title: [6S]-5-Methyltetrahydrofolate enhances folate status in rats fed growing-up milk.
abstract: OBJECTIVE
  To investigate the efficiency of [6S]-5-methyltetrahydrofolate or Metafolin ([6S]-5-CH(3)-H(4)folate) on the recovery of folate status, we conducted a depletion-repletion rat model study using a growing-up milk as the folate carrier.
  
  
  METHODS
  The effect of [6S]-5-CH(3)-H(4)folate was compared to that of folic acid (PGA or Pte-Glu), by feeding two groups of folate-depleted rats a diet of fortified growing-up milk containing either 1,000 microg/l (2.2655 micromol/l) of Pte-Glu or 1,041.91 microg/l (2.2655 micromol/l) of [6S]-5-CH(3)-H(4)folate over a 4-week period. At the end of the study, the folate concentration in plasma, erythrocytes and liver was measured to establish the folate status of the animals. The folate content was determined in the plasma and erythrocytes by a time-resolved fluoroimmunoassay method and in the liver by a HPLC method.
  
  
  RESULTS
  Plasma, erythrocyte and liver folate concentrations were significantly (P < 0.001) lower after a depletion period in rats fed the folate-deficient diet compared to rats fed a control diet. The folate form used significantly influenced the folate concentration in erythrocytes and liver, but not in plasma, after the rats' body folate reserves were replenished by consuming the fortified growing-up milk. Thus, rats fed [6S]-5-CH(3)-H(4)folate-fortified growing-up milk showed significantly higher folate content in erythrocytes and liver (1,100.37 ng/ml and 4.22 microg/g, respectively), than did those fed Pte-Glu-fortified growing-up milk (827.71 ng/ml and 3.04 microg/g, respectively, in erythrocytes and liver).
  
  
  CONCLUSIONS
  We conclude that the natural diastereomer [6S]-5-CH(3)-H(4)folate may adequately serve as an alternative to folic acid for the folate fortification of infant foods.
authors.affiliation: Nutrición y Bromatología, Facultad de Veterinaria, Universidad de Murcia, Campus Universitario de Espinardo, Murcia, Spain. dario@um.es
authors.forename: Darío
authors.initials: D
authors.lastname: Pérez-Conesa
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Haro-Vicente
authors.forename: Fernando Romero
authors.initials: FR
authors.lastname: Braquehais
authors.forename: Gaspar
authors.initials: G
authors.lastname: Ros
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D004032:Diet; D004912:Erythrocytes / Q000737:chemistry; D005492:Folic Acid / Q000032:analysis* / Q000097:blood; D005494:Folic Acid Deficiency / Q000097:blood / Q000517:prevention & control; D041943:Infant Formula / Q000008:administration & dosage; D057230:Limit of Detection; D008099:Liver / Q000737:chemistry; D008297:Male; D009752:Nutritional Status; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013237:Stereoisomerism; D013763:Tetrahydrofolates / Q000008:administration & dosage*
chemical_list: D013763:Tetrahydrofolates; D005492:Folic Acid; C005984:5-methyltetrahydrofolate