High dietary intake of vitamin E (alpha tocopherol) was reported to decrease bone mass in rodents by Keio University team in 20121. However, this assumption may not be true based on a new study conducted by researchers, led by the renowned Prof. Maret Traber, at Linus Pauling Institute, Oregon State University. The new study demonstrates that oral administration of high dose of alpha-tocopherol as well as mixed-tocotrienol do not cause any significant negative effects on bone mass, bone microarchitecture, bone formation, and bone marrow osteogenic (ie: bone forming) gene expressions.
In this study, eighteen 10-week male Sprague Dawley rats are divided evenly into 3 treatment groups-adequate-dietary alpha-tocopherol (A-AT, 40.2 mg/kg diet per day); high-dietary alpha-tocopherol (H-AT, 500 mg/kg diet per day), and high dietary mixed-tocotrienols ( H-T3, 250 mg/kg diet) per day (EVNol™ 50%, supplied by ExcelVite) for 18 weeks. After the supplementation period, vitamin E concentrations in plasma, liver and bone marrow in rats are measured. Additionally, bone mass of tibia (ie: bone mineral content, bone area, bone mineral density), bone formation by measuring osteocalcin (ie: serum marker of bone turnover), gene profiling associated to osteogenesis and bone turnover were also being examined.
Results reveal high level of plasma and liver alpha-tocopherol as well as gamma-tocopherol concentrations in H-AT rats. On the other hand, H-T3 fed rats show 10 fold higher tocotrienol concentration of alpha- and gamma-tocotrienols in rats’ plasma, bone marrow and liver. Even at such high concentrations of tocopherols and tocotrienols, there is no detection of significant difference in bone mass and bone architecture (ie: tibia epiphysis, metaphysis, lumbar vertebra cancellous bone volume), bone formation (ie: mineralizing perimeter, mineral apposition rate, bone formation rate in tibia metaphysis) and bone marrow osteogenic gene expressions, among all 3 treatment groups.
“The difference between the results published by researchers from Keio University and this new in vivo study suggests that high amount of vitamin E (both alpha tocopherol and mixed tocotrienols) does not pose negative effects on bone mass, bone density and even bone structure at an equivalent human daily dose of approximately 390mg and 4838mg of alpha-tocopherol, and 2420mg of palm mixed-tocotrienol respectively (human equivalent dose in a 60kg adult). These are extremely high daily doses of vitamin E – which generally one will unlikely to consume. But we are glad to know that no adverse effects are reported with regard to bone mass, density and structure,” says Chee Yen Lau, Nutritionist of ExcelVite.
“In fact, researchers from the National University of Malaysia have been studying the effects of vitamin E tocotrienols in relation to bone health. Published papers from this group of researchers have demonstrated that palm mixed-tocotrienol complex confers significant bone protective effects when compared to estrogen replacement therapy2 and calcium3 in ovariectomised rats (ie: postmenopausal osteoporosis models). These studies further reinforce the safety of vitamin E (both tocopherol and mixed tocotrienol complex) and the bone protective effects of palm mixed-tocotrienol,” added Lau.
- Fujita, K., et.al (2012). Vitamin E decreases bone mass by stimulating osteoclast fusion. Nature Medicine, 18, 589-594. Doi:10.1038/nm.2659.
- Aktifanus, A.T., et.al (2012). Comparison of the Effects of Tocotrienol and Estrogen on the Bone Markers and Dynamic Changes in Postmenopausal Osteoporosis Rat Model. Asian Journal of Animal and Veterinary Advances. doi: 10.3923/ajava.
- Soelaiman, I. N., et.al (2012). Palm Tocotrienol Supplementation Enhanced Bone Formation in Oestrogen-Deficient Rats. International Journal of Endocrinology. Doi:10.1155/2012/532862.
- Tennant KG, et al. (2017, Apr 6). High-dietary alpha-tocopherol or mixed tocotrienol has no effect on bone mass, density, or turnover in male rats during skeletal maturation. J Med Food, doi: 10.1089/jmf.2016.0147. [Epub ahead of print].
For more information, visit the Tocotrienol educational website.
Disclaimer: The statements in the above article have not been evaluated by the Food and Drug Administration. They are not intended to diagnose, treat, cure or prevent any disease.