The former status of anthranilic acid as a vitamin stemmed from work carried out by a Japanese research group working in the 1930s. Led by Dr. W. Nakahara, the group successfully isolated two distinct factors that were believed to be essential for the lactation of female rats. Dubbing them “vitamin L,” the researchers proposed that the factors were essential to the metabolism of humans. Through additional studies, it was determined that the factor L(1), which was extracted from the liver of a bovine calf, was anthranilic acid, while the second factor, which was extracted from yeast, was demonstrated to be adenyl thiomethylpentose. Since this early work, however, research has shown that neither of these factors is necessary for the lactation of rodents or humans, nor have any proven symptoms of dietary deficiences of the biochemicals been found.