Low Potassium Levels Linked to Increased Risk of Chronic Kidney Disease
New research determined a link between potassium levels, with the risk of developing chronic kidney disease in a mostly white population.
Potassium is a mineral that aids in proper bodily functioning. Levels of potassium are tightly regulated by the kidneys to help control blood pressure. In chronic kidney disease, a condition that results from kidney malfunction, patients may suffer from unregulated potassium levels in the blood. Hypokalemia is a condition when potassium levels are low (<3.5mmol/L) and hyperkalemia (>5.0 mmol/L) results from increased levels of potassium. Chronic kidney disease (CKD) patients with either hypo or hyperkalemia have a higher risk of mortality, heart attack, and hospitalization. Previous kidney studies have also found that hypokalemia may lead to kidney damage. However, the evidence demonstrating the association of hypokalemia with risk of developing CKD is not yet established.
In a recent study published in Plos One, researchers conducted a prospective study to examine the association between potassium blood level and the risk for developing CKD in predominantly white population. The study enrolled 6,000 participants with a urinary albumin concentration of 10 mg/L, a metric for hypertension and risk for CKD. Furthermore, the study also enrolled 2,592 participants with <10mg/L urinary albumin concentration. Participants who were diabetic, who already suffered from CKD and who were pregnant were excluded, leaving 5,130 participants. Circulating potassium levels, glomerular filtration rate (GFR), serum creatinine, and cystatin C were measured. Hypokalemia was defined as <3.5 mmol/L, normokalemia at 4-4.4 mmol/L, and hyperkalemia at a concentration equal to or greater than 5.0 mmol/L. CKD was determined by low GFR (<60ml/min per 1.73m2) and/or low urinary albumin excretion (UAE) (> 30mg/24h).
The researchers found mean plasma potassium levels of 4.4 mmol/L across the 5,130 participants. Hypokalemia had a low prevalence at 0.5% while hyperkalemia was slightly more common with a3.8% prevalence. Interestingly, participants with hypokalemia do not consume alcohol or smoke. They were also likely to be older, less educated and have high blood pressure as well as likely users of beta blockers and diuretics. In contrast, participants with hyperkalemia were likely to be male, to smoke, and to be White. They also have a higher UAE and non-usage of diuretics.
With regards to hypokalemia and risk of CKD, with a median follow-up of 10.3 years, researchers found that 753 participants eventually developed CKD. Participants with hypokalemia were about 5 times likely to develop CKD than those with normal potassium levels, and the risk further increased in participants who used diuretics. Participants with hyperkalemia, however, were not likely to develop CKD. Furthermore, the link between potassium levels with the risk of developing CKD changed when subjects used diuretics. In non-hypokalemic participants who used diuretics, researchers found an increased risk of CKD. Overall, the researchers concluded that hypokalemia was associated with a higher risk of CKD regardless of use of diuretics. The precise mechanism as to how hypokalemia induces kidney damage remains unclear. The current study could not yet be generalized to a broader population due to a lack of diversity in the participants. It remains to be seen whether a similar association between hypokalemia and CKD would be observed for other patients from other racial ethnicities.
Dietary reference values: advice on potassium
EFSA has set dietary reference values for potassium as part of its review of scientific advice on nutrient intakes. Potassium is an essential mineral in the human diet and plays an important role in many physiological processes in the human body including the distribution of body fluids, nerve impulse transmission and muscle contraction.
The Panel on Dietetic Products, Nutrition and Allergies (NDA) defines daily adequate intakes (AIs) for potassium as follows:
750mg for infants aged 7-11 months.
800mg for children aged 1-3 years.
1,100mg for children aged 4-6.
1,800mg for children aged 7-10.
2,700mg for children aged 11-14.
3,500mg for adolescents aged 15-17.
3,500mg for adults including pregnant women.
4,000mg for lactating women.
Low potassium intakes are associated with raised blood pressure and increased risk of stroke. The Panel considered data on these relationships when setting DRVs.
Food sources of potassium include starchy roots or tubers, vegetables and fruit, whole grains, dairy products and coffee.
EFSA received comments and input on the draft scientific opinion during a six-week public consultation in mid-2016.
