Helping your kidneys comes down to a handful of habits: staying hydrated, managing blood pressure and blood sugar, eating moderate amounts of sodium and protein, maintaining a healthy weight, and being cautious with certain medications and supplements. Most kidney damage builds gradually over years, so the earlier you adopt these habits, the more function you preserve.
Drink Enough Fluid to Keep Urine Dilute
Your kidneys filter about 50 gallons of blood every day, concentrating waste products into roughly 1 to 2 liters of urine. When you’re chronically under-hydrated, that waste becomes more concentrated, which raises the risk of kidney stones and forces the kidneys to work harder. Increasing fluid intake to 2.5 to 3 liters per day (about 10 to 12 cups) produces enough urine output to keep solute concentrations low. In clinical trials, people who maintained urine output above 2 liters per day reduced their risk of recurrent kidney stones by 45%.
Water is the best choice. Sugary drinks contribute to weight gain and metabolic problems that indirectly stress the kidneys. A simple way to gauge your hydration: your urine should be pale yellow, not dark or amber. If you exercise heavily, live in a hot climate, or take medications that cause fluid loss, you’ll need more.
Keep Sodium Under Control
Excess sodium raises blood pressure, and high blood pressure is one of the two leading causes of kidney disease. The small blood vessels inside your kidneys are especially vulnerable to pressure damage over time. The National Kidney Foundation recommends staying at or below 2,300 mg of sodium per day to maintain healthy blood pressure. If you already have high blood pressure or early kidney disease, 1,500 mg per day is a better target.
Most sodium in the average diet doesn’t come from a salt shaker. It’s hidden in processed foods, canned soups, deli meats, frozen meals, sauces, and restaurant food. Reading nutrition labels and cooking more meals at home are the two most effective ways to cut sodium without overhauling your entire diet. Swapping salt for herbs, citrus, garlic, and vinegar in cooking makes the transition easier.
Manage Blood Sugar If You Have Diabetes
Diabetes is the other leading cause of kidney failure. Persistently high blood sugar damages the tiny filtering units inside each kidney, gradually allowing protein to leak into the urine. Over years, this progresses to significant loss of kidney function. Guidelines from KDIGO, the international kidney disease organization, recommend keeping your A1C (a measure of average blood sugar over three months) somewhere between 6.5% and 8%, depending on your individual health profile. The key point is that tighter blood sugar control in the earlier stages of kidney involvement slows the progression considerably.
If you have diabetes, regular kidney screening matters. A simple urine test measures the albumin-to-creatinine ratio (ACR). A normal result is less than 30 mg/g. Anything above that threshold can signal early kidney damage, often before you notice any symptoms. Catching this early gives you the most room to intervene.
Be Careful With Pain Medications
Over-the-counter anti-inflammatory drugs like ibuprofen and naproxen can harm kidneys when used frequently or over long periods. These drugs work by blocking chemicals called prostaglandins throughout the body. In the kidneys specifically, prostaglandins help keep blood flowing to the filtering units by dilating a key incoming blood vessel. Block that signal, and blood flow to the kidney drops. In young, healthy people with no other risk factors, occasional use is generally fine. But the risk climbs significantly if you’re dehydrated, over 60, have high blood pressure, or already have reduced kidney function.
The effect is most pronounced after about 3 to 7 days of consistent use, when the drug reaches steady levels in your bloodstream. If you need regular pain relief, talk to your doctor about alternatives. Acetaminophen, for instance, doesn’t affect kidney blood flow in the same way, though it carries its own risks for the liver at high doses.
Watch Your Protein Intake
Protein is essential, but your kidneys are responsible for filtering out the nitrogen-containing waste products that protein metabolism generates. Eating far more protein than your body needs creates extra filtration work. For healthy adults, the baseline recommendation is 0.8 grams of protein per kilogram of body weight per day. For a 150-pound person, that works out to about 55 grams daily, roughly the amount in two chicken breasts.
This doesn’t mean protein is bad for your kidneys. It means that the extremely high-protein diets popular in some fitness circles (2 grams per kilogram or more) may put unnecessary strain on kidneys over time, especially if other risk factors are present. If your kidney function is already reduced, your doctor may recommend a lower protein target to slow further decline.
Maintain a Healthy Weight
Excess body weight forces your kidneys to filter more blood to meet the metabolic demands of a larger body. The problem is that you’re born with a fixed number of filtering units (nephrons), and that number doesn’t increase when you gain weight. Instead, each individual nephron has to work harder, filtering at a higher rate than it was designed for. This state, called hyperfiltration, can damage the filtering units over time and is recognized as an independent risk factor for kidney failure.
Even modest weight loss, in the range of 5% to 10% of body weight, can reduce blood pressure, improve blood sugar control, and lower the strain on each nephron. The kidney benefits compound because losing weight improves nearly every other risk factor on this list simultaneously.
Avoid Nephrotoxic Supplements
Certain herbal supplements can directly damage kidney tissue. The most well-documented example is aristolochic acid, found naturally in plants from the birthwort (Aristolochia) and some wild ginger (Asarum) families. These plants appear in herbal products marketed for arthritis, gout, and inflammation. Aristolochic acids don’t just cause kidney damage; they’ve been linked to cancers of the upper urinary tract and bladder. The FDA has not approved any products containing these compounds, but they still circulate as dietary supplements and “traditional medicines.”
Other supplements to be cautious with include high-dose vitamin C (which can increase oxalate and raise kidney stone risk), creatine in excessive amounts, and any herbal product with unclear ingredient sourcing. Because supplements aren’t regulated the way prescription drugs are, contamination and mislabeling are common. If you take supplements regularly, let your doctor know so they can factor that into any kidney-related lab work.
Know Your Numbers
Kidney disease is often called a “silent” condition because it rarely produces noticeable symptoms until significant damage has occurred. Two routine tests can catch problems early. The first is estimated glomerular filtration rate (eGFR), which measures how efficiently your kidneys filter blood. In adults, a normal eGFR is above 90, but it declines naturally with age:
- Ages 20 to 29: average eGFR of 116
- Ages 30 to 39: average eGFR of 107
- Ages 40 to 49: average eGFR of 99
- Ages 50 to 59: average eGFR of 93
- Ages 60 to 69: average eGFR of 85
- Ages 70 and older: average eGFR of 75
The second test is the urine albumin-to-creatinine ratio (ACR), which detects protein leaking into your urine. A normal result is below 30 mg/g. Values above that suggest your kidney’s filtering barriers are damaged, even if your eGFR still looks normal. Together, these two tests give a much clearer picture than either one alone. If you have diabetes, high blood pressure, a family history of kidney disease, or you’re over 60, periodic screening is especially valuable.