Fructose Glucose

suchandra · January 23, 2008

Feeding mice with food that contains fructose makes them fat and overweight within a short periode of time of 2 months. Why fructose is being used in almost all foodstuffs and fruit juices - it is cheaper and more sweet than glucose.

Studies point to high fructose corn syrup as a culprit in obesity

http://www.active.com/nutrition/Articles/Studies_point_to_high_fructose_corn_syrup_as_a_culprit_in_obesity.htm

Janet Helm

Chicago Tribune Just as our country's obesity rates shifted into high gear, so did our intake of a now ubiquitous ingredient: high fructose corn syrup.  Is this a mere coincidence? Or is there something more insidious about this liquid sweetener that is literally short-wiring our metabolism and making us fat? The debate is in full swing.

High fructose corn syrup is not the same as the corn syrup you use to make pecan pie or candy during the holidays. Made by treating cornstarch with enzymes, it's about half fructose and half glucose (regular corn syrup is all glucose).

You won't find bottles of this stuff on supermarket shelves. But you will see it listed as a primary ingredient in soft drinks and fruit beverages, which are the leading sources of high fructose corn syrup in the American diet.

It also pops up in some surprising places -- everything from applesauce to energy bars. Even ketchup, barbecue sauce and bottled marinades contain the sweetener.

Fructose: Treated differently than other sugars?

So what's the big deal? Some experts believe our bodies treat high fructose corn syrup more like a fat than a sugar. They think it may even trigger metabolic changes -- tricking us to eat more and store more fat.

Peter Havel, a nutrition researcher at the University of California, Davis, who has studied the metabolic effects of fructose, has found that several hormones involved in the regulation of body weight do not respond to fructose as they do to other types of sugars, such as glucose.

"Fructose doesn't appear to signal the hormonal systems involved in the long-term regulation of food intake and energy metabolism," he said.

Havel's research shows that fructose does not stimulate insulin and leptin -- two hormones that help turn down the appetite and control body weight. At the same time, fructose does not suppress our body's production of ghrelin, a hormone that increases hunger and appetite.

Other studies have shown that fructose kicks more fat into the bloodstream in the form of triglycerides, which may increase the risk of heart disease.

The debate picked up steam recently with the release of a new study in the July issue of Obesity Research that suggests fructose alters our metabolic rate in a way that favors fat storage.

Havel and researchers at the University of Cincinnati and the German Institute of Human Nutrition fed mice a fructose-sweetened drink, which caused them to store more fat than mice that drank water -- even though they did not consume more calories.

These findings suggest that calorie intake may not be the only explanation for weight gain when people include fructose in their diets, the authors concluded.

Only part of the blame

The fructose-sweetened drink given to the mice was chosen to imitate the high fructose corn syrup found in soft drinks, but some food-industry groups are crying foul.

Richard Adamson, vice president of scientific and technical affairs for the American Beverage Association, said the study was "seriously flawed" because "mice are not humans and fructose is not high fructose corn syrup."

The researchers used pure fructose rather than a high fructose corn syrup mixture (typically 42 or 55 percent fructose in combination with glucose). In fact, all of the studies to date have focused on a fabricated fructose fluid and not high fructose corn syrup.

Compare Glucose and Fructose in the Chair Structures

The mice in the study also drank diet soda and a soft drink sweetened with sucrose or table sugar -- and neither increased body fat. Adamson said he predicts a soda sweetened with high fructose corn syrup would have similar results since this corn-derived sweetener has virtually the same composition as sucrose, which is 50 percent fructose and 50 percent glucose.

Because both sweeteners break down into glucose and fructose in about equal proportion, our bodies can't really tell the difference, Adamson said.

Though our intake of high fructose corn syrup appears to mirror the rise in obesity, there's no evidence linking the sweetener to the cause, according to Audrae Erickson, president of the Corn Refiners Association, a trade organization representing companies that make corn-based products and ingredients.

"Obesity is a complex health problem and no single food or ingredient is to blame," she said.

One of the arguments the corn refiners group makes is that obesity rates are escalating throughout the world -- including Australia, Mexico and Russia -- even though sucrose is the main sweetener. The use of high fructose corn syrup outside of the U.S. is limited or nonexistent, according to the association.

Even Havel isn't convinced that high fructose corn syrup by itself is to blame for our widening waistlines because it would be "too simplistic" to single it out. Inactivity and dietary fat are major contributors to the problem, he said.

Roberta Anding, a dietitian and spokesperson for the American Dietetic Association, agreed, adding that today's supersized portions and decline in fruit and vegetable consumption are also part of the equation.

However, even if high fructose corn syrup is not any worse than sucrose, we need to cut down on all added sugars, Anding advised. The best place to start is with soft drinks, which are the leading source of calories in a teenager's diet and have been linked to obesity and type 2 diabetes in adults. "It all comes down to calories," Anding said.

Awash in syrup

Price was the major factor spurring the switch from cane and beet sugar to a corn-based sweetener during the 1970s. Since then, high fructose corn syrup has flooded the food supply -- particularly in beverages.

Last year, the average American consumed about 200 calories a day from high fructose corn syrup, up from 2 calories in 1970, according to the USDA. That's about 12 1/2 teaspoons daily.

An advantage of high fructose corn syrup is that it's easier to blend into beverages and it maintains the sweetness better than refined sugar. Because it helps prevent freezer burn and reduces crystallization, it's used in many frozen foods, like ice cream and juice concentrate.

High fructose corn syrup also helps baked goods brown and keeps them soft, which is why dinner rolls, buns, cookies and granola bars often contain appreciable amounts. It's also a major ingredient in pancake syrup, jams and jellies.

Cutting back the sugar

Here are some easy ways to cut down on high fructose corn syrup and other added sugars:

Buy only 100 percent juice instead of fruit "drinks,punches,cocktails" or "-ades," which are simply code names for added sugar -- primarily high fructose corn syrup.

That said, choose whole fruits over fruit juices. Even 100 percent juices supply a concentrated source of fructose and calories without the fiber and nutrients found in whole fruits. Limit juice to one 8-ounce serving a day.

Cut back on soda. A single 12-ounce can contains about 13 teaspoons of sugar in the form of high fructose corn syrup. Drink water, seltzer, sugar-free iced teas and low-fat milk instead.

Choose fruits canned in juice instead of heavy syrup and opt for unsweetened applesauce and frozen fruits.

Snack on a handful of nuts, a chunk of cheese or piece of fruit instead of sweets.

At breakfast, eat a bowl of low-sugar whole-grain cereal with milk instead of a cereal bar, toaster pastry, doughnut or sweet roll.

High on sugar

The federal dietary guidelines recommend that we limit added sugars to about 8 teaspoons (32 grams) a day for an average 2,000-calorie diet. But many soft drinks far exceed that. Although the following bottles are labeled as 2 1/2 servings per container, most people consume them in one sitting.