Electrolyte Imbalance Causes Hypertension

The May 10, 2007 issue of the New England Journal of Medicine contains an excellent review of the role of excess salt and too little potassium in promoting the development of hypertension. To their credit, Drs. Adrogue and Madias do an excellent job of explaining the physiological mechanisms by which an excess of sodium chloride in the diet, coupled with an inadequate intake of potassium, induce an electrolyte imbalance in the body.

They go on to explain how this electrolyte imbalance is the dominant environmental insult ultimately leading the vast majority of people to develop high blood pressure. They start off their review by noting that primary hypertension accounts for about 95% of all cases. Furthermore, primary hypertension is virtually unknown in isolated human population groups that add little or no salt to their food and have daily dietary sodium intakes of no more than 50mmol (or 1150mg sodium). These isolated population groups all eat minimally processed foods that are also high in potassium by American standards.

The INTERSALT study showed that blood pressure rises with age in all human populations that consume about 2300mg of sodium daily or more. In all these salt-added populations, the vast majority of people develop hypertension sooner or later. Much of this review deals with pathological mechanisms whereby a high salt and low potassium diet alters the electrolyte balance in the vascular smooth muscle cells and other tissues leading to all the observed abnormalities seen in hypertensive patients. They also do a nice job of tying in the mechanism of action of pharmaceutical agents that lower blood pressure largely because they partially correct some of the metabolic abnormalities caused by an unnatural sodium/potassium ratio seen in modern diets. Of course, they note these drugs can often create other undesirable metabolic effects so they should not be viewed as the solution to the growing prevalence of hypertension worldwide. Rather they suggest that the solution would be to adopt the electrolyte guidelines set forth in the Institute of Medicine’s report on the nutritional requirements for electrolytes. Just to review, this report said sodium intake should be less than 1,500mg of sodium daily for those under 50y and even less for older people. At the same time the report stated Americans need to roughly double their intake of potassium. The authors note that this increase in potassium needs to come from fruits and vegetables and other unrefined foods rather than from potassium chloride because excess chloride contributes to hypertension as well as too much sodium.

Better blood pressure, better heart health and better health for the rest of your life!

All the right stuff
Fruits
Vegetables
Unsalted nuts & seeds
Beans
Whole grains without added salt
Condiments with little or no added salt
Low-sodium whole grain bread
Canned foods without added salt
Fat-free milk, yogurt and ricotta cheese
All the wrong stuff
Cheese including most nonfat cheeses
Cured meats, imitation seafood, soy “meat”
Salty snack foods
Canned foods with added salt or “sea salt”
Condiments, sauces, dressings
Nearly all restaurant meals
Most frozen and boxed convenience meals
Bread, packaged cereals, refined grains

If you want to lower your blood pressure, get your cholesterol down to a safe level and stay healthy for life, there is good news! You only need to follow one sensible diet.
An overwhelming amount of scientific evidence points to our diet and activity level as being the keys to better health.  The bottom line is that you don’t need special drinks, supplements or designer foods. Simply limit the amount of  refined carbohydrates, sodium-laden processed foods, and foods high in fat (especially saturated and trans fat) that you eat
Replace these unhealthy food choices with a low-fat, low-sodium diet based on fruits and vegetables, whole grains and a modest amount of seafood and fat-free dairy items .
For more information, consult www.nhlbi.nih.gov for the DASH diet.