Can You Really Lower Your Creatinine? Myth-Busting Facts

In today’s video, I’ll address one of the most frequently asked questions: "How can I reduce my creatinine levels?" While this video might not provide a direct answer to that question, it aims to offer a scientific demonstration and explanation that could help you understand whether you need to reduce your creatinine levels and, if so, how it might be done.

Understanding Creatinine and Kidney Function

Before diving into the methods of reducing creatinine, it’s essential to understand the basics of how our kidneys function. On average, the human heart pumps approximately 5 liters of blood throughout the body every minute. Of this, about one-fifth (roughly 1250 milliliters) passes through the kidneys. The kidneys' primary function is to filter this blood, removing waste products and returning the purified blood back to the body.

One critical aspect of kidney function is the Glomerular Filtration Rate (GFR). This is a measure of how well your kidneys are filtering blood. To understand GFR, it's important to know that blood consists of two main components: plasma (the liquid part) and cells. Plasma makes up about 55% of the total blood volume. So, if 1250 milliliters of blood pass through the kidneys each minute, around 700 milliliters of this is plasma, which is what the kidneys filter.

However, the kidneys do not filter the entire plasma in one go. In fact, they filter only about 20% of the plasma in each pass. Therefore, out of the 700 milliliters of plasma, only approximately 140 milliliters is filtered by the kidneys each minute. This filtration rate, when averaged out, comes to about 125 milliliters per minute for a healthy adult—this is the GFR.

To put it simply, the GFR is a measure of how efficiently your kidneys are cleaning your blood. For an average person with healthy kidneys, this rate is about 125 milliliters per minute, meaning that both kidneys combined filter roughly 125 milliliters of blood every minute.

Measuring GFR: The Role of Creatinine

Traditionally, the GFR was measured using a technique involving nuclear isotopes, where a specific isotope is injected into the patient, and its clearance is measured in the blood and urine. This method, while accurate, is not practical for everyday use due to its cost and complexity.

Scientists, therefore, sought a more practical molecule that could serve as a reliable indicator of kidney function without the need for invasive procedures. This is where creatinine comes into play. Creatinine is a waste product produced by muscle metabolism, and it is filtered out of the blood by the kidneys. By measuring the levels of creatinine in the blood, scientists realized they could estimate GFR, giving rise to what is now known as the estimated GFR (eGFR).

The eGFR is derived from creatinine levels and provides a close approximation to the GFR obtained from the nuclear isotope method. Because creatinine is a natural byproduct of muscle metabolism and does not require any external substance to be introduced into the body, it became a standard laboratory test worldwide. This test is now one of the most common, second only to hemoglobin testing.

When Should Creatinine Be Reduced?

Now, let’s address the critical question: Should you be concerned about reducing your creatinine levels? Scientifically, modern medicine suggests that when the kidneys are damaged or begin to lose their filtering capability—resulting in fewer functional nephrons (the filtering units within the kidneys)—the creatinine levels in the blood start to rise.

Each human kidney contains about one million nephrons, and collectively, the two kidneys filter blood effectively. However, if the number of nephrons decreases significantly—such as in cases of chronic kidney disease (CKD)—the remaining nephrons cannot filter blood as efficiently. For example, if one kidney is lost (as in kidney donors), the remaining kidney, with its one million nephrons, can often still maintain normal blood creatinine levels. However, as the number of functioning nephrons decreases further, creatinine levels will begin to rise, signaling declining kidney function.

Understanding Kidney Fibrosis and its Impact

The loss of kidney function is often due to a condition known as fibrosis. Fibrosis refers to the formation of excess fibrous connective tissue, which can occur in various parts of the kidney. It can happen in the interstitial tissue that holds the nephrons together, in the glomeruli (the filtering units), or around the kidney tubules. This scarring process reduces the kidney's ability to filter blood effectively.

Unfortunately, once fibrosis occurs, it is irreversible—much like a scar on your skin that cannot return to its original state. This is why advanced countries are investing in research to find ways to prevent chronic kidney disease or slow its progression rather than relying solely on treatment after kidney failure has occurred.

Creatinine: Not a Perfect Indicator

While creatinine is widely used, it is not without its flaws. There are critics who argue that it may not always provide an accurate measure of kidney function, especially in certain populations. Alternatives like Cystatin C are sometimes recommended, but creatinine remains the most accessible and cost-effective option for most people.

Conclusion: Managing Creatinine Levels

In summary, while lowering creatinine might be the focus for many, the real concern should be addressing the underlying kidney function. If your kidneys are healthy, your creatinine levels should naturally stay within the normal range. However, if you’re experiencing high creatinine levels due to decreased kidney function, it's crucial to address the root cause, which may involve managing chronic kidney disease, slowing its progression, or, in some cases, exploring treatment options like dialysis or kidney transplantation.

By understanding the science behind creatinine and kidney function, you can better manage your health and take the necessary steps to maintain kidney function over the long term.