ADH7 encodes class IV alcohol dehydrogenase, a NAD-dependent enzyme primarily expressed in the stomach rather than liver 1. The enzyme catalyzes oxidation of all-trans-retinol, alcohol, and omega-hydroxy fatty acids with highest efficiency in the oxidative direction 234. ADH7 is particularly efficient at retinol dehydrogenase activity, positioning it as a key participant in retinoic acid synthesis 5. The enzyme also reduces aldehydes and retinal in vitro and may eliminate cytotoxic aldehydes from lipid peroxidation 23. Gastric ADH7 contributes to first-pass ethanol metabolism, reducing blood alcohol by approximately 10% of consumed dose 6. Gene expression is regulated by AP-1 and C/EBP binding sites rather than typical TATA boxes, with potential modulation by retinoic acid and zinc 71. Located on chromosome 4-q24, ADH7 spans ~22 kb with nine exons 8. Evolutionary analyses show extensive sequence variation across mammalian species, particularly in frugivorous species, suggesting dietary influences on ADH7 evolution 9. However, ADH7 genetic polymorphisms show limited association with alcohol abuse risk in Polish populations 6.