Last year, the Federal CDC backed off from 50 years of advising everyone (and especially heart patients) to limit their salt intake. A meta-analysis of many studies showed that eating salt was not associated with increased risk for any disease. Here is my post on the subject from last June.
Now that the doors have been opened to question long-established medical advice, a bit more of the truth has emerged: Cutting back salt is dangerous. Risks for mortality and various cardiovascular outcomes were 10-15% higher for people who cut back on salt, compared to people who salted their food to taste. That’s a lot of excess disease, and the number of people who have been affected is many millions. In my opinion, it is a major scandal that epidemiologists have failed to correct their stand over a period of 50 years.
Results were consolidated from 25 different published studies, using different criteria and different age ranges. It took some fancy statistical footwork. Even more challenging is the fact that most people who are limiting sodium intake are doing so because doctors have told them they have elevated risk for heart attacks. So it’s not straightforward to compare the risks among low-salt and normal-salt groups, because they’re not comparable populations. The authors of this study understand this, of course, and claim to have done the statistics appropriately. My guess is that there was a tendency to under-state the difference, both because the results are so damning to the medical establishment, and because larger claims expose the authors to more criticism. For these reasons, it is likely that the reported cost of lowering salt intake may rise further from 10-15% reported here in coming years.
Lead author of the study, Dr Niels Graudal of Copenhagen University says, “The good news,” he says, “is that around 95% of the global population already consumes within the range we’ve found to generate the least instances of mortality and cardiovascular disease.”
This post originally appeared on Josh’s blog here: http://joshmitteldorf.scienceblog.com/