Cystatin C Levels as an Aging Biomarker
Understanding Kidney Function and Aging: A Deep Dive into Biomarkers
The Decline of Kidney Function with Age
Summarized from Michael Lustgartens Video
As we age, our bodies undergo various changes, and one of the critical areas affected is kidney function. Michael Lustgarten, in his video, elucidates this by examining the relationship between estimated Glomerular Filtration Rate (eGFR), a crucial biomarker of kidney function, and age. This decline in eGFR is observable in both men and women from the age of 18 to 95 years. But the measurement of eGFR, which heavily relies on creatinine levels in the blood, presents its own set of complexities.
Creatinine: Not a Foolproof Indicator
Creatinine, a waste product generated from muscle metabolism, is traditionally used to assess kidney function. However, its reliability as a biomarker decreases with age, especially after 40. This is primarily due to the significant variability in creatinine levels observed in older populations compared to younger ones. Moreover, since creatinine is proportional to muscle mass, which also tends to diminish with age, its effectiveness as a standalone indicator of kidney health comes into question.
Cystatin C: A More Reliable Biomarker?
Enter Cystatin C, a protein that offers a potentially more accurate measure of kidney function. This is particularly important in the context of aging, as Cystatin C levels exhibit an age-related increase. In the case of individuals without clinical risk factors, a clear upward trend in Cystatin C levels is noticeable from around 30 to 100 years of age.
The Link to All-Cause Mortality
Interestingly, the significance of Cystatin C extends beyond kidney function. Lustgarten highlights its association with all-cause mortality risk. In a study, individuals with lower initial levels of Cystatin C (around 0.7 milligrams per liter) showed remarkably higher survival probabilities over an 18-year period compared to those with higher levels. This positions Cystatin C as a robust predictor of biological age, even overshadowing traditional metabolic health markers like glucose or glycated hemoglobin (HbA1c) in its correlation with mortality risk.
Broader Implications and Biohacking Aging
Lustgarten's exploration of these biomarkers is part of a broader quest to understand and potentially 'biohack' aging. He expresses a keen interest in various aspects of health quantification, including epigenetic testing, oral microbiome composition, and at-home metabolomics. His approach underscores a growing trend in personal health management, where individuals take proactive steps to monitor and potentially influence their aging process through science-backed methods.
Conclusion: A Forward-Thinking Approach to Aging
Michael Lustgarten's insights into kidney function biomarkers shed light on the complexities of aging and the limitations of traditional health metrics. By bringing attention to more nuanced indicators like Cystatin C, he not only enhances our understanding of biological aging but also paves the way for more personalized and effective health interventions. His work exemplifies the intersection of scientific research and practical health optimization, offering a glimpse into the future of aging and health management.