Salt: New Research on Sodium and Health

Although research has long implicated high sodium levels as a means of aggravating already high blood pressure, individuals without hypertension have long been thought to be immune to the effects of higher levels of sodium intake. After all, salt is ubiquitous in our food, used in everything from soups to preserved meats to do-it-yourself sauce packets. Even some vegetables (kale and seaweed for instance) contain salt as a natural ingredient. Avoiding salt entirely is virtually impossible, and recent research argues that a truly salt-free diet is far unhealthier than a heavily salted one.

However, recently published research from the University of Minnesota indicates that high levels of salt intake are injurious to all individuals regardless of hypertensivity. The research, published in the journal Hypertension, replicated the 1990 study of Tobian and Hanlon. Specially-bred rats which are highly resistant to sodium-induced hypertension were fed a high-sodium diet, while a control group was fed a low-sodium diet. Although blood pressures in both groups stayed well within normal bounds, arterial lesions rapidly formed in the high-salt group. Indeed, by 15 weeks on the high-salt diet all 49 rats had died, whereas the 51 control rats were still alive.

This seems to unambiguously state that high-salt diets, regardless of blood pressure problems, are injurious to health. Many people, realizing the salt intake levels in their diets are unhealthily high, have chosen to switch to a “light” salt, a blend of sodium chloride and potassium chloride. As the taste of salt is produced by the halide reaction on the salt-sensing taste buds (unlike most of the rest of our sense of “taste” which is actually smell-driven), the blend works well when on simply considers the flavor. No real change can be detected by 87% of the population; the remaining 13% may taste a slightly bitter or metallic aftertaste as a result of switching to the blend.

However, researchers in Australia have recently uncovered a new fact: high potassium levels are as injurious, if not more so, than high sodium levels. The two elements are linked in biochemistry: the sodium and potassium balance is what causes muscular activity. Essentially, the interior environment of the muscle cell is “unbalanced” as compared to the exterior environment by means of a sub-cellular mechanism that pumps sodium out and potassium into the cell. When the level reaches a critical imbalance point, the muscle cell contracts, squeezing the potassium out and forcing sodium back in. The relaxation of the cell occurs when the balance is restored, but severe cramps can occur easily when one of the elements is in relatively low concentration as compared to the other.

Normally, three sodium ions move out while two potassium ions move in. However, when the concentration of one or the other element is low, the pump must work harder, and the muscle remains contracted for longer periods of time. This leads, ultimately, a muscle that squeezes harder, and when that muscle happens to be the heart, an increase in blood pressure is seen. In Americans, the element in low concentrations is almost always potassium; sodium is in more than plentiful supply, so much so that hedge wisdom suggests the eating of a banana to prevent cramps. No magic involved here: the banana is naturally high in potassium, which helps to somewhat restore the concentration levels of the missing element and thus prevents the cramp.

But when potassium chloride is used as a substitute for sodium chloride, the concentrations can go the other direction. Remember that the sodium/potassium pump requires three sodium, but only two potassium. When potassium levels are inordinately high, the pump again must work harder, but the muscle contracts less well (think of it as though a 60-watt bulb were connected to a lower-level power supply; the bulb would burn less brightly). Thus, hypotension, or low blood pressure, can result, with a wide variety of health problems as well.

So what’s the solution? Try regulating your sodium levels by increasing non-salt additives. The two additives you should get to know are dulse and thyme. Dulse, a non-sodium alternative to salt, is made from processed seaweed and algae, and can be found at most natural-food markets. A dark gray in color, the substance may cause a raised eyebrow when it looks like you peppered your food instead of salting it, but the flavor is that of slat, not pepper. Thyme, an herb, also has no salt. However, for some strange reason, it can partially imitate the halide reaction of the salt-sensing taste buds, leading to a slightly salty flavor even in a non-salted item. A small pinch of the dried herb can be successfully added to virtually any dish without causing a problem in flavor clash.

Finally, there are a few cases when salt must be used. Yeast-based breads, for instance, must have salt; the salt regulates the growth of the yeast to allow an even rise in the dough. Additionally, when compared to many of the other chemicals used to preserve flavor in meats, salt is much better for you than, say, sodium BHT, an artificially produced item used extensively in pork products. With time, and a little experimentation, you will find that many of the items you used to eat with salt can be enjoyed at the lower-sodium levels.

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