Potassium is an important mineral for your body that helps manage fluid balance and normal cell function. Low potassium in the diet has been linked to increase risk of high blood pressure and stroke. Potassium can be found in a variety of foods including meats, fish, soy, fruits, vegetables, and dairy products but it can be reduced or lost when these foods are processed. Since many of today's diets have a lot of processed foods without a lot of vegetables and fruits, many people may not be getting the adequate amounts of potassium in their diet.
A review of previous studies was done to look for benefits of potassium in people with hypertension. The review not only looked for benefits but also potential risks of increasing potassium such as kidney problems or cholesterol levels. The trial, published in British Medical Journal, found that increased potassium levels were associated with lower blood pressure and lower risk of stroke in patients with hypertension. Increased potassium was also not associated with kidney or blood lipid problems.
The systematic review included 22 randomized trials with 1,606 patients and 11 cohort studies with 127,038 participants. Three trials had child participants. The patients were followed for death, cardiovascular disease, stroke, or heart disease. Potassium was either measured and compared or increased with supplements and/or dietary changes. Participants were also monitored for an adverse effects of increased potassium.
In adults participants with hypertension, higher potassium levels were associated with a reduction in both systolic and diastolic blood pressure. However, adults without hypertension or children with higher potassium levels did not show the same benefits.
Participants with higher potassium intake also had a 24% lower risk of stroke. There was no difference in the risk of heart disease between participants with low potassium levels compared to those with the highest level of potassium.
Harmful side effects associated with high potassium such as decrease kidney function, increase in blood lipids, or change in catecholamine concentrations were not found in patients with higher levels of potassium.
A systematic review is considered a desirable form of research since it pools several small studies to reach a conclusion. Higher number of participants means the results are more likely to be true and not due to chance. But, the review is only as reliable as the studies that make it up. In this case, there are several high quality randomized trials which are considered a very reliable form of research. The cohort studies are observational studies which can not determine cause and effect but simply point out potential relationships which may make the overall outcomes a little less reliable.
Although potassium is an important mineral, certain people can get too much of it. High potassium can cause problems in people who have poor kidney function and for people taking certain medications. These studies included people without these problems. If you have kidney problems or take medicines that affect your kidneys, talk to your doctor before trying to increase the potassium in your diet.
The included studies used not only supplements but also diet changes to raise potassium levels. Healthy eating choices such as decreasing the amount of processed foods you eat and getting plenty of fruits and vegetables may not only improve your potassium but also help your overall health. Talk to your doctor about any changes to your diet, including supplements, especially if you have a chronic health condition.
Aburto NJ, Hanson S, Gutierrez H, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ. 2013 Apr 3;346.
Last reviewed June 2013 by Brian Randall, MD