Hey there, time traveller!
This article was published 5/12/2016 (260 days ago), so information in it may no longer be current.
Cardiologist Dr. David Mymin has been in the blood-plumbing business long enough to see his share of conflicting, confusing and downright erroneous information about heart health.
He helped found the Reh-Fit Centre, which started in the 1970s to get heart attack survivors active at a time when the prevailing wisdom wrongly suggested otherwise.
Today, he’s the director of the Lipid Clinic at St. Boniface Hospital, which helps patients with failing grades for cholesterol get back to where they are not at high risk for heart attack and stroke.
Information on cholesterol has changed a lot over the decades, but the statistics are stark — nearly four in 10 Canadians have hazardous cholesterol levels.
"Overall, the basics haven’t changed a whole lot," Mymin says. "It’s still important to keep blood cholesterol levels down and under control."
A constant stream of evolving evidence has led to confusion though, he adds.
Take dietary cholesterol, for instance.
"We know now it is reasonably safe and it’s OK to eat eggs," he says.
Previously, food high in cholesterol was thought to raise levels of bad cholesterol in the blood known as low-density lipoprotein, or LDL for short.
Other groundbreaking research that has reversed previously prevailing thinking about fats, cholesterol and health involved trans fats — liquid vegetable fats turned into solids. Researchers found hydrogenated oils containing high levels of trans fatty acids, which had been in wide use as a healthy alternative to butter, were more harmful to cardiovascular health than saturated fats.
Even more notable is a 2014 study that indicated consumption of saturated fats — a culprit in raising "bad cholesterol" — did not raise heart-disease risk more than diets rich in unsaturated fats, which are generally considered protective.
Moreover, it pointed the finger at trans fats and refined sugar.
"There’s an element of truth to that," Mymin says.
Saturated fats — like most substances — usually aren’t harmful when taken in small amounts, but eating a lot of saturated fats is still not a good idea because saturated fats — largely animal fats — are still considered a primary cause of high bad cholesterol levels, he adds.
LDL is not intrinsically "bad" however. The body needs it to produce hormones and maintain cell function. Our liver meets most of those needs, and excess amounts can become a problem when plaque builds up in the walls of arteries, leading to blockages that can cause heart attacks and strokes.
But bad cholesterol is only part of the cholesterol picture, Mymin says.
You’ve probably heard a lot about "good cholesterol," too. Epidemiological (population-based data) points to increased levels of good cholesterol — high density lipoprotein or HDL cholesterol — as beneficial to cardiovascular health, in part because HDL helps remove excess LDL from the bloodstream.
Some foods such as olive oil may even bolster HDL levels. Alcohol is thought help a little too, Mymin says.
"It’s not to say we should all start drinking, but if you like alcohol, in moderation, it does raise HDL levels," he says, before issuing a warning: "It’s very rich in calories, and that can lead to being overweight."
That’s also true about saturated fats, or any other food rich in calories. And being overweight is perhaps the biggest cardiovascular risk of all, Mymin says.
"Excess weight is the big enemy, so anything that causes it is bad, and that includes extra calories."
Mymin says too much body fat is associated with elevated bad cholesterol and decreased good-cholesterol levels. Research reveals being overweight is also linked to bad health indicators referred to collectively as metabolic syndrome. If you have any three of the following health risk factors — excess body fat (particularly around the waist), high bad cholesterol, high blood sugar or high blood pressure — then chances are you’ve got metabolic syndrome, he says.
"All of these risks are connected" to an increased risk for cardiovascular disease, Mymin adds. Moreover, metabolic syndrome is associated with higher risk of Type 2 diabetes, which can increase the risk of heart disease all by itself.
Keeping off excess weight often can help people avoid metabolic syndrome or even reverse these disease’s symptoms.
"If you’re lean, then you’re likely going to avoid insulin resistance and diabetes, which put you at high risk for heart disease," Mymin says, adding the conditions are often related to elevated bad cholesterol and lower good-cholesterol levels.
That’s not to say thin people can’t have cholesterol problems, develop Type 2 diabetes or have a heart disease. For most folks, however, keeping cholesterol levels under control remains an effective means to reduce risk, yet rather than worrying about what or what not to eat, Mymin suggests keeping it simple.
"You can boil it down to avoid being overweight at all costs and that means controlling not what you eat, but how much you eat."
Exercise is important, too, but a workout regimen isn’t a cure-all, he says.
"It takes a lot of exercise to equal a small amount of excess food, so eat those extra cookies and you’ll need to do a lot of running to compensate."