Normal kidney function, measured by eGFR, peaks in young adulthood and naturally declines with age, meaning a lower number is expected as you get older, but a healthy eGFR is generally above 90 mL/min/1.73m² for younger adults, with values dropping to around 75-85 for those 70+. While a drop below 60 may signal kidney disease, this decline with age is normal; doctors assess context like protein in urine (albuminuria) to distinguish normal aging from actual kidney damage.
In the general population, approximately 38% of adults aged 70 or older have an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2, with most having moderate reductions in eGFR in the 30-59 ml/min/1.73 m2 range (1).
A GFR of 60 or higher is in the normal range. A GFR below 60 may mean kidney disease. A GFR of 15 or lower may mean kidney failure.
Additional symptoms include high blood pressure, feeling nauseated, vomiting, chest pain and fluid retention. When it comes to lowering creatinine levels, there is no single solution. Because meat is a source of creatine, from which creatinine is derived, lowering the amount of meat in the diet is important.
When you reach stage 4, your condition has worsened to the point where you may need dialysis or a kidney transplant in the near future. In addition to the symptoms of stage 3, you may also experience: Nausea and/or vomiting.
To improve kidney function, focus on lifestyle changes like staying hydrated, eating a balanced diet low in salt and processed foods, exercising regularly, quitting smoking, limiting alcohol, managing blood pressure and blood sugar, and avoiding kidney-harming medications like NSAIDs. Consulting your doctor for regular checkups and tailored advice, especially for protein intake, is crucial, as early intervention with healthy habits can slow disease progression.
Symptoms can include:
The decline in kidney function could be considered a normal part of healthy ageing. The normal decline rate could be considered between −0.37 and −1.07 mL/min/year in healthy adults without hypertension.
Kidney checkup: two simple tests
CKD is evaluated using two simple tests – a blood test known as the estimated glomerular filtration rate (eGFR) and a urine test known as the urine albumin-creatinine ratio (uACR). Both tests are needed to have a clear picture of your kidney health.
If your kidney function drops below 15 percent of normal, you are said to have kidney failure. You may have symptoms from the buildup of waste products and extra water in your body. To replace your lost kidney function, you may have one of three treatment options: hemodialysis.
Drinking adequate water is crucial for overall kidney function by helping blood flow and toxin removal, but for most people with normal kidney function or even mild kidney disease, simply drinking more water won't significantly raise a chronically low GFR, and it could be harmful if you have advanced kidney disease; instead, focus on consistent hydration to prevent dehydration, as severe dehydration can damage kidneys, but excess fluids can overwhelm damaged kidneys, so consult a doctor for personalized advice.
Nausea and vomiting, muscle cramps, loss of appetite, swelling via feet and ankles, dry, itchy skin, shortness of breath, trouble sleeping, urinating either too much or too little. However, these are usually in the later stages, but they can also happen in other disorders.
Diabetes and high blood pressure are the top culprits damaging kidneys most, as they harm the delicate filtering blood vessels, leading to chronic kidney disease (CKD) and failure; other major factors include smoking, obesity, dehydration, poor diet (high sugar/salt/red meat), certain medications (NSAIDs), lack of sleep, and genetic conditions. These factors create a cycle where damaged kidneys worsen blood pressure, further damaging them.
You can check kidney function at home using at-home test kits for urine (detecting protein/albumin) or finger-prick blood tests (checking creatinine/eGFR), often with smartphone apps for analysis, or by monitoring symptoms like increased nighttime urination (nocturia), swelling, or changes in urine (blood, foam) and discussing results with a doctor, as home tests screen but don't replace professional diagnosis.
The best drink for kidney repair and overall health is plain water, as it helps flush toxins, but mineral water, unsweetened green tea, black coffee (in moderation), low-potassium juices (like unsweetened cranberry), and herbal teas (like ginger or mint) are also great for variety and added benefits, while sugary sodas, alcohol, and coconut water should generally be avoided. Always consult a doctor for personalized advice, especially with kidney disease.
Canned foods, some frozen foods, and most processed meats contain large amounts of salt. Snack foods such as chips and crackers are also high in salt. Table salt, some seasonings, ketchup, mustard, and certain sauces such as barbecue, soy, and teriyaki sauces are high in sodium.
Because diabetes and high blood pressure are the main causes of CKD, it's vital to keep both under control. Other ways to boost your kidney health are to: Avoid processed foods, which are high in salt. Eat plenty of fruits and veggies.
You feel kidney pain near the middle of your back, just under your ribcage, on each side of your spine where your kidneys are. Your kidneys are part of the urinary tract, the organs that make and remove urine from the body. (pee). You may feel kidney pain on one or both sides of your back.
Key Warning Signs That You May Need Dialysis Soon
Chronic kidney disease usually progresses slowly. Regular blood and urine tests can help doctors to decide whether the kidneys are still working well enough, whether the treatment needs to be adjusted, or whether dialysis will be needed soon, for example.