05.15.17
High dietary intake of vitamin E (alpha tocopherol) was reported to decrease bone mass in rodents by Keio University team in 2012 (Nature Medicine). However, a new study conducted by researchers, led by Prof. Maret Traber, at Linus Pauling Institute, Oregon State University indicated otherwise. The new study, published in the Journal of Medicinal Food, demonstrated that oral administration of high doses of alpha-tocopherol as well as mixed-tocotrienols does not cause any significant negative effects on bone mass, bone microarchitecture, bone formation, and bone marrow osteogenic (i.e., bone forming) gene expressions.
In this study, eighteen 10-week 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. Researchers also examined bone mass of tibia (i.e., bone mineral content, bone area, bone mineral density); bone formation by measuring osteocalcin (i.e., serum marker of bone turnover); gene profiling associated with osteogenesis; and bone turnover.
Results showed high levels 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 concentration of alpha- and gamma-tocotrienols in rats’ plasma, bone marrow, and liver. Even at such high concentrations of tocopherols and tocotrienols, there was no 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 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 390 mg and 4,838 mg of alpha-tocopherol, and 2,420 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 be unlikely to consume. But we are glad to know that no adverse effects are reported with regard to bone mass, density, and structure,” said Chee Yen Lau, nutritionist at 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 therapy (Asian Journal of Animal and Veterinary Advances, 2012), and calcium (International Journal of Endocrinology, 2012) in ovariectomised rats (i.e., 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 Ms. Lau.
In this study, eighteen 10-week 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. Researchers also examined bone mass of tibia (i.e., bone mineral content, bone area, bone mineral density); bone formation by measuring osteocalcin (i.e., serum marker of bone turnover); gene profiling associated with osteogenesis; and bone turnover.
Results showed high levels 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 concentration of alpha- and gamma-tocotrienols in rats’ plasma, bone marrow, and liver. Even at such high concentrations of tocopherols and tocotrienols, there was no 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 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 390 mg and 4,838 mg of alpha-tocopherol, and 2,420 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 be unlikely to consume. But we are glad to know that no adverse effects are reported with regard to bone mass, density, and structure,” said Chee Yen Lau, nutritionist at 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 therapy (Asian Journal of Animal and Veterinary Advances, 2012), and calcium (International Journal of Endocrinology, 2012) in ovariectomised rats (i.e., 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 Ms. Lau.
