Low Dietary Potassium & Stroke Risk
Potassium plays a key role in all muscle contractions, including and most importantly the rhythmic contractions of the heart. It is also involved in maintaining normal blood pressure, pH and electrolyte balance. Large drops in serum potassium, called hypokalemia, can cause abnormal heart rhythms and paralysis. According to a 2002 study published in “Neurology,” low serum potassium is also associated with increased future stroke risk, though “data regarding stroke incidence has been limited.” There is some evidence that the converse is true, too — foods that provide “at least 350 mg of potassium per serving and are low in sodium, saturated fat and cholesterol may help reduce the risk of stroke.” There is no evidence, though, that taking potassium supplements decreases stroke risk.
Stroke, or cerebrovascular accident, is the third leading cause of death in the United States, behind heart disease and cancer. It is the top cause of serious, long-term disability. More than 50 percent of strokes are preventable when contributing factors are addressed proactively. Sometimes called “brain attack,” stroke is caused by vascular dysfunction that occurs when blood flow to one or more arteries supplying the brain is impeded, either by a clot or internal brain bleeding. This impediment prevents delivery of needed oxygen and nutrition to tissues and causes brain cells to start to die. If the condition is not caught and treated early, permanent brain damage can occur.
High blood pressure, or hypertension, is a major risk factor for stroke and is also often associated with suboptimal serum potassium levels. High sodium intake, which is prevalent in the American diet, has long been associated with hypertension. Less well-known is that dietary potassium has the opposite effect, in that it lowers above-normal blood pressure. Limiting sodium intake and eating potassium-rich foods is helpful in keeping blood pressure normal and diminishing related stroke risk. If you have hypertension, work closely with a medical professional to determine a management strategy.
Of all the food choices, sweet potatoes and beet greens contain the highest levels of potassium. One cup of boiled beet greens has 1,309 mg of potassium; one large baked sweet potato has 855 mg. Baked potatoes, including the skin, are another excellent source. Prune, carrot and orange juices offer a sweet solution for increasing dietary potassium, as do banana, kiwi, peach and cantaloupe. Mix any of these fruity choices in a blender with plain yogurt for a creamy double dose of potassium. Granola or bran can also be mixed with yogurt for an extra potassium boost. Tomatoes, peas and winter squash are a great start to a potassium-rich soup or stew. Lima or canned white beans add protein, fiber and extra potassium. Meaty sources of the mineral include halibut, yellowfin tuna, Pacific rockfish, flounder, salmon, cod, clams and chicken.
In studying the effects of dietary potassium on stroke risk, researchers have evaluated magnesium, calcium, sodium and iron as well. Findings suggest that high levels of dietary calcium and magnesium are helpful in lowering risk of stroke when you maintain low levels of dietary sodium. Dairy products provide high levels of calcium, as do soybean products, sesame seeds, nuts, green leafy vegetables and broccoli, and the soft bones of sardines, herring and canned pink salmon. As a general rule, foods that are high in fiber, such as legumes and whole grains, are high in magnesium. Leafy green vegetables, soybeans, almonds and dark chocolate are all good sources of magnesium.
References
- University of Maryland Medical Center: Potassium
http://www.umm.edu/altmed/articles/potassium-000320.htm - “Neurology”; Serum Potassium and Dietary Potassium Intake as Risk Factors for Stroke; D.M. Green, et al.; August 2002
http://www.neurology.org/content/59/3/314.abstract - MedlinePlus: Hypokalemia
http://www.nlm.nih.gov/medlineplus/ency/article/000479.htm - “American Journal of Hypertension”; Serum Potassium and Stroke Risk Among Treated Hypertensive Adults; N.L. Smith, et al.; October 2003
http://www.ncbi.nlm.nih.gov/pubmed/14553958 - U.S. Department of Health and Human Services: Health Facts: Sodium and Potassium
www.csrees.usda.gov/nea/food/pdfs/hhs_facts_sodium.pdf - Natural Medicines Comprehensive Database: Potassium, Calcium, Magnesium
http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?rn=2&pt=100&id=851&ds=&name=POTASSIUM&searchid=25569163&cs=&s=ND - “Preventing Chronic Disease”; Dietary Intake of Minerals and the Risk of Ischemic Stroke in Guangdong Province, China, 2007-2008; W. Liang, et al.; March 2011
http://www.cdc.gov/pcd/issues/2011/mar/10_0056.htm
