Tocotrienols as an Anti-Osteoporotic Agent: The Progress So Far

Therapeutic effect of Vitamin E in preventing bone loss: An evidence-based review

The present review explored the anti-inflammatory and immunomodulatory properties of vitamin E, which has protective action against osteoporosis. A systematic review of the literature was conducted to identify the published bone studies on vitamin E. The studies included inflammatory or immunology-related parameters. Medline and Scopus databases were searched for relevant studies published from 2005 till 2015. Research articles published in English and confined to the effect of vitamin E on bone were included. It is pertinent to mention that these studies took into consideration inflammatory or immunology parameters including interleukin (IL)-1, IL-6, receptor activator of nuclear factor kappa-B ligand (RANKL), inducible nitric oxide synthases (iNOS), serum amyloid A (SAA), e-selection and high-sensitivity C-reactive protein (hs-CRP). An extended literature search yielded 127 potentially relevant articles with seven articles meeting the inclusion and exclusion criteria. Another recent article was added with the total number accounting to eight. All these included literature comprised five animal studies, one in-vitro study and two human studies. These studies demonstrated that vitamin E, especially tocotrienol, was able to alleviate IL-1, IL-6, RANKL, iNOS and hs-CRP levels in relation to bone metabolism. In conclusion, vitamin E exerts its anti-osteoporotic actions via its anti-inflammatory and immunomodulatory effects.

Tocotrienols, health and ageing: A systematic review

OBJECTIVES

A systematic review of studies was undertaken to evaluate the potential effect of intake of tocotrienols or circulating levels of tocotrienols on parameters associated with successful ageing, specifically in relation to cognitive function, osteoporosis and DNA damage.

METHODS

Following PRISMA guidelines a systematic review of epidemiological observational studies and clinical trials was undertaken. Inclusion criteria included all English language publications in the databases PubMed and Scopus, through to the end of July 2016.

RESULTS

Evidence from prospective and case-control studies suggested that increased blood levels of tocotrienols were associated with favorable cognitive function outcomes. A clinical trial of tocotrienol supplementation for 6 months suggested a beneficial effect of intake on DNA damage rates, but only in elderly people. Regarding osteoporosis, only in vitro studies with cultures of human bone cells were identified, and these demonstrated significant inhibition of osteoclast activity and promotion of osteoblast activity.

CONCLUSIONS

Research in middle-aged and elderly humans suggests that tocotrienols have a potential beneficial anti-ageing action with respect to cognitive impairment and DNA damage. Clinical trials are required to elucidate these effects.

Tocotrienol supplementation improves late-phase fracture healing compared to alpha-tocopherol in a rat model of postmenopausal osteoporosis: a biomechanical evaluation

This study investigated the effects of α-tocopherol and palm oil tocotrienol supplementations on bone fracture healing in postmenopausal osteoporosis rats. 32 female Sprague-Dawley rats were divided into four groups. The first group was sham operated (SO), while the others were ovariectomised. After 2 months, the right femora were fractured under anesthesia and fixed with K-wire. The SO and ovariectomised-control rats (OVXC) were given olive oil (vehicle), while both the alpha-tocopherol (ATF) and tocotrienol-enriched fraction (TEF) groups were given alpha-tocopherol and tocotrienol-enriched fraction, respectively, at the dose of 60 mg/kg via oral gavages 6 days per week for 8 weeks. The rats were then euthanized and the femora dissected out for bone biomechanical testing to assess their strength. The callous of the TEF group had significantly higher stress parameter than the SO and OVXC groups. Only the SO group showed significantly higher strain parameter compared to the other treatment groups. The load parameter of the OVXC and ATF groups was significantly lower than the SO group. There was no significant difference in the Young's modulus between the groups. In conclusion, tocotrienol is better than α-tocopherol in improving the biomechanical properties of the fracture callous in postmenopausal osteoporosis rat model.