"These novel findings suggest that the bitter-taste phenotype contributes to the development of vegetable acceptance and consumption patterns during early childhood," wrote lead author Kendra Bell in the American Journal of Clinical Nutrition (Vol. 84, pp. 245-251).
Finding out more about why children like and dislike foods could be important for the understanding of eating problems, such as obesity- a topic that has gained significant attention in the health care and child welfare arenas over the past five years. Worldwide, over 22 million children under five are severely overweight.
A recent study from University College and Kings College London reported that a child's taste for protein-rich foods like meat and fish is inherited, but taste for vegetables and desserts are influenced.
But new research from Rutgers University in New Jersey suggests that genetic variations in a gene that controls for bitter flavour may indeed affect a kid's acceptance and preference of bitter tasting foods, such as vegetables.
The gene, TAS2R38, has been reported to have variations that cause some children and people to be especially sensitive to bitter tastes.
"Genetic variation in sensitivity to the bitterness of 6-n-propylthiouracil (PROP) is thought to play a role in the acceptance and rejection of bitter-tasting vegetables by young children," explained the researchers.
To test the hypothesis that non-tasters of PROP would have increased hedonic ratings to vegetables that are bitter tasting, the researchers recruited 65 pre-school kids who were identified as tasters (24 kids) or non-tasters.
Five types of vegetables (black olives, cucumbers, carrots, red pepper, and raw broccoli) were offered to the children for consumption in a free-choice intake test. The children were asked to give hedonic ratings to the vegetables.
It was found that the tasters ate significantly fewer bitter vegetables (black olives, broccoli and cucumbers) than the non-tasters (0.48 servings compared with 0.91 servings).
Thirty-two per cent of the taster children ate no vegetables at all in the free-choice test, compared with eight per cent of non-taster children. It was also found that, according to the hedonic test, the non-taster children liked raw broccoli more than did the taster children.
"The non-taster children consumed more vegetables, particularly the vegetables that were bitter tasting, than did the taster children during a free-choice intake test," concluded the researchers.
These data echo that of a study from the University of Connecticut (Physiology and Behavior, Vol. 87, pp. 304-313), which reported that it was "the first study to examine how bitterness and sweetness are negative and positive predictors of vegetable preference and intake."
These kind of studies have implications for the food industry, said the Connecticut researchers: If more attention is paid to taste and sensory qualities, they said, then the intake of vegetables can be improved, along with the associated health benefits and protection from chronic diseases.