Friday, February 4, 2011

The Nutrition Debate #9: Metabolic Syndrome, the American Disease of Civilization

What exactly is Metabolic Syndrome and how is it diagnosed? There are several definitions but most have five “risk factors” in common, with the first always being obesity. It is variously defined as “central obesity” (what I have coined “omental adiposity”), or a Body Mass Index (BMI) ≥30, or elevated waist circumference (men ≥40 inches, women ≥35 inches). The other four “risk factors” are elevated triglycerides (≥150mg/dl), reduced HDL, the “good” cholesterol (men ≤40mg/dl, women ≤50mg/dl), elevated blood pressure (≥130/85mm Hg, or use of medications for hypertension) and elevated fasting glucose (≥100 mg/dl, or use of medications for hyperglycemia).

Metabolic Syndrome is just one of a larger class of disorders that have become known as the Diseases of Civilization. Metabolic Syndrome, because it is increasingly affecting Westernized populations at younger and younger ages, especially in the last fifty years, is more closely identified with diet and lifestyle factors. Gary Taubes (of “Good Calories-Bad Calories” fame) and many others, including (most humbly) me, identify Metabolic Syndrome primarily, I would say exclusively, with diet alone. To support this assertion, let’s look at some statistics of how the Western, and specifically the American diet, has changed in modern times. Granted, these are also only associations -- not causal relationships – and so need to be closely examined.

Annual sugar consumption in the US is now in excess 160 pounds per capita, and most of that is triglyceride-raising high fructose corn syrup (HFCS). HFCS is 55% fructose and 45% glucose. It was first introduced into the food supply in 1978 and today is ubiquitous. Look for it on food labels, in soft drinks, and also in breads, cereals, breakfast bars, lunch meats, yogurts, soups and condiments, and avoid it like the plague. Americans consumed only about 100 pounds of sugar (sucrose) per person in 1920 and only about 15 pounds in 1830, most of it molasses, according to the Diet Heart Publishing timeline cited in Installment #3.

Older readers will remember Vitamin D rich lard, the rendered fat from pigs. It was once the #1 cooking fat with 70% of the market. Today, highly processed soybean oil has 70% of the market, and zero vitamin D. And, again as the Diet Heart Publishing timeline points out, “now the experts who told us not to eat lard are telling us we are deficient in Vitamin D!”

Per capita butter consumption in 1910 was 18 pounds. By 2000 it was less than 4 pounds. By 1957 margarine outsold butter for the first time. We gave up butter’s beneficial vitamin A for the excess, inflammation-inducing omega 6 fatty acids found in margarine, vegetable shortening and processed vegetable oils. Interestingly, as the trans fat dangers of margarine have become apparent, by 2005 butter had started to enjoy a comeback and for the first time was outselling margarine, again according to the Diet Heart Publishing timeline.

Finally, we Americans, for the last half century in particular, have been buying and eating more and more refined, highly processed carbohydrates, starches and sugars included as ingredients in the prepared foods that increasingly dominate the choices available to us. We choose them largely for convenience as we go about our busy lives. These daily dietary choices portend our own destruction, metabolically speaking. The Metabolic Syndrome is becoming, indeed has become, the American Disease of Civilization and it is associated with a long list of related conditions, known as co-morbidities.

Research has yet to firmly establish the causal relationship, but it is common for a patient with metabolic syndrome to progress to T2 diabetes and cardio vascular disease (CVD). In the United States, CVD is the leading cause of death among both men and women, and the presence of type 2 diabetes double the risk. In fact, over 50% of deaths in patients with type 2 diabetes are due to CVD. People with Metabolic Syndrome have a significantly greater risk of CVD, particularly men over age 45 and women over 55. These people also have a fivefold risk of developing type 2 diabetes.

Metabolic Syndrome, a growing and commonly silent condition, thus poses a significant public health threat. Left unchecked, it will have a staggering effect on healthcare in the United States in the years ahead. So, what can be done to check this “epidemic”? If overweight and obesity is the common risk factor, then we have to ask, why do we get fat?

© Dan Brown 1/30/11

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