Read this article if you have ever attributed excess creatine use to poor kidney health.
Creatine:
Function: Creatine is a compound found primarily in muscle cells. It helps produce energy during high-intensity activities, such as weightlifting or sprinting, by replenishing adenosine triphosphate (ATP), the energy currency of the cell.
Source: The body produces creatine naturally from amino acids (arginine, glycine, and methionine), and it can also be obtained through food, especially from meat and fish, or via supplementation.
Usage in fitness: Many athletes and gym-goers take creatine supplements to improve performance, increase muscle mass, and enhance recovery.
Supplement form: Creatine monohydrate is the most common and researched supplement form.
Creatinine:
Function: Creatinine is a waste product formed when creatine breaks down in the muscles after being used for energy. It is filtered out of the blood by the kidneys and excreted in urine.
Medical significance: High levels of creatinine in the blood can indicate impaired kidney function, as it suggests that the kidneys are not efficiently filtering waste. Blood and urine creatinine levels are commonly measured in health assessments, particularly for kidney health.
Creatine supplementation by athletes can sometimes be linked to elevated creatinine levels, which might affect eGFR (estimated Glomerular Filtration Rate) readings in routine lab work. This can be misleading, as it doesn't necessarily indicate poor kidney function.
Here's why:
Creatinine and eGFR: Creatinine is a byproduct of muscle metabolism, and its levels are used in formulas to calculate eGFR, a measure of kidney function. If creatinine levels are high, it may artificially lower eGFR numbers, suggesting impaired kidney function when the kidneys might be functioning normally.
Creatine supplementation: When taking creatine supplements, your body has more creatine available, which naturally leads to higher creatinine levels due to increased creatine breakdown. This can show up in blood tests as higher-than-normal creatinine levels, which may trigger concerns about kidney function based on eGFR readings.
False indication of kidney issues: In some cases, elevated creatinine from creatine use doesn't reflect actual kidney damage, but rather the increased turnover of creatine into creatinine. Many doctors now understand this and may look at other indicators of kidney health (e.g., urine protein levels or cystatin C) before concluding that there's a problem.
Creatine can cause a rise in creatinine levels, leading to potentially misleading eGFR results, but it doesn't necessarily mean there is a problem with kidney function. If there's concern about kidney health, additional tests beyond eGFR should be considered.
Comments