Tocotrienol (T3) is an unsaturated form of natural vitamin E that has been focused on because of its potential health benefits (i.e., antioxidative, antihypercholesterolemic, and antiangiogenic effects). The presence of T3 in some plant sources (e.g., rice bran and palm oil) is known, but its distribution in other edible sources and its daily intake remain unclear. In this study, we aimed at clarifying the distribution of T3 in various food sources and estimating the daily T3 intake of Japanese population. T3 contents of 242 food items and 64 meal items were measured by using normal-phase HPLC with fluorescence detection. As for the results, T3 contents were nondetectable to 12 mg T3/kg wet wt of food items, and nondetectable to 1.3 mg T3/item of processed (cooked) meal. Accordingly, the daily intake of T3 was estimated as 1.9-2.1 mg T3/day/person. The estimated daily intake of T3 appears rather low compared with the intake of tocopherol (8-10 mg/day/person as reported in the Japanese National Nutrition Survey), and additional T3 is important for its therapeutic aspects.

BACKGROUND AND AIMS: Intake of the antioxidant vitamins C and E lowers the oxidative stress. The study aimed to determine plasma concentrations of vitamin C and tocotrienols after supplementation of both vitamins in young male adults.

MATERIALS AND METHODS: A total of 64 police recruits were randomly assigned to one of these groups: (a) 500 mg vitamin C (Vitamin C), (b) 200 mg Tocovid (Tocotrienol), (c) combination of 500 mg vitamin C and 200 mg Tocovid (Combination) or (d) placebo (Placebo) for eight-weeks of supplementation followed by six-week washout period.

RESULTS: In Combination group, mean plasma vitamin C concentration significantly increased from baseline 2.86 +/- 1.19 mg/L to 10.37 +/- 1.29 mg/L and 15.63 +/- 1.27 mg/L after four- and eight-week supplementation, respectively. The corresponding figures for alpha-, delta- and gamma-tocotrienols were 9.9 +/- 2.5 ng/ml to 104.1 +/- 19.8 ng/ml and 112.8 +/- 38.0 ng/ml; 2.5 +/- 0.9 ng/ml to 29.9 +/- 7.0 ng/ml and 17.9 +/- 4.7 ng/ml; 19.2 +/- 3.1 ng/ml to 75.2 +/- 24.1 ng/ml and 161.7 +/- 49.9 ng/ml, respectively. In Vitamin C group, plasma vitamin C concentrations were significantly increased. Conversely, concentration of plasma vitamin C in Tocotrienol group increased from baseline of 2.72 +/- 0.20 mg/L to 6.80 +/- 0.63 mg/L and 8.9 +/- 0.77 mg/L respectively. Plasma concentrations of alpha-, delta- and gamma-tocotrienols in this group were significantly elevated. After 6-week washout period, all the elevated concentrations returned to basal levels.

Vitamin E, like tocotrienols and tocopherols, is constituted of compounds essential for animal cells. Vitamin E is exclusively synthesized by photosynthetic eukaryotes and other oxygenic photosynthetic organisms such as cyanobacteria. In order to prevent lipid oxidation, the plants mainly accumulate tocochromanols in oily seeds and fruits or in young tissues undergoing active cell divisions. From a health point of view, at the moment there is a great interest in the natural forms of tocochromanols, because they are considered promising compounds able to maintain a healthy cardiovascular system and satisfactory blood cholesterol levels. Some evidence suggests that the potency of the antioxidant effects may differ between natural or synthetic source of tocochromanols (vitamin E).

Recently, vitamin E has been found to promote the bone structure of nicotine-treated rats well above their baseline values, thus suggesting that vitamin E may have some anabolic action. A bone anabolic agent acts by improving the bone structure leading to stronger bone. To assess the possible anabolic action vitamin E on bone, we supplemented alpha-tocopherol (ATF) or gamma-tocotrienol (GTT) at 60 mg/kg or vehicle [normal control (NC) group] for 4 months to normal male rats and measured their bone structure and biomechanical properties. Histomorphometric analysis revealed that vitamin E-supplemented rats have better trabecular volume, thickness, number, and separation than rats receiving vehicle only. For the first time we reported that GTT improves all the parameters of bone biomechanical strength, while ATF only improved some of the parameters compared to the NC group. Vitamin E supplementation, especially with the gamma isomer, improves bone structure, which contributed to stronger bone. Therefore, vitamin E has the potential to be used as an anabolic agent to treat osteoporosis or as bone supplements for young adults to prevent osteoporosis in later years.