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Sweet on Sweets: Scientists Investigate Addictive Properties of Sugar

Shedding light on the dangerous aspects of sugar through research and education will help address the issue of sugar as a national health risk.
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By Hannah Gibson

Hannah is a teen media team member of Science Club for Girls and a high school student in Cambridge, MA.

Sugary foods and beverages are frequently marketed as if they have addictive qualities, especially in advertising geared toward children. Many of us remember the "Cocoa Puffs" commercials, in which Sonny the Cuckoo bird tries all sorts of crazy schemes to stop eating Cocoa Puffs. He inevitably gets jittery, sees Cocoa Puffs everywhere, and starts screaming "Cuckoo for Cocoa Puffs, Cuckoo for Cocoa Puffs!" Advertisements often feature phrases like "Too good to resist." An Australian cereal made of chocolate filled squares even has the name "Krave."

The average American child consumes one or more soda or soft drinks per day, which provides 10 percent of their daily calorie intake. In an interview this year with Radio Boston, Kelly Brownell, Director of Yale's Rudd Center for Food Policy and Obesity, stated that sugary soft drinks are especially damaging to health because our bodies do not recognize them as food. Instead, the sugar in the drink acts like a drug and triggers an addictive process.

It's hard to say whether sugar actually is an addictive substance, since it is unclear what an addiction actually is. Webster's New World Dictionary defines chemical addiction, or dependence, as a "compulsive physiological and psychological need for a habit-forming substance." Certain physical and psychological signs separate true chemical dependence from habitual enjoyment of a substance or activity. According to the American Psychiatric Organization, addiction is characterized by three behaviors: binging (consuming large amounts of food in a small amount of time after a period of abstinence), withdrawal (depression and anxiety if the substance is not available) and cravings. The cravings increase the longer the substance is not available.

Rochelle Schwarts-Bloom, a professor at the Duke University Medical center, explains that addictive drugs affect the brain by triggering the release of chemical neurotransmitters, which create a "high."

There is evidence that sugar has addictive properties. A team of Princeton University psychologists, lead by Dr. Bart Hoebel, produced in rats the behaviors and brain chemistry of addiction. The rats were divided into four groups. The experimental group was given access to feed and sugar for 12 hours then deprived of both for 12 hours. Hoebel also set up three control groups. One group had access to sugar and feed at all times, one had access to only feed at all times, and one had access to only feed in 12-hour periods. The rats in the control groups displayed no signs of addiction, but the group on the 12-hour on, 12-hour off sugar and feed schedule did. Rats in the experimental group that were later denied sugar for 24 hours tended to binge, exhibit withdrawal symptoms -- like tremors and anxiety -- and display behaviors consistent with craving; this response was similar to rats on morphine or cocaine. Hoebel and his team also found that sugar consumption triggered the release of the neurotransmitter, dopamine, in the rat's brains. Addictive drugs like morphine and cocaine trigger a similar response, suggesting an addictive quality to sugar.

Other researchers, like University of Swansea neuroscientist David Benton, have criticized Hoebel's work, pointing out that a huge variety of actions and substances trigger a release of dopamine in the brain. Sure, sugar and cocaine stimulate release of neurotransmitters, but so do music, humor, winning a prize, familiar faces, attractive faces, smiling faces, and being in love. Clearly, the release of dopamine isn't sufficient evidence of addiction! Further, rats on the alternating sugar and feed schedule showed the neurological and behavioral signs of addiction, but the rats with constant access to sugar did not. This suggests that perhaps sugar is not an addictive substance, like heroin or cocaine, but that addiction to sugar may occur if it's eaten in a period of binging followed by long periods of restraint.

Even if Americans are not clinically "addicted" to sugar, they are definitely eating way too much of it. The average American eats 64 pounds of sugar a year; that's about 124 grams (31 teaspoons) of sugar per day, which is more than three times the recommended amount. The American Heart Association recommends that a person following a 2,000-calorie a day diet consume 36 grams (nine teaspoons) of sugar daily. There are many health conditions linked to a diet too high in sugar, including an increased risk for heart disease, kidney disease, liver disease, diabetes, gout, hypertension, gum disease, tooth decay, obesity, and the substance potentially has addictive properties.

There has been a push in recent years to limit the amount of sugar in packaged food. Many parents are concerned about the aggressive marketing of sugary, unhealthy foods and beverages to children and are trying to limit their sale in school cafeterias. Robert Lustig, Laura A. Schmidt and Claire D. Brindis, in their February article "The toxic truth about sugar," advocate for regulations and a tax on sugary products. In May, Mayor of New York City Michael Bloomberg proposed a ban on oversized sugary beverages. Recently in Massachusetts, a legislative attempt to end the sales tax exemption for soda failed; the exemption makes it easier to for sodas to be cheaper. In some places, soda can be cheaper than water.

According to Ashley Gearhardt, a researcher at Yale University, sugar is minimally regulated, and food companies receive subsidies form the federal government, making it possible for them to produce extremely sugary foods. Gearhardt is concerned about the rapid increase in the amount of sugar in the American diet and feels that "although much research needs to be done, the evidence that sugar can trigger an addictive process is impressive and convincing, is definitely a public health issue." While it is still unclear if sugar is addictive, there is enough evidence to suggest that foods too high in sugar do present public health risks. Shedding light on the dangerous aspects of sugar through research and education will help address the issue of sugar as a national health risk.

Check out our stop motion video, "The Sour on Sugar," below.