Calcium Bioavailability in the Soluble and Insoluble Fibers Extracted from Opuntia ficus indica at Different Maturity Stages in Growing Rats.

Childhood and adolescence are crucial stages of life for bone health. Therefore, an adequate calcium intake and a healthy life style constitute the main strategies to prevent the risk of osteoporosis-related fractures during adulthood. It has been demonstrated that inclusion of indigestible carbohydrates in foods can help improve calcium absorption in growing stages. The objective of this study was to evaluate the effect of supplementation of soluble and insoluble fibers extracted from O. ficus indica cladodes on calcium bioavailability. Male Wistar rats 4-week old were fed diets added with soluble and insoluble fibers extracted from O. ficus indica cladodes at early and late maturity stages, as the only source of calcium. The mineral content, bone mineral density (BMD), physical, microstructural, and biomechanical properties of rat femurs were determined. The bones of rats fed with diets containing a soluble fiber extracted from O. ficus indica at early and late maturity stages exhibited better bone properties (resistance to fracture, microarchitecture, and calcium content) than control rats and rats fed with an insoluble fiber from O. ficusindica cladodes at both maturity stages. As expected, based on these results, the BMD values were higher in adolescent and pubertal rats fed with a diet containing the O. ficus indica soluble fiber. These results demonstrate that the soluble fiber from O. ficus indica cladodes is indeed a valuable source of bioavailable calcium, which contributes to improve physical, densitometric, biomechanical, and microstructural properties of bone in growing rats.

Calcium Bioavailability of Opuntia ficus-indica Cladodes in an Ovariectomized Rat Model of Postmenopausal Bone Loss.

Osteoporosis is a disease of the skeletal system characterized by low bone mass and bone weakening, which increase the risk of fracture. This disease is associated with menopause because hypoestrogenism induces the maturation and activation of osteoclasts. In addition, a low dietary intake of calcium leads to low bone mineral density and postmenopausal osteoporosis. The objectives of this work were to determine calcium bioavailability of Opuntia ficus-indica cladodes at a late maturity stage and to assess its contribution in improving bone health in an ovariectomized rat model. Two-month-old Wistar female rats (n = 35) were used and distributed in seven experimental groups: (i) control group (Crtl), (ii) sham group (SH), (iii) ovariectomized group (OVX), (iv) ovariectomized group supplemented with calcium citrate (CCa), (v) ovariectomized group supplemented with O. ficus-indica powder (NI), (vi) ovariectomized group supplemented with soluble fiber from O. ficus-indica (FS) and (vii) ovariectomized group supplemented with insoluble fiber from O. ficus-indica (FI). Our results showed that calcium in the soluble fiber of O. ficus-indica is bioavailable and contributes to improve the physical, densitometric, biomechanical and microstructural properties of bones in ovariectomized rats. These findings indicated that O. ficus-indica cladodes at a late maturity stage represent a good source of bioavailable calcium and consumption of these cladodes might be beneficial for the prevention of osteoporosis and other bone diseases.

Effect of Nopal (Opuntia ficus indica) Consumption at Different Maturity Stages as an Only Calcium Source on Bone Mineral Metabolism in Growing Rats.

This work determines the effect nopal consumption at different maturity stages (60, 200, 400, and 600 g) as the only calcium source in bone metabolism. The apparent mineral absorption, the biomarkers of bone metabolism, the bone mineral density at different femoral regions, and crystal properties of the bone were evaluated during the growth stage. The Ca absorption was increased with the rat age in most of the experimental groups, while Mg supplementation decreased intestinal absorption probably due to a saturation process. Intestinal Ca and Mg absorption showed an opposite trend; this result suggests that both ions can compete for vitamin D absorption sites. The percentage of absorption of K was lower in the groups fed with Nopal; nevertheless, due to supplementation, the net absorption was higher than the control group. In all groups, osteocalcin levels decreased with the rat age. Nopal consumption increased osteocalcin levels during the adolescence stage in comparison to the control group. Amino N-terminal propeptide of type I procollagen levels increased in puberty and adolescence in all groups compared to the control group. Bone mineral density in different femoral regions was lower in the groups fed with nopal at early maturity stages (N-60 and N-200) than the groups fed with nopal at late maturity stages (N-400 and N-600). The crystal size of hydroxyapatite exhibited changes for all the groups, indicating the inclusion of mono and divalent ions in calcium replacement. On this basis, the nopal at late maturity stage contributed to bone formation.