Children's fear of new foods may be in their genes

NEW YORK (Reuters Health) - UK researchers have provided an explanation for why some children hate to try new foods -- it's in the genes.

In a large study of twins, which included both identical and fraternal twin pairs, Dr. Lucy J. Cooke of University College London and her colleagues found that nearly 80 percent of children's tendency to avoid unfamiliar foods was inherited.

"Parents can be reassured that their child's reluctance to try new foods is not simply the result of poor parental feeding practices, but it is partly in the genes," Cooke and her team write. And, they add, repeatedly offering foods to children can make the foods more familiar, and eventually even liked.

Both humans and other animals show a reluctance to try new foods, known scientifically as "food neophobia." This avoidance may have had an evolutionary advantage in preventing exposure to potentially toxic foods, the researchers note in the American Journal of Clinical Nutrition. "In the modern environment where foods are generally safe to eat, neophobia appears principally to have an adverse effect on food choices, particularly on intake of foods and vegetables," they say.

To investigate the role of inheritance and upbringing in food neophobia, Cooke and her team surveyed the parents of 5,390 twin pairs 8 to 11 years old. Studying twins allows researchers to separate out the effects of genes and environment -- identical twins share 100 percent of their genes; fraternal twins share only about half; while both types of twins have the same childhood home environment if they are raised together.

Identical twins were much more likely to share tendencies toward food neophobia than fraternal twins were, the researchers found, with inheritance accounting for 78 percent of these tendencies. Shared environment had no effect, with the remaining 22 percent influenced by non-shared environmental factors.

Past studies of other behavioral similarities among family members have also found they are strongly influenced by genes and "surprisingly little" by the shared environment, Cooke and her colleagues note.

But these findings do not mean that parenting is unimportant in these behaviors. It's more likely, they add, that parents treat children differently, possibly because they sense differences in their needs, or that more genetically different children experience the same situation differently.

And inheritance doesn't have to determine this behavior, the researchers add. Laboratory research has shown that the more frequently children are offered a particular food, the more likely they are to come to like it.

"New foods can become familiar, and disliked foods become liked, with repeated presentation, although the process might be more laborious with a highly neophobic child," they write. "Guidance in effective feeding techniques and modification of other influential environmental factors may help to minimize the negative effects of neophobia on children's diets."

SOURCE: American Journal of Clinical Nutrition, August 2007.