Tuesday, August 09, 2005

Salt vs. Sodium

Christian Scales noted to me many months back that he heard a doctor or nutritionist saying, "the problem is not salt but sodium."

"What's he talking about?" He asked me. "Isn't it the same thing?"

I have as little scientific knowledge as any ignoramus you're likely to find, so it's a difficult question to answer. I suggested that salt, being sodium chloride, isn't just sodium, so it would seem that that's somehow the point. Though why that makes a difference nutritionally I wasn't able to guess.

Some explanation comes from this 2004 MSNBC article from Phil Lempert, Today show food editor, in which he says,
The right amount of salt intake — and the correct balance between its two main ingredients, sodium and chloride — is essential to our health. According the Institutes of Medicine, healthy 19- to 50-year-old adults should consume 1,500 milligrams of sodium and 2,300 milligrams of chloride each day — or a total of 3,800 milligrams of salt — to replace the amount lost daily on average through sweat and other excretive processes.
This would seem to imply that different varieties of salt have differing proportions of sodium to chloride. Disappointingly, Lempert doesn't offer examples of such variations, nor have I so far been able to find instances searching in Google.

Lempert does helpfully explain the difference between refined and unrefined salts:
Unrefined sea salt is 98 percent sodium chloride, with the other two percent consisting of up to 80 essential and accessory minerals.

Refined salt
is higher in sodium chloride (99.9%). It is also likely to contain aluminum silicate to stabilize and prevent caking. Bleaching agents may be use to both table or sea salts.

That's helpful in understanding that if most of the salt we consume is refined, we're missing out on the 80 accessory minerals that Lempert describes as essential. However, this description of different percentages of sodium chloride does nothing to clarify his earlier reference to correct or incorrect balances between sodium and chloride. I've emailed him about that reference, asking him to elaborate.

This risk assessment of sodium chloride from a British "Expert Group on Vitamins and Minerals" discusses the functions and behaviors of sodium and chloride separately but also notes, "no relevant data are available relating to the toxicity of the chloride ion, and therefore the EVM decided to consider sodium chloride as a salt, rather than the separate elements."

This suggests to me that the statement from the expert Christian heard wasn't implying that the problems of sodium aren't consequently problems of salt but probably was emphasizing that the dangers are from sodium specifically, rather than chloride or any accessory minerals: The health effects of sodium chloride are strictly the health effects of sodium.

Moreover, it may also be pointing toward what Lempert notes in his article--"Processed foods can be loaded with...other forms of sodium [besides salt] such as sodium benzoate, sodium citrate, sodium nitrite or monosodium glutamate." So the most important point here is that we need to watch out for sodium in whatever form it reaches us.

On the matter of the troublesome processed foods, Lempert cites as examples canned soups, frozen dinners, sauces and condiments, packaged convenience foods, and fast foods. That describes most of my diet. He says to "look on the label for the 'percent daily value for sodium' and try to choose foods that are under 5 percent." I just looked at the labels of what's on the shelves in my kitchen and found most of it is at least 35%. And that's per serving. A can of soup has two servings in it, they say, and I always eat the whole can's worth.

As Lempert notes, "Medical studies have linked high consumption of salt"--let's presume that implies sodium generally--"with increased blood pressure or hypertension, which can lead to heart attack or stroke." So I have that to look forward to.

Damn Scales and the newfound clarity of his expert's remark, bringing into focus my eventual doom.

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