Philip J. Goscienski, M.D.
It's possible that more people know it as an ingredient of fertilizer (potash) than as an essential component of every cell in the body. Potassium is one of the most ignored nutrients in the American diet. Endurance athletes recognize it as an important electrolyte that is included in sports drinks. The average person takes in less than what nutritionists recommend but the body conserves it so efficiently that dietary deficiency rarely causes obvious symptoms.
The diet of modern hunter-gatherers provides them with the amount of potassium that the human body requires, at least 3500 milligrams a day. They get a much smaller amount of sodium, about 600 milligrams a day. Today's Western diet has reversed these numbers almost exactly. The result is an epidemic of high blood pressure, an important cause of heart disease and stroke.
Population groups that eat the most fruits and vegetables have lower blood pressure than those with the lowest intake. Years-long studies among large groups of subjects show that increasing potassium intake in the form of fruits and vegetables could significantly lower the risk of stroke, especially among blacks, whose propensity toward high blood pressure and stroke have been recognized by the medical community for decades.
Potassium supplements are not the answer. Promoters of low-carbohydrate diets, notable for their very low content of fruits and vegetables, sometimes suggest potassium tablets. Over-the-counter preparations can contain no more than 99 milligrams per tablet in order to prevent excessive blood levels, especially in children who might take them accidentally. An overdose usually causes nausea and vomiting and persons with significant kidney disease may experience an abnormal heart rhythm.
Interestingly, 99 milligrams of potassium in food isn't much. Just one-quarter of a medium banana, an ounce of salmon, a single dried fig or only one-twelfth of an avocado would provide that amount. The tablet, of course, wouldn't bring with it any vitamins, minerals or antioxidants. And no one ever overdosed on vegetables.
Getting enough potassium is only one of the benefits of a diet rich in fruits and vegetables. Refined grains and meat produce an acid load that causes a loss of calcium through the kidneys. The result is bone loss that leads to osteoporosis and to kidney stones. Plant foods, but not grains, reduce the acid load.
We should eat 10 servings of fruits and vegetables every day. The average teenager gets less than one. What are we setting them up for?
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.