Your kidneys filter about half a cup of blood every minute, removing waste and excess fluid while keeping the minerals your body needs in balance. Taking care of them comes down to a handful of consistent habits: staying hydrated, managing blood pressure and blood sugar, eating well, and avoiding substances that force your kidneys to work harder than they should. Most of these habits overlap with general health advice, but the specifics matter.
What Your Kidneys Actually Do
Each kidney contains roughly a million tiny filtering units called nephrons. In a single day, your kidneys process about 150 quarts of blood. Nearly all of the water and useful nutrients get reabsorbed back into your bloodstream. Only 1 to 2 quarts leave your body as urine.
Beyond filtering waste, your kidneys produce hormones that control blood pressure, signal your body to make red blood cells, and help keep your bones strong. They also regulate sodium, potassium, calcium, and phosphorus levels in your blood and clear excess acid produced by your cells. When kidney function declines, all of these processes suffer, often without noticeable symptoms until significant damage has occurred.
Stay Hydrated, but Don’t Overthink It
Water helps your kidneys flush waste and prevents the mineral buildup that leads to kidney stones. If you’ve had a kidney stone before, aim for at least 2 liters (about 8 cups) of water daily, and ideally 3 liters (12 cups). If you haven’t, a general target of 8 cups works for most people, though you’ll need more if you’re sweating heavily from heat or exercise.
Your urine color is a reliable gauge. Pale yellow means you’re well hydrated. Dark yellow or amber means you need more water. You don’t need to drink gallons. Overhydrating is rarely a concern for healthy adults, but forcing excessive amounts of water offers no extra kidney benefit.
Keep Blood Pressure in Check
High blood pressure is one of the two leading causes of kidney disease. It damages the small blood vessels that supply your nephrons, gradually reducing their ability to filter blood. The CDC recommends keeping blood pressure below 140/90 mm Hg, though your doctor may set a lower target depending on your individual risk.
The connection runs both directions: damaged kidneys can raise blood pressure further, creating a cycle that accelerates decline. Reducing sodium intake is one of the most direct ways to lower blood pressure. The National Kidney Foundation recommends no more than 2,300 mg of sodium per day for general health. If you already have high blood pressure or kidney disease, 1,500 mg is a better target. Most excess sodium doesn’t come from your salt shaker. It hides in processed foods, canned goods, restaurant meals, and even poultry that’s been soaked in brine to retain moisture. Reading nutrition labels and cooking at home more often makes a noticeable difference.
Manage Blood Sugar if You Have Diabetes
Diabetes is the other leading cause of kidney disease. Persistently high blood sugar damages the delicate filtering structures inside your kidneys over time. If you have diabetes, keeping your blood sugar within a target range is one of the most protective things you can do for your kidneys.
The international kidney disease guidelines (KDIGO) recommend an individualized HbA1c target between 6.5% and 8.0% for people with diabetes, depending on factors like age and how advanced the disease is. If you use a continuous glucose monitor, keeping your blood sugar between 70 and 180 mg/dL for most of the day is another way to track how well you’re doing. Work with your care team to find the range that fits your situation.
Watch Your Protein and Phosphorus Intake
High-protein diets force your kidneys to filter more blood. Research shows that high protein intake increases the filtration rate, blood flow through the kidneys, and overall kidney workload. In animal studies, high-protein diets increased filtration rates by roughly 34% compared to low-protein diets. For people with healthy kidneys, this extra work is manageable in the short term, but sustained high-protein eating over years may raise the long-term risk of kidney damage.
You don’t need to avoid protein. You need a reasonable amount. For most adults, 0.8 grams of protein per kilogram of body weight per day is sufficient. If you’re very active or building muscle, slightly more is fine, but the extreme protein loads common in some fitness diets (well above 2 grams per kilogram) push your kidneys harder than necessary.
Phosphorus is another nutrient worth watching. Your kidneys are responsible for clearing excess phosphorus from your blood, and when they can’t keep up, it pulls calcium from your bones and damages blood vessels. Natural phosphorus from plant foods is absorbed at lower rates and is less of a concern. Phosphorus from animal products is absorbed more readily. But the real problem is inorganic phosphorus, the kind added to processed foods, fast food, bottled drinks, and enhanced meats as a preservative. Your body absorbs essentially 100% of these additives, making them far more taxing on your kidneys than the phosphorus found naturally in whole foods.
Be Careful With Pain Relievers
Over-the-counter anti-inflammatory drugs like ibuprofen and naproxen can harm your kidneys, especially with frequent use. These medications block the production of compounds that help keep blood flowing to your kidneys. Without those protective compounds, blood vessels in the kidneys constrict, reducing filtration and oxygen delivery. Occasional use for a headache or sore muscle is generally fine for people with healthy kidneys, but regular or long-term use creates real risk.
If you rely on these painkillers for chronic pain, talk to your provider about alternatives. Acetaminophen (Tylenol) is easier on the kidneys, though it carries its own risks for the liver at high doses. The key point: don’t treat ibuprofen as harmless just because it’s available without a prescription.
Stop Smoking
Smoking damages the lining of blood vessels throughout your body, and your kidneys are especially vulnerable. The chemicals in tobacco stiffen and narrow renal blood vessels, reducing the blood, oxygen, and nutrients your kidneys receive. Over time, this limits how well they can filter waste. Smoking also raises blood pressure independently, compounding the damage.
Quitting at any stage slows the progression of kidney damage. Even cutting back helps, though complete cessation is the goal.
Get Screened if You’re at Risk
Kidney disease is often called a “silent” condition because symptoms like fatigue, swelling, or changes in urination don’t typically appear until function has dropped significantly. Two simple tests catch problems early. A blood test estimates how well your kidneys are filtering (your eGFR score), and a urine test measures whether protein is leaking into your urine. A urine albumin level above 30 mg/g signals kidney damage, even if you feel perfectly fine.
You’re at higher risk if you have diabetes, high blood pressure, heart disease, obesity, or a family history of kidney failure. If any of those apply, regular screening (typically once a year) gives you the best chance of catching problems when they’re still manageable. Early-stage kidney disease responds well to the same lifestyle changes described above: controlling blood pressure, managing blood sugar, reducing sodium, and staying active.