Bruce N. Ames, a researcher at the University of California, Berkeley, and Children’s Hospital and Research Center at Oakland, California, presented a paper at the 11th International Symposium on Trace Elements in Man and Animals. In this paper published in the Journal of Nutrition, May 2003, he hypothesized that micronutrient (vitamin and mineral) deficiency counteracts the normal feeling of satiety after sufficient calories have been eaten. He suggested that this may be a biological strategy for obtaining missing nutrients and that part of the reason for the obesity epidemic in this country might be that energy-dense, nutrient-poor diets leave the consumer deficient in key micronutrients and thus constantly hungry.
He cited in support of his theory a study by Ashima K. Kant published in the October 2000 American Journal of Clinical Nutrition. The study was a survey of the effects on American adults of consumption of energy-dense, nutrient-poor foods (that is, foods high in calories and low in nutrients). The study concluded that with increasing consumption of energy-dense, nutrient-poor foods, the levels of micronutrients in the blood decreased and the intake of calories increased.
Sugar As An Addictive Substance
One of the most energy-dense and nutrient-poor of all foods is sugar. It is a substance that is pervasive in the American diet. Americans consume about 130 pounds per person per year. Sugar comprises approximately 24 percent of the daily caloric intake of a typical American. In some people, especially children, it is 50 percent of their daily calories.
This high intake of sugar, which seems to be continually increasing, could explain the high and increasing incidence of overweight and obesity in this country.
There is evidence that sugar is an addictive substance. Researchers have discovered that sugar stimulates the same areas of the brain that morphine, heroin and cocaine do. When we eat sugar, dopamine ( a pleasure-producing neurotransmitter) is released in a part of the brain called the nucleus accumbens.
A study reported in Brain Research, May 19, 2004, by Spangler and other researchers found that sugar dependent rats show alterations in dopamine and opioid levels similar to morphine-dependent rats. The researchers concluded that their study provided an animal model for studying the common mechanisms of drug addiction and eating disorders.
The First Stages of Addiction
Because sugar activates the same areas in the brain that drugs of abuse do, researchers hypothesized that sugar can cause dependency ( that is, addiction) just as these drugs do.
There are two stages of dependency. The first stage is expressed when animals escalate their intake of a substance and show underlying neurochemical changes that indicate sensitization or tolerance. The second stage is the emergence of withdrawal symptoms, both behavioral and neurochemical.
In next month’s article, we will discuss these two stages of addiction and how sugar follows the same pattern of dependency that drugs of abuse do.
