Dietary induced subclinical vitamin K deficiency in normal human subjects.

Abstract

A subclinical vitamin K deficiency was induced in 32 healthy subjects (four groups of eight males and females) aged 20-40 and 60-80 yr residing in the Metabolic Research Unit of the Human Nutrition Research Center on Aging at Tufts University. Volunteers were initially fed (4 d) a baseline-period diet containing the recommended daily allowance for vitamin K which is equivalent to 80 ;tg/d of phylloquinone (vitamin K1).During the baseline period various parameters of vitamin K nutritional status were monitored. The baseline period was followed by a 13-d depletion period during which the subjects were fed a very low vitamin K1 diet (-10 ;ug/d). After depletion, the subjects entered a 16-d repletion period (four stages lasting 4 d each) during which time they were repleted with 5, 15, 25, and 45 ,ug of vitamin K1 per day. Vitamin K1 depletion dramatically and significantly decreased plasma vitamin K1 levels (P < 0.0001) in both elderly and young groups to values 13-18% of day 1 (elderly 0.22 nM, young 0.14 nM). Repleting the subjects with up to 45 ;ig of vitamin K1 per day failed, in the case of the young subjects, to bring plasma vitamin K1 levels back into the normal range. Dietary vitamin K1 restriction induced different responses in the urinary excretion of-y-carboxyglutamic acid between the young and the elderly subjects with values decreasing significantly (P < 0.03) in the young while remaining unchanged in the elderly. The vitamin K1 depletion period had no significant effect on either prothrombin and activated partial thromboplastin times, or Factor VII and protein C (as determined by antigenic and functional assays). By using a monoclonal antibody, descarboxy prothrombin was found to increase slightly but significantly in both groups (P < 0.05) as a consequence of the low vitamin K1 diet. This study clearly shows that a diet low in vitamin K1 can result in a functional subclinical deficiency of vitamin K (decreased urinary y-carboxyglutamic