Sugary treats are often used to 'sweeten the pill' for children, be it in persuading them to take a medicine, or even just rewarding them for tidying their room. But there are indications that sugar can have an analgesic effect on children, soothing them after they suffer some physical hurt or mishap.
Previous research has indicated that this analgesic effect is linked to taste, since it is not produced by direct stomach loading. Artificial sweeteners, on the other hand, have been seen to have the same effect as sugar when taken orally.
In a study published in the journal Pain (2005.09.029), researchers from the Monell Chemical Senses Center in Pennsylvania set out to taste the hypothesis that sucrose would reduce pain more effectively in those who have a preference for sweet tastes.
The study involved 242 children aged five to 10 years and their mothers (198 women). First, the researchers established their preferred sweetness concentration by adding teaspoonfuls of sugar to an 8-ounce glass of water.
As a whole, the children preferred higher levels of sweetness than their mothers, with a favourite concentration of 11 teaspoons per glass (19 percent sucrose solution). But half of the children and a quarter of the mothers preferred 14 teaspoons or more per glass (24 percent sucrose).
During the next session the researchers evaluated responses to pain in the study group, using the cold pressure test, which measured how long the participants could keep their hand in a bath of cold water. The test was carried out twice - once while each subject held water in their mouth and once with a 24 percent sucrose solution.
They found that the sucrose reduced the experience of pain in the children with the higher sweet taste preference, but not in those with a lower preference.
Interestingly, the analgesic effect of the sucrose also seemed to be blunted in children who were overweight or at risk of overweight who had a higher sweet taste preference.
The researchers could not explain for sure why these results were seen - it is not yet known whether they could be due to in impairment of the hypothalamopituary control and high beta-endorphin plasma levels observed in obese children, or whether it could, somehow, be linked to higher consumption of carbohydrates and sweet-tasting foods by these children.
"The role that dietary habits and individual differences contribute to the preferences for sweet taste and its physiological consequences in children is an important area for future," they concluded.
As for the adults, it seems that sugar loses its power as we grow older; the sweet solution seemed to have no effect pain threshold or tolerance, regardless of their sweetness preference.