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In the last post, I reviewed a study by Gerald Reaven's group showing that insulin resistance strongly predicts the risk of cardiovascular disease over a 5-year period.  In 2001, Reaven's group published an even more striking follow-up result from the same cohort ( 1 ).  This study shows that not only does insulin resistance predict cardiovascular disease risk, it also predicts a variety of age-related diseases, including hypertension, coronary heart disease, stroke, cancer, type 2 diabetes, and even overall mortality risk. Read more »

There is little remaining doubt in the scientific/medical community that high levels of LDL, so-called "bad cholesterol", cause heart disease.  Yet in some alternative health circles, the debate continues.  A new study adds substantially to the evidence that LDL plays a causal role in heart disease. Read more »

When we consider the health impacts of eating meat, cardiovascular disease is the first thing that comes to mind.  Popular diet advocates often hold diametrically opposed views on the role of meat in cardiovascular disease.  Even among researchers and public health officials, opinions vary.  In this post, I'll do my best to sort through the literature and determine what the weight of the evidence suggests. Ancel Keys and the Seven Countries Study Ancel Keys was one of the first researchers to contribute substantially to the study of the link between diet and cardiovascular disease.  Sadly, there is a lot of low-quality information circulating about Ancel Keys and his research ( 1 ).  The truth is that Keys was a pioneering researcher who conducted some of the most impressive nutritional science of his time.  The military "K ration" was designed by Keys, much of what we know about the physiology of starvation comes from his detailed studies during World War II, and he was ...

The meta-analysis by Chowdhury et al. raised quite a furor from certain segments of researchers and the popular media.  I find this reaction interesting.  I usually write about obesity, which is a topic of great interest to people, but my post about the review paper received more than twice my usual traffic.  People whose findings or opinions are questioned by the paper are aggressively denouncing it in the media, even calling for retraction ( 1 ).  This resembles what happens every time a high-profile review paper is published that doesn't support the conventional stance on fatty acids and health (e.g., Siri-Tarino et al. [ 2 ], which despite much gnashing of teeth is still standing*).  I'm not sure why this issue in particular arouses such excitement, but I find it amusing and disturbing at the same time.  This kind of reaction would be totally out of place in most other fields of science, where aggressive public media outbursts by researchers are usually frowned upon. As it ...

A new review paper on dietary fatty acids and heart disease risk was just published by Dr. Rajiv Chowdhury and colleagues in the Annals of Internal Medicine-- one of the top medical journals ( 1 ).  The goal of the paper is to comprehensively review the studies evaluating the effect of dietary fatty acids on heart (coronary) disease.  The review covers observational and intervention studies pertaining to saturated, monounsaturated,  trans , omega-6 polyunsaturated, and omega-3 polyunsaturated fats.  The paper is notable for its comprehensiveness (inclusion criteria were very lax). Here is a summary of the results: In observational studies that measured diet, only trans fat was related to cardiovascular risk.  Saturated, monounsaturated, and polyunsaturated fats were unrelated to risk. In observational studies that measured circulating concentrations of fatty acids, long-chain polyunsaturated fatty acids (DHA, DPA, EPA, AA) were associated with lower risk.  The dairy-fat-derived margar...

Obesity is strongly associated with metabolic alterations and negative health outcomes including diabetes, cardiovascular disease, and some types of cancer ( 1 ,  2 ,  3 ,  4 ).  Excess body fat is one of the primary causes of preventable health problems and mortality in the United States and many other affluent nations, ranking in importance with cigarette smoking and physical inactivity.  Obesity is thought to contribute to disease via the metabolic disturbances it causes, including excess glucose and lipids in the circulation, dysregulated hormone activity including insulin and leptin, and inflammatory effects.  This immediately raises two questions: Does metabolically healthy obesity exist? If so, are metabolically healthy obese people at an elevated risk of disease and death? Does metabolically healthy obesity exist? Read more »

Last week, I attended a Keystone conference, "Neuronal Control of Appetite, Metabolism and Weight", in Banff.  Keystone conferences are small, focused meetings that tend to attract high quality science.  This particular conference centered around my own professional research interests, and it was incredibly informative.  This post is a summary of some of the most salient points. Rapid Pace of Scientific Progress Read more »

Many of you are already aware of the recent study that examined atherosclerosis in 137 ancient mummies from four different cultures ( 1 ).  Investigators used computed tomography (CT; a form of X-ray) to examine artery calcification in mummies from ancient Egypt, Peru, Puebloans, and arctic Unangan hunter-gatherers.  Artery calcification is the accumulation of calcium in the vessel wall, and it is a marker of severe atherosclerosis.  Where there is calcification, the artery wall is thickened and extensively damaged.  Not surprisingly, this is a risk factor for heart attack.  Pockets of calcification are typical as people age. I'm not going to re-hash the paper in detail because that has been done elsewhere.  However, I do want to make a few key points about the study and its interpretation.  First, all groups had atherosclerosis to a similar degree, and it increased with advancing age.  This suggests that atherosclerosis may be part of the human condition, and not a modern disease....

By now, most of you have probably heard about the recent study on the "Mediterranean diet" ( 1 ), a diet that was designed by diet-heart researchers and is based loosely on the traditional diet of Crete and certain other Mediterranean regions.  The popular press has been enthusiastically reporting this trial as long-awaited proof that the Mediterranean diet reduces the risk of cardiovascular events-- by a full 30 percent over a 4.8-year period.  I wish I could share their enthusiasm for the study. Read more »

I recently revisited a really cool paper published in the Lancet in 2009 on body fatness, biomarkers, health, and mortality ( 1 ). It's a meta-analysis that compiled body mass index (BMI) data from nearly 900,000 individual people, and related it to circulating lipids and various health outcomes.  This is one of the most authoritative papers on the subject. Read more »