Metabolic profiling strategy for discovery of nutritional biomarkers: proline betaine as a marker of citrus consumption

• Published in: The American journal of clinical nutrition Vol. 92; no. 2; pp. 436 - 443
• Main Authors: Heinzmann, Silke S, Brown, Ian J, Chan, Queenie, Bictash, Magda, Dumas, Marc-Emmanuel, Kochhar, Sunil, Stamler, Jeremiah, Holmes, Elaine, Elliott, Paul, Nicholson, Jeremy K
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.08.2010; American Society for Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: Adult; adults; betaine; Biological and medical sciences; Biomarkers; Biomarkers - urine; Citrus; citrus fruits; Diet; dietary fiber; dietary protein; eating habits; Effects; Epidemiology; excretion; fat intake; Feeding. Feeding behavior; Female; food intake; Fruit; Fundamental and applied biological sciences. Psychology; Genotype & phenotype; human nutrition; Humans; INTERMAP; Intervention; kinetics; Magnetic Resonance Spectroscopy; Male; metabolomics; Middle Aged; Multivariate Analysis; NMR; Nuclear magnetic resonance; nutrient intake; Nutrition; Nutritional Status; phenotype; Plant Preparations - pharmacokinetics; potassium; proline; Proline - analogs & derivatives; Proline - urine; protein sources; sodium; urine; validity; vegetable protein; Vertebrates: anatomy and physiology, studies on body, several organs or systems; United Kingdom; United Kingdom > UK; Human; Nutrition; Betaine; Food intake; Biological marker; Proline; Strategy
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.2010.29672

BACKGROUND: New food biomarkers are needed to objectively evaluate the effect of diet on health and to check adherence to dietary recommendations and healthy eating patterns. OBJECTIVE: We developed a strategy for food biomarker discovery, which combined nutritional intervention with metabolic phenotyping and biomarker validation in a large-scale epidemiologic study. DESIGN: We administered a standardized diet to 8 individuals and established a putative urinary biomarker of fruit consumption by using ¹H nuclear magnetic resonance (NMR) spectroscopic profiling. The origin of the biomarker was confirmed by using targeted NMR spectroscopy of various fruit. Excretion kinetics of the biomarker were measured. The biomarker was validated by using urinary NMR spectra from UK participants of the INTERMAP (International Collaborative Study of Macronutrients, Micronutrients, and Blood Pressure) (n = 499) in which citrus consumption was ascertained from four 24-h dietary recalls per person. Finally, dietary patterns of citrus consumers (n = 787) and nonconsumers (n = 1211) were compared. RESULTS: We identified proline betaine as a putative biomarker of citrus consumption. High concentrations were observed only in citrus fruit. Most proline betaine was excreted [less-than or equal to]14 h after a first-order excretion profile. Biomarker validation in the epidemiologic data showed a sensitivity of 86.3% for elevated proline betaine excretion in participants who reported citrus consumption and a specificity of 90.6% (P < 0.0001). In comparison with noncitrus consumers, citrus consumers had lower intakes of fats, lower urinary sodium-potassium ratios, and higher intakes of vegetable protein, fiber, and most micronutrients. CONCLUSION: The biomarker identification and validation strategy has the potential to identify biomarkers for healthier eating patterns associated with a reduced risk of major chronic diseases. The trials were registered at clinicaltrials.gov as NCT01102049 and NCT01102062.