13C natural abundance in serum retinol acts as a biomarker for increases in dietary provitamin A

Julie A. Howe, Ashley R. Valentine, Angela K. Hull, Sherry A. Tanumihardjo

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


The natural isotopic composition of 13C and 12C in tissues is largely determined by the diet. Sources of provitamin A carotenoids (e.g., vegetables) typically have a lower 13Cto 12C ratio ( 13C: 12C) than preformed vitamin A sources (i.e., dairy and meat) from corn-fed animals, which are prevalent in the US. The 13C: 12C of serum retinol ( 13C: 12C-retinol) was evaluated as a biomarker for vegetable intake in a 3-mo dietary intervention designedtopromoteweight-loss by increased vegetable consumption or reduced calorie and fat intake. Subjects were 21-50 y of age with a BMI between 30-40 kg/m 2 and were enrolled from one geographic area in the US. The high vegetable group (n = 20) was encouraged to increase daily vegetable and fruit consumption to 0.95 liter vegetables and 0.24-0.35 liter fruits. The caloric reduction group (n = 17) was encouraged to lower caloric intake by 500 kcal and consume ≤25% kcal from fat daily. Provided meals supplied 75-100% vegetable and fruit goals and 50-67% kcal and fat g per day. Carotenoid supplementation was discontinued by subjects during the study. Serum retinol and provitamin A carotenoid concentrations; intake of preformed vitamin A, provitamin A, and fat; and body weight, fat mass, and lean mass were analyzed for correlations to 13C: 12C-retinol. 13C: 12C-Retinol decreased in the vegetable group after intervention (P = 0.050) and the correlation with provitamin A intake was approaching significance (P = 0.079). 13C: 12C-Retinol did not change in the caloric reduction group (P = 0.43). 13C: 12C-Retinol changes with the vitamin A source in the diet and can be used as a biomarker for increases in dietary provitamin A vegetable intake.

Original languageEnglish (US)
Pages (from-to)140-147
Number of pages8
JournalExperimental Biology and Medicine
Issue number2
StatePublished - Feb 2009
Externally publishedYes


  • C
  • Isotope
  • Natural abundance
  • Vegetable intake
  • Vitamin A
  • β -S-carotene

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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