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Serum bone‐building metabolites are enhanced by a restricted vitamin A intervention in Zambian children with high liver reserves of vitamin A
Author(s) -
Olsen Kiersten E,
Binkley Neil,
Gan Bryan M,
Tanumihardjo Sherry A
Publication year - 2016
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.30.1_supplement.678.24
Subject(s) - medicine , n terminal telopeptide , vitamin d and neurology , parathyroid hormone , bone remodeling , vitamin , placebo , bone resorption , hypervitaminosis , physiology , endocrinology , calcium , chemistry , alkaline phosphatase , biochemistry , osteocalcin , alternative medicine , pathology , enzyme
Background Various programs to alleviate vitamin A (VA) deficiency include supplementation and fortification with preformed VA. Therefore, VA toxicity is of potential concern. The physiological effects and cut‐offs associated with hypervitaminosis A remain to be elucidated. The effect of VA status on bone health is still controversial, but high intake of preformed VA may lead to bone disease. Objectives This study investigated serum markers of bone formation, intact N‐terminal propeptide of type 1 procollagen (P1NP), and bone resorption, C‐terminal telopeptide of type 1 collagen (CTX), along with serum calcium, parathyroid hormone (PTH), 25‐hydroxy vitamin D, and VA esters in 5–7 year old Zambian children whose total body VA stores were measured (n = 133). Methods A randomized, controlled, 90‐day feeding trial was completed. All children were fed a low VA‐containing diet during the intervention. Three treatment groups consisted of a negative control group (VA−, n = 47), who ate white maize and received daily placebo oil; the test group (orange, n = 46), who ate orange maize and received daily placebo oil; and a positive control group (VA+, n = 47), who ate white maize and received VA [retinyl palmitate, 400 μg RAEs (current U.S. Recommended Daily Allowance for children this age)] in oil. Blood samples were taken at baseline, endline, and after a 14‐day washout period. P1NP, CTX, and PTH were analyzed using ELISA kits. Vitamin A esters were analyzed by HPLC and 25‐OH‐vitamin D was analyzed by ultra‐performance LC. Serum calcium was determined with inductively coupled plasma optical emission spectrometry. Results P1NP did not differ among treatment groups at baseline (670 ± 202 microg/L) but showed a treatment effect over the course of the intervention with the VA− group having the highest overall mean (1270 ± 482 microg/L) followed by the orange maize group (1002 ± 507 microg/L) and the VA+ group (748 ± 195 microg/L) ( P < 0.0001). CTX, serum calcium, 25‐hydroxy vitamin D, and VA esters did not differ among the treatment groups ( P >0.31) at endline. After the intervention, CTX (2.2 ± 0.6 ng/mL) was above the reference range, and low serum calcium (<88 microg/mL) and low 25(OH) D (<30 ng/mL) were prevalent (94% and 92%, respectively). Although normal, PTH differed among treatment groups ( P =0.0089) with the orange maize treatment group being higher than the VA− and VA+ groups, which did not differ. Conclusions This study found that bone formation was enhanced during VA restriction in children with hypervitaminosis A. Further research is needed to tease out the influence of VA on bone metabolism considering food fortification is with preformed VA. Support or Funding Information This work was supported by an endowment entitled “Friday Chair for Vegetable Processing Research”, Global Health funds, and HarvestPlus Agreement 8256.