A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents.
BACKGROUND
Short-term studies in adolescents have generally shown an enhancement of calcium absorption by inulin-type fructans (prebiotics). Results have been inconsistent; however, and no studies have been conducted to determine whether this effect persists with long-term use.


OBJECTIVE
The objective was to assess the effects on calcium absorption and bone mineral accretion after 8 wk and 1 y of supplementation with an inulin-type fructan.


METHODS
Pubertal adolescents were randomly assigned to receive 8 g/d of a mixed short and long degree of polymerization inulin-type fructan product (fructan group) or maltodextrin placebo (control group). Bone mineral content and bone mineral density were measured before randomization and after 1 y. Calcium absorption was measured with the use of stable isotopes at baseline and 8 wk and 1 y after supplementation. Polymorphisms of the Fok1 vitamin D receptor gene were determined.


RESULTS
Calcium absorption was significantly greater in the fructan group than in the control group at 8 wk (difference: 8.5 +/- 1.6%; P < 0.001) and at 1 y (difference: 5.9 +/- 2.8%; P = 0.04). An interaction with Fok1 genotype was present such that subjects with an ff genotype had the least initial response to fructan. After 1 y, the fructan group had a greater increment in both whole-body bone mineral content (difference: 35 +/- 16 g; P = 0.03) and whole-body bone mineral density (difference: 0.015 +/- 0.004 g/cm(2); P = 0.01) than did the control group.


CONCLUSIONS
Daily consumption of a combination of prebiotic short- and long-chain inulin-type fructans significantly increases calcium absorption and enhances bone mineralization during pubertal growth. Effects of dietary factors on calcium absorption may be modulated by genetic factors, including specific vitamin D receptor gene polymorphisms.
Abrams
Steven A
SA
US Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030, USA. sabrams@bcm.edu
Griffin
Ian J
IJ
Hawthorne
Keli M
KM
Liang
Lily
L
Gunn
Sheila K
SK
Darlington
Gretchen
G
Ellis
Kenneth J
KJ
D000042:Absorption; D000293:Adolescent; D015519:Bone Density; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism*; D002648:Child; D005260:Female; D005630:Fructans / Q000008:administration & dosage*; D005838:Genotype; D006801:Humans; D007444:Inulin / Q000008:administration & dosage*; D008297:Male
D005630:Fructans; D007444:Inulin; D002118:Calcium