A
diagnosis of metabolic syndrome means it’s time to change your lifestyle
At
57, Michel Fortier of Vancouver considered himself reasonably active, trim, and
healthy, and would have said he felt fine. So it came as something for a
surprise when his doctor informed him he’d developed metabolic syndrome, a
cluster or risk factors that doubled his chances of having a heart attack over
the next decade, and at least tripled his odds of ending up with Type II
diabetes. (Depending o the severity, metabolic syndrome can increase diabetes
risk 15- to 20- fold, according to Dr. Jean-Pierre Després, scientific director
of the International Chair on Cardiometabolic Risk at University in Quebec
city.)
The
history of metabolic syndrome stretches back to the late 1960s, when Dr. Gerald
Reaven of Stanford University discovered that people with higher than normal,
but not yet diabetic blood sugar levels made abundant amounts of insulin ( the
hormone responsible for regulating blood sugar), but their bodies were
resistant to its effects. Until then, scientist had believed a shortage of
insulin was responsible for Type II diabetes. Over the next 25 years, Reaven
also observed that these patients who often went to develop elevated blood
pressure and abnormalities in the levels of certain blood fats ran a much
higher than expected risk of heart attack. Originally dubbed “syndrome X,” this
set of risk factors has since been acknowledged by the international medical
community as a harbinger of heart disease and diabetes, and renamed metabolic
syndrome. It’ also very common: estimates based on data from the Canadian
Health Measures Survey place the prevalence in the Canadian population overall
at one in five, and two in five among those aged 70 to 79.
It’s
not yet clear whether all of the abnormalities that occur in metabolic syndrome
stem from the same underlying mechanism, or, for that matter, whether the risk
they confer together is exponential rather than simply additive. “There‘s a big
debate in the literature as to whether the metabolic syndrome is greater than
the sum of its parts,” explains Dr. Sofia Anand, a researcher and professor of
medicine and epidemiology at McMaster University in Hamilton, ON.
Nonetheless,
most experts agree the concept is useful in the doctor’s office because it
raises the suspicion that if a patient has one risk factor, he or she may well
have others too, says Dr. Arya Sharma, chair of obesity research and management
at the University of Alberta in Edmonton. “From a diagnostic perspective, you
need to look for the other problems, and, if they are present, you have to
treat them to really reduce the patient’s risk,” he says.
Experts
also agree that metabolic syndrome is the result of too little physical
activity calories. In an environment that discourages exercise and presents us
with high-calorie, high-fat, high-salt snacks at every turn, “you’re not
exception if you’re overweight,” Després observes. “What’s really exceptional
these days is having a healthy body weight. It’s over lifestyle; we wouldn’t be
talking about metabolic syndrome if we were still living like hunter/
gatherers.”
The Big
Six
According
to the definition developed by the American Heart Association, someone who
meets any three of the six following criteria has metabolic syndrome.
- Large waist circumference. (40 inches/102 cm or greater
for men; 35 inches/88 cm or greater for women). It was Després who pioneered
the idea that a simple tape measure could help predict heart disease and
diabetes risks. “It turns out that a measurement around the belly (roughly
at belly-button-level) is a good indicator of the amount of fat that’s
deep in the abdomen, surrounding the organs,” says Dr. Robert Hegele, an
endocrinologist and director of the Blackburn Cardiovascular Genetics Lab
at the Roberts Research Institute in London, ON, and the London Regional
Genomics Centre. This so-called visceral fat acts almost like a gland,
pumping out substances that decrease insulin sensitivity, drive up blood
pressure, and promote inflammation and blood clotting, thereby increasing
heart attack risk. This is why “apple-shaped” people rin a greater risk of
heart attack than “pears,” who accumulate their excess weight in the
thighs and buttocks. (It’s also worth noting that waist size is not only
one of six criteria for metabolic syndrome, it’s also a risk factor for
developing the condition.) Scientists aren’t certain whether insulin resistance
leads to abdominal obesity or vice versa, but there’s no question both
imperil artery and heart health.
- Elevated fasting blood sugar. As noted above, blood sugar
levels that are higher than normal but not yet in the diabetic range
(meaning between 5.7 and 7.0 mmol/L) are linked with an increased risk of
heart disease. Among other things, the high levels of insulin that go
hand-in-hand with high blood sugars damage blood vessel linings (which can
in turn lead to atherosclerosis and heart attack, as well as kidney
disease) and nerves.
- Elevated systolic blood pressure. A systolic blood pressure (the
top number in a blood pressure reading) above 130 in one market of
metabolic syndrome; ditto for having to take medications to keep it below
130. Persistent elevations in blood pressure signal that blood vessel and
arties are starting to stiffen.
- Elevated diastolic blood pressure. Similarly, a diastolic
blood pressure ( the bottom number) greater than 85, or needing to take
medications to keep it below that level, is another potential indicator of
metabolic syndrome.
- Elevated triglycerides. (1.7 mmol/L or greater).
Creamlike fat (in contrast to waxy cholesterol) in the blood,
triglycerides are burned up by muscle cells for energy. However, if too
abundant, they can build up on blood vessel walls, which can lead to
problems like peripheral artery disease (leg pain triggered by a shortage
of blood and, therefore, oxygen) and heart attack. Two dietary demons that
raise triglycerides: excess sugar and trans fats, a type of fat found
mostly in processed foods.
- Low HDL cholesterol. (Less than 1.0 mmol/L for
men;less than 1.1 mmol/L for women). HDL cholesterol acts as a sort of
natural drain cleaner in arteries and blood vessels, clearing away
potentially damaging LDL cholesterol. The goods news (yes, there is
some!) is that regardless of whether or not the above-listed abnormalities
stem from a common cause, all can be prevented or failing that, managed
with the same simple tweaks in life style.
