No doubt the UK's anti-salt publicity machine was feeling pleased with their success in generating headlines for a recent piece that suggested that infants need to cut their salt in half. That is, until junkfoodscience called their bluff.

We don't know if blogger-nurse Sandy Szwarc knew anything about the multi-million pound British anti-salt ad campaign featuring "Sid, the Slug," a cartoon reminder of one of the 14,000 beneficial uses of salt -- to kill slugs. Szwarc suggests the public "pour salt on it" -- the study in question. As she laments:

Such extraordinary claims require extraordinary evidence. Does this study hold up?

This study is said to be the "first ever meta-analysis of salt reduction studies in children." And it epitomizes every caveat of these types of studies. MacGregor and He "developed a strategy" of their own design to look for words in several databases and through reference lists at the end of articles to find studies of salt reduction in children. They only used studies published in English and of the 33 they found, decided to use 10 on children for this report. The studies all had different designs, with only one being a double-blind trail and only 9 were randomized; the studies varied in length from 2 weeks to 3 years; compliance with salt reductions appeared poor in two of the studies; we have no information on the racial/ethnic mix of the children and if it is representative of the general population; and only 3 measured 24-hour urinary sodium levels - which the researchers admitted is "the only accurate way to assess dietary salt intake." Simplifying what they did next, they pooled the data on blood pressures and net changes in salt intake, and used statistics to estimate the changes as needed to fill in missing data. Then, they applied two computer models to plot the results and more statistical analyses to reach their findings.

What they reported was that cutting salt intake by 42% reduced systolic blood pressures in the children by 1.17 mmHg. Most parents and children would consider such a salt reduction - nearly in half - to be extreme; while most doctors would debate the clinical significance of a mere 1 point reduction in blood pressure. Taking blood pressures in young children is an imprecise task at best and the children in these different studies were also at varying stages of development, with corresponding variable changes in blood pressures over the study durations, according to their growth and size.

The researchers stated that the "physiological need for salt intake in children has not been studied," but concluded anyway that "current salt intake in children is unnecessarily high and is very likely to predispose children to develop hypertension later."

They went on to declare that these results "provide strong support for a reduction in salt intake for children. [And] if continued, may well lessen the subsequent rise in BP with age and prevent the development of hypertension. This would result in major reductions in cardiovascular disease."

Their press release promised possible "massive population health gains."

·But this study did not examine a single child.

·It conducted no clinical research to learn how much salt is needed or might be harmful for children.

·It offered no clinical evidence to know if a lower blood pressure reading of 1 point means anything for children's health or is maintained as a child grows.

·It offered no proof that a blood pressure reading during childhood has any bearing on adult blood pressures or heart disease.

·And worse, it didn't follow a single child to see if there were any health effects from the salt restrictions they are recommending.

In other words, this study offered no clinically meaningful evidence, only speculations. ...

Shouldn't we have something tenable to go on before experimenting on an entire generation of children? I suspect most parents would think so.

She notes approvingly the award-winning expose of games-playing by the anti-salt crowd as documented in Science magazine and recent research showing that low-salt diets may be creating additional risk .