Tuesday, December 10, 2013

Beyond the Basics of Sodium

We hear a lot about Sodium. It's all over, really. Sodium takes credit in popular media for increasing blood pressure and causing fluid retention. It also takes credit for enhancing flavor (especially in processed foods). As a result, when sodium is conspicuously absent from these foods, they are advertised with a big shiny label that says "No Sodium Added!" or "Low-Sodium!".

But what does it actually do?

In terms of taste, yes, it makes things taste salty, but it also enhances the flavor of sweet things and can add depth to savory foods. So removing salt from a food doesn't just keep it from being salty, it may also completely change the flavor profile.

In the body, sodium is pretty important, and it does a lot of things. Yes, that includes influencing blood pressure (in some people, but not everyone) and can cause fluid retention. 

But why? And how?

Well, as it happens....

Sodium and water get along just beautifully. Specifically, NaCl (sodium [Na] chloride [Cl]) really likes to be around water. Have you ever put salt on an avocado? Or noticed the way a salad will wilt if you leave salad dressing on the leaves for too long? Sodium actually pulls water to come with it. Chemists will call this "osmolality" but really it just means sodium and water love to hang out.

As it happens, this is pretty important in human physiology. Humans are somewhere between 60-80% water (we are born closer to 80% and dry out as we age). That's a LOT of water to keep in the right place. Sodium helps us do that. In the case of water retention, all it means is your body will hang on to a bit of that water until it has time to flush out the excess sodium. Excess water can influence blood pressure for some people (meaning your blood has more water in it, which means more pressure by your heart to pump, thus higher blood pressure). This can also be the case for people with difficulty maintaining sodium balance, such as those with renal disorders.

Sodium is also important in nerve transmission, and it moves frequently in-and-out of the cells to help maintain water balance and electrical current.

So, in essence, what does this all mean? Sodium is pretty important! We have requirements for Sodium each day, and for the most part, the body can take care of a little fluctuation in one direction or another. In general, the Institute of Medicine recommends no more than 2300 mg daily of sodium. Naturally, certain conditions, such as blood pressure, kidney issues and diabetes, will have other recommendations for sodium intake. Be sure to ask your physician about your specific needs before you make any changes in your own diet or exercise routines.

The more you know!

-- Les, MS RD LD
 

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