June 24, 2013

222 Salt – how much is too little? [24 June 2013]

The Canadian Heart & Stroke Foundation’s DASH diet for lowering high blood pressure recommends no more than 2,300 mg of sodium per day. But some organizations like the American Heart Association are pushing for as little as 1,500 mg (half a teaspoon) per day. A recent report questions the benefits and safety of this lower amount.

The report, titled “Sodium Intake in Populations: Assessment of Evidence” by an expert group of the Institute of Medicine for the Centers for Disease Control and Prevention, was published in May 2013. The group looked at new evidence that had been published since the last report in 2005. The new data showed no health benefit in restricting sodium below 2,300 and indications of possible harm. The “possible harm” included increased rate of heart attacks and risk of death. It looks like the Canadians, with their more conservative recommendation, got it right this time.

Previous predictions on benefits of sodium reduction (like the prevention of 14,500 heart attacks each year in Canada that I quoted in my column #022 July 27, 2009) are based solely on salt’s effect on blood pressure. Actual studies of health outcomes found that groups with the lowest salt intake often had worse health outcomes, including higher death rates. Obviously salt plays many important roles other than affecting one’s blood pressure.

Over-restricting salt in seniors is especially dangerous because symptoms of hyponatraemia (low sodium levels) are commonly associated with aging – fatigue, confusion and poor balance – and can easily be overlooked.

Potassium in balance with sodium is more important than just sodium levels – see my columns #129 and #211 for more on potassium.

Hyperinsulinism (high insulin levels) is the underlying cause of metabolic syndrome which includes high blood pressure. See my column #084 Insulin and Blood Pressure (03 Oct 2010). The insulin causes the body to retain sodium and excrete potassium. Normalizing insulin not only prevents type 2 diabetes but also reverses high blood pressure with normal salt consumption.

Additional points not mentioned in the Eagle ad article:

Salt is a nutrient and is essential for life so can't be completely eliminated. There are however sources of sodium other than salt that are not essential (and likely harmful) so should be avoided: sodium benzoate, sodium nitrate, and MSG.

80% of sodium in the typical American diet comes from processed foods; 10% from natural foods; and only 10% added at the table. The best way to reduce sodium would appear to be to reduce processed foods.

Iodine is added to commercial table salt which is believed responsible for the lower rates of hypothyroidism in North America. There is some concern that reducing salt, or switching to the marginally more nutritious sea salts, could lead to more iodine deficiencies. Probably true but it need not be the case. There are other sources of iodine supplementation readily available, either as a liquid supplement or some form of kelp supplement.

To recap, the only benefit to reducing salt is to lower blood pressure. Levels below 2,300 mg have no blood pressure lowering effect. Levels lower than 2,300 can be detrimental to our health.

IOM Report
New York Times article and opinion piece
Health Sciences Institute articles 1 and 2
Canadian Heart & Stroke Foundation – DASH diet

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.

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