Serum iron levels are one of the key biomarkers used in assessing longevity and overall health. Maintaining optimal serum iron levels is crucial for various bodily functions such as oxygen transportation, DNA synthesis, and energy production. However, both low and high levels of serum iron can be detrimental to longevity. Low levels may indicate anemia or chronic diseases, while high levels can lead to oxidative stress and age-related conditions. Monitoring serum iron levels through regular blood tests is essential for individuals seeking to optimize their longevity. A balanced diet rich in iron, along with proper supplementation, can help maintain healthy serum iron levels and promote longevity.