Some people with a penchant for salty
snacks may have been born with it, a new study suggests.
In a study of 41 children and teenagers who'd been born prematurely,
researchers found that those who'd had low sodium levels in
their blood at birth had a particular fondness for salty food.
In tests where the children could choose from salty or sweet
snacks, those born with low sodium levels reached for a salty
snack more often. They also consumed substantially more sodium
each day, based on interviews with children and their parents.
The study also found that children with the most severe sodium
deficiency at birth weighed 30 percent more, on average, than
their peers born with the highest sodium levels.
High salt intake is considered a marker for the risk of obesity,
possibly because it signifies a person's consumption of calorie-dense
processed foods.
It's too soon, however, to say that sodium deficiency early
in life is a risk factor for obesity, according to study co-author
Dr. Micah Leshem of the University of Haifa in
Israel.
"There is insufficient evidence for parents to take a preference
for salty food resulting from early sodium loss, of itself,
as a predictor of weight gain in their children," Leshem stated.
All of the children in the study had been born prematurely,
which increases the chances that a newborn will have low blood
sodium levels. Low birth weight itself is thought to promote
excessive weight gain later in life, Leshem pointed out, and
this may offer a "better explanation" for the link between
early sodium deficiency and childhood weight.
He and his colleagues report their findings in the American
Journal of Physiology - Regulatory, Integrative, and Comparative
Physiology.
Premature newborns are at greatest risk of sodium deficiency
at birth and soon after, although it's also sometimes seen
in full-term infants -- particularly those with risk factors
such as kidney dysfunction.
A number of factors, both before and after birth, can contribute
to early sodium loss, Leshem noted.
Before birth, severe maternal vomiting can deplete fetal
sodium, for example; after birth, infant vomiting or diarrhea,
and infant formulas lacking electrolytes are among the potential
causes.
This is not the first study to link low sodium levels in
early life to a bigger "salt appetite" down the road, Leshem
said. Other research suggests early sodium loss can affect
salt preferences even into adulthood.
The current findings, Leshem's team writes, "accentuate the
importance of monitoring and balancing sodium levels in premature
babies."
But they also hint at the mechanisms that influence people's
salt intake, pointing to a direction for future research,
Leshem noted. "And that," he said, "is relevant to all of
us, not just premature babies."
SOURCE: American Journal of Physiology - Regulatory, Integrative,
and Comparative Physiology.
