Metabolic syndrome 101

You can't see it or feel it. But metabolic syndrome — a cluster of risk factors indicating out-of-kilter body chemistry — may affect thousands of Canadians. Here's a primer on this insidious condition.

Metabolic syndrome has been referred to as a "public health time bomb" because it is a condition that may not be recognized until it's too late. But metabolic syndrome isn't some sort of newly discovered disease — rather, it is a cluster of conditions, including obesity, insulin resistance or Type 2 diabetes, hypertension, high triglycerides and low HDL cholesterol levels that, in combination, raise the risk of cardiovascular disease and diabetes.

The condition is a basic malfunction of the systems that keep your cells fuelled with blood sugar. Suppose you've just eaten a bowl of oatmeal. Normally, levels of the hormone insulin rise slightly after you eat a meal, persuading cells to absorb the blood sugar that your breakfast provides. In metabolic syndrome, the cells cannot obey insulin's signal. It appears that central fat — the abdominal fat you've already read about — releases some surprising chemicals into the bloodstream, including immune system messengers called cytokines.

Cytokines block signals from insulin to cells to let sugar in, so then your cells have no fuel and blood sugar is building up in the bloodstream. Your pancreas then produces more insulin in response and continues to do so until, eventually, insulin overcomes the cytokines and cells get the blood sugar they need.

Metabolic syndrome also involves a raise in concentrations of fibrinogen in the bloodstream, allowing blood to clot more easily.

Along with the above conditions, metabolic syndrome is also linked to infertility and cancers of the breast, prostate and colon.

The main reasons for metabolic syndrome's current prevalence are simple — pot-bellies and too little exercise. The numbers are going up in direct proportion to Canada's epidemics of obesity and inactivity. Interestingly, researchers have found that insulin resistance seems also to be linked with poor fetal nutrition, especially in combination with rapid growth in childhood.

Thousands of Canadians are believed to have metabolic syndrome, and some experts estimate that the figure could be much higher, saying that every overweight and obese adult (60 percent) and child (26 percent) may have it.

People with metabolic syndrome can have insulin levels two or three times higher than normal — levels that can stay elevated for decades. All that excess insulin is a recipe for heart disease. It boosts triglycerides in your bloodstream, lowers levels of "good" HDLs and allows higher than normal amounts of fat to end up in your bloodstream after a meal — and stay there longer. Insulin also converts "bad" LDLs into smaller, denser particles that can easily enter artery walls forming the foundation for plaque.

There's no simple test for it, though your doctor may use a two-hour glucose-tolerance test as an indicator. The only signs are a few slightly worrying symptoms that, individually, may not even bother you or your doctor.

If you're concerned about metabolic syndrome, remember the information in this primer when you visit your doctor and start a conversation about the condition.