Try to get your potassium from foods, not supplements
DEAR DOCTOR K: I have high blood pressure. Should I take a potassium supplement?
DEAR READER: This is a great question, but before I answer, let me take a step back to explain the connection between potassium and blood pressure.
Tens of thousands of years ago, our ancestors survived on wild animals and a variety of plant foods. This diet delivered plenty of potassium but scant sodium. Today, the average American diet contains about twice as much sodium as potassium, as a result of the high levels of salt in processed foods. This sodium-potassium imbalance is thought to be a major contributor to high blood pressure.
Now, back to your question. The short answer is no, you should not take potassium supplements unless your doctor prescribes them. People on blood pressure medications, in particular, need to be careful about potassium supplements.
Many blood pressure medications can lower your potassium level. Very low potassium can lead to dangerous heart rhythms. Many commonly prescribed diuretics lower potassium levels. If you are taking potassium-lowering diuretics, your doctor will check the level of potassium in your blood. If it is low, the doctor may prescribe potassium supplements.
But other types of diuretics, and other commonly prescribed blood pressure medicines, can raise potassium levels. Examples of such drugs are the diuretic called spironolactone, the drugs called ACE inhibitors, and drugs called angiotensin receptor blockers (ARBs). Common painkillers such as ibuprofen (Advil, Motrin) or naproxen (Aleve) can raise potassium levels. Abnormally high potassium levels also can cause dangerous heart rhythms.
If you are taking any medicines known to either raise or lower your potassium to dangerous levels, your doctor should periodically check your blood potassium level. Keeping that level in the correct range is important. This mineral also plays a key role in the function of nerves and muscles, including heart muscle.
Your kidneys help regulate potassium levels in your blood. They tend to keep your potassium level from going abnormally high or low. But age and medical conditions may impair kidney function. As a result, the kidneys are not as good at protecting you against abnormal potassium levels.
The FDA limits over-the-counter potassium supplements to less than 100 milligrams (mg). However, grocery stores carry salt substitutes that may contain much higher amounts of potassium. People trying to curb their sodium intake may use salt substitutes. That's a bad idea if you take a blood pressure medicine that tends to raise potassium levels.
Your best bet is to get your potassium from foods instead of pills. Many fruits and vegetables are rich in potassium. Spinach, sweet potatoes, cantaloupe, bananas and avocado are all good sources. Potassium-rich diets help control blood pressure and also lower your risk of stroke.
Another connection between potassium and high blood pressure is a rare condition of the adrenal glands that can cause both high blood pressure and very low blood potassium levels.
So if you have high blood pressure, ask your doctor what your potassium level is. If the doctor hasn't checked your potassium, gently suggest that it might be a good idea.
New Studies Show Shrinking P + K in Farmer Fields
More and more fields are lacking in P and K, according to recent testing by separate DuPont Pioneer and PotashCorp studies.
A new DuPont Pioneer study, comprised of more than 22,000 soil samples, suggests phosphorus (P) and potassium (K) levels are deficient in a “significant” number of fields tested. The research also confirmed that P and K deficiencies hurt both yields and grain quality, according to agronomy research manager Andy Heggenstaller.
“Growers often think first of nitrogen management when they consider soil fertility decisions because of its important influence on corn production,” he says. “However, deficiencies in P and K can inhibit yields over the long term in both corn and soybeans, limiting profit potential over time.
Testing over a 12-state geography, DuPont Pioneer found P and K deficiencies in a “significant amount” of tested fields. Heggenstaller notes that many states have modified their p and K fertility recommendations and encourages farmers to stay current on the higher nutrient requirements demanded by today’s more productive hybrids and varieties.
At PotashCorp, director of agronomy Robert Mullen says his company conducted a separate state-by-state nutrient balance analysis and also found major P and K deficits. In some states, including Iowa, Minnesota, Wisconsin, Michigan and Arkansas, more than half of the samples were “below critical level” for both P and K.
Mullen says farmers can conduct a simple five-step check of their fields to get the upper hand on potential nutrient deficiencies.
1. Visual assessment. “When in the field, nutrient deficient crops can often be identified by discoloration of the crop,” he says.
