title: Plasma biomarker of dietary phytosterol intake.
abstract: BACKGROUND
  Dietary phytosterols, plant sterols structurally similar to cholesterol, reduce intestinal cholesterol absorption and have many other potentially beneficial biological effects in humans. Due to limited information on phytosterol levels in foods, however, it is difficult to quantify habitual dietary phytosterol intake (DPI). Therefore, we sought to identify a plasma biomarker of DPI.
  
  
  RESULTS
  Data were analyzed from two feeding studies with a total of 38 subjects during 94 dietary periods. DPI was carefully controlled at low, intermediate, and high levels. Plasma levels of phytosterols and cholesterol metabolites were assessed at the end of each diet period. Based on simple ordinary least squares regression analysis, the best biomarker for DPI was the ratio of plasma campesterol to the endogenous cholesterol metabolite 5-α-cholestanol (R2 = 0.785, P < 0.0001). Plasma campesterol and 5-α-cholestanol levels varied greatly among subjects at the same DPI level, but were positively correlated at each DPI level in both studies (r > 0.600; P < 0.01).
  
  
  CONCLUSIONS
  The ratio of plasma campesterol to the coordinately regulated endogenous cholesterol metabolite 5-α-cholestanol is a biomarker of dietary phytosterol intake. Conversely, plasma phytosterol levels alone are not ideal biomarkers of DPI because they are confounded by large inter-individual variation in absorption and turnover of non-cholesterol sterols. Further work is needed to assess the relation between non-cholesterol sterol metabolism and associated cholesterol transport in the genesis of coronary heart disease.
authors: Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Xiaobo
authors: X
authors: Lin
authors: Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America; Program in Physical Therapy, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Susan B
authors: SB
authors: Racette
authors: Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Lina
authors: L
authors: Ma
authors: Division of Biostatistics, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Michael
authors: M
authors: Wallendorf
authors: Lifestyle Intervention Research Core, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Catherine Anderson
authors: CA
authors: Spearie
authors: Division of Endocrinology, Metabolism & Lipid Research, Department of Medicine, Institute for Clinical and Translational Sciences, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO, 63110, United States of America.
authors: Richard E
authors: RE
authors: Ostlund
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D004083:Cholestanol / Q000097:blood; D002784:Cholesterol / Q000031:analogs & derivatives / Q000097:blood; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010840:Phytosterols / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010840:Phytosterols; C021273:campesterol; D004083:Cholestanol; D002784:Cholesterol