The findings, revealed by researchers at the Monell Chemical Senses Center in the US, demonstrate that, in general, not only are childhood preferences for salt and sugar linked, but that children prefer sweeter and saltier tastes more than do adults.
Led by Dr Julie Mennella of Monell, the team suggested that such preferences relate not only to tends in food intake but also to measures of growth - and could also have important implications for efforts to change children's diets.
"Our research shows that the liking of salty and sweet tastes reflects in part the biology of the child," commented Mennella - who noted that many illnesses of modern society are related to poor food choices.
Because children consume far more sugar and salt than recommended, which contributes to poor health, understanding the biology behind children's preferences for these tastes is a crucial first step to reducing their intake, said the team.
"Children's heightened preferences for sweet and salty tastes make them more vulnerable to the modern diet, which differs from the diet of our past, when salt and sugars were once rare and expensive commodities," added Mennella.
She added that the findings also reveal that the 'struggle' that parents have in modifying their children's diets to comply with recommendations "appears to have a biological basis."
Understanding the basic biology that drives the desire for sweet and salty tastes in children illustrates their vulnerability to the current food environment, she added.
But on a positive note, "it also paves the way toward developing more insightful and informed strategies for promoting healthy eating that meet the particular needs of growing children," she said,
Writing in PLoS One, Mennella and her colleagues tested 108 children between five and 10 years old, and their mothers, for salt and sweet taste preferences. The same testing method was used for both children and their mothers, who tasted broth and crackers that varied in salt content, and sugar water and jellies that varied in sugar content.
The method, developed by Mennella and her colleagues at Monell, scientifically determines taste preferences, even for very young children, by having them compare two different levels of a taste, pick their favourite, and then compare that favourite with another, over and again until the most favourite is identified.
Participants were also asked to list foods and beverages they consumed in the past 24 hours, from which daily sodium, calorie, and added sugar intakes were estimated.
Subjects then gave a saliva sample, which was genotyped for a sweet receptor gene, and a urine sample to measure levels of Ntx, a marker for bone growth. Weight, height, and percent body fat were measured for all subjects.
Analyses of all these data showed that not only were sweet and salty preferences correlated in children, and higher overall than those in adults, but also children's taste preferences related to measures of growth and development: children who were tall for their age preferred sweeter solutions, and children with higher amounts of body fat preferred saltier soups.
Both children and adults who preferred higher levels of salt in food also reported consuming more dietary salt in the past 24 hours, but no such relationship was found between sweet preferences and sugar intake, found Mennella and her team.
This difference may reflect parents exerting greater control in their children's diet for added sugar than for added salt. Or it could reflect increased use of non-nutritive sweeteners in foods geared for children – in other words, the sweetness of some foods doesn't reflect their sugar content, they added.
There was also some indication that higher sweet liking related to spurts in bone growth, said the team - who suggested that this result needs confirmation in a larger group of children.
Source: PLoS One
Published online ahead of print, doi: 10.1371/journal.pone.0092201
"Preferences for Salty and Sweet Tastes Are Elevated and Related to Each Other during Childhood"
Authors: Julie A. Mennella, Susana Finkbeiner, et al