Why Potassium May Be the Most Overlooked Nutrient for Kidney Health

The Mineral Most Americans Are Missing

Despite being widely available in everyday foods, nutrition experts have flagged potassium as a nutrient of public health concern — because most Americans simply aren't getting enough of it, and evidence suggests the risks of some common chronic diseases may rise with inadequate intake. Yet for most people, potassium barely registers as a dietary priority. That oversight may come with real consequences, especially for the kidneys.

The recommended adequate intake is 3,400 milligrams per day for adult men and 2,600 mg for adult women, yet surveys suggest many Americans fall short. Part of the gap stems from people not eating enough fruits, vegetables, and especially legumes, according to Teresa Fung, adjunct professor of nutrition at Harvard's T.H. Chan School of Public Health. Compounding the problem, the modern American diet is heavily weighted toward ultra-processed foods, which are typically low in potassium and high in sodium — the exact opposite of what the body needs.

What Potassium Actually Does for Your Kidneys

Healthy kidneys keep the right amount of potassium in your body. But the relationship runs both ways. In the past decade, understanding of the mechanisms by which the kidneys sense dietary potassium imbalance has substantially advanced. Those mechanisms explain why low-potassium diets promote salt-sensitive hypertension, whereas potassium-rich diets enhance the body's ability to excrete sodium and lower blood pressure.

Emerging evidence suggests that low dietary potassium intake contributes to kidney injury, and low urinary potassium excretion is associated with accelerated chronic kidney disease progression. A large study tracking over 4,000 patients found that lower estimated potassium intake is associated with CKD progression — and researchers recommend adequate potassium intake, taking care not to cause serious adverse events. Put simply, not eating enough potassium may quietly accelerate kidney damage over time.

The Sodium Connection You Can't Ignore

Potassium, like sodium, is an essential electrolyte — a mineral that carries a tiny electrical charge. It helps relax blood vessel walls and signals the kidneys to excrete excess sodium, naturally lowering blood pressure and helping to reduce the risk of stroke and cardiovascular disease. This sodium-flushing effect is one of the most clinically significant things potassium does, and it's directly relevant to kidney health.

The two main causes of kidney disease worldwide are diabetes and high blood pressure. Low potassium intake is associated with high blood pressure, high glucose levels, and diabetes. High intake of potassium helps to lower blood pressure and is associated with decreased risk of cardiovascular mortality. Not eating enough potassium can therefore increase the risk of having high blood pressure and diabetes — both of which are linked to the development and progression of chronic kidney disease.

A More Nuanced Picture for Those Already Diagnosed

For many years, people with moderate to advanced chronic kidney disease have been advised to limit their intake of potassium — a mineral found in many foods such as fruit, vegetables, legumes, whole grains, and nuts — because of the risk of hyperkalemia, a condition in which potassium levels in the blood become dangerously high. In recent years, however, this view has been questioned, as new research suggests the link between potassium in food and high potassium levels in the blood may not be as clear as previously thought.

Today, many experts advocate a more individualized approach to potassium intake: instead of generally restricting potassium, the goal should be to maintain normal potassium levels in the blood while encouraging a healthy diet. Additional benefits of a more liberal potassium diet include slower CKD progression due to improved control of metabolic acidosis, reduced inflammation and fibrosis, improved gut health, reduced production of uremic toxins, and decreased risk of kidney stones. For healthy adults without kidney disease, however, the message from experts is clear: eat more potassium-rich whole foods — bananas, beans, leafy greens, potatoes, and dairy — and worry less about getting too much. The kidneys will thank you for it.