Salt and High Blood Pressure

If you are hypertensive, how often should you say “please pass the salt?”

Salt (sodium chloride) may be indispensable in food preparation, but it is optional for people at risk with high blood pressure.

To understand the subtle interplay between salt and hypertension, let us first take a look at the basic concept of blood pressure.

Blood pressure (BP) is simply the force of blood pushing against the arterial walls as it courses through the body.  This force is determined by how strong or weak your heart pumps blood.  Hence, your BP level soars when you are excited, agitated or stressed, and conversely, drops when you are depressed or lethargic.  Blood pressure is a vital sign of life; it is the first thing checked when a person is pronounced dead.

Salt does not directly affect cardiovascular rhythm, so what does it have to do with blood pressure?

Turns out, salt triggers the body to retain water.  When there is extra water sloshing around the system, the kidneys filter it and extract excess fluid to be removed through the bladder.  Though drinking enough water is a universal rule of thumb, in practice, we should not drink more than 4 liters of water a day.  Too much of it can lead to hydrocephaly; excess water not drained by the kidneys in time is stored in the brain.

For the kidneys to neutralize water levels, a delicate balance of sodium and potassium works to draw out, through permeable membranes in the cells, extra water from the bloodstream, and channels this water to a collecting organ – the bladder.  The pressure that this drawing out creates, is enough to increase the force of blood pushing against arterial walls.  Now you know why kidney problems might manifest as chronic hypertension.

It is no surprise then that anti-hypertension medicines are also diuretics:  They stimulate the kidneys to make more urine.  The more urine is eliminated, the more we need to replenish lost fluids.  As more fluid is replenished, the sodium levels are diluted, restoring ideal balance between potassium and sodium.  Blood pressure then returns to normal.

So how do you cut down on salt without sacrificing taste?  Of course, this should not be a concern if you are not hypertensive (although salt, as in any other food item, should be consumed in moderation); if you are, you may have to do some modifications in your diet and in your lifestyle in general:

  • Diversify your sources of condiments.  Avoid soy sauce, curry powders and stock cubes (they are rich in sodium).  Sprinkle extra flavor using herbs and spices like chili, ginger, lemon or lime juice;
  • Steer clear of smoked fish and meat, as they also contain high levels of salt;
  • Be wary of bread.  Salt is one of the primary ingredients.  Ditto with ketchup, mustard and pickles;
  • Read labels carefully. Manufacturers are notorious at getting unhealthy food across their market with misleading labeling.  Sodium and salt are two different things: 1g of sodium is equivalent to 2.5g of salt.  If there is no nutrition information, take a look at the ingredients:  the higher the sodium or salt in the list, the more the product contains of it.

If all these salt restrictions make you lose your appetite, take heart. Very few can live without salt (even cavemen craved for it), so make an effort to cook up low-sodium diets, with deviations every now and then.  You need to be prepared though to consume another mineral to do the check and balance:  potassium.  Since it is the interplay of sodium and potassium that determines how much water you retain, and consequently how much blood pressure you have to put up with, consuming potassium will cancel out the negative effects of sodium in the body.  So the trick to getting around salt restrictions?  Eat lots of potassium-rich fruits and leafy greens, and wash it down with enough water.