Misunderstood Salt: The Facts About Limiting Intake

For dec­ades we have been told, with cer­tainty, to lim­it our salt intake or risk heart dis­ease and high blood pressure—but is this advice based on sound sci­entif­ic find­ings? The short answer is No.

The evid­ence is incon­sist­ent, incon­clus­ive and con­tra­dict­ory, says prom­in­ent car­di­olo­gist Jeremi­ah Stamler (who used to be an advoc­ate for the eat-less-salt cam­paign back in the 60s and 80s), and there­fore the “eat-less-salt” mes­sage is pre­ma­ture and may even be harm­ful.

Last year, two [meta-ana­lyses] were pub­lished by the Cochrane Col­lab­or­a­tion, an inter­na­tion­al non­profit organ­iz­a­tion foun­ded to con­duct unbiased reviews of med­ic­al evid­ence. The first of the two reviews con­cluded that cut­ting back “the amount of salt eaten reduces blood pres­sure, but there is insuf­fi­cient evid­ence to con­firm the pre­dicted reduc­tions in people dying pre­ma­turely or suf­fer­ing car­di­ovas­cu­lar disease.” The second con­cluded that “we do not know if low salt diets improve or worsen health outcomes.”The idea that eat­ing less salt can worsen health out­comes may sound bizarre, but it also has bio­lo­gic­al plaus­ib­il­ity and is cel­eb­rat­ing its 40th anniversary this year, too. A 1972 paper in The New Eng­land Journ­al of Medi­cine repor­ted that the less salt people ate, the high­er their levels of a sub­stance secreted by the kid­neys, called ren­in, which set off a physiolo­gic­al cas­cade of events that seemed to end with an increased risk of heart dis­ease. In this scen­ario: eat less salt, secrete more ren­in, get heart dis­ease, die pre­ma­turely. […]

[Four stud­ies] involving Type 1 dia­bet­ics, Type 2 dia­bet­ics, healthy Europeans and patients with chron­ic heart fail­ure — repor­ted that the people eat­ing salt at the lower lim­it of nor­mal were more likely to have heart dis­ease than those eat­ing smack in the middle of the nor­mal range.

via The Browser