Lithium naturally only occurs in traces in biological systems and has no known biological role, but does have effects on the body when ingested.
lˈɪθiəm nˈætʃɚɹəli ˈoʊnli əkˈɜːz ɪn tɹˈeɪsᵻz ɪn bˌaɪəlˈɑːdʒɪkəl sˈɪstəmz ænd hɐz nˈoʊ nˈoʊn bˌaɪəlˈɑːdʒɪkəl ɹˈoʊl, bˌʌt dˈʌz hæv ɪfˈɛkts ɔnðə bˈɑːdi wɛn ɪndʒˈɛstᵻd.