High dietary folate supplementation: effects on diet utilization and methionine metabolism in aged rats

J Nutr Health Aging. 2002;6(1):51-4.


Background: Folate supplementation or food fortification is being nowadays recommended because of its effect on the prevention of neural tube defects and the lowering of homocysteine levels. We have previously reported a negative effect of high dose folate supplementation on dietary metabolic protein utilization in pregnant and virgin rats.

Objectives: To determine the effects of such folate supplementation on nutritional and some biochemical markers in aged rats.

Design: Aged male Wistar rats were given free access either to a folate supplemented diet (40 mg/kg diet) or a control diet (1 mg/kg diet) for 29 days following a week adaptation period. Two critical periods were used for metabolic balance studies (experimental days 1 to 8 and 22 to 29), involving the determination of digestive and metabolic protein utilization. Several biochemical markers involved in the methylation cycle were also determined.

Results: Data show that long term high folate supplementation reduces nitrogen digestive function in aged rats (P<0,03) during the second metabolic period (days 22 to 29). However, supplementation did not alter metabolic protein utilization. Plasma homocysteine and serum vitamin B6 and B12 levels, hepatic S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) concentrations -and thus methylation ratio, SAM/SAH-, were neither affected by folate supplementation.

Conclusion: Folate supplementation at high doses may have a negative effect on diet utilization, related to protein status.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Analysis of Variance
  • Animals
  • Biomarkers / blood
  • Biomarkers / urine
  • DNA Methylation
  • Dietary Fats / metabolism
  • Dietary Proteins / blood
  • Dietary Proteins / urine
  • Dietary Supplements*
  • Folic Acid / administration & dosage*
  • Male
  • Methionine / metabolism*
  • Rats
  • Rats, Wistar


  • Biomarkers
  • Dietary Fats
  • Dietary Proteins
  • Folic Acid
  • Methionine