Our kidneys do a tremendous amount of work. Every day, they filter about 150 quarts of blood, cleaning it of waste, toxins and extra water. They regulate how much fluid is in the body and balance our electrolytes, ensuring that the rest of the body’s systems can do their job. Kidneys also produce proteins and hormones that help to manage blood pressure, make red blood cells and keep bones healthy.
Unfortunately, our kidneys don’t give us much warning when they’re not working as well as they should. More than 1 in 7 adults are estimated to have chronic kidney disease, which is a progressive decrease in kidney function. As many as 9 in 10 of them don’t know they have it.
“Early kidney disease has no signs or symptoms, so many people are walking around with no idea they have it,” says UNC Health nephrologist Emily Chang, MD. “One in 3 people with severe kidney disease don’t know they have it, so people may actually get down to about 10 percent of kidney function before showing symptoms, and when you’re at that stage, we’re starting to talk about dialysis, a process in which a machine filters your blood, or transplant.”
Fortunately, there are steps you can take to keep your kidneys healthy and to slow the progression of early disease. A bonus: These steps improve your wellness in other ways, too.
“The things that are good for the kidneys are also good for your general health,” Dr. Chang says.
1. Drink more water.
Kidneys need water to do their job. Water helps maintain good blood flow by keeping your vessels open, allowing blood to travel to the kidneys for filtering. Then your kidneys use water to remove waste from your body via urine. When you’re dehydrated, this whole process becomes harder and can eventually damage the kidneys.
That’s why it’s important to drink water every day. Dr. Chang says there’s no set amount of water every person should drink but that your body will give you signs if you’re not getting enough.
“Look at your urine,” she says. “If it’s dark, drink more. Try to listen to your body, and if you’re thirsty, drink water.”
Aim for urine that’s consistently clear or light yellow. Your hydration needs can change—you will need more water after intense exercise or during warmer weather, if you’re pregnant or breastfeeding, or on some medications, for example—which is why there’s no set amount that each person should drink per day. Still, if you don’t drink much water now, setting a goal can help you get started on this healthy habit.
“You don’t need a fancy bottle with those water measurements unless that helps you remember to drink,” Dr. Chang says. “Don’t count coffee or sodas, because much of that liquid is not absorbed in your body.”
As for alcohol, moderate drinking doesn’t directly affect the kidneys, but it does contribute to dehydration.
“If you drink alcohol, stay hydrated,” Dr. Chang says. “Alcohol is a diuretic—it makes you pee and dries you out, and that dehydration makes you feel bad the next day. Try to avoid recurrent episodes of dehydration.”
2. Reduce your salt intake.
A nutritious, well-balanced diet helps keep your body performing at its best, but if you’re struggling to know where to start with changing your eating habits, focus on salty foods.
“Americans eat too much salt,” Dr. Chang says. “It’s important to watch your salt intake. To start, try to avoid fast food—pretty much all fast food is too salty.”
Sodium, the mineral in salt, is one of the electrolytes that our kidneys work to balance, and when you have too much, everything has to work harder. Your blood vessels shrink, your heart has to pump harder to carry blood throughout the body and your kidneys may not be able to fully filter it, which can create fluid buildup.
According to current dietary recommendations, adults should limit sodium intake to less than 2,300 mg per day, or about 1 teaspoon of table salt, but most consume, on average, 3,400 mg in a day. This added salt tends to come from processed or prepared foods rather than salt from a shaker.
Avoiding ultraprocessed foods and cooking more at home, where you can control the amount of salt in your food, can help. If you need more specific guidelines, the DASH (Dietary Approaches to Stop Hypertension) diet focuses on reducing sodium consumption.
You may have heard that eating too much protein could hurt your kidneys. Dr. Chang says that most people do not need to limit protein intake for kidney health, with only minor exceptions for patients with advanced kidney disease.
3. Exercise regularly.
It’s good for your heart, it’s good for your lungs, it’s good for your brain … and yes, exercise is also great for your kidneys.
“It’s important to get regular exercise and stay active,” Dr. Chang says. “I encourage baby steps if this will be a big change. You don’t have to go all out. You can start by walking 10 to 30 minutes every day. Even with baby steps, some people see that things are very different for them a year later.”
4. Quit smoking.
It’s bad for your heart, it’s bad for your lungs, it’s bad for your brain … and yes, smoking is also really bad for your kidneys.
Smoking reduces the blood flow to your kidneys and force your kidneys to work much harder to filter waste. Smoking also increases your risk for several kinds of cancer, including kidney cancer.
5. See your primary care provider regularly.
If you’re struggling with any of the above steps, your primary care provider can help you set attainable goals and connect you with resources and supports.
They can test your kidney function and for the conditions that lead to kidney disease.
When your primary care provider orders blood work—typically, a basic or comprehensive metabolic panel—one of the tests will look at the amount of creatinine, a waste product created by the normal breakdown of tissue, in your blood.
“The test gives an estimated glomerular filtration rate, or eGFR, which shows how well the kidney is doing at filtering and clearing the blood,” Dr. Chang says.
A urine test that measures protein also can be an effective measure of how the kidneys are working, Dr. Chang says. This test is less commonly ordered, so you may need to ask your doctor for it, particularly if you have a family history of kidney disease or are diagnosed with a condition that’s a risk factor for chronic kidney disease.
“Diabetes is the number one cause of kidney disease, and high blood pressure is number two,” Dr. Chang says. “If you have diabetes, you need to have your kidneys monitored by your primary care provider every six to 12 months.”
Seeing your primary care provider regularly helps you get diagnosed and take action quickly before chronic diseases affect your kidneys. Like chronic kidney disease, hypertension, or high blood pressure, often has no symptoms.
6. Manage other conditions.
Keeping diabetes and high blood pressure well-controlled can go a long way to protecting your kidneys.
“Kidney disease is not a foregone conclusion with diabetes or high blood pressure,” Dr. Chang says. “But if either is not well-controlled, you are more likely to have problems.”
If you are working with your doctor to manage diabetes or blood pressure, ask how your medications will affect your kidney health. Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can affect kidney function, so if your risk for kidney disease has increased, you should discuss how often you use them with your provider.
Some medications that treat blood pressure or diabetes, including ACE inhibitors, diuretics and metformin, shouldn’t be taken when you’re sick because if you take them while dehydrated, they can impair kidney function.
“When you start a medication, you should know if it’s a ‘sick day med’ that you temporarily hold when needed,” Dr. Chang says. “It doesn’t mean it’s bad for the kidneys to use them, or that they should never be used again, but it’s good for the kidneys to stop them if there’s an acute problem.”
Staying aware of these risk factors and regularly measuring kidney function can help to find kidney disease early, when it’s most treatable.
“We have medications that can help to maintain function and avoid kidney failure. That’s what the doctor can do,” Dr. Chang says. “What the patient can do is make these lifestyle changes, which are very important.”
If you’re concerned about your kidney health, talk to your doctor. If you need a doctor, find one near you.