2. Soil testing. Mullen recommends collecting about 10 to 15 samples from both unaffected and affected soil areas to get an accurate representation of their field.
3. Conduct a plant tissue analysis. Like diagnostic soil testing, farmers should collect samples form unaffected and affected area, Mullen says. Collect twice in the season – once early season and once midseason, he suggests.
4. Analyze historical information. “If farmers know their fields have a proven history of micronutrient issues, they can skip to step four and be prepared to apply fertilizer to deal with that issue,” Mullen says. “During this step farmers should consider that there is a chance some of their crops won’t show any symptoms, but the fields will produce yields that are lower than predicted. This is an indication of hidden hunger, which can be fixed by paying close attention to the soil test results.”
5. Prescribe corrective course of action. Hopefully, steps 1 through 4 reveal the solution needed, Mullen says. Even if it doesn’t, consider taking an educated guess and apply strips within the field to see what takes care of the problem, he says.
“With nutrient balance levels declining nationwide, it’s important for farmers to be vigilant and identify deficiencies in their crops before it’s too late,” Mullen says. “After conducting this process, there is a chance not every problem will be solved, but these five steps will help get your yields back on the right track.”
The #1 Nutrient You Need To Avoid A Stroke
New studies show that this mineral can significantly help keep your health in check—especially for women.
Quick: What foods are rich in potassium? If you’re drawing a blank, you could be missing out on important protection from stroke, particularly ischemic stroke—the type caused by a blockage in a blood vessel supplying blood to the brain.
Women are more likely than men to have a stroke and to die from it. But a recent study of more than 90,000 women ages 50 to 70 from New York’s Albert Einstein College of Medicine found that those who consumed the highest amounts of potassium in their diet were least likely to experience a stroke. Potassium-rich diets reduced stroke risk in general by 12 percent and the risk of ischemic stroke by 16 percent.
The benefit was even greater among women who did not have hypertension, or high blood pressure. In this subset of women, high potassium levels lowered the risk for all types of strokes by 21 percent and by 27 percent for ischemic stroke, compared to women with hypertension.
Other research has linked high potassium levels to lower blood pressure, which helps prevent stroke. But the study showed that potassium itself reduces stroke risk. “We think the beneficial effects act through other pathways, beyond the effects on blood pressure,” says study author Sylvia Wassertheil-Smoller, Ph.D., an epidemiologist at Albert Einstein and a principal investigator with the Women’s Health Initiative.
Unfortunately, both women and men fall far short of the recommended levels for potassium, which is needed for many body functions including heart and muscle function. “In the study, the average potassium intake from foods was 2611 mg/day,” says Wassertheil-Smoller. “That’s well below the recommended amount of 4700 mg/day by the Department of Agriculture or even the lower recommended amount of 3600 mg/day by the World Health Organization.”
Dependence on fast and processed food appears to be the culprit. “Many people don’t get enough potassium because they rely on convenience and restaurant foods and aren’t eating enough fruits and vegetables, which are rich sources of potassium,” says Alissa Rumsey, R.D., a spokesperson for the Academy of Nutrition and Dietetics.
Yet, “potassium is pretty ubiquitous,” says Wassertheil-Smoller. “Foods rich in potassium are bananas, orange juice, yogurt, potatoes, unprocessed meats, and green, leafy vegetables like spinach.” Winter squash, sweet potatoes, white beans, halibut, broccoli, cantaloupe, pork tenderloin, lentils, milk, salmon, pistachios, raisins, chicken breast, and tuna boast especially plentiful potassium stores.
To boost your intake of this heart-healthy nutrient, Rumsey suggests aiming to consume at least five servings per day of fruits and vegetables and eat more fish and legumes. These measures can help you reach this goal:
Steam or roast a good supply of vegetables on Sunday, and use them for lunch and dinner during the week.
Keep fresh fruit around your home or office, and snack on it instead of processed snack foods like crackers or chips.
Aim to eat at least two to three servings of fatty fish per week.
Add beans or lentils to salads, soups, and stir-fries.
When dining out, order a salad, bean-based dishes, fish, fruit side dish, or steamed or roasted vegetables.
Drink low-fat milk instead of soda.