Animal Study: Alpha-Tocopherol Has Insignificant Effects on Tocotrienol and its Metabolites
30 July 2013 --- A recent animal study in rats proves that regular vitamin E alpha-tocopherol intake does not deplete tocotrienols and gamma-tocopherol levels in various tissues and neither does it increase the excretion of their metabolites into urine.
Stimulation of ω-hydroxylation of the other vitamin E-isoforms by alpha-tocopherol in the liver has non-significant effect on tissue concentrations of other tocopherol and tocotrienol in vivo.
In this study, Japanese researchers fed rats with a gamma-tocopherol-rich diet (containing 150mg gamma-tocopherol/kg) for 6 weeks followed by a gamma-tocopherol-free diet with or without alpha-tocopherol (100mg/kg) for 7 days. In order to investigate the effect of alpha-tocopherol on tocotrienol depletion, researchers fed rats with a tocotrienol-rich diet (containing 103mg alpha-tocotrienol/kg and 150mg gamma-tocotrienol/kg) for 6 weeks followed by a tocotrienol free diet with or without alpha-tocopherol (100mg/kg) for 7 days.
The results showed that dietary alpha-tocopherol did not influence gamma-tocopherol and tocotrienol concentration in the serum and tissues - including liver, adrenal glands, small intestine, heart, muscle as well as adipose tissues.
In addition, the urinary excretion of gamma-tocopherol and tocotrienol metabolites was not affected by dietary alpha-tocopherol.
The researchers concluded that dietary alpha-tocopherol did not accelerate the breakdown of the other vitamin E isoforms (including gamma-tocopherol and tocotrienol) in vivo and did not influence the tissue concentration of the other vitamin E isoforms in serum and almost all tissues.
“Prof. Chandan Sen of OSU Medical Center, in his paper published recently in the Journal of Nutrition, showed that the absorption and distribution of tocotrienols, from Tocomin SupraBio, to vital human organs and tissues were not affected by the presence of alpha-tocopherol. This is the first ever actual human tissue distribution study with tocotrienols. I am pleased to see that this latest rat study lends further support that alpha-tocopherol does not interfere with the catabolism of other vitamin E isoforms, including tocotrienols and gamma-tocopherol. It also did not increase the excretion of metabolites of these important vitamin E isoforms,” says Mr. WH Leong, Vice President of Carotech Inc.
“We have stressed numerous times that nature makes both tocopherols and tocotrienols and therefore, there is no reason (scientifically or otherwise) to purposely remove tocopherol or limit tocopherol intake with tocotrienols. We need to take vitamin E as nature makes it – in wholesome and full spectrum formula. Mimicking nature is the best way for dietary supplementation as nature knows best,” added WH Leong.
Reference: Uchida T, et al., 2013. Alpha-tocopherol does not accelerate depletion of gamma-tocopherol and tocotrienol or excretion of their metabolites in rats. Lipids, 48(7), pp. 687-95.
