page of references. A subsequent independent review of those references revealed that 1/2 of them did not support the recommendations, details, details.

My last blog looked at a meta-analysis of the major studies subsequently published on this topic and found that implementation of that recommendation does not reduce heart attacks or cardiac deaths and in fact there was a trend (not statistically significant) for worse outcomes associated with substituting PUFA (polyunsaturated fatty acids, primarily linoleic acid) for SFA (saturated fatty acids).

Please note that we are talking hard endpoints here, death and heart attack. So much of the literature that consumes this issue only looks at the effect on so called risk factors. When you actually look at the clinical outcomes (death, heart attack, stroke)  there is no benefit demonstrated when saturated fats are reduced.

In 1966 the makers of Mazola Corn Oil and Mazola Margarine sponsored publication of Your Heart Has Nine Lives, a book advocating the substitution of vegetable oils for butter and other “artery clogging” saturated fats.

The history of this campaign to demonize SFA and glorify PUFA is well described in Gary Taubes Good Calories, Bad Calories, as well as in Mary Enig’s essay The Oiling of America. I would encourage you to read both.  The latter is available on line as is Gary Taubes’ famous essay What if its all a big fat lie?

http://www.westonaprice.org/know-your-fats/the-oiling-of-america

In 2010 a highly respected lipid research group published what should have been a wake-up call study for the medical profession.

Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.

The data included 5 to 23 years follow up on 347,747 subjects. 11,006 developed coronary heart disease or stroke. Intake of saturated fat was not associated with an increased risk of coronary heart disease (CHD), stroke, or  cardiovascular disease (CVD =CHD plus stroke).

“there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”

To be clear, association (statistical correlation) does not prove or disprove causation, but if such a large amount of data from prospective studies shows no statistically significant correlation, than a causative theory should be rejected until and unless randomized controlled clinical trials suggest otherwise.

This study should have created a tsunami in the media and in the medical community but it hardly caused a ripple in the pond. Michael Eades explains why in an excellent post here.

http://www.proteinpower.com/drmike/lipid-hypothesis/eat-less-move-die-anyway/

The editors of the journal published a scathing rebuke of the authors but could not find anything wrong with the data and conclusions except that the data refuted their belief system. Busy physicians tend to read the editorials and place more credence in an editorial than in a study that questions or refutes a major thesis.

Lets look at some other studies that considered hard clinical endpoints.

Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial.

The objective of this study was:

“To test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk.”

This study was a randomized controlled trial of 48,835 postmenopausal women aged 50-79 years of diverse backgrounds and ethnicity.

“RESULTS: By year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d).”

Did this decrease heart attacks or strokes? NO

“The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05).”

Now lets look at a study where women were followed after a heart attack to see if reducing saturated fat helped.

Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr. 2004 Nov;80(5):1175-84.

In this study quantitative coronary angiography was performed at baseline and after mean follow up of 3.1 years. 2243 coronary artery segments in 235 women were studied.

Here is what they found.

  • a higher saturated fat intake was associated with a smaller decline in mean minimal coronary diameter (P = 0.001) and less progression of coronary stenosis (P = 0.002) during follow-up
  • Carbohydrate intake was positively associated with atherosclerotic progression (P = 0.001), particularly when the glycemic index was high
  • Polyunsaturated fat intake was positively associated with progression (of coronary atherosclerosis) when replacing other fats (P = 0.04) but not when replacing carbohydrate or protein
  • Monounsaturated and total fat intakes were not associated with progression. (extra virgin olive oil and macadamia nuts are rich in monounsaturated fat)

The P values cited demonstrate unequivocal statistical significance for all of these associations.

So intake of carbohydrate and polyunsaturated fat was positively associated with progression of coronary atherosclerosis. Conversely, saturated fat intake was associated with less progression of coronary stenosis.  Again, I must point out that association does not prove or disprove causation. Nevertheless, there have been no prospective studies that demonstrate an association between saturated fat consumption and cardiovascular events (real clinical endpoints). Here we have data that show a negative association with saturated fat but positive association with carbohydrate and polyunsaturated fat consumption.

The logic has always been that substituting PUFA for SFA reduces cholesterol levels (short term studies) and therefore it should reduce heart attacks and strokes. But if you search the medical literature you find that the overwhelming body of data shows no reduction in hard clinical outcomes by reducing saturated fat, in fact just the opposite is true as in the two Ramsden studies cited in my previous post.

Uffe Ravnskov has pointed out that the proponents of the dietary  saturated fat-cholesterol theory often times misrepresent the data from published studies and cite those studies in support of the theory when in fact the data actually refute the theory. (as was the case for the AHA’s first dietary recommendations demonizing saturated fat in 1961) Uffe’s letters to the editor have been a nuisance to the proponents of that theory for decades.

An exhaustive review of the literature by Ravnskov was published in 1996. The summary deserves a complete quotation here.

J Clin Epidemiol. 1998 Jun;51(6):443-60.

The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease.

Source

uffe.ravnskov@swipnet.se

Abstract

A fat diet, rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA), is said to be an important cause of atherosclerosis and cardiovascular diseases (CVD). The evidence for this hypothesis was sought by reviewing studies of the direct link between dietary fats and atherosclerotic vascular disease in human beings. The review included ecological, dynamic population, cross-sectional, cohort, and case-control studies, as well as controlled, randomized trials of the effect of fat reduction alone. The positive ecological correlations between national intakes of total fat (TF) and SFA and cardiovascular mortality found in earlier studies were absent or negative in the larger, more recent studies. Secular trends of national fat consumption and mortality from coronary heart disease (CHD) in 18-35 countries (four studies) during different time periods diverged from each other as often as they coincided. In cross-sectional studies of CHD and atherosclerosis, one group of studies (Bantu people vs. Caucasians) were supportive; six groups of studies (West Indians vs. Americans, Japanese, and Japanese migrants vs. Americans, Yemenite Jews vs. Yemenite migrants; Seminole and Pima Indians vs. Americans, Seven Countries) gave partly supportive, partly contradictive results; in seven groups of studies (Navajo Indians vs. Americans; pure vegetarians vs. lacto-ovo-vegetarians and non-vegetarians, Masai people vs. Americans, Asiatic Indians vs. non-Indians, north vs. south Indians, Indian migrants vs. British residents, Geographic Study of Atherosclerosis) the findings were contradictory. Among 21 cohort studies of CHD including 28 cohorts, CHD patients had eaten significantly more SFA in three cohorts and significantly less in one cohort than had CHD-free individuals; in 22 cohorts no significant difference was noted. In three cohorts, CHD patients had eaten significantly more PUFA, in 24 cohorts no significant difference was noted. In three of four cohort studies of atherosclerosis, the vascular changes were unassociated with SFA or PUFA; in one study they were inversely related to TF. No significant differences in fat intake were noted in six case-control studies of CVD patients and CVD-free controls; and neither total or CHD mortality were lowered in a meta-analysis of nine controlled, randomized dietary trials with substantial reductions of dietary fats, in six trials combined with addition of PUFA. The harmful effect of dietary SFA and the protective effect of dietary PUFA on atherosclerosis and CVD are questioned.

That was published in 1998, since then the evidence remains as Uffe described it 15 years ago. More studies show no relationship between saturated fat consumption and cardiovascular death, heart attack, or stroke.

Finally, multiple autopsy studies around the world have been conducted to investigate an association between diet and atherosclerosis. None of these studies have demonstrated a positive association between degree of atherosclerosis and saturated fat intake.

Yet the AHA continues to recommend lower levels of saturated fat consumption while showing little concern for the problem of sugar and refined carbohydrates.

In my next post I will discuss why sugar and refined carbohydrates are major players in the physiology of atherosclerosis. Future posts will address the China Study, Forks Over Knives, the Ornish Diet and related topics. Additionally I will discuss why an egg a day keeps the doctor away.

Go in peace.

Bob Hansen MD.