Staying well-hydrated, eating a balanced diet low in sodium, staying active, and avoiding unnecessary painkillers are the most impactful things you can do for your kidneys. Your kidneys filter about 50 gallons of blood every day, removing waste and balancing fluids, so the habits that keep them healthy overlap heavily with the habits that keep the rest of your body healthy. But a few specifics matter more than you might expect.
Water Is the Single Best Thing
Your kidneys need a steady supply of fluid to flush waste into urine. When you’re chronically underhydrated, waste products concentrate in the kidneys and can contribute to stone formation and long-term damage. The general target for healthy adults is 11.5 to 15.5 cups (2.7 to 3.7 liters) of total fluid per day, including what you get from food. That range covers most people, but you’ll need more if you exercise heavily, live in a hot or humid climate, or spend time at high altitude.
Plain water is ideal. If you’ve had kidney stones or urinary tract infections, increasing your fluid intake beyond the baseline is one of the simplest and most effective preventive steps. You don’t need to force massive quantities; consistent, moderate intake throughout the day is more useful than drinking a lot all at once.
Foods That Support Kidney Health
No single “superfood” will protect your kidneys on its own, but certain categories show up consistently in kidney-friendly dietary guidance. Berries, especially blueberries and strawberries, are rich in antioxidants and fiber while being low in calories. Fatty fish provides high-quality protein without the saturated fat load of red meat, plus it delivers minerals like zinc, magnesium, and potassium. Leafy greens pack vitamins, minerals, and antioxidants into very few calories.
The broader pattern matters more than individual ingredients. Diets built around fruits, vegetables, whole grains, lean protein, and healthy fats (think along the lines of a Mediterranean or DASH-style eating pattern) are consistently linked to better kidney outcomes. These diets naturally limit the processed foods, added sugars, and excess sodium that put kidneys under strain.
Keep Sodium Under Control
Sodium is one of the biggest dietary threats to kidney health because it raises blood pressure, and high blood pressure is a leading cause of kidney disease. The recommendation for people with existing kidney disease is no more than 2,000 milligrams of sodium per day. Even if your kidneys are currently healthy, staying near or below that threshold is a smart long-term strategy.
For context, a single fast-food meal can easily exceed 2,000 mg. Most excess sodium comes not from the salt shaker but from processed and restaurant foods: canned soups, deli meats, frozen meals, chips, and sauces. Reading nutrition labels and cooking more meals at home are the two most practical ways to bring your intake down. Seasoning with herbs, spices, citrus, and vinegar instead of salt makes the transition easier than you’d think.
Watch Your Protein Intake
Protein is essential, but your kidneys do the work of filtering out its waste products. For people with reduced kidney function, a common guideline is to limit protein to about 0.8 grams per kilogram of body weight per day. That works out to roughly 55 grams of protein daily for a 150-pound person.
If your kidneys are healthy, you have more flexibility, but consistently eating very high-protein diets (common with certain fitness regimens) does increase the filtering workload over time. You don’t need to count every gram, but if you’re regularly consuming protein shakes on top of meat-heavy meals, it’s worth being aware that your kidneys are handling the surplus.
Manage Blood Sugar and Blood Pressure
Diabetes and high blood pressure are the two most common causes of kidney disease. Persistently high blood sugar damages the tiny blood vessels inside the kidneys that do the actual filtering. Over years, this can quietly erode kidney function before you notice any symptoms. For people with diabetes, keeping blood sugar well-managed is one of the most protective things you can do for your kidneys.
High blood pressure works similarly, putting excess mechanical stress on those same delicate filtering structures. The combination of diabetes and high blood pressure is especially damaging. Maintaining a healthy weight, staying active, limiting sodium, and following any prescribed treatment plans all reduce this risk significantly.
Exercise Helps Your Kidneys Too
Regular physical activity supports kidney health indirectly by improving blood pressure, blood sugar control, and cardiovascular fitness. Some research has found that exercise training can modestly improve filtration rate, though the effect appears small (around 2 to 3 points on the standard kidney function scale). The bigger benefit is that exercise reduces the conditions that cause kidney disease in the first place.
You don’t need anything extreme. Consistent moderate activity, like brisk walking, cycling, or swimming for 30 minutes most days, delivers the cardiovascular benefits your kidneys depend on. The goal is regularity, not intensity.
Painkillers That Can Harm Your Kidneys
Over-the-counter anti-inflammatory painkillers like ibuprofen and naproxen (NSAIDs) reduce blood flow to the kidneys by blocking the chemical signals that help maintain it. Occasional use in a healthy person is generally fine, but chronic or frequent use raises the risk of acute kidney injury. The risk climbs sharply if you’re also taking blood pressure medications or diuretics, particularly within the first 30 days of combining them.
If you rely on NSAIDs regularly for pain management, that’s worth a conversation with your doctor. Acetaminophen (Tylenol) is generally considered safer for the kidneys, though it carries its own risks for the liver at high doses.
Supplements to Be Cautious About
Many people assume herbal supplements are safe because they’re “natural,” but several have documented kidney toxicity. St. John’s wort, creatine, chromium supplements, and high doses of vitamins A, C, and D have all been linked to kidney injury in case reports. Less common but particularly dangerous are products containing aristolochic acid, an ingredient found in some traditional herbal preparations that can cause severe and irreversible kidney damage.
Star fruit is worth a specific mention: it’s safe for most people but can be toxic to those with existing kidney disease. The general rule is to be skeptical of any supplement that promises kidney “detox” or “cleanse.” Your kidneys already are the cleanse. What they need is less toxic exposure, not more pills.
Know Your Numbers
Kidney disease is often called a “silent” condition because it rarely causes symptoms until significant damage has occurred. A simple blood test can estimate your glomerular filtration rate (eGFR), which measures how well your kidneys are filtering. Normal values decline naturally with age: the average is around 116 in your twenties, dropping to about 75 by age 70 and beyond. A result below 60 sustained over three months generally indicates chronic kidney disease.
If you have diabetes, high blood pressure, a family history of kidney disease, or you’re over 60, periodic kidney function testing gives you early warning when it’s still possible to slow or stop progression. A urine test checking for protein is another useful screening tool, since healthy kidneys keep protein in the blood rather than letting it spill into urine.