Angiotensin-converting enzyme (ACE) insertion/deletion gene polymorphism across ethnicity: a narrative review of performance gene

Angiotensin-converting enzyme (ACE) gene has been reported to be one of the candidate genes for endurance performance. The ACE gene insertion/deletion (I/D) polymorphism (rs4646994) is responsible for the variation in the ACE plasma level. The insertion (I allele) of ACE I/D gene polymorphism decreases the level of ACE plasma, thus reducing skeletal muscle vasoconstriction. Skeletal muscle vasoconstriction increases oxygenated blood supply to working muscles for endurance performance. On the other hand, the D allele of ACE I/D gene polymorphism increases the level of ACE plasma, leading to skeletal muscle hypertrophy. Therefore, the D allele may be helpful for strength or power performance. However, evidence for the involvement of these alleles in improving endurance performance and muscle strength is inconsistent and warrants further studies. These inconsistencies may be attributed to the small sample size and the potential causes of the racial and ethnic differences used in the previous studies. Therefore, this brief review reported a summary of the current literature on the association of the ACE I/D gene polymorphism on human physical performance across populations. The findings of this review may serve as a reliable platform and guidance for future research to provide a better understanding of the potential role of this variant on human physical performance concerning ethnicity.