Category Archives: coronary heart disease

Do Low-Carb Diets Cause Premature Death?

Adult life is a battle against gravity. Eventually we all lose.

Adult life is a battle against gravity. Eventually we all lose.

Japanese researchers say low-carb diets are causing premature death. I’m skeptical.

The potentially healthful side effects linked to low-carb eating include reduced weight, higher HDL cholesterol, and lower triglycerides and blood pressure. The Japanese investigators wondered if the improved cardiovascular risk factors seen with low-carb diets actually translate into less heart disease and death.

How Was the Study At Hand Done?

The best way to test long-term health effects of a low-carb diet (or any diet) is to do a randomized controlled trial. You take 20,000 healthy and very similar people—not rodents—and randomize half of them to follow a specific low-carb diet while the other half all eat a standard or control diet. Teach them how to eat, make damn sure they do it, and monitor their health for five, 10, or 20 years. This has never been, and never will be, done in humans. The Nazis may have done it, but it’s not published. In the old days, we could do this study on inmates of insane asylums or prisons.

What we have instead are observational studies in which people voluntarily choose what they’re eating, and we assume they keep eating that way for five or 10+ years. You also assume that folks who choose low-carb diets are very similar to other people at the outset. You depend on regular people to accurately report what and how much they’re eating. You can then estimate how much of their diet is derived from carbohydrate and other macronutrients (protein and fat), then compare health outcomes of those who were in the top 10% of carb eaters with those in the bottom 10%. (We’ve made a lot of assumptions, perhaps too many.)

Of the observational studies the authors reviewed, the majority of the study participants were from the U.S. or Sweden. So any true conclusions may not apply to you if you’re not in those countries. In looking for articles, they found no randomized controlled trials.

The observational studies estimated carb consumption at the outset, but few ever re-checked to see if participants changed their diets. That alone is a problem. I don’t know about you, but I’ve had significant changes in my diet depending on when I was in college and med school, when I was a bachelor versus married, when my income was higher or lower, and when I had young children versus teenagers. But maybe that’s just me.

The researchers looked at all-cause mortality, deaths from cardiovascular disease, and incidence of cardiovascular disease. They don’t bother to define cardiovascular disease. I assume heart attack, strokes, and peripheral vascular disease. (But aren’t aneurysms, deep vein thrombosis, and pulmonary embolism vascular diseases, too?) Wouldn’t you think they’d carefully define their end-points? I would. Since they were going to all this trouble, why not look at cancer deaths, too?

What Did the Investigators Conclude?

Very low-carbohydrate dieters had a 30% higher risk of death from any cause (aka all-cause mortality) compared to very high-carb eaters. The risk of cardiovascular disease incidence or death were not linked with low-carb diets. Nor did they find protection against cardiovascular disease.

Finally, “Given the facts that low-carbohydrate diets are likely unsafe and that calorie restriction has been demonstrated to be effective in weight loss regardless of nutritional composition, it would be prudent not to recommend low-carbohydrate diets for the time being.”

If Low-Carb Dieters Die Prematurely, What Are They Dying From?

The top four causes of death in the U.S. in 2011, in order, are:

  1. heart attacks
  2. cancer
  3. chronic lower respiratory tract disease
  4. stroke

You’ll note that two of those are cardiovascular disease (heart attacks and stroke). So if low-carb diets promote premature death, it’s from cancer, chronic lung disease, or myriad other possibilities. Seventy-five percent of Americans die from one of the top 10 causes. Causes five through 10 are:

  • accidents
  • Alzheimer disease
  • diabetes
  • flu and pneumonia
  • kidney disease
  • suicide

Problem is, no one has ever linked low-carb diets to higher risk of death from any specific disease, whether or not in the top ten. Our researchers don’t mention that. That’s one reason I’m very skeptical about their conclusion. If you’re telling me low-carb diets cause premature death, tell me the cause of death.

