The Effects of a-Tocopherol on Bone: A Double-Edged Sword?

Recent studies have found conflicting evidence on the role of -tocopherol (TF) on bone health. This nonsystematic review aimed to summarize the current evidence on the effects of TF on bone health from cell culture, animal, and human studies in order to clarify the role of TF on bone health. Our review found that TF exerted beneficial, harmful or null effects on bone formation cells. Animal studies generally showed positive effects of TF supplementation on bone in various models of osteoporosis. However, high-dose TF was possibly detrimental to bone in normal animals. Human studies mostly demonstrated a positive relationship between TF, as assessed using high performance liquid chromatography and/or dietary questionnaire, and bone health, as assessed using bone mineral density and/or fracture incidence. Three possible reasons high dosage of TF can be detrimental to bone include its interference with Vitamin K function on bone, the blocking of the entry of other Vitamin E isomers beneficial to bone, and the role of TF as a prooxidant. However, these adverse effects have not been shown in human studies. In conclusion, TF may have a dual role in bone health, whereby in the appropriate doses it is beneficial but in high doses it may be harmful to bone.