Children in the U.S. eat almost as much salt as adults, according to a new government study that finds a clear link between sodium intake and higher blood pressure.
The connection was particularly strong among overweight and obese children, said Dr Quanhe Yang from the Centers for Disease Control and Prevention (CDC) in Atlanta, who worked on the study.
"Our American diet clearly is very high in sodium," said Dr Frederick Kaskel, chief of paediatric nephrology at Children's Hospital at Montefiore in New York, who was not involved in the research.
"Not only is the high sodium something to be avoided, but it is also indicative of an unhealthy diet," he said. The results, released in Pediatrics, are likely to fan the hot debate over the health effects of salt.
The right balance
While health authorities across the globe warn consumers to cut back on dietary salt, a number of recent studies have suggested that not getting enough salt can be as harmful as getting too much.
The salt industry has pounced on that research, saying the dietary guidelines for sodium intake are flawed and should be withdrawn.
The CDC study is based on national surveys of more than 6 200 children and adolescents aged 8-18. The youths had their blood pressure measured between one and three times and also reported their diet in the prior 24 hours.
On average, they ate 3 387 milligrams of sodium a day - considerably more than the 2 300 mg the government recommends as the upper limit.
According to previous data from the CDC, U.S. adults consume 3 466 mg of sodium per day by comparison. "Kids are consuming as much sodium as adults, which far exceeds the recommended amount," said Dr Yang.
Dr Yang and his colleagues found that for every 1 000 mg of extra sodium in the children's diets, there was a one-point increase in blood pressure. Among overweight and obese kids, each 1 000 mg of sodium was tied to a blood pressure increase of 1.5 points.
Health benefits unclear
The potential health effects of the small blood pressure variations seen in the study are not clear. But Dr Kaskel said they could spell trouble later on.
"The antecedents of adult cardiovascular disease are seen early on in the paediatric age group," he said. "We shouldn't underestimate the potential harms of a 1-mm increase in systolic blood pressure."
"Many times the higher intakes of sodium may simply be a marker of a higher intake of fast food and processed foods," said nutritionist Lauren Graf of Children's Hospital at Montefiore.
She added that several ingredients in such foods, including fructose, have been tied to higher blood pressure.
Dr Michael Alderman of the Albert Einstein College of Medicine in New York cautioned that it's not clear that cutting back on sodium will do most kids any good.
"There is nothing in this paper - and there is no information that I'm familiar with - that suggests reducing sodium intake is of value for people eating an average of 3 400 milligrams of sodium a day," he said.
Dr Alderman said he has been an adviser to the Salt Institute, which represents the industry, and received $750 from the group in 1995. He said he has no ties to the group today.
(Reuters Health, September 2012)
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