Keeping your kidneys healthy comes down to a handful of habits: staying hydrated, managing blood pressure and blood sugar, eating well, and avoiding substances that quietly damage kidney tissue over time. Most kidney disease develops slowly and without symptoms, so the earlier you build these habits, the better your long-term protection.
Stay Hydrated, but Don’t Overthink It
Your kidneys need adequate fluid to filter waste from your blood and move it out through urine. The average healthy adult needs roughly 11.5 to 15.5 cups (2.7 to 3.7 liters) of total fluid per day, and that includes water from food and other beverages, not just glasses of water. Most people who drink when they’re thirsty and have pale yellow urine are doing fine.
You’ll need more fluid if you exercise heavily, live in a hot or humid climate, or spend time at high altitude. All of these increase water loss through sweat and breathing. There’s no need to force enormous amounts of water, though. For people with healthy kidneys, drinking beyond thirst hasn’t been shown to offer extra protection.
Keep Your Blood Pressure in Check
High blood pressure is one of the leading causes of kidney disease. Your kidneys are packed with tiny blood vessels that filter your blood, and sustained high pressure damages those vessels over time. The general target is below 140/90 mmHg, though your doctor may recommend a lower number depending on your age and other health conditions.
Reducing sodium is one of the most effective dietary changes you can make for both blood pressure and kidney health. The recommended limit for people concerned about kidney function is 2,000 mg of sodium per day, which is less than a teaspoon of table salt. Most excess sodium comes from packaged and restaurant food rather than the salt shaker, so reading labels and cooking more at home makes a measurable difference. Regular physical activity, maintaining a healthy weight, and limiting alcohol also help keep blood pressure down without medication.
Manage Blood Sugar if You Have Diabetes
Diabetes is the other major driver of kidney disease. Persistently high blood sugar damages the small blood vessels in the kidneys the same way high blood pressure does, gradually reducing their ability to filter waste. If you have diabetes, keeping your blood sugar well controlled is one of the most important things you can do for your kidneys.
The target range for hemoglobin A1c (a measure of average blood sugar over roughly three months) varies from below 6.5% to below 8%, depending on how advanced your kidney disease is, what medications you take, and your risk of low blood sugar episodes. People with early-stage kidney changes and low risk of hypoglycemia generally aim for the tighter end of that range, while those with more advanced disease or other complications may have a higher target. Your doctor sets this number based on your individual situation.
Be Careful With Painkillers
Common over-the-counter painkillers like ibuprofen, naproxen, and high-dose aspirin (above 325 mg per day) belong to a class called NSAIDs. These drugs reduce blood flow to the kidneys, and using them frequently or at high doses can cause acute kidney injury or worsen existing kidney disease. The occasional dose for a headache is generally fine for people with healthy kidneys, but long-term or daily use is where the risk climbs.
If you need regular pain relief, the safest approach is to use the lowest effective dose for the shortest time possible. People whose kidney filtration rate is already below 60 (a marker of reduced function) should avoid NSAIDs altogether unless directed by a doctor. Acetaminophen is typically easier on the kidneys for routine pain, though it has its own limits for liver safety.
Watch Out for Supplements and Herbal Products
Many people assume that because something is “natural” or sold over the counter, it’s safe for the kidneys. That’s not always true. A number of herbal supplements have documented cases of kidney toxicity, including St. John’s wort, tribulus, thundergod vine, and wormwood. Dietary supplements like creatine, chromium, hydrazine, and even excessive doses of vitamins A, C, and D have also been linked to kidney injury in case reports.
Processed supplement blends can be particularly risky because their ingredient lists are long and not always transparent. If you take any supplements regularly, it’s worth checking whether they’ve been associated with kidney problems, especially if you already have reduced kidney function or other risk factors.
Quit Smoking
Smoking damages the lining of blood vessels throughout your body, causing them to stiffen and narrow. When this happens in the kidneys, they receive less blood, oxygen, and nutrients. On top of that, nicotine triggers stress hormones that raise blood pressure and heart rate, creating constant extra strain on the kidneys’ delicate filters. People who smoke have a higher risk of developing kidney disease and of progressing faster if they already have it.
Eat a Kidney-Friendly Diet
Beyond limiting sodium, a few other dietary habits protect kidney health. Protein is essential, but the amount matters. Research on a large nationally representative group found that very low protein intake (below 0.6 grams per kilogram of body weight per day) was actually associated with higher mortality in people with normal kidney function, while higher intakes up to and above 1.4 grams per kilogram showed no increased risk. In other words, healthy adults don’t need to restrict protein, but there’s no benefit to pushing extremely high amounts either.
If you already have some degree of kidney disease, two minerals become especially important to watch: phosphorus and potassium. Damaged kidneys have trouble clearing both from the blood, and elevated levels can cause problems ranging from bone weakening to dangerous heart rhythms.
- Phosphorus is found naturally in meat, dairy, and beans, but the bigger concern is phosphorus additives in processed foods. Look for words containing “PHOS” on ingredient labels, such as phosphoric acid or disodium phosphate. Your body absorbs more phosphorus from animal sources than from plant sources like beans and seeds.
- Potassium is abundant in many fruits, vegetables, and salt substitutes. If you need to limit it, drain the liquid from canned fruits and vegetables (it concentrates potassium), avoid salt substitutes that contain potassium chloride, and choose lower-potassium juices like apple or grape over orange juice.
For people with healthy kidneys, these mineral restrictions aren’t necessary. A balanced diet rich in fruits, vegetables, whole grains, and lean protein supports kidney function without requiring you to track individual nutrients.
Get Tested if You’re at Risk
Kidney disease rarely causes symptoms until it’s well advanced, which is why screening matters. The two key tests are a blood test measuring your estimated glomerular filtration rate (eGFR) and a urine test checking for albumin, a protein that leaks into urine when the kidneys’ filters are damaged. A GFR of 60 or higher is considered normal. Below 60 suggests kidney disease, and 15 or lower indicates kidney failure.
If you have diabetes, high blood pressure, heart disease, or a family history of kidney problems, guidelines recommend at least annual screening with both tests. If you don’t have any of these risk factors and feel healthy, routine kidney screening isn’t currently recommended for the general population. That said, these tests are simple and inexpensive, and many doctors include a basic kidney panel in standard bloodwork, so it’s easy to keep an eye on your numbers over time.