Canadians are consuming less natural sugar than they were a few decades ago, according to figures released by Statistics Canada. Sound like reason to celebrate? Maybe not.

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Corn is found in just about all U.S. fast food burgers and chicken sandwiches, a U.S. study says. It's also used to make the liquid sweetener high fructose corn syrup. ((Mark Blinch/Reuters))

Most people would never open a bag of sugar and then feed themselves 10½ teaspoons of the stuff. But that's exactly what you're doing if you drink your average can of soda pop.

Except it's not called sugar. It's high-fructose corn syrup and it's been a cornerstone of the food and beverage industry since it began to be produced on a large scale in the 1970s. Between the start of that decade and 1990, Americans' consumption of high-fructose corn syrup has increased by 1,000 per cent.

Statistics Canada says a marked increase in the use of high-fructose corn syrup and glucose means we're relying less on sucrose — or sugar from honey, maple, sugar cane, sugar beets and other refined sources.

High-fructose corn syrup is made from corn. After it's milled, the resulting starch is processed into a syrup. By adding enzymes, the syrup is converted into fructose. Glucose syrup is then added to the mix to make high-fructose corn syrup. The most common form of the syrup contains 45 per cent glucose and 55 per cent fructose.

Corn is abundant in North America, which helps make high-fructose corn syrup a cheaper alternative. It's sweeter than sugar and helps extend the shelf life of processed foods. It's also easier to blend and transport because it's a liquid.

As a mixture, its chemical composition differs from sucrose, and some say that's critical in its effect on the human body. Critics suggest there's a link between the increased use of high-fructose corn syrup and a growing North American diabetes and obesity epidemic.

Tips on reducing consumption of added sugar

Cut back on soft drinks — liquid candy — by far the biggest source of sugar in the average diet. Drink water, seltzer, low-fat milk or orange juice instead.

Fruit "drinks," "beverages," "ades," and "cocktails" are essentially non-carbonated soda pop. Many contain only 5 to 10 per cent juice.

Limit candy, cookies, cakes, pies, doughnuts, granola bars, pastries, and other sweet baked goods. Eat fruit instead.

Fat-free cakes, cookies, and ice cream may have as much added sugar as their fatty counterparts and they're often high in calories. "Fat-free" on the package doesn't necessarily mean low calorie.

Look for breakfast cereals that have no more than eight grams of sugar per serving.

At the American Chemical Society conference in August 2007, U.S. researchers suggested soft drinks containing high-fructose corn syrup may be linked to the development of diabetes, especially in children. Their study found that drinks sweetened with high-fructose corn syrup contained "astonishingly high" levels of reactive carbonyls, which are highly reactive compounds associated with "unbound" fructose and glucose molecules that are believed to cause tissue damage.

Levels of reactive carbonyls tend to be elevated in the blood of people with diabetes.

Reactive carbonyls are not present in table sugar, whose fructose and glucose components are "bound" and chemically stable.

Other studies have found that appetite, which normally decreases after eating, decreased less after drinking fructose-sweetened beverages — and that it caused triglycerides to increase, an indicator of risk for cardiovascular disease.

In March 2010, there was evidence of harmful health effects associated with high-fructose corn syrup, this time for a type of liver disease.

About 30 per cent of adults in the U.S. have non-alcoholic fatty liver disease, said study author Dr. Manal Abdelmalek, an associate professor of medicine at Duke University Medical Center. When fat builds up in the liver, it can cause inflammation, then scarring known as cirrhosis of the liver — permanent damage to the liver that leads to a blockage of blood flow through the organ.

The study linked frequent consumption of the sweetener to progression or worsening of liver injury in patients with non-alcoholic fatty liver disease.  

"High-fructose corn syrup, which is predominately in soft drinks and processed foods, may not be as benign as we previously thought," Abdelmalek said. 

In November 2010, research led by Dr. Richard Johnson of Colorado University was published in the Journal of the American Society of Nephrology, suggesting high fructose corn syrup may play a role in hypertension and kidney disease.

"Science shows us there is a potentially negative impact of excessive amounts of sugar and high fructose corn syrup on cardiovascular and kidney health," Johnson said.

New research from UCLA associated high-fructose corn syrup with pancreatic cancer, while still another study found a link between beverages containing the sweet syrup and gout in women.

"Excessive fructose intake could be viewed as an increasingly risky food and beverage additive," Johnson said.

The food industry disputes studies that suggest there may be adverse health effects associated with high-fructose corn syrup.

The Corn Refiners Association has launched an aggressive advertising campaign to counter criticisms of high-fructose corn syrup. Among the ads' claims are that high-fructose corn syrup "has the same natural sweeteners as table sugar" and is natural.

The Center for Science in the Public Interest points out that while high-fructose corn syrup consists almost entirely of glucose and fructose, sugar is 100 per cent sucrose. The Center for Science notes that if you add a water molecule to sucrose and split it in half, you'll be left with one molecule of glucose and one molecule of fructose — but that's not the same as saying that high-fructose corn syrup and sugar contain the same sweeteners.

As for the Corn Refiners Association's claim that table sugar is natural, the Center for Science says you can't find high-fructose corn syrup in nature — somebody has to make it.

The centre also says that — nutritionally — high-fructose corn syrup and sucrose may be identical and the special harmfulness of high-fructose corn syrup may be an urban myth.

The jury may be out on whether high-fructose corn syrup is fuelling an epidemic of obesity and diabetes. But it is clear that — overall — North Americans are consuming a lot more sweeteners than they should be.

The average Canadian drank more than 95 litres of soft drinks in 2007, according to Statistics Canada — that's more than any other beverage except coffee.