Another frustration of mine with this report is that they never specify how many carbohydrates are in this lethal low-carb diet. Is it 20 grams, 100, 150? The typical American eats 250-300 grams of carb a day. If you’re going to sound the alarm against low-carb diets, you need to specify the lowest safe daily carb intake.

For most of my career—like most physicians—I’ve been wary of low-carb diets causing cardiovascular disease. That’s because they can be relatively high in total fat and saturated fat. In 2009, however, I did my own review of the scientific literature and found little evidence of fats causing cardiovascular disease.

If you’re looking for a reason to avoid low-carb diets, you can cite this study and its finding of premature death. I’m not convinced. I’ll turn it around on you and note this study found no evidence that low-carb diets cause cardiovascular disease. The risk of cardiovascular disease had been the traditional reason for physicians to recommend against low-carb diets.

Steve Parker, M.D.

Reference: Noto, Hiroshi et al. Low-Carbohydrate diets and all-cause mortality: A systematic review and meta-analysis of observational studies. PLoS One, 2013; 8(1): e55050

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Filed under Carbohydrate, coronary heart disease, Longevity, Weight Loss

Why Do I Recommend Nuts to All My Patients?

Nuts with more omega-3 fatty acids (compared to omega-6) may be the healthiest

Nuts with the lowest omega-6/omega-3 fatty acid ratios may be the healthiest. In other words, increase your omega-3s and decrease omega-6s.

Conner Middelmann-Whitney explains in her recent post at Psychology Today. In a nutshell, they are linked to longer life and better health. For example:

In the largest study of its kind, Harvard scientists found that people who ate a handful of nuts every day were 20% less likely to die from any cause over a 30-year period than those who didn’t consume nuts. The study also found that regular nut-eaters were leaner than those who didn’t eat nuts, a finding that should calm any fears that eating nuts will make you gain weight.

The report also looked at the protective effect on specific causes of death. “The most obvious benefit was a reduction of 29% in deaths from heart disease—the major killer of people in America,” according to Charles S. Fuchs, director of the Gastrointestinal Cancer Treatment Center at Dana-Farber, the senior author of the report and a professor of medicine at Harvard Medical School. “But we also saw a significant reduction—11% —in the risk of dying from cancer,” added Fuchs.

Read the whole enchilada.

Nuts are integral to my Advanced Mediterranean Diet, Low-Carb Mediterranean Diet, Paleobetic Diet, and Ketogenic Mediterranean Diet.

Walnuts seem to have the lowest omega-6/omega-3 fatty acid ratio of all the common nuts. That may make them the healthiest nut. The jury is still out. Macadamia nuts also have a good ratio. Paleo dieters focus on cutting out omega-6s and increasing omega-3s. Julianne Taylor has a great post on how to do that with a variety of foods, not just nuts.

Steve Parker, M.D.

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Filed under cancer, coronary heart disease, Heart Disease, Longevity, nuts

Supplemental Omega-3 Fats’ Effect on Heart Disease, Stroke, Cancer, and Death: No Relationship In a General Population

Salmon is one the the cold-water fatty fish loaded with omega-3 fatty acids

Salmon is one the the cold-water fatty fish loaded with omega-3 fatty acids

I’ve been sitting on this research report a few years, waiting until I had time to dig into it. That time never came. The full report is free online (thanks, British Medical Journal!). I scanned the full paper to learn that nearly all the studies in this meta-analysis used fish oil supplements, not the cold-water fatty fish the I recommend my patients eat twice a week.

Here’s the abstract:

Objective: To review systematically the evidence for an effect of long chain and shorter chain omega 3 fatty acids on total mortality, cardiovascular events, and cancer.

Data sources: Electronic databases searched to February 2002; authors contacted and bibliographies of randomised controlled trials (RCTs) checked to locate studies.

Review methods Review of RCTs of omega 3 intake for 3 6 months in adults (with or without risk factors for cardiovascular disease) with data on a relevant outcome. Cohort studies that estimated omega 3 intake and related this to clinical outcome during at least 6 months were also included. Application of inclusion criteria, data extraction, and quality assessments were performed independently in duplicate.

