More salt controversy

OLYMPUS DIGITAL CAMERAThe experts are arguing about sodium again, after a recent report from the Institute of Medicine questions the American Heart Associations strict sodium dogma.  Despite the negative and guilt-laden image of salt consumption, sodium is essential to life and health.  Sodium balances fluids and plays a key role in most metabolic processes.  If you lose too much sodium from heavy sweating, kidney losses or gastrointestinal disease, you can very quickly develop a medical emergency.

We do eat a lot of sodium, mostly from commercially processed foods.  But it’s not all in the form of simple table salt.  Additives like monosodium glutamate and sodium nitrite also contribute sodium.  Salt enhances the flavor of foods, and in some cases also impacts the texture or helps with preservation.

If you eat too much salt, your kidneys flush it out.  Everyday you lose salt, although the amounts will vary according to how much you eat, how much fluid you drink, how much you sweat and how well your digestion is working.

The ongoing sodium controversy goes like this: people with high sodium intake tend to have higher risk for heart disease.  It’s easy to jump to the conclusion that salt causes heart disease.  Official recommendations from the American Heart Association and other advocacy groups have progressively lowered recommended salt intake, even though few people seem to be following up on that advice, in an attempt to reduce incidence of heart disease.  The latest recommendation is 1500 mg per day which is extremely low.  It’s also probably not achievable unless you stay home all day, cooking your meals from scratch with pure organic whole foods, and never ever add salt for flavor.

The AHA recommendations have been criticized by other experts in the past few months, and the Institute of Medicine adds to the chorus.  The IOM looked at several studies and failed to find evidence that lowering salt intake actually improved health outcomes.   In other words, lowering salt intake below 2300 mg/day doesn’t necessarily improve health.  And health outcomes are ultimately what it’s all about.

Why is the effect of salt so hard to pin down?  One major problem is that only about 1/4 of us are salt sensitive: in other words eating more salt has clear health effects.  The other 75% have more leeway in salt intake.  But studies fail to sort these people out.  Subjects with different salt sensitivity are lumped together, and the data ends up being very murky.

Another major problem: a so-called high sodium diet has a lot of other nutritional differences that never get mentioned:

  • lower potassium — Potassium is known to have a beneficial effect on blood pressure but the sodium critics never mention it.  Most people eat too little potassium, and most so-called low sodium diets are by default higher potassium due to the focus on vegetables and fruit.
  • lower calcium
  • lower fiber
  • lower intake of all the known and unknown nutrients and antioxidants in vegetables and fruits
  • higher intake of many food additives common to processed foods
  • higher intake of certain fats, like saturated fat
  • higher intake of animal protein
  • higher sugar.  And there’s also evidence that high sugar intake can raise blood pressure.
  • higher calorie intake in general — the sodium critics always fail to mention that simply losing weight helps improve blood pressure.

There is no highly processed diet that’s low sodium.  Switching to a low sodium diet means making hundreds of other changes in your nutritional intake.  You’ll end up eating foods that are mostly cooked from scratch and you will not at restaurants or use convenience foods.  You may end up eating a much healthier diet in general, maybe even losing weight.

In fact the IOM is right: there’s no evidence that just changing sodium is beneficial, because the study to prove that has never been done and probably never will be done.  You’d have to put thousands of subjects on a highly controlled diet for years, and make sure they only added permitted levels of salt to that diet.  It would be extremely inconvenient, hard to police and impossible to do without locking everyone up.

So what is the anti-sodium crowd really up to?  Their anti-sodium mantra starts to sound like snobbish elitism.  High sodium foods are mostly inexpensive and processed.  The food police hate that kind of food.  They eat only local organic food cooked from scratch, and they think everyone should follow their high-minded example.  An attack on salt is an attack on a lifestyle.

The single minded attack on salt is also a distraction from all the other dietary factors that also contribute to high blood pressure and heart disease:

  • excess body weight.  And no, salt doesn’t cause weight gain.
  • poor potassium intake
  • high intake of added sugars
  • sedentary lifestyles.

Focusing so much on salt leads people to conclude that as long as they buy low sodium versions of their favorite processed foods, they’ve done enough.  Certainly food companies would love for you to think that was the solution.

What should you do if you’re concerned about your blood pressure?  The better plan is to add many more plant foods to your diet: fresh vegetables and fruits, more legumes and whole greens.  All of these are high potassium and naturally low sodium.  Limit your use of fast foods, salty snack foods and foods loaded with sugar.  But frankly, you should be limiting those anyway since they just add calories.  And one of the most effective ways to lower blood pressure is weight loss.

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