Published in:
Open Access 01-12-2006 | Research
Extrahepatic tissue concentrations of vitamin K are lower in rats fed a high vitamin E diet
Published in: Nutrition & Metabolism | Issue 1/2006
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Background
An adverse hematological interaction between vitamins E and K has been reported, primarily in patients on anticoagulants. However, little is known regarding circulating levels or tissue concentrations of vitamin K in response to vitamin E supplementation. The purpose of this study was to examine the effect of different levels of dietary α-tocopherol on phylloquinone and menaquinone-4 concentrations, while maintaining a constant intake of phylloquinone, in rat tissues.
Methods
Male 4-wk old Fischer 344 rats (n = 33) were fed one of 3 diets for 12 wk: control (n = 13) with 30 mg all-rac-α-tocopherol acetate/kg diet; vitamin E-supplemented (n = 10) with 100 mg all-rac-α-tocopherol acetate/kg diet; and vitamin E-restricted (n = 10) with <10 mg total tocopherols/kg diet. All 3 diets contained 470 ± 80 μg phylloquinone/kg diet.
Results
Phylloquinone concentrations were lower (P ≤ 0.05) in the vitamin E-supplemented compared to the vitamin E-restricted group (mean ± SD spleen: 531 ± 58 vs.735 ± 77; kidney: 20 ± 17 vs. 94 ± 31, brain: 53 ± 19 vs.136 ± 97 pmol/g protein respectively); no statistically significant differences between groups were found in plasma, liver or testis. Similar results were noted with menaquinone-4 concentrations in response to vitamin E supplementation.
Conclusion
There appears to be a tissue-specific interaction between vitamins E and K when vitamin E is supplemented in rat diets. Future research is required to elucidate the mechanism for this nutrient-nutrient interaction.