Beating the Sodium horse one last time...

[petero]

Hi Jeff,

I know you've answered similar questions ad naseum, but if I could take one last swing at the dead horse of sodium consumption I would appreciate your response, since I value your opinion immensely.

I know, from your previous posts, that it is generally impossible to get too little sodium from natural foods. And that the body maintains a tight control over sodium through the kidneys. But what about exercise?

Now, Dr. Fuhrman claims that Na won't be excreted through the sweat glands unless the body is used to excess consumption (actually he claims the reverse, that once your body gets used to lower intake, it won't be excreted anymore). I've also read about desert nomads whose practice it is to never add any sodium to food because it would increase fluid loss, but they get their sodium through high-sodium sources of water.

I enjoy exercise and, with spring coming, am eager to get outdoors. Would you be concerned if I told you that I was going to the Grand Canyon tomorrow, and that I hadn't taken in any pure sodium in two weeks? Just a hypothetical, I'm not really going there, but that's where you get warnings about Na tablets and all that jive...

I prefer the way my food tastes without Na and would like to be physically active without this dubious "supplement". In fact, I generally add no salt to any food except for seaweed once a week and if I eat some pickled condiment (one or twice a week at most). On one level, it seems logical to say that those those taste buds were no more meant to taste pure salt than they were meant to taste pure sugar, but I was wondering if you had any concerns?

Thanks,
Peter

[JeffN]

Now, Dr. Fuhrman claims that Na won't be excreted through the sweat glands unless the body is used to excess consumption (actually he claims the reverse, that once your body gets used to lower intake, it won't be excreted anymore). I've also read about desert nomads whose practice it is to never add any sodium to food because it would increase fluid loss, but they get their sodium through high-sodium sources of water.

Sodium loss in sweat drops very low when people eat a low salt diet. However, like adjusting physiologically to high altitudes, it takes several days.

The real problem arises when there is a sudden change in sodium intake where a typical high-salt eating American does an ultra-endurance event or takes a long hike in a hot environment and consumes water or other low sodium beverages while losing large amounts of salt in their sweat.

The problem most people would have hiking in hot environment is that their aldosterone levels are too low because their body is accustomed to high salt foods. If they sweat a lot and drink a lot of plain water or fruit juice they can easily become hyponatremic because of the large salt losses in their sweat are not being replaced.

The same person after a week on a low-salt diet would have much higher aldosterone levels and so see their sweat sodium drop from about 1000mgNa/L to perhaps 10-50mg/L and now they are at far less risk of depleting their body's sodium (and chloride). When sweat sodium is that low the risk of hyponatremia is pretty much eliminated. For someone who is truly accustomed to a low salt diet the only concern hiking for hours in a hot environment would be dehydration.

In Health
Jeff

[Clary]

The same person after a week on a low-salt diet would have much higher aldosterone levels ...
In Health
Jeff

I am always delighted to learn more about how "wonderfully made" are our bodies, and how rapidly our amazing bodies can adapt to and benefit from a healthful lifestyle change.

[Love the Lorax]

Totally agreeing! I had never heard of such a thing .... our bodies truly are amazing!

The same person after a week on a low-salt diet would have much higher aldosterone levels ...
In Health
Jeff

I am always delighted to learn more about how "wonderfully made" are our bodies, and how rapidly our amazing bodies can adapt to and benefit from a healthful lifestyle change.

[petero]

Thanks very much for your response, Jeff!

--Peter