Vanillic acid excretion can be used to assess compliance with dietary supplements

  • Sayavongsa P
  • Cooper M
  • Jackson E
 et al. 
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Background & aims: Current self-report methods to monitor dietary intake are often unreliable. As part of a dietary intervention study, we investigated whether adding a common food flavor (vanillin) to test diets and measuring the major metabolic end product vanillic acid in urine, could provide assessment of compliance with dietary supplements. Methods: After baseline urine was collected 10 subjects (6 control and 4 study patients) consumed 1.3 g of vanillin in a liquid test meal as the last food at bedtime and collected the first morning urine. Next a kinetic excretion study was performed in which 6 controls consumed a vanillin spiked drink with continued urine sampling at 30-min intervals for 5 h. Vanillic acid concentrations were measured by reverse phase high-performance liquid chromatography. Results: The test diet was consumed just before bedtime; the first morning void vanillic acid concentration gave a reliable indication of compliance (3 males 0.224±0.041 and 3 females 0.290±0.099 mg/ml; mean±SD). Thirty-minute sampling of vanillic acid excretion for 6 controls was maximal 1 h after the test diet, returning to baseline after 4 h. Conclusion: Vanillin is a useful, inexpensive and non-toxic biochemical marker for confirming compliance with experimental diets. © 2007 European Society for Clinical Nutrition and Metabolism.

Author-supplied keywords

  • Dietary intervention
  • Phenolic acid
  • Test diet
  • Urinary metabolite
  • Vanillin

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  • Phouyong Sayavongsa

  • Melanie L. Cooper

  • Elizabeth M. Jackson

  • Lillianne Harris

  • Thomas R. Ziegler

  • Jacqueline M. Hibbert

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