Friday, February 1, 2013

Metabolic Syndrome Diet Recommendations

Recall from the last blog that the metabolic syndrome is a condition that has exploded in the American population in the last few years (the CDC estimates that 1 out of 3 American adults meet the criteria for metabolic syndrome) and that the syndrome is diagnosed when an individual has 3 of the following risk factors: high waist circumference (abdominal obesity), high triglycerides, high blood pressure, low HDL (good) cholesterol, high-normal blood sugar.   Recall also that individuals that have the constellation of risk factors that comprises the metabolic syndrome are at significantly higher risk of developing cardiovascular disease and/or diabetes.  The metabolic syndrome, which also goes by other names (Syndrome X, insulin resistance, pre-diabetes, hyperinsulinemia) is resolvable with weight-loss and exercise. 

The effectiveness of the traditionally-recommended high-carbohydrate diet (55-65% carbs) for cardiovascular disease came into debate because of the evidence that at least 10-30% of the population may be "hyperinsulinemic” (they have an overproduction of insulin in response to carbohydrates) resulting in the now widely recognized Syndrome X.  Here’s how it works--             

After we eat, blood sugar level rises triggering the pancreas to secrete the hormone insulin which stimulates the body’s cells to take in and store glucose, or use it for energy.  In insulin “resistant” people, the cells become less and less sensitive to insulin, so the body pumps out more insulin (hyperinsulinemia) to do the job of getting sugar into the cells.  The excess insulin manages to keep blood glucose levels within the normal range, though usually at the upper end (called “high-normal” glucose or “impaired glucose tolerance”) so diabetes does not occur (yet).  In years past this was often overlooked by doctors, but in reality the steadily rising blood glucose measures year after year (if it was even measured at all) was often an indication that more and more insulin was being produced in an effort to keep “pushing down” the steadily rising blood sugar level.  The gradual but steadily rising blood glucose was a sign that insulin was losing the battle and having to call on more and more insulin to do the job (hyperinsulinemia).  But the patient could go home with a pat on the back that he was not, at least yet, diabetic as often other family members were (the reason for testing blood sugar in the first place, also the reason for the "good news" that blood sugar was still in the "healthy" range for this patient).  Silently, however, the consistently increasing insulin had its own metabolic cascade of effects as the blood sugar slowly climbed its way up to diabetes diagnosis anyway.  That metabolic cascade is now widely recognized as Syndrome X or metabolic syndrome, the common cluster of disordered symptoms described above (in red) which contribute to increased risk of cardiovascular disease and diabetes.

The CDC confirmed in a 2011 Diabetes Fact Sheet that in 2005−2008, based on fasting glucose or hemoglobin A1c levels, 35% of U.S. adults aged 20 years or older had    pre-diabetes (50% of those aged 65 years or older).

One more important note (to be continued in the next blog)—while the the Mediterranean and Syndrome X diets are lower carb (45%) than the traditionally recommended higher carbohydrate diets of the past (55-65%), they are not low carbohydrate diets.  The popular high-protein (carbo-phobic) diets recommended in many recent popular diet books are based on 30% carbs which is way too low, the physiological reasons (i.e., inducing a state of ketosis) to be discussed in a future blog.  These diets are to be avoided, at all cost (or it will cost you).  There is a kernel of truth in the high-protein diet proponents’ claims that carbohydrates in the diet are problematic.  However, they neglect to distinguish between the real culprits, simple carbohydrates, and healthy complex carbohydrates. 

It is the simple carbohydrates which Americans consume in excess that are known to affect insulin and inflammation, and there is no evidence that complex carbohydrates are to blame.

You'd never know that from the carbo-phobia which persists in the culture.  In insulin resistant individuals refined carbohydrates should be replaced with monounsaturated fats (as in the 40% fat Syndrome X diet and Mediterranean diet of the traditional Greeks based predominantly on olive oil).  Refined carbohydrates should not be replaced with protein (as in popular high-protein diets) because protein stimulates insulin secretion (recall that hyperinsulinemia is the problem!).  Monounsaturated fats do not stimulate insulin secretion and do lower triglycerides.  Furthermore, the Standard American Diet is already based on a preponderance of animal protein accompanied by saturated fat and cholesterol which raises the risk for cardiovascular disease further.

The high-protein diet self-professed “experts” (book authors) got a kernel of the truth right (replacing excess refined carbs) but in the not-too-long run are critically wrong!

All the best-selling anti-carbohydrate diet books cite the work of Gerald Reaven, and they all misinterpret that work, says Reaven, so he wrote his own book to combat the misinformation.  If you want to know the truth about Syndrome X, read Reaven’s book:

“I wrote the book because I got so upset about the misinformation in the other books,” he explains.

Let’s get this right!

Diane Preves, M.S., R.D.

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1 comment:

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