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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

Location: Human Nutrition Research Center on Aging

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

Authors
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: February 13, 2012
Publication Date: May 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: 9/10/2014