Potassium: A Non-Celebrity Cation
Thomas D. Giles, MD, Tulane University School of Medicine, 109 Holly Drive, Metarie, LA 70005
I don’t get no respect.—Rodney Dangerfield
It is mysterious how some things or people catch the public eye, while others, equally important, are curiously ignored. For example, the sympathetic nervous system, systole, and arteries as compared with the parasympathetic nervous system, diastole, and veins. It probably has to do with why some people are famous for just being famous.
Dietary sodium has certainly reached the celebrity status. The public-at-large, government, public health agencies, food manufacturers, political activists, among others, all warn the public about the possible adverse effects of increased sodium in the diet, and there are efforts to limit sodium intake in commercial establishments that provide food as well as in commercially prepared foods. Recently, in these pages, there was an appeal for worldwide action to reduce sodium intake.1 Even so, controversy remains regarding the widespread implementation of a low-sodium diet.
Dietary potassium, on the other hand, receives comparatively little notice. Potassium is ignored despite the following proven results of increased dietary potassium: lower blood pressure (additive to lower-sodium intake), reduction in the risk of stroke and progression of kidney disease, reduction in the risk of kidney stones, and preservation of bone density, and decrease in the risk of cardiac arrhythmias in patients with ischemic heart disease, heart failure, and left ventricular hypertrophy.2 Remarkably, a 30-mmol to 45-mmol increase in potassium intake is associated with an average reduction in population systolic blood pressure of 2 mm Hg to 3 mm Hg. Increasing consumption of potassium to 4.7 g/d predicts lower event rates for future cardiovascular disease with estimated decreases in stroke by 8% to 15% and myocardial infarction by 6% to 11%. What is impressive is that the effect of potassium is even greater in patients consuming increased quantities of sodium.
Endothelial dysfunction may be the root cause of most hypertension. A study comparing treatment of individuals with untreated, increased blood pressure with potassium chloride vs potassium bicarbonate vs placebo on endothelial function was recently reported.3 Compared with placebo, both potassium chloride and potassium bicarbonate significantly improved endothelial function and left ventricular diastolic function and decreased left ventricular mass.
A recent report of meta-analyses of prospective studies of potassium intake, stroke, and cardiovascular disease found that 1.64 g (42 mmol)/d higher potassium intake was associated with a 21% lower risk of stroke and a trend toward lower risk of coronary heart disease and total cardiovascular disease.4
Strategies for Increasing Potassium Intake in Children and Adults
Because cardiovascular disease, including hypertension, often begins at an early age, it seems reasonable that increased potassium ingestion be encouraged early in life and continued into adulthood. Americans are consuming insufficient potassium during their lifespan and most Americans are not meeting their daily potassium needs according to the 2010 Dietary Guidelines Advisory Committee.5 Adequate intake of potassium for persons aged 1 to 3 years is 3000 mg, aged 4 to 8 years is 3800 mg, aged 9 to 13 is 4500 mg, and aged 14 to 70 years is 4700 mg/d. Obviously, anyone with kidney disease or taking medications that influence potassium excretion, eg, potassium-sparing diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, should consult with their health care provider on guidance for potassium intake.
Potassium is found in a variety of foods, with fruits, vegetables, low-fat dairy foods, and beans as excellent sources. Potassium-rich foods include potatoes, prune juice, tomato juice, white beans, nonfat yogurt, orange juice, halibut, soybeans, bananas, cantaloupe, spinach, skim milk, apricots, pork loin, lentils, kidney beans, and strawberries, to name a few. Children and adults can easily increase their daily intake of potassium by incorporating these simple steps in their diet: For breakfast, include a serving of orange juice or add strawberries to nonfat yogurt; for lunch, enjoy bean soup and add leafy greens, such as spinach, to your sandwich; throughout the day, snack on healthy choices such as bananas, cantaloupe, or dried apricots; and for dinner, include a serving of skim milk and add broccoli and baked regular or sweet potatoes to your meal to boost your potassium intake. It is recommended to select from a variety of food sources to meet individual dietary needs for potassium.
As stated by the 2010 Dietary Guidelines Advisory Committee, in view of the health benefits of adequate potassium intake and its relatively low current intake by the general population, increased intake of dietary potassium is warranted.6 The low consumption of potassium by Americans is now considered a public health concern, with more efforts stressing the importance of consuming increased potassium in the diet. The Dietary Approaches to Stop Hypertension (DASH) diet follows heart-healthy guidelines to limit saturated fat and cholesterol and increase foods that are rich in potassium, calcium, and magnesium. The DASH diet is rich in fruits and vegetables, whole grains, and low-fat dairy foods. It includes meats, fish, poultry, nuts, and beans, and is lower in sodium, sugar-sweetened beverages, red meats, and added fats. Research studies have shown that following the DASH diet is proven to lower blood pressure and reduce cardiovascular disease risk.
The national interest in caloric intake, sodium intake, carbohydrates, trans-fats, and fiber adds to the education of the public. We should not forget that nutrition information was once included in high school curricula in courses on hygiene where students also learned about dental care and other aspects of health. We should be vigilant not to ignore the myriad components of a proper diet, including trace elements. As with most things in medicine, there is almost never an over-arching recommendation that is perfect for each individual. However, awareness of the various components of a good diet makes it easier to craft a regimen that will improve health and assist in treating disease states. All components of a good diet deserve respect.
Disclosure: The views expressed in this editorial do not necessarily reflect the opinion of the San Antonio Metropolitan Health District.