Snell is widely recognized as one of the foremost nutritional biochemists of the 20th century. His early work developing microbiological assays for key nutrients has been credited with facilitating the discovery of at least half of known vitamins due to their ease of use compared to more traditional animal studies. A version of Snell's microbiological assay method based on the experimental organism
Lactobacillus casei (now known as
Lactobacillus rhamnosus) is still used as a method for detecting folates in blood. Snell's interest in isolating and characterizing unknown nutrients and growth factors also led to the serendipitous discovery of useful biochemical tools. While working to characterize the yeast growth factor that would become known as
biotin, Snell and coworkers discovered the egg white protein
avidin, which binds biotin with extremely high affinity. At the time avidin was noted as a cause of "egg white injury", a form of biotin deficiency in animals. The rarity and expense of obtaining biotin at the time limited further investigations, but the extremely high avidin-biotin binding affinity was later exploited and is now widely used in
molecular biology for purification and molecular detection applications. work he conducted at Texas with
Beverly Guirard, a long time associate in his lab. He and Soviet scientist
Alexander E. Braunstein have been cited as the "fathers of vitamin B6". Recalling his own work with pyridoxal, French biophysicist
Michel E. Goldberg described Snell as "the pope of pyridoxal catalysis". ==Awards and honors==