Gah! To much salt!

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One of the big problems in endurance racing nutrition is hyponatremia [*] [*]. In hot conditions you can lose over 3g of sodium per hour. Old-style sports drinks like Gatorade or Cytomax contain something like 50 mg of sodium/8 oz, so you'd need to eat drink like 15 quarts of fluid an hour to keep up--clearly not a practical solution. The standard solution is to eat salty foods or take salt tablets, but this makes life a lot more complicated than you'd like when you're trying to output maximum effort. Ideally, you'd like whatever energy drink or gel you're taking to have enough sodium in it.

The sports nutrition guys have been paying attention and started jacking up the sodium levels of their products. For instance, Gatorade's new Performance series contains 200 mg of sodium/8 oz. Similarly, PowerBar's Endurance energy drink contains 680 mg sodium/liter. I haven't tried the PowerBar product (though I liked their old one) but the Gatorade drink is pretty good.

Not all of these attempts have been successful, though: PowerBar has updated their energy gel to include 4x as much sodium as before: 200 mg/gel. I really liked the old gel, but the new one is so salty it's extremely unpalatable. I went for a long run in the heat on Sunday with only the new chocolate gel and was really glad I had water when I tried it, because otherwise I don't think I could have gotten it down at all.

Balancing taste and the requisite sodium content is a perennial problem for nutrition designers. The standard approach seems to be to add sweeteners in an attempt to balance the salt, but this makes getting the simple sugar/complex carbohydrate balance tricky. This raises the interesting question: is there a way to add sodium without making things taste saltier? Obviously, sodium chloride won't do, and the problem is the sodium, so any other sodium salt that ionizes in water won't help either (remember, you have to keep the sodium in a water solution). What you need is a sodium compound that ionizes in the gut but not in the drink or gel. If you had one, you could use it to salt-boost your drink or gel without affecting the taste. So, is there some edible (and tasteless) sodium salt that ionizes at low pH levels (the stomach is around pH 2-4) or under the action of some stomach enzyme?

My inorganic (and organic) chemistry is pretty rusty for that matter. Any chemists out there want to suggest a compound?

9 Comments

Sodium Caseinate is a common food additive that is mostly tasteless and odorless.

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Sodium Caseinate is probably not a very good way of supplying sodium. As with most sodium salts of random organics, the organic part is very high mass compared to the sodium. You would need an enormous amount of it.

There aren't a lot of good solutions that I know for the specific idea Ekr has here, but I think his goal is achievable.

If we were to do exactly what Ekr suggests, there are a variety of things that will trap sodium ions in some conditions, such as crown ethers or similar structures. The problem with such things, however, is that they are unlikely to be things you want to ingest. Actually, let me qualify that -- I don't know that people have explored the use of such things in biological environments enough to make them practical. There is also the fact that many of these compounds are not soluble in water.

I have a much, much simpler solution here to propose. Why not just encapsulate the sodium chloride in a pH sensitive gel, so that it is bound as a solid within the gel until you let it into your stomach acid? I suspect that something like sodium alginate (just a coincidence that it is a sodium salt) might work out, and as it is a common food additive, Ekr should have no trouble getting his hands on it. If I recall correctly (I may be mistaken), it will form a fairly hard preciptate in mildly basic conditions and soften markedly in acid conditions. One could thus trap finely powdered table salt in a hard sodium alginate gel, swallow the gel, and release the salt in your stomach. If not this particular compound, some similar quite common food additive should work.

Instead of a different salt, think encapsulation.

Encapsulate the salt in beads about 1mm in diameter, coated in gelatin or better yet, some drug capsule that dissolves at pH 4.

Or perhaps down to .1mm or even less.

Thus you still use sodium chloride, you jsut wrap it up so you don't taste it in your mouth.

I have had pretty good luck with Endurolytes, which are electrolytes (sodium chloride, potassium, magnesium) in a gel cap. So you don't taste anything. Having suffered from hyponatremia on the Death Ride I know that on hot rides over 5 hours I need some salt. On this years Death Ride they had some buffered salt tablets at some of the rest stops. I took a few and they seemed to be kind to my stomach.

I think that it's better to have the salt supplement seperate from the calories, so you can adjust as needed. Enough salt for 95 degree Death Ride would be way too much for a cool spring century.

The nice thing about sodium caseinate as a source of sodium in sports drinks/gels is that it's a protein source as well. 1tsp (31g) has 250mg of sodium and 23g of protein. Now, I wouldn't want 12tsp of it per hour. But it could be part of the solution (pun intended).

It's not actually clear that having it be a protein source is a feature. There's a lot of controversy about whether you want to have protein in your energy food, and many formulations deliberately exclude it.

I use a combination of evaporated sea salt (450mg/tablet) and Potassium Gluconate (595mg/tablet) taken as one pill of each per 50lbs of body weight, plus at least 8oz water. It's a trick I got from some of the motorcycle racers down near LA, and works like a charm.

(I realize that taking tablets isn't exactly what you were asking for, but I've found that being able to keep my calories and salt separate is an overall plus - it's much easier to adjust to what my body's demanding at that particular point in time)

How about using a non-digestable sweetener instead of sucrose/dextrose/whatever, so that you mask the saltiness but don't jack the carb balance?

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