The amount consumed from each bottle along with the infants' facial expressions were used to calculate their preference for salt. One percent of the two-month old infants were indifferent to the salt solutions and two percent rejected them entirely, preferring water.

When the infants were six months old, the test was repeated. By this time, twenty-six of the infants were already eating solid starchy foods, and those infants showed a preference for the salt solutions using the same testing method. In fact, they consumed 55 percent more salt. The 35 infants who had not yet been introduced to solid foods either rejected or were still indifferent to the salt solutions.

Starchy foods such as breakfast cereals, breads, and crackers are frequently used as beginning solid foods for babies, and they usually contain added salt. Babies who had been introduced to other types of table foods, like fruit, did not exhibit the increased preference for salt.

When these children reached preschool age (four years old), the researchers again examined their salt preferences and surveyed their mothers about their child's salt preferences. The children who had begun eating starchy foods with added salt early on had a greater preference for salt as preschoolers. Twelve of these children were more likely to lick salt from foods or eat plain salt.

While the study doesn't prove that exposure to salt early in life causes a preference for salt later in life, it does show a correlation between the two. Should it turn out to be true, though, the results of the study suggest that efforts to reduce salt intake among Americans should begin early in life.

Despite government calls to reduce salt intake, Americans still love it. According to the Dietary Guidelines for Americans, most Americans should consume no more than 2,300 milligrams of sodium per day which is the equivalent of about one teaspoon. A report released by the Institute of Medicine in 2010 concluded that Americans over the age of two consume an average of 3,436 milligrams of sodium per day and that government standards are needed to reduce the amount of salt in restaurant and processed foods.

The main adverse health effect of excess sodium intake is high blood pressure which can lead to stroke, heart disease, and heart failure. It is estimated that reducing the sodium intake of Americans could prevent more than 100,000 deaths a year and save several billions in health care dollars.

Sodium is an essential nutrient in the body. It helps to maintain fluid balance; it helps to transmit nerve impulses; and it works along with other minerals helping muscles to contract and relax. To ensure adequacy of all nutrients and replace the sodium lost in sweat, healthy adults need only about 1,500 milligrams per day.

The study was published in the American Journal of Clinical Nutrition.

Image: Aaron Amat/Shutterstock.

This article originally appeared on TheDoctorWillSeeYouNow.com, an Atlantic partner site.

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