fitness master An explanation of the sodium-potassium relationship
While you're probably a bit too busy to study for a degree in science in your spare time, you're definitely educated enough to appreciate an appropriate analogy. So instead of making your brain hurt with references to "electromechanical gradient," "resetting electrical potential," and "the sodium-potassium pump," let's consider the relationship between the two forms of exercise absolutely essential in creating a fabulous physique: weightlifting and aerobic exercise.
One cannot dominate the other if you want to win an elite-level bodybuilding contest.
If you spend too much time developing muscle size and not enough time on the treadmill or the elliptical trainer, the definition of your muscles the separations and striations gets obscured by body fat. If you spend too much time on the treadmill or the elliptical trainer and not enough time handling heavy weights, you can see all the details in your muscles and that they're noticeably smaller than those of your competitors.
The best bodybuilders find a balance between the amount of time they lift weights and the amount of time they perform cardio in order to build their body in the best way.
That same balancing act is what's required of you to achieve optimal health and fitness, and it's especially true for the two elements featured in today's column: your ingestion of sodium and potassium.
For years you've read about how the typical American diet contains too much sodium and how you should strive to limit your ingestion of it. While that is true, for too long that concern has obscured another truth: that the typical American diet is deficient in potassium.
And since they work much in the same way that weightlifting and aerobic exercise work for elite-level bodybuilders, it's the ratio between the two, as much or even more so than the excess or dearth of one or the other, that really counts.
In fact, that was the finding of a rather comprehensive study published in Archives of Internal Medicine last July. Researchers studied the dietary patterns of more than 12,000 people for nearly 15 years.
What the researchers found was that not only did a higher intake of sodium increase the incidence of all sorts of death, but it also increased the risk all types of heart disease. Yet the same was true for those in the study who had a lower total intake of sodium but a high sodium-to-potassium ratio.
This prompted the authors of the study to write that "examining the joint effects of sodium and potassium intakes on cardio vascular disease is particularly important because most of the U.S. population consumes more sodium and less potassium than recommended" and that "public health recommendations should emphasize simultaneous reduction in sodium intake and increase in potassium intake."
This study from last July supports the findings of another published in the same periodical in 2009 that found a correlation between cardiovascular disease and a high ratio of sodium and potassium.
Stressing the ratio between the two as opposed to simply reducing sodium intake also seems prudent based on other related research.
A study published in Hypertension linked a deficiency in potassium with hypertension, a harbinger of heart disease, as well as type 2 diabetes. Numerous other studies have found high levels of potassium in the body decrease the likelihood of stroke.
Stressing the ratio between sodium and potassium instead of simply reducing the intake of sodium seems prudent for another reason: in the typical American diet, a dramatic reduction of sodium simply isn't going to happen. The American Heart Association, for instance suggests ingesting no more than 1,500 mg, but most Americans consume 3 to 4 times that amount.
Cutting back to the AHA recommendation would require a substantial decrease in your use of processed foods. Currently, that's the source of 77 percent of the sodium you ingest.
It's easy to rack up a ridiculously high amount of sodium if you eat processed foods. Consider that even 100 calories of a rather healthy processed soup, Campbell's Select Harvest Light Southwestern-Style Vegetable, contains 960 mg of sodium, more than two-thirds of the AHA daily suggestion.
Even fast foods not associated with sodium can contain considerable amounts. Three Aunt Jemima Buttermilk Pancakes, what's considered a single serving, have 460 mg of sodium. Most cheeses contain a significant amount with one of the healthiest types, fat-free cottage cheese, possessing about 900 mg per cup.
To counteract the processed foods you eat that are loaded with sodium, eat potassium-packed fruits and vegetables. One cup of broccoli, for instance, contains 448 mg; one medium banana, 451 mg.
The following amounts are all found in a single cup: spinach, 625 mg; Brussels sprouts, 495 mg; butternut squash, 582 mg; cantaloupe, 494 mg; strawberries, 254 mg; seedless raisins, 998 mg.