WEDNESDAY, Jan. 24, 2007 (HealthDay News) -- If you crave salty foods, you may have been born prematurely and lacking in sodium. And this might leave you vulnerable to weight gain, a new study suggests.
Israeli researchers analyzed 41 children born prematurely in Israel and found that the lower the level of sodium in the bloodstream at birth, the more sodium the children consumed at ages 8 to 15.
Those with low sodium levels at birth also weighed about 30 percent more than their peers by early childhood or the early teen years. The finding suggests that very low blood levels of sodium in premature and newborn infants seems to be a contributing factor for long-term sodium intake, a key risk factor for obesity, the researchers said.
The study, published in the current issue of the American Journal of Physiology -- Regulatory, Integrative, and Comparative Physiology, isn't the first to suggest such a link, said Micah Leshem, a study co-author and a researcher at the University of Haifa's psychology department.
"There are about eight studies now that show that some form of sodium loss or deficiency [before or after birth] is associated with increased salt appetite in later childhood or adulthood," he said.
"These findings are consistent with laboratory rat studies that have produced the phenomenon experimentally -- that is, sodium-deficit before birth, as well as after it, causes greater intake of salt in adulthood."
The study participants with the lowest blood sodium at birth ate about 1,700 milligrams more sodium a day than those who didn't have low blood sodium when they were born.
The researchers analyzed each child's sodium appetite at ages 8 to 15 and gave each a physical exam. The children were tested whether they preferred a lot of salt in soup and sugar in tea. And they were invited to eat freely from a table of salty and sugary snacks.
The children with the lowest sodium levels at birth ate double the number of salty snacks years later than those who did not have low blood levels of sodium at birth.
The link may be due to self-protection, Leshem speculated. "Researchers have proposed that evolution has provided us with the ability to respond to sodium loss by increasing our avidity for it," he said.
Connie Diekman, director of university nutrition at Washington University in St Louis, called the study interesting but said it has limitations.
"The assessment of food intake was based on food frequency questionnaires as opposed to food records or food collection, leaving the accuracy of intake to recall, which is not a good tool for scientific accuracy," Diekman said.
The study also looked only at premature infants, not normal-weight babies, she said, adding that more research is needed.
Until that research is performed, parents can simply be aware of the link, according to Leshem. "In guiding the development of their child's dietary habits and preferences, our findings, together with those of others, now show that there is a cause for their child's preferences for sodium or sodium-rich foods," he said.
Your child's pediatrician can advise you on how much salt your child should be consuming daily.
To learn more about how much sodium is ideal, visit the American Society for Nutrition.