The Glomerular Filtration Rate, or GFR, is recognized as the best overall measure of kidney function. It represents how effectively the tiny filtering units within your kidneys, called glomeruli, are clearing waste products from your blood each minute. The estimated GFR (eGFR) is commonly calculated using a blood test that measures creatinine, a waste product from muscle activity, along with your age and sex.
When GFR declines, it indicates the kidneys are struggling to keep the blood clean, leading to a buildup of toxins. Whether this number can be raised is complex, depending on the cause and extent of the damage. While reversing advanced damage is often impossible, the primary goal is stabilization, which involves aggressive management to prevent further decline and preserve remaining function.
Interpreting Your GFR Score and Kidney Disease Stages
A healthy GFR for a young adult typically falls within the range of 90 to 120 milliliters per minute per 1.73 square meters. This rate naturally decreases with age, so a lower number in an older adult may not automatically signify disease. A GFR below 60 that lasts for three months or more, or any GFR accompanied by signs of kidney damage, confirms a diagnosis of Chronic Kidney Disease (CKD).
CKD is classified into five stages based on the GFR result, which guides treatment. Stage 1 is defined by a GFR of 90 or higher, but with evidence of damage like protein in the urine. Stage 2 represents a mild decrease, with a GFR between 60 and 89, also with existing kidney damage.
Stage 3 is divided into two sub-stages: 3a (GFR 45 to 59) and 3b (GFR 30 to 44), marking a moderate reduction in function. Stage 4 is characterized by a severely reduced GFR between 15 and 29, often when symptoms of waste buildup become noticeable. The final stage, Stage 5, is kidney failure, where the GFR drops below 15, requiring dialysis or a kidney transplant to survive.
Lifestyle Modifications to Support Kidney Function
Personal lifestyle adjustments are a powerful approach to stabilizing GFR and supporting kidney health. Dietary changes often focus on regulating nutrients that stress the filtering system. Reducing sodium is particularly important, as high intake contributes to elevated blood pressure, a major factor in kidney damage. Many people with CKD are advised to limit daily sodium intake to less than 2,000 milligrams, requiring attention to packaged and processed foods.
Limiting protein intake is another common recommendation, though this must be discussed with a healthcare provider or renal dietitian. While protein is necessary, an excessive amount increases the workload on the kidneys because they must filter out the waste products of protein metabolism. A shift toward more plant-based foods, which contain less creatine, can also be beneficial.
Maintaining appropriate hydration is necessary for the kidneys to effectively flush out toxins. However, for individuals with advanced CKD or those experiencing fluid retention and swelling (edema), excessive water intake can be harmful. Damaged kidneys may struggle to remove extra fluid, which can lead to complications, so fluid intake must be tailored by a medical professional.
Regular, moderate physical activity, such as brisk walking for at least 150 minutes per week, helps manage high blood pressure and diabetes. Exercise improves heart health and helps maintain a healthy weight, reducing the overall strain on the body’s systems. Weight management makes it easier for blood to circulate efficiently and for the kidneys to perform their filtering job.
Eliminating toxins is a necessary step for kidney protection. Smoking significantly decreases blood flow to the kidneys and heightens the risk of kidney failure. Excessive alcohol consumption can cause dehydration and force the kidneys to work harder, leading to long-term damage. Quitting smoking and limiting alcohol intake are immediate, effective actions to halt disease progression.
Medical Strategies for GFR Stabilization and Improvement
The most effective medical approach for managing a low GFR is aggressively treating the underlying causes of kidney damage, primarily high blood pressure (hypertension) and diabetes. Uncontrolled high blood pressure damages the tiny blood vessels within the glomeruli, accelerating the loss of filtering function. High blood sugar levels in diabetes similarly injure the kidney structures over time.
Renin-Angiotensin System (RAS) blockers, including Angiotensin-Converting Enzyme (ACE) inhibitors and Angiotensin Receptor Blockers (ARBs), are often prescribed for kidney protection. These drugs reduce pressure within the glomeruli and lower the amount of protein leaking into the urine, slowing the progression of kidney disease. They are recommended for people with CKD, especially those with diabetes or high levels of protein in their urine.
These medications may cause a small, temporary dip in GFR upon initiation, which is an expected functional effect. However, the long-term benefit of kidney preservation is substantial. ACE inhibitors and ARBs reduce the risk of kidney failure, even in patients with advanced CKD. Regular medical monitoring is essential when taking these medications.
Frequent blood and urine tests allow doctors to track GFR changes and manage potential side effects, such as elevated potassium levels (hyperkalemia) and anemia. Monitoring ensures that treatment plans, including medication dosages and dietary restrictions, are adjusted promptly to maintain stability and prevent progression toward kidney failure.