Serum markers of bone turnover change in response to depletion and repletion of fruit and vegetable intake in adults: a 28‐wk single‐arm experimental feeding intervention

Abstract

Data from controlled intervention trials are lacking to support observational evidence suggesting a positive association between intake of fruit and vegetable (FV) and bone health. The objective of this study was to assess serum markers of bone turnover change in response to FV depletion and repletion. Twenty‐nine subjects participated in a 28‐wk single‐arm experimental feeding intervention trial and consumed low FV diets for 6 wks (depletion phases 1 and 3), a provided high FV diet based upon the Dietary Guidelines for Americans for 8 wks (6‐cup equivalents, phase 2), and usual diet for 8 wks (phase 4). At baseline, phases 1, 2, 3, and 4, intakes of total carotenoids, the most commonly used biomarker of FV intake, were 11.5 ± 1.2, 1.4 ± 0.2, 62.3 ± 0.9, 1.5 ± 0.4, and 9.0 ± 1.0 mg/d (mean ± SE), respectively, and the calculated dietary potential renal acid loads, a measure of the acid‐base load of foods, were 19.5 ± 4.6, −16.7 ± 5.3, 20.9 ± 2.8, 21.1 ± 2.8, and 14.2 ± 3.5 mEq/d, respectively. Compared to the baseline, depletion in FV intake (phase 1) resulted in an increase (p < 0.05) in serum C‐terminal telopeptide of type 1 collagen (CTX, 0.68 ± 0.05 vs 0.97 ± 0.08 ng/ml, respectively), a bone resorption marker, and a decrease in serum bone specific alkaline phosphatase (BALP, 10.7 ±0.7 vs 9.5 ± 0.8 μg/L, respectively), a bone formation maker. High FV intake (phase 2) decreased serum CTX (p < 0.05) to 0.60 ± 0.04 ng/ml and increased serum BALP to 11.3 ± 0.7μg/L (p < 0.05), compared to the depletion phase 1. These data demonstrate that increased fruit and vegetable consumption at or above federal dietary guidance is beneficial to bone health potentially through decreased dietary acidity.Support or Funding InformationThe study was supported by USDA ARS Current Research Information System no. 3062‐51000‐053‐00D and no. 3062‐51000‐051‐00D.