Declining eGFR value? 6 tips to support your kidney function also with creatine supplements.

A declining eGFR does not immediately mean kidney damage, but does require attention and possibly repeat measurements. With the right lifestyle, blood tests and counseling, you can often stabilize or improve your kidney function.

An eGFR (estimated glomerular filtration rate) value gives an estimate of how well your kidneys are working. A declining eGFR value can be quite scary, especially if you see it drop a bit every six months. But there is good news: there are several ways to support your kidneys, and it is important to look at the measurements in the right context.

Creatinine and eGFR: snapshots

The eGFR value is calculated based on the creatinine level in your blood. Creatinine is a waste product produced by muscle metabolism. The amount of creatinine in your blood is influenced by, among other things, your muscle mass, nutrition, fluid balance and the use of certain supplements or medications. Because of this, a creatinine measurement is always a snapshot in time. So a one-time abnormal eGFR does not immediately mean that your kidneys have permanently deteriorated.

If the eGFR is lower than expected and there are no obvious causes or symptoms, it is wise to repeat the measurement after a few weeks or months. If the value remains abnormal, discuss this with your doctor or nephrologist. Sometimes additional tests are needed to get more clarity.

What can you do yourself to support your kidney function?

1. Watch your protein intake
   Your kidneys filter waste products from protein-rich foods. Too much protein - especially of animal origin - can put extra strain on your kidneys. Choose vegetable proteins more often and consult with a (natural) dietician whether a protein-restricted diet is suitable for you.
2. Ensure healthy blood pressure
   High blood pressure is one of the biggest contributors to kidney problems. Have your blood pressure checked regularly. Target values are usually around 120/80 mmHg. Exercise, rest, and possibly medication can help.
3. Be careful with medications and supplements
   Do not use NSAIDs (such as ibuprofen or naproxen) without consulting a healthcare professional.
   Use herbal remedies, such as licorice or Ayurvedic herbs, with caution.
   Do you take supplements? Have them checked to ensure they’re safe for use with reduced kidney function, especially potassium or magnesium supplements. Book an e-consultation for advice on combining your medications and supplements. The order in which you take them may also be important. https://www.bloodtesting.nl/apotheker-email-consult.html
4. Drink plenty (but not excessively)
   Drinking too much is not always better. Usually 1.5 to 2 liters of fluid per day is enough, unless your doctor advises otherwise.
5. Have your blood and urine thoroughly checked
   Get a comprehensive blood test that includes:
   – Vitamin D, B12, folic acid
   – Ferritin and hemoglobin
   – Potassium, sodium, calcium, phosphate
   – Kidney function (creatinine, eGFR)
   – Urinalysis for protein loss (albumin-to-creatinine ratio)
6. Find out the cause
   Declining kidney function is not a diagnosis, but a signal. Causes may be high blood pressure, diabetes, autoimmune diseases, medications, hereditary predisposition or other health factors. It is important to discuss the possible underlying cause with your doctor or nephrologist.

It is important because blood and urine tests can give you a more complete picture of your kidney health as well as identify possible causes or consequences of a declining eGFR.

Vitamin D, B12 and folic acid

These vitamins play a role in cell metabolism, blood production and immune system. With impaired kidney function, you can develop deficiencies, especially of vitamin D, because kidneys are involved in conversion to the active form.

Ferritin and hemoglobin (Hb).

Declining kidney function can lead to anemia because the kidneys make less erythropoietin - a hormone needed for red blood cells. This is reflected in lowered Hb and/or ferritin levels.

Potassium, sodium, calcium, phosphate

The kidneys keep these minerals in balance. When kidney function declines, these values can become dysregulated - with risks such as cardiac arrhythmias (for potassium abnormalities) or osteoporosis (for calcium/phosphate dysregulation).

Creatinine and eGFR

These give an estimate of your kidney filtration. It is important to monitor whether these values remain stable, worsen or improve.

Urinalysis for protein loss (albumin/creatinine ratio)

Protein in the urine is an early sign of kidney damage, sometimes even before the eGFR drops. An elevated ACR (albumin/creatinine ratio) indicates leakage in the renal filters, which can predict further deterioration.

These blood and urine tests help you assess not only kidney function itself, but also its consequences, causes, and risks.

For example, combine the tests into a single screening:

insidetracker-ultimate and Urine Test Screening

For athletes: creatine supplements can skew your results

Do you use creatine supplements as an athlete or bodybuilder? Then it's good to know that this can artificially increase your creatinine levels. Creatine is partially converted into creatinine in the body, and that is exactly the substance on which the eGFR calculation is based.

Increased creatinine levels from supplement use does not automatically mean that your kidneys are functioning worse, but it can lead to a biased low eGFR value. This can cause unnecessary concern or even lead doctors or therapists to wrong conclusions.

A better option for athletes who use creatine is to measure kidney function using the protein cystatin C. This value is not affected by muscle mass or supplement use and provides a more reliable picture of kidney function. You can easily request this test at: Cystatin C Kidney Function

An eGFR measurement is a valuable tool, but should always be interpreted in the proper context. Repeat an abnormal result after several weeks if there is no obvious cause, and discuss the results with your doctor. With the right lifestyle, proper monitoring and medical guidance where necessary, you can do a lot to keep your kidneys healthy.

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