The study, appearing in the September issue of the journal Hypertension, shows that healthy babies who had a “preferential response” to salt taste and who had at least one grandparent inflicted with hypertension had higher blood pressures than other infants.
Researched by Davidson Professor of Medicine Stephen H. Zinner and entitled “Neonatal Blood Pressure and Salt Taste Responsiveness,” the study is a culmination of over a decade of research done at hospitals in Providence, R.I.
Using an artificially-constructed rubber nipple, Zinner administered microdrops of three solutions—a “weak” salt solution, an “even weaker” salt solution and water—to 283 healthy, two-to-four-day old infants.
The majority of the babies did not suck as vigorously on the salty solution. But 20 percent of the infants had a less adverse reaction to the salt, relative to the others.
Zinner found that of this 20 percent, those infants who had one or more grandparents afflicted with hypertension reported strikingly higher blood pressures than the other infants, although none of the infants in the study were reported to have full-blown hypertension.
“Overall, the results are marginal, but if you focus on those infants with family history of hypertension, the relation between salt taste and blood pressure is quite strong,” said Bernard A. Rosner, a professor of medicine at Harvard, who also authored the study.
Salt intake has long been connected to high blood pressure in adults. This study is unique because it advances the idea that through certain risk factors, such as diet and family background, hypertension can be predicted in infants and children.
“For a long time, people did not believe that you could measure the risk of high blood pressure in very young infants,” Rosner said.
“The question is ‘Are these salt-tolerant babies destined to acquire hypertension later in life?’” asked Zinner. “And if you were to remove salt from these infants’ diets, could you blunt the development of hypertension?’”
Both Zinner and Rosner said they have plans to explore if their findings apply to older children.
“The results of this study hold together well,” Rosner added. “The next steps are to repeat the experiment, and to follow these infants into later life to see if these tendencies continue.”