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Food, Health, and Eco-news
Potassium May Curb Stroke
We've reported on the evidence linking higher intake of fish-source omega-3s to lower risk of stroke.
For example, see “Omega-3 Shows Stroke-Blunting Benefits,” which includes links to our prior coverage of research in this realm.
Sadly, diets high in fried fish actually raise stroke risk, probably due to the load of generally pro-inflammatory omega-6 fats in its oil-soaked breading ... see “Fried Fish Seen to Raise Stroke Risk.”
Conversely, antioxidant-rich plant foods seem to pack an anti-stroke punch … see “Fruits and Veggies Linked to Lower Stroke Risk,” “Tea and Chocolate May Deter Strokes, Brain Damage,” and “Berries Seen Reducing Brain Damage from Strokes”.
Which foods
provide the most potassium?
The average American consumes only about 2500 milligrams per day … far below the official Adequate Intake of 4700 milligrams (5100 for women who are lactating), and the U.S. Daily Value of 3500mg.
Good sources of potassium (i.e., 10 percent of Daily Value or more) include cod, prawns, halibut, tuna, trout, chard, crimini mushrooms, spinach, fennel, kale, mustard greens, Brussels sprouts, broccoli, winter squash, blackstrap molasses, eggplant, cantaloupe, tomatoes, parsley, cucumber, bell pepper, turmeric, apricots, ginger root, strawberries, avocado, banana, cauliflower and cabbage.
Of course, excessive sodium intake can raise the risk of stroke, especially in people who are genetically predisposed to this vulnerability.
But other dietary minerals can help suppress stroke risk, as we reported in “Magnesium May Cut Stroke and Diabetes Risks.”
Now, a study from Sweden suggests that potassium may be another ally in the fight to prevent stroke.
Swedish evidence review links potassium to reduced stroke risk
Researchers from Stockholm's renowned Karolinska Institute analyzed data from 10 “prospective” epidemiological studies, in which people's diets, lifestyles, and health status are recorded over a set time period.
But they identified higher potassium intake as another possible stroke-suppressing aspect of diet, and linked it to lower blood pressure.
The Swedes found a statistically significant relationship between higher potassium intake and reduced stroke risk.
The scientists wrote that a 1000mg per day increase in potassium intake was associated with an 11 percent reduction in the risk of ischemic (iss-keem-ik) stroke, which is the by far most common kind (see our sidebar, “Basic stroke facts”).
However, higher potassium intake was not associated with reduced risk of hemorrhagic strokes, which result from a ruptured blood vessel in the brain.
Animal and test tube studies show that high-potassium diets suppress free radicals and may protect against the artery-lining problems known as “endothelial dysfunction” and “vascular smooth muscle cell proliferation.”
The scientists noted that most studies within the meta-analysis had been adjusted to account for risk factors such as smoking, age, body mass index, diabetes history, and alcohol consumption.
Basic stroke facts
A stroke or “brain attack” occurs when either of two things happens:
A blood clot blocks the blood flow in a vessel or artery. These “ischemic” strokes account for about 88 percent of all strokes.
A blood vessel breaks, interrupting blood flow to an area of the brain and smothering surrounding brain cells. These are called “hemorrhagic” strokes.
When either of these things happens, brain cells begin to die.
About 800,000 Americans suffer a new or recurrent stroke annually, and more than 137,000 of these die, making stroke the third largest cause of death
About 40 percent of stroke deaths occur in men, and 60 percent in women, with black Americans at greatest risk.
Americans will pay about $73.7 billion in 2010 for stroke-related medical costs and disability.
Well-established anti-stroke factors include healthy blood pressure, lower salt intake, healthy weight, and moderate alcohol consumption.
They also noted that potassium-rich fruits and vegetables are also rich in antioxidants, fiber, and nutrients such as vitamin C, folate, magnesium, which may reduce stroke risk.
However, as they wrote, “The inverse association between potassium intake and risk of stroke persisted when we restricted the analysis to studies that adjusted for other nutrients.”
  • He K, Song Y, Daviglus ML, Liu K, Van Horn L, Dyer AR, Goldbourt U, Greenland P. Fish consumption and incidence of stroke: a meta-analysis of cohort studies. Stroke. 2004 Jul;35(7):1538-42. Epub 2004 May 20.
  • Iso H, Stampfer MJ, Manson JE, Rexrode K, Hennekens CH, Colditz GA, Speizer FE, Willett WC. Prospective study of calcium, potassium, and magnesium intake and risk of stroke in women. Stroke. 1999 Sep;30(9):1772-9.
  • Larsson SC, Orsini N, Wolk A. Dietary Potassium Intake and Risk of Stroke: A Dose-Response Meta-Analysis of Prospective Studies. Stroke. 2011 Jul 28. [Epub ahead of print]
  • Larsson SC, Orsini N. Fish Consumption and the Risk of Stroke: A Dose-Response Meta-Analysis. Stroke. 2011 Sep 8. [Epub ahead of print]