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United States Department of Agriculture

Agricultural Research Service

Research Project: VITAMIN K: FOOD COMPOSITION, BIOAVAILABILITY AND IT'S ROLE IN HUMAN HEALTH

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Title: Age, group, or sex do not influence responses of vitamin K biomarkers to changes in dietary vitamin K)

Author
item Truong, Jennifer t.
item Fu, Xueyan
item Saltzman, Edward
item Al rajabi, Ala
item Dallal, Gerard
item Gundberg, Caren m.
item Booth, Sarah l.

Submitted to: Journal of Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/13/2012
Publication Date: 5/1/2012
Citation: Truong, J., Fu, X., Saltzman, E., Al Rajabi, A., Dallal, G., Gundberg, C., Booth, S. 2012. Age,group,or sex do not influence responses of vitamin K biomarkers to changes in dietary vitamin K. Journal of Nutrition. 142(5):936-941.

Interpretive Summary: Inadequate vitamin K intake has been associated with abnormal soft tissue calcification. Older adults may have insufficient intakes of vitamin K and respond less to vitamin K supplementation compared to younger adults. However, little is known about the determinants that influence response to vitamin K supplementation. The primary objective was to assess dietary and non-dietary determinants of vitamin K status in healthy younger and older adults. Twenty one younger adults, aged 18 to 40 years, and 21 older adults, aged 55 to 80 years, were enrolled in a feeding study. To stabilize their vitamin K status over a period of five days, each participant was fed a diet that contained an amount of vitamin K that was twice the amount of vitamin K considered an adequate intake. Then each participant was switched to a vitamin K-restricted diet for 28 days, followed by 28 days of vitamin K supplementation. Changes in vitamin K status markers were compared in response to vitamin K restriction and supplementation. Influence of body composition, including the proportion of body fat, and circulating lipid concentrations on the response of vitamin K status markers were assessed in both groups of younger and older men and women. Despite baseline differences in measures of vitamin K status, the majority of the markers responded equally to vitamin K restriction and supplementation, regardless of age group or sex. Only excretion of urinary menadione, a vitamin K metabolite, was greater among younger adults in response to vitamin K restriction than older adults. Body composition measures and circulating lipids did not predict response of any status markers. In conclusion, poor vitamin K status can be similarly improved with vitamin K supplementation, regardless of age group or sex.

Technical Abstract: Inadequate vitamin K intake has been associated with abnormal soft tissue calcification. Elderly may have insufficient intakes of vitamin K and respond less to vitamin K supplementation compared to younger adults. However, little is known about the determinants that influence response to vitamin K supplementation. The primary objective was to assess dietary and non-dietary determinants of vitamin K status in healthy younger and older adults. In a non-randomized, non-masked study, 21 younger (18-40 y) and 21 older (55-80 y) adults were fed a 5-d baseline diet (200 micrograms phylloquinone/d; d1-5), a 28-d phylloquinone-restricted diet (10 micrograms phylloquinone/d; d6-33), followed by 28-d of phylloquinone supplementation (500 micrograms phylloquinone/d; d34-61). Changes in vitamin K status markers were compared in response to vitamin K depletion and repletion. Influence of age, sex, BMI, body fat, and triglycerides (TG) on the response of vitamin K status markers were assessed. Despite baseline differences in measures of vitamin K status [plasma phylloquinone, percent uncarboxylated osteocalcin and uncarboxylated prothrombin], all improved with phylloquinone supplementation, regardless of age and sex (P=0.07, <0.0001 and 0.007, respectively). Only excretion of urinary menadione, a vitamin K metabolite, was greater among younger adults in response to depletion than older adults (P=0.012). TG and adiposity measures did not predict response of any measures. In conclusion, poor vitamin K status can be similarly improved with vitamin K supplementation, regardless of age and sex.

Last Modified: 8/24/2016
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