[1] Univ Buenos Aires, Sch Pharm & Biochem, Dept Phys, Stable Isotopes Lab Appl Biol & Med, RA-1113 Buenos Aires, DF, Argentina
[2] Children Hosp Super Sor Maria Ludovica, Gastroenterol Unit, Buenos Aires, DF, Argentina
[3] Univ Buenos Aires, Sch Med, Dept Nutr, RA-1113 Buenos Aires, DF, Argentina