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Cystatin C is a protein filtered by the kidneys at a near-constant production rate. Most commonly, it is used as a marker of kidney health and function. It is also associated with cardiovascular function and systemic inflammation. (source, source, source)
Unlike creatinine, cystatin C production is independent of muscle mass, age, sex, and diet, making it a more accurate marker of glomerular filtration in athletes and individuals with high or low muscle mass. As a cysteine protease inhibitor produced by all nucleated cells, cystatin C reflects true filtration capacity without the confounders that make creatinine-based estimates unreliable in performance populations. Emerging research also links elevated cystatin C to cardiovascular mortality and systemic inflammation independent of kidney function, positioning it as a multi-system health indicator. (source, source, source)
Low levels of cystatin C are considered a marker of good health and kidney function. Low values indicate that the kidneys are efficiently filtering this protein from the blood, reflecting strong glomerular filtration capacity. (source, source, source)
There is no need for optimization, as low concentrations suggest optimal health. Maintain current nutrition, lifestyle, and nutrition activities.
High levels of cystatin C are generally considered to be a sign of suboptimal function. Primarily, this acts as an indicator of hindered kidney function, though this biomarker is also associated with compromised cardiovascular function and systemic inflammation. (source, source, source)
Potential Performance Impact:
Eat Mediterranean-style meals. Adherence to the Mediterranean diet has been shown to lower cystatin C by lowering systemic inflammation and cardiometabolic strain. The anti-inflammatory and antioxidant properties of this dietary pattern directly support kidney and cardiovascular health. (source, source)
Protocol: Consume a Mediterranean-style diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats.
Avoid smoking: Smoking has been shown to result in hyperfiltration, causing increased kidney strain resulting in higher serum cystatin C levels. The oxidative damage from smoking directly impairs glomerular endothelial function and accelerates renal decline. (source, source)
Protocol: If a smoker, take the steps to quit. If not, avoid areas where secondhand smoke is present.
Supplement with CoQ10: CoQ10 possesses anti-inflammatory and anti-oxidative characteristics, which have been shown to promote kidney and cardiovascular function, two systems that increase cystatin C levels when strained. By supporting these systems, CoQ10 can help reduce cystatin C. (source, source, source)
Protocol: Supplement with at least 100 mg of CoQ10.
