Boost Potassium Intake to Cut Stroke by 20%

March 01, 2011

February 28, 2011 (Naples, Italy)— The largest meta-analysis so far conducted examining the impact of potassium intake on cardiovascular outcomes has found that higher dietary consumption of this mineral is associated with lower rates of stroke and could also reduce the risk of coronary heart disease (CHD) and total CVD [1].

The results apply to all sectors of society and not just to specific "at-risk" subgroups, say Dr Lanfranc D'Elia (University of Naples Medical School, Italy) and colleagues in the study, published in the March 8, 2011 issue of the Journal of the American College of Cardiology. "Potassium intake may be increased by well-described dietary changes, mainly an increase in fruit and vegetable consumption, as recommended by all guidelines to prevent vascular diseases," they state.

Most doctors are not aware of what huge benefits one might derive from this measure.

The researchers are not the first to urge people to eat more potassium-containing foods, and recent updated USDA dietary guidelines recommend increasing intake of foods rich in potassium. Senior author of this new research, Dr Pasquale Strazzullo (University of Naples Medical School, Italy), told heartwire that it is important to convey this to clinicians: "Most doctors are not aware of what huge benefits one might derive from this measure," he observes.

But doctors must also be careful not to confuse patients with too much detail on different nutrients, he says. Simple advice to eat more fruits and vegetables, in particular those that are very rich in potassium--including bananas, tomatoes, oranges, apricots, and most legumes--is probably best, he says. "The most practical advice we can give is that people should have five or six servings of fruit and vegetables a day," he says.

Potassium Intake Far Lower Than Recommended in All Participants

The researchers identified 11 studies on the association between habitual dietary potassium intake and incidence of vascular events over the past 30 years, including 247 510 participants with follow-up of five to 19 years, for their meta-analysis. There were 7066 strokes, 3058 CHD events, and 2497 total CVD events. Potassium intake was assessed by 24-hour dietary recall in two studies, by food frequency questionnaire (FFQ) in six, and by 24-hour urinary excretion in three.

In the pooled analysis, a 1.64-g (42 mmol)/day higher potassium intake--which Strazzullo says is equivalent to around three pieces of fruit high in potassium--was associated with a 21% lower risk of stroke (risk ratio 0.79; p=0.0007), with a trend toward lower risk of CHD and total CVD that attained statistical significance after the exclusion of a single cohort (RR 0.93; p=0.03 and RR 0.74; p=0.0037).

In all of the populations studied in the present meta-analysis, potassium intake was far lower than the recommended intake of 100 mmol or more per day, they note.

The Italian doctors say the protective effect of potassium against stroke is in part due to its BP-lowering effects, particularly in hypertensive individuals and in those with elevated sodium intake, but also likely due to other properties of the mineral, such as the inhibition of free radical formation, as demonstrated in experimental studies.

Increasing Potassium=Reducing Salt: Prevent One Million Strokes/Year

They add that the magnitude of risk reduction with increasing potassium intake by 1.64 g per day is similar to that which would result from lowering dietary sodium consumption by 5 g (85 mmol) per day and would translate "into a reduction of 1 155 000 stroke deaths per year on a worldwide scale."

It is not a good idea to convey two key messages together; it's much better to give them separately.

But Strazzullo says doctors must tread carefully when it comes to giving advice on sodium and potassium intake: "In general, there is a rule that it is not a good idea to convey two key messages together; it's much better to give them separately," he says. "That's why when we talk about reducing sodium we don't talk about increasing potassium intake. People do know about salt, but they are not so familiar with potassium and where it can be found. So perhaps it is sufficient, and better, that doctors talk to patients and people in general more about increasing fruit, vegetable, and legume intake."

Of course, "some education is not bad, and one could mention the word potassium," he adds, but stresses that it is important that people are not misguided into thinking that they can make up for excessive salt intake just by increasing potassium consumption. "One should not consider the two as alternatives, and we should be careful not to give this impression," he stresses.

"In fact, in the DASHstudy, they found that reduction of sodium intake had a BP-lowering effect that was additive to that of fruit and vegetable intake," Strazzullo adds.

The authors report that they have no conflicts of interest.


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