I hid the candy from my 11-year old in the candy bowl. Oddly, it has not occurred to him to look for it there.  I, on the other hand, have eaten almost all of it. But, according to a recent study, I may be too old for this childish craving.

In the July 2011 issue of Current Opinion in Clinical Nutrition and Metabolic Care (1), researchers suggest children’s craving for sugar is more a reflection of biology, rather than a media-fueled desire for sugared cereals.

Most of us learned in school that carbohydrates are the primary source of energy. But how does a baby know? True to evolutionary form, humans have developed a sensory system that can detect calorie-rich foods – which taste sweet, mineral-rich foods – which taste salty, and likely toxic foods – which taste bitter.  Cravings for the sweet-tasting, calorie-rich foods are more intense during childhood (a behavior proven to be universal from similar studies conducted in several different countries and cultures including Mexico, Brazil, France, Iraq and North America). The body wants the calorie-rich food for growth and energy. Perhaps most revealing of this is the brain’s hedonic response after tasting something sweet.

The human brain has G-protein-coupled receptors that activate taste cells, alerting the brain something good is coming in. The receptors are able to detect the difference between the nutritional (sucrose) and non-nutritional (sucralose, or fake sugars) substances. Sweet taste receptors can be found in other parts of the body including the gut and pancreas, but only the brain is capable of detecting the nutritive differences. Once the brain determines the nutritive value and the food is ingested, the gastrointestinal and central nervous systems are activated.

Infants exhibit an increased heart hate when a sweet-tasting substance is put in its mouth.(2) They can detect the degree of sweetness and will consume more of the sweeter substance. And, they have a facial reflex of relaxation when exposed to the sweet-tasting solution.  As infants grow into children, their intensity of sugar desire declines, though children still have a much higher preference than adults. One hypothesis is that growing children crave sweet foods due to high calorie needs. A 2009 study in Physiology & Behavior (3) of a group of 11-15 year olds showed children who had a higher preference for sugar exhibited greater rates of linear growth than the children who preferred lower concentrations of sugar.

So, in conclusion, sugar is necessary and good for growth. Right? Right? Wrong. Carbohydrates are indeed necessary and good for growth and well-being, but the wrong kinds (you know what I’m talking about junk foodies!) can lead to life threatening diseases such as obesity, diabetes and heart disease. And while children’s preference for sweetness may be a common biological drive, studies have also shown that a high consumption of sweetened foods can lead to an even higher craving that does not level off with growth. Further, the preference for sweet tastes developed to help in finding nutritive substances (i.e. mother’s milk and nature’s foods that taste sweet and are calorie-rich), but recent research has revealed that non-nutritive sweeteners (which taste sweet but have no caloric value) and high concentrations of natural sugars may disrupt the bodies balance between taste, nutrients and appetite (4).

So, take it easy on Halloween. Do your body a favor, have one piece of candy and give away the rest.

1. Ventura, AK, Mennella, JA. (2011) Innate and learned preferences for sweet taste during childhood. Current Opinion in Clinical Nutrition and Metabolic Care. 14:379-384.

2. Steiner JE, Glaser D, Hawilo ME, Berridge KC. (2001). Comparative expression of hedonic impact: affective reactions to taste by human infants and other primates. Neuroscience Biobehavioral Reviews. 25:53–74.

3. Coldwell SE, Oswald TK, Reed DR. (2009). A marker of growth differs between adolescents with high vs. low sugar preference. Physiology and Behavior. 96:574–580.

4. Egan JM, Margolskee RF. (2008). Taste cells of the gut and gastrointestinal chemosensation. Molecular Intervention. 8:78–81.

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