High-Dose α-Tocopherol Supplementation Does Not Induce Bone Loss in Normal Rats

Abstract

Oxidative stress affects bone turnover. Preventative effects of antioxidants such as vitamin E on reduced bone mineral density and fractures associated with aging, osteoporosis, and smoking have been examined in animals and humans. The effects of vitamin E (α-tocopherol; αT) on bone health have yielded conflicting and inconclusive results from animal studies. In this study, to determine the bone effects of αT, we investigated the in vivo effects of αT on the bone mineral density, bone mass, bone microstructure, bone resorption, and osteogenesis through peripheral quantitative computed tomography (pQCT) measurements, micro-computed tomography (micro-CT) analyses, and bone histomorphometry of lumbar vertebrae and femurs in normal female Wistar rats fed diets containing αT in different quantities (0, 30, 120, or 600 mg/kg diet) for 8 weeks. To validate our hypotheses regarding bone changes, we examined ovariectomized rats as an osteoporosis model and control sham-operated rats in parallel. As expected, ovariectomized rats had reduced bone mineral density in lumbar vertebrae and the distal metaphyses of their femurs, reduced bone mass and deteriorated microstructure of cancellous bones in the vertebral body and distal femur metaphyses, and reduced bone mass due to resorption-dominant enhanced bone turnover in secondary cancellous bones in these sites. In comparison, αT administered to normal rats, even at the highest dose, did not induce reduced bone mineral density of lumbar vertebrae and femurs or a reduced bone mass or fragile microstructure of cancellous bones of the vertebral body and distal femur metaphyses. Instead, αT-fed rats showed a tendency for an osteogenesis-dominant bone mass increase in secondary cancellous bones in the vertebral body, in which active bone remodeling occurs. Thus, αT consumption may have beneficial effects on bone health.

Effects of nano-emulsion preparations of tocopherols and tocotrienols on oxidative stress and osteoblast differentiation

“…Vitamin E supplements are widely consumed at the rate of ~ 250 mg/day, while the recommended daily dose is around ~ 150 mg/day. While the supplement intake is justifiable by its beneficial effects, recent reports on the role of vitamin E in bone functions have raised serious concerns due to its effect on bone homeostasis [13,[35][36][37]. Recently, Fujita et al [13] utilized mouse genetics and showed that vitamin E could promote osteoclast formation.…”

α-Tocopherol Intake Decreases Phylloquinone Concentration in Bone but Does Not Affect Bone Metabolism in Rats

“…APTT, activated partial thromboplastin time; MK-4, menaquinone-4; PK, phylloquinone; ucOC, uncarboxylated osteocalcin. young female rats (11), or male mice and ovariectomized female mice fed a high-fat diet (12). In the present study, we used young male rats as the experimental animal, following the report of Fujita et al The PK and RRR-a-tocopherol contents in the control diet were at 0.75 mg/kg and 50 mg/kg, respectively, in accordance with the AIN93 rodent diet (15).…”

“…Recently, Fujita et al reported that excess intake of a-tocopherol reduced bone mass in rats and mice (9). After that, other researchers also examined the effect of excess a-tocopherol on the bone mass of rats and mice, but no reduction of bone mass was confirmed (10)(11)(12). The reason for these contradictory results is still unknown.…”

Evaluación de la Administración Infiltrativa de vitamina E y alendronato en la Reparación de Alvéolos Post Exodoncia de Ratas

“…De acuerdo con los resultados del presente trabajo, Kasai et al (2015) evaluaron los efectos de la Vitamina E en los huesos en ratas normales alimentados con dietas que contenían diferentes niveles de a-Tocoferol, encontrando una tendencia a un aumento de la masa ósea dominante en la osteogénesis en el hueso esponjoso vertebral secundario, en el que se produce la remodelación ósea activa en los animales tratados con esta vitamina.…”