High dietary intake of vitamin E (alpha tocopherol) was reported to decrease bone mass in rodents by Keio University team in 2012 1. However, this assumption may not be true, based on a new study conducted by researchers — led by the renowned Professor 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 (bone forming) gene expressions.
In this study, 18 10-week-old male Sprague Dawley rats were divided evenly into three 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%, previously known as Tocomin 50%, supplied by ExcelVite) for 18 weeks. After the supplementation period, vitamin E concentrations in plasma, liver and bone marrow in rats were measured. Additionally, bone mass of tibia (bone mineral content, bone area, bone mineral density), bone formation by measuring osteocalcin (serum marker of bone turnover), gene profiling associated to osteogenesis and bone turnover were also being examined.
Results revealed 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 showed 10-fold higher tocotrienol concentrations of alpha- and gamma-tocotrienols in the rats’ plasma, bone marrow and liver. Even at such high concentrations of tocopherols and tocotrienols, there was no detection of significant difference in bone mass and bone architecture (i.e. tibia epiphysis, metaphysis, lumbar vertebra cancellous bone volume), bone formation (i.e. mineralizing perimeter, mineral apposition rate, bone formation rate in tibia metaphysis) and bone marrow osteogenic gene expressions, among all three 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 390 mg and 4838 mg of alpha-tocopherol, and 2420 mg of palm mixed-tocotrienol respectively (human equivalent dose in a 60 kg 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,” said ExcelVite Nutritionist Chee Yen Lau.
“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 therapy 2 and calcium 3 in ovariectomised rats (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].