It's been blamed for a host of health problems including obesity, diabetes, high triglycerides (blood fats), metabolic syndrome and fatty liver.
Now, a study published last week in the journal Cancer Research adds to the growing controversy over the potential health risks of fructose, a form of sugar added to thousands of foods and soft drinks.
According to researchers from the University of California, Los Angeles, the sweetener triggers pancreatic cancer cells to grow more quickly.
The major sources of fructose in our diet are sucrose (table sugar) and high fructose corn syrup, a sweetener found in soft drinks, fruit drinks, candy, cookies, ketchup, salad dressings, cereal bars, frozen dinners and countless other processed foods.
In the study, researchers took pancreatic tumours from patients and grew the cancerous cells in petri dishes. They then added glucose to one set of cells and fructose to another. Using mass spectrometry, a technique that measures how much of a compound is in a mixture, the scientists were able to follow the sugars in the cells to determine what they were being used for.
While it's widely known that cancer cells use glucose to fuel their growth, last week's findings were the first to link fructose to cancer growth. The cancer cells grew at fructose concentrations easily attainable in our North American diet and they did so at a similar rate to glucose.
However, the data showed that cancer cells used fructose and glucose in very different ways, even though they are structurally similar. Compared to glucose, fructose was a potent activator of a key cellular pathway that drives cancer cell division.
Not only did cancer cells prefer fructose, the sugar also triggered cellular activities that enabled malignant cells to use both glucose and fructose more rapidly.
Although this study was done in pancreatic cancer, the researchers noted that the results may not be unique to that type of cancer.
The findings have significance for people with pancreatic cancer, given our dramatically increased consumption of refined fructose over the past 40 years.
Since its introduction in the 1970s, high-fructose corn syrup - often listed as glucose-fructose on ingredient lists - has been a boon to the food industry. It's cheaper than table sugar, easier to blend into foods, and tastes sweeter.
This isn't the first time the potential health hazards of refined fructose have made headlines. Last year, a study conducted in overweight adults found that drinking fructose-sweetened beverages - three servings a day for 10 weeks - led to elevated blood triglyceride (fat) and LDL (bad) cholesterol levels, risk factors for heart disease.
Fructose-sweetened drinks also caused increased fat production in the liver and deep intra-abdominal fat gain. (Intra-abdominal fat sits closer to the organs and increases the risk of heart disease and diabetes.)
And earlier this year, a Princeton University research team found that rats with access to high-fructose corn syrup gained significantly more weight and had higher blood triglycerides than those with access to table sugar (sucrose), even though their overall calorie intake was the same.
Fructose is handled almost exclusively by the liver where it's more likely be metabolized into fat.
Recent work also suggests that fructose influences appetite hormones. A high intake of fructose may blunt satiety and trick you into overeating.
It's becoming more and more evident that fructose and high-fructose corn syrup are different from other sweeteners when it comes to weight gain and obesity. And last week's findings hint that the same may be true for cancer cell growth.
It's estimated that Canadians consume 13 per cent of our day's calories - about 16 teaspoons worth - from added sugars, including sucrose, maple syrup, honey, high-fructose corn syrup, glucose syrup and dextrose.
In an effort to help cut heart disease risk, the American Heart Association advises slashing added sugars to 5 per cent of daily calories - five teaspoons worth (80 calories) for women and 9 teaspoons (144 calories) for men.
The following tips will help you reduce your intake of added sugars, especially high-fructose corn syrup and sucrose:
Scan ingredient lists
Added sugars go by many names such as brown sugar, corn syrup, dextrose, fructose, fruit juice concentrate, glucose-fructose, honey, invert sugar, liquid sugar, malt, maltose, molasses, rice syrup, table sugar and sucrose. You might be surprised to see how many different types of sugars are added to one product.
Read nutrition labels
The Nutrition Facts box discloses the grams of sugar in one serving of food. (Four grams of sugar is equivalent to one teaspoon of table sugar.) Keep in mind, however, the sugar number includes both naturally occurring sugars (e.g. fruit or milk sugars) and sugars added during processing.
When buying packaged baked goods or cereal bars, choose products with no more than half the total carbohydrate from sugar.
Choose breakfast cereals with no more than six to eight grams of sugar per serving. Cereal with dried fruit is an exception.
Avoid sugary drinks
Replace soft drinks, fruit drinks, lemonade, sweetened iced tea and the like with plain water, low fat milk, unflavoured soy beverage, vegetable juice or tea.
Rein in your sweet tooth
Make a plan to reduce the amount of sweets you eat. Reserve these foods for a once-a-week treat. Gradually reduce the amount of sugar added to coffee, tea and other foods.
Leslie Beck