Sugar: Not so Sweet?

You might know that it would be best to keep your sugar intake to a minimum—after all, it can cause cavities and weight gain, and offers no nutritional value. But lately, there has been some buzz that sugar may not only be injurious to your waistline, but to many other aspects of your health, too. Georgia State has done some interesting research looking at the consumption of high-fructose corn syrup, a type of sugar made from refined corn, in rats. Several years ago, associate professor in the Neuroscience Institute and Department of Psychology Marise Parent and fellow researchers examined the effect of high-fructose corn syrup intake on memory function and dysfunction in rats, and found some startling results. After feeding rats a diet where 60% of the calories came from fructose, they placed the rats in water to see if they could learn to find an underwater platform, which helped them find their way out of the water. After doing the same test two days later, the rats who were fed the fructose swam more randomly than those fed the control diet—in other words, they did not remember where the underwater platform was located.

Unfortunately, sugar may not only cloud your thinking. Fructose is metabolized by the liver, whereas other sugars, like glucose, are metabolized by many cells throughout the body; however, the liver is limited in its ability to process this sugar. Therefore, when it’s bombarded with too much fructose—like a large hit of high-fructose corn syrup—it may store some of the sugar as fat. This can lead to insulin resistance, one of the precursors to developing diabetes, as well as heart disease and obesity. Dr. William J. Whelan of the University of Miami School of Medicine also suggests that eating too much fructose can lead to weight gain. How? Eating fructose increases the body’s levels of ghrelin, a hormone that increases appetite, after eating.

A recent New York Times article also discusses Dr. Robert Lustig’s assertion that sugar is not simply an empty calorie, but that it is actually a “poison.” The professor of Clinical Pediatrics at the University of California, San Francisco, School of Medicine, says that there are many toxic effects both refined sugar and high-fructose corn syrup have on the body. “’If Lustig is right,’” says author Gary Taub, “’it would mean that sugar is also the likely dietary cause of several other chronic ailments widely considered to be diseases of Western lifestyles—heart disease, hypertension and many common cancers among them.’” Lustig compares the potential dangers of the sweet stuff to cigarettes and alcohol, in terms of their abilities to do harm.

Some argue that anything in excess can lead to health problems, not just sugar. The FDA has found no conclusive harmful effects of up to 40 pounds of added sugars per person, per year. However, Taub explains that most Americans are eating far more than that every year—about 90 pounds per year, more than double that amount. And while an increase in sugar consumption correlates to a rise in the diabetes epidemic, some scientists argue that this represents an association, not a causation.

However, Taub makes a strong argument. He cites another study by Michael Pagliassotti, a biochemist who performed animal studies on the subject in the 1990s at Colorado State University. After feeding high amounts of fructose or sugar—60 to 70 percent—to animals, Pagliassotti found that fatty liver can develop in just a week. If the sugars are in smaller amounts—about 20 percent of the calories consumed, close to what many Americans eat—fatty liver still takes hold, it just takes months rather than one week. Once the sugar was withheld, the fatty liver and the insulin resistance subsided. Although comparable studies have been done in humans with similar findings, the researchers only used fructose, which is almost never eaten in isolation without glucose.

Although the ongoing research looks promising, albeit depressing, these theories are preliminary—and controversial. Only excessive amounts of fructose seem to have this effect on the body, and in a concentrated, refined source often found in processed foods. The synergistic qualities of eating fructose in fruit may provide some protective qualities. Be on the lookout for more details ahead. In the meantime, enjoy your fruit but watch your (processed) fructose and sugar!

To read more, visit http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.html.