Canada
I was forwarded this article the other day http://www.ericcressey.com/sodium-intake-is-salt-bad-for-you and thought it was time to respond to the question ‘Is salt bad for us?’ as it is something I get asked about very frequently; especially in relation to sports people. Whilst there’s never going to be a totally conclusive answer my thoughts are laid out below…
Salt - Friend or Foe?
In my role as a medic almost everyday I tell patients that their coronary artery disease is down to 5 major risk factors - high cholesterol, diabetes, smoking, high blood pressure (hypertension) and genetics. Some have all risk factors and some have none. But almost all who have hypertension are on a low salt diet. Imagine how shocked they would be if they looked at published scientific evidence and discovered that in fact a low sodium diet actually gives them a HIGHER risk of dying from cardiovascular disease? The US-based National Health and Nutrition Examination Survey (NHANES I) study published in 1998 showed that a low sodium diet is associated with a 20% higher risk of death. The NAHNES II published in the Amercian Journal of Medicine much later http://www.jhsph.edu/bin/s/m/May_9_2006.pdf went to on show that an intake of less than 2300mg sodium/day was associated with a higher risk of death from cardiovascular disease.
So what's all this hype about? Well, to put it simply salt metabolism, intake, excretion, physiology are extremely complex. They get even more complex in disease states such as hypertension and heart disease so prescribing bold cut-off points for what is arguably the most important mineral in the body will simply not work for everyone. What has not helped is that over decades the threshold of who is hypertensive has lowered making many 'normal' people now either patients or potential patients. There is no doubt that reducing salt will reduce blood pressure slightly BUT if you collate all the evidence as was done during a meta-analysis of 58 trials by Graudal in 1998, the conclusion is that the clinical benefit is so weak that the authors state the 'results do not support a general recommendation to reduce sodium intake'. It is generally agreed reduction of salt intake can be used as supplementary treatment but if you examine the literature closely the reduction by lowering salt intake is not more than can be acheived by eating a high omega-3 fatty acid diet or weight reduction or in fact relaxation therapy.
So my take on the matter.......! Eat sensibly and eat enough salt - not too much and certainly not too little, especially if ou are an athlete and sweating a lot. Avoid PROCESSED food that contain far too much salt- you'll be horrified to see how mcuh a can of tomato soup or even a slice of bread contains. REPLACE what you lose when exercising using an electrolyte drink matched to your rate of loss. Your sodium losses will predominantly be via sweat, as little as 100 ml/24 hr in normal weather, 20 degree C and no exercise and as much as 5000ml/24hr in warm weather, 29 degree C with exercise in the same person. Research shows that human sweat sodium losses vary as much as 10-fold in humans. So figure out how much sodium you lose and simply REPLACE it like for like.
Dr Raj Jutley
Chief Medical Office
