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Urine potassium is a valid biomarker for diet potassium and a surrogate measure of compliance to a high dairy intervention in teenage girls
Author(s) -
Rafferty Karen,
Lappe Joan
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.917.13
Subject(s) - potassium , urine , meal , medicine , zoology , urinary system , crossover study , urine sodium , chemistry , biology , organic chemistry , alternative medicine , pathology , placebo
Dietary intake records are used in nutrition intervention studies not only as a tool to assess reported intakes, but as a measure of compliance to a planned intervention. In this crossover study we assessed the validity of urinary potassium as a recovery biomarker and surrogate indicator of compliance to a dairy milk intervention. Ten healthy teenage girls 13–18 years old (mean 15.2) were assigned to consume a nutritionally adequate diet controlled for potassium and calcium, for four days. The study included one neutral control (water) and a test substance (milk and/or yogurt.). Each subject was studied twice and served as her own control. The control and test substances were consumed as part of pre‐selected meals for 2 consecutive 24‐hours periods one week apart. The control meal (with water) provided approximately 1500 mg potassium. The test meal (with dairy) provided approximately 3000 mg potassium. Consecutive 24‐hour urines were collected during the dietary tests. Previously we have shown correlations between diet potassium and urinary potassium in adult women studied under metabolic conditions, with a urineK:dietK ratio of 0.92. In the present study the mean 24‐hr. urine K was 1071 mg/d on the low potassium (control) diet, with a urineK:dietK ratio diet of 0.776. On the high potassium (dairy) diet the mean 24‐hr. urine K was 1742 and the urineK:dietK ratio was 0.664.