Results: Of 15 159 titles and abstracts assessed, 48 RCTs (36 913 participants) and 41 cohort studies were analysed. The trial results were inconsistent. The pooled estimate showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03) or combined cardiovascular events (0.95, 0.82 to 1.12) in participants taking additional omega 3 fats. The few studies at low risk of bias were more consistent, but they showed no effect of omega 3 on total mortality (0.98, 0.70 to 1.36) or cardiovascular events (1.09, 0.87 to 1.37). When data from the subgroup of studies of long chain omega 3 fats were analysed separately, total mortality (0.86, 0.70 to 1.04; 138 events) and cardiovascular events (0.93, 0.79 to 1.11) were not clearly reduced. Neither RCTs nor cohort studies suggested increased risk of cancer with a higher intake of omega 3 (trials: 1.07, 0.88 to 1.30; cohort studies: 1.02, 0.87 to 1.19), but clinically important harm could not be excluded.

Conclusion: Long chain and shorter chain omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer.

Reference: Hooper, Lee et al. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ  2006;332:752-760 (1 April), doi:10.1136/bmj.38755.366331.2F (published 24 March 2006).

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Filed under coronary heart disease, Diabetes Complications, Fat in Diet, Fish, Heart Disease, Longevity, Stroke

Live Longer With The Mediterranean Diet Even If You Already Have Cardiovascular Disease

Conquer Diabetes and Prediabetes, Steve Parker MD

Olive oil and vinegar: prominent components of the Mediterranean diet

We’ve known for years that the Mediterranean diet helps prolong life and prevent cancer, heart attacks, type 2 diabetes, dementia, and strokes in folks who start out healthy.

What about patients with existing cardiovascular disease? I’m talking about history of heart attacks, strokes, angina, and coronary artery disease.

Yep. The Mediterranean diet helps them live longer, too.

Details of the study are at the American Journal of Clinical Nutrition. The research was done at Harvard.

Steve Parker, M.D.

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Filed under coronary heart disease, Health Benefits, Heart Disease, Longevity, Mediterranean Diet, Stroke

Heart Attack and Amputation Rates Much Improved in Diabetics

MedPageToday has the details. This jibes with my experience over the last 30 years. A quote:

An analysis of national data found that rates of myocardial infarction (MI) in diabetic patients dropped about 68%, and amputation rates were halved between 1990 and 2010, Edward Gregg, PhD, of the CDC in Atlanta, and colleagues reported in the April 17 issue of the New England Journal of Medicine.

Strokes and deaths from hyperglycemic crisis also fell dramatically.

The number of adults reporting a diagnosis of diabetes more than tripled during the study period.

Steve Parker, M.D.

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Filed under coronary heart disease, Diabetes Complications

Your Oral Health May Help You Prevent Heart Disease

…according to an article at University Herald.

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The idea is that nasty bacteria around your gums somehow cause arterial inflammation in your heart arteries, which could lead to heart attacks. I’ve written about this before.

A quote from the article:

The researchers followed 420 adults as part of the Oral Infections and Vascular Disease Epidemiology Study (INVEST), a randomly sampled prospective cohort of Northern Manhattan residents. Participants were examined for periodontal infection. Overall, 5,008 plaque samples were taken from several teeth, beneath the gum, and analyzed for 11 bacterial strains linked to periodontal disease and seven control bacteria. Fluid around the gums was sampled to assess levels of Interleukin-1β, a marker of inflammation. Atherosclerosis in both carotid arteries was measured using high-resolution ultrasound.

Over a median follow-up period of three years, the researchers found that improvement in periodontal health-health of the gums-and a reduction in the proportion of specific bacteria linked to periodontal disease correlated to a slower intima-medial thickness (IMT) progression, and worsening periodontal infections paralleled the progression of IMT. Results were adjusted for potential confounders such as body mass index, cholesterol levels, diabetes, and smoking status.

Thickening of the arterial lining is linked to higher rates of heart attack and stroke.

It remains to be seen whether alteration of gum bacteria and periodontal disease via oral self-care and dental care will reduce cardiovascular risk going forward. Stay tuned.

Read more at http://www.universityherald.com/articles/5322/20131101/brushing-your-teeth-could-prevent-heart-disease.htm#rvx294vC7VKJ6Qu3.99

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Filed under coronary heart disease, Heart Disease

Worried About Future Heart Attack? Check Your LDL Cholesterol Particle Number (LDL-P)

…according to Drs. Thomas Dayspring and James Underberg. I don’t know if these guys are right or not. I bet it’s more complicated than simple LDL particle number.

Even if you eat lots of eggs, most of your cholesterol is made by your liver. That's where statin drugs work.

Even if you eat lots of eggs, most of your cholesterol is made by your liver. That’s where statin drugs work.

Most heart attacks (aka myocardial infarctions) do indeed seem to be caused by acute rupture of an atherosclerotic plaque that’s been present for years. Two key questions are:

  1. What causes the plaque?
  2. Why causes them to rupture?

Underberg and Dayspring write:

The only absolute requirement for plaque development is the presence of cholesterol in the artery: although there are additional heart risk factors like smoking, hypertension, obesity, family history, diabetes, kidney disease, etc., none of those need to be present. Unfortunately, measuring cholesterol in the blood, where it cannot cause plaque, until recently has been the standard of risk-testing. That belief was erroneous and we now have much better biomarkers to use for CV risk-assessment. The graveyard and coronary care units are filled with individuals whose pre-death cholesterol levels were perfect. We now understand that the major way cholesterol gets into the arteries is as a passenger, in protein-enwrapped particles, called lipoproteins.

Particle entry into the artery wall is driven by the amount of particles (particle number) not by how much cholesterol they contain. Coronary heart disease is very often found in those with normal total or LDL-cholesterol (LDL-C) levels in the presence of a high LDL particle number (LDL-P). By far, the most common underlying condition that increases LDL particle concentration is insulin resistance, or prediabetes, a state where the body actually resists the action of the sugar controlling hormone insulin. This is the most common scenario where patients have significant heart attack risk with perfectly normal cholesterol levels. The good news is that we can easily fix this, sometimes without medication. The key to understanding how comes with the knowledge that the driving forces are dietary carbohydrates, especially fructose and high-fructose corn syrup. In the past, we’ve often been told that elimination of saturated fats from the diet would help solve the problem. That was bad advice. The fact is that until those predisposed to insulin resistance drastically reduce their carbohydrate intake, sudden deaths from coronary heart disease and the exploding diabetes epidemic will continue to prematurely kill those so afflicted.

***

And for goodness’ sake, if you want to live longer, start reducing the amount of dietary carbohydrates, including bread, potatoes, rice, soda and sweetened beverages (including fruit juices), cereal, candy – the list is large).

Underberg and Dayspring don’t mention don’t mention LDL particle size, such as small/dense and large/fluffy; the former are thought by many to be much more highly atherogenic. Is that outdated?

Whoever figures out the immediate cause of plaque rupture and how to reliably prevent it will win a Nobel Prize in Medicine.

Read the whole enchilada.

Steve Parker, M.D.

About Dayspring and Underberg:

Thomas Dayspring MD, FACP, FNLA   Director of Cardiovascular Education, The Foundation for Health Improvement and Technology, Richmond, VA. Clinical Assistant Professor of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School.

James Underberg MD, FACP, FNLA   Clinical Assistant Professor of Medicine in the Division of General Internal Medicine at NYU Medical School and the NYU Center for Cardiovascular Disease Prevention . Director of the Bellevue Hospital Primary Care Lipid Management Clinic.

h/t Dr. Axel Sigurdsson

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Filed under coronary heart disease, Heart Disease, Uncategorized