Salt

By Mariel Emrich, Columbia Grammar and Preparatory School

Six-month-old infants who have been introduced to starchy table foods, that often contain salt, have a greater preference for salty foods than do infants not yet eating these foods, according to a recent study by researchers from the Monell Center and published in the American Journal of Clinical Nutrition. Lead author Leslie J. Stein, a physiological psychologist, and senior author Gary Beauchamp, a behavioral biologist, found that infants exposed to salt consumed 55% more salt during a preference test than infants who were not exposed to salty foods.

At a preschool age, the infants who were exposed to salty, starchy foods were more likely to eat plain salt, showing the significant influence of the early dietary exposure. The foods we eat the first months of our lives shape our flavor preferences. Doctors are trying to keep young infants away from salty foods, so they won’t depend on them in later years, reducing their chance of getting a heart disease.

It has been estimated that reducing sodium intakes could prevent more than 100,000 deaths yearly. Additionally, it could save billions of dollars in medical costs in the United States alone. In 1969, the United State’s government started issuing statements calling for a reduction in sodium intake. Even in 2011, these statements have not been successful, partly due to the fact that humans love the taste of salt. Nearly 90% of Americans consume more sodium per day than is recommended, according to an October report from the Centers for Disease Control and Prevention.

Gary Beauchamp believes that many people eat too much salt because it is very hard to change an adult’s diet preferences. Beauchamp wondered if it would be possible to change an adult’s preferences by changing their experiences with salty food earlier in life. If so, this may lead to the development of public health initiatives that could help people reduce their salt intake.

In this study, salt preference was tested on a group of 61 infants, which included infants at two-months of age and six-months of age. At each age, the infant was allowed to drink from three bottles for two minutes each. One bottle contained water, another contained a medium concentration of salt (1%-- about the amount of salt in a commercial soup), and a third that contained a high concentration of salt (2%--which tastes extremely salty to adults). If the infant drank more of the 1% salt solution than water, it was considered to have a preference for the 1% solution.

The two-month-old infants generally didn’t like the 1% solution and rejected the 2% solution. The 26 six-month old infants who had already been exposed to starchy foods, drank more of the 1% and 2% solutions than the water. However, the 35 six-month old infants who hadn’t ever been exposed to starchy foods remained indifferent to or rejected the salt solutions.

To explore whether the early effect extended into childhood, 26 of the children returned at preschool age. Their mothers answered surveys about their child’s eating habits. This revealed that the 12 children who were introduced to starchy foods before six months of age were more likely to lick salt from foods and also were likely to eat plain salt voluntarily. These findings show that early dietary habits influence a child’s preference in their later years.

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Mariel is currently a sophomore at Columbia Grammar and Preparatory School in New York City. She loves learning about science and particularly enjoys genetics, cancer research, radiology, and forensics.