Fructose, simply put - fruit sugar. We've all heard about it; good (few and far between), bad (most common), and otherwise (the controversy). The most common 'bad guy' is not just plain old fructose but its evil counterpart - high fructose corn syrup (HFCS). This stuff has been linked to hypertension, obesity, diabetes, insulin resistance, elevated blood lipids, atherosclerosis, non-alcoholic fatty liver disease, kidney stones, gout, and metabolic syndrome.
Before we break into all the in's and out's of the "F" word (fructose), here's a look at some not so sweet sugar stats. We (Americans) consume on average 38 teaspoons of sugar every day - that adds up to 130 pounds of the stuff each year; 36% percent of it comes from energy drinks, soda, and sports drinks.
Now, back to fructose and HFCS. What is it and is one really worse than the other? First, some basics:
Fructose is a 'simple sugar' (monosaccharide), just like glucose and galactose. All three have roughly 15 calories per teaspoon. It's a combination of these 'simple sugars' that make up the other
-oses (sucrose or table sugar is a combination of fructose + glucose). Unlike glucose, which serves as the body's main fuel source and is readily used for energy, fructose is not so easily metabolized. Let's get 'sciencey' for a minute. Glucose, the body's preferred fuel source, uses insulin as a shuttle to get into cells where it is used for energy. Insulin controls the amount of glucose in the blood at any one time. Unfortunately, fructose requires a little more work. It isn't regulated by insulin nor is it shuttled into cells for use. Fructose is carried from the small intestine to the liver via a special carrier protein called GLUT-2. The liver metabolizes fructose into a variety of different things including glycogen, triglycerides, LDL cholesterol and uric acid. It is this special processing that results in fructose's negative health effects.
Now onto the controversy - for every study or ad telling us that HFCS is bad there's another one sending the opposite message. What's the deal? Now that we see how fructose is metabolized, (this applies to ALL fructose - from fruit, from soda, and from HFCS and other sweeteners), is HFCS really any worse than plain old fructose, table sugar, honey, agave, etc.? Consider this - HFCS and table sugar have nearly the same amount of fructose. Table sugar (sucrose) is 50% glucose and 50% fructose. There are two types of HFCS; one of which is 55% fructose and 42% glucose (used in beverages) and one that's 42% fructose and 53% glucose (used in cereals, yogurt, etc.). Compare that with honey - 50% fructose and 50% glucose, agave - 56-92% fructose depending on the brand, and an apple - 70% fructose. Even the 'innocent' strawberry is about 52% fructose... Does that help clear up the 'limit fruit' recommendation...? Fruit's redeeming factors are that, comparatively speaking, it's low in calories, has some fiber, vitamins and minerals unlike the 'hard' sugars. Whether it's fructose, sucrose, dextrose, maltose, xylose, invert sugar, molasses, fruit , fruit juice concentrate, maltodextrin, turbinado sugar, malt syrup, brown rice syrup, agave nectar, maple syrup, HFCS and yes, even straight-up fruit, it's all going to the liver and the net result will be the same.
There really is no definitive answer as to which is the worst. As I like to say "Sugar is as sugar does." And what does 'sugar do' - not a whole heck of a lot of anything good.
So, what the fruc(tose)?!? Let's make it a 'sugar-free summer'!