Salt and high blood pressure: Why the big hoo-ha?

Salt’s been in the news a bit lately, mostly addressing the FDA’s unusual move to request that restaurants and food companies reduce the salt content of the foods they produce (where the bulk of your salt can be found unless you have a special relationship with the shaker) .  Our palates are adjusted a bit high for the taste of salt, but stepping down consumption gradually can really help.

Why is it such a big deal, though?

The short answer: sodium consumption can increase blood pressure, and high blood pressure can increase the chances of a heart attack or stroke.  But you probably knew that.  Perhaps you would like to know why:

It all begins with osmosis, which will likely bring about images of some weird diagram with solutes and solvents and something about permeable

If this looks like a freeze frame of a video game, it’s all right.

membranes…like this!  No, wait, come back!

Perhaps you never took biology and you’ve just heard expressions like “learning by osmosis” where you learn by immersing yourself in a subject and effortlessly, you start to master the subject as it enters your semi-permeable membrane (!).  It’s not much more difficult than that if you just ignore the diagrams and remember the important thing:

Water goes where the party is.  It might have been easier if your teacher had just explained that water is a socialite.  Back to this in a minute…

Sodium and chloride (table salt) are outsiders who like to bang around in between cells wearing leather jackets while enjoying a clove ciggie, while potassium and phosphate enjoy the great indoor area of the cell.  (Salt is Heathcliff  to Potassium phosphate’s Catherine, for you literary types).

If salt is consumed in excess, and you’re young and healthy, much of the excess sodium and chloride (and in fact, most minerals) will head out toward the kidneys and will be eliminated through urine (provided you are hydrated, and gah, be hydrated!).

But what if you’re a little older, say, middle aged?  Or your kidneys are plain tired of your wily ways? Well, unless you’re just sitting in your easy chair shining up your halo because your eating habits are without fault of any kind, there’s probably a couple of things at work.  A) You probably have a little (or a lot of) arterial plaque built up and B) your kidneys are functioning fine, but not as fine as they used to when you were younger.  And that’s where things start to get a little hinky if you’re downloading too much salt.

If the salt hangs around on the outside of the cell, and there’s nothing inside the cell to counterbalance it (like potassium and phosphorus in the form of phosphate), water goes where the party is: it hugs up the sodium and chloride like a socialite working a charity function.  What’s the problem with that?  When all’s going well, 2/3 of the body’s water is supposed to be inside the cells.  When too much comes out to meet and greet the salt, the extra water gets into the arteries and swells up the volume of the blood, without the arteries able to expand to accommodate the shift.  And that’s high blood pressure.

When blood pressure is high, the arteries are like a garden hose spurting water full blast with your thumb over the end.  Lots of pressure, instead of just enough to propel the blood and nutrients to the outer edges of your body.  If you’ve got a little plaque in there, the pressure can dislodge the plaque and send it careening for your head, your heart, or your feet.  Hence, stroke, heart attack or cutting off circulation to some unfortunate part of your foot, which may then have to be removed (not a doctor but this is an embolism and ACK!).

And if that doesn’t happen, young ones, you can still cause damage to the arteries that leave it open to the idea of gathering some plaque — arterial damage starts the process, and this is one of the causes.

So how much salt?  Well, you only need a paltry 200 mg to survive (think: Caveman, because that’s probably the last person to consume so little).  1500 mg or less is the recommendation (hardy har har, oh what?  Sorry.  I’d like to see that.), and the food label shows 2400 mg (a teaspoon of salt) or less.  The Upper Level — the level we’re not supposed to go over, is a mysteriously lower number: 2300 mg.  Why?  Because the Daily Values on the food label, at 2400 mg, haven’t been updated in AGES.  Here is a some great info from the American Heart Association.

The best way to cut back on salt is to avoid processed foods and watch out at restaurants. People who sell food are in the business of getting you to buy it and making it tasty seems to be a key component of that process.  Fat and salt are big players in that arena, which might be why corporations are less than keen on cutting back.  (However, if we all cut back, our palate for salt would change and it might just work!  Just saying.)

Also: read labels.  When the sodium on a food label reads over 20% of the Daily Value (DV is the % thing on the label – hm, I feel another blog post coming on), it’s too damned much.  Soup is usually a huge culprit here.  Sorry, bacon lovers (and those of you who love bacon really have a thing for it, huh?).

What else can you do?  Well, eating more fresh fruits and vegetables will boost your potassium consumption.  And boosting your potassium consumption can send water back into the civilized atmosphere of the cell (if that’s the club where everyone, and by everyone I mean more potassium than sodium, has gone to dance), lowering blood pressure.

What is good blood pressure?  120/80 or below.  The top number is the pressure on the artery (in milligrams of mercury or mm/Hg, a fancy way of saying “How high the thermometer thingy goes when they’re testing the point at which the cuff on your arm cuts off pressure and then releases with a gush”) while the heart is beating (systolic), and the bottom number is the pressure between beats (diastolic).  Oh that American Heart Association is just bomb diggity at explaining more about this, so here you go.

Go to the doctor (or that free thing at the mall or the drug store where you can check your blood pressure) and make sure you’ve got things under control.  African Americans are especially at risk, and this is likely due to a genetic tendency toward salt sensitivity.  Medications include diuretics, which wash out the excess sodium and potassium as well — which is why you’ll likely be given a potassium supplement.

And you young whippersnappers?  Start now, kids.  You’ll be older before you know it, and you want to keep those arteries clean and mean so you can grow up to be old and wise and happy instead of, well, dead!!

My dog has decided that this is the end of my blog post.  If I’ve forgotten anything, blame it on Poppy.

One response to “Salt and high blood pressure: Why the big hoo-ha?

  1. I randomly came across your blog after looking for information on osmosis and salt. I enjoyed having a read of your ‘postings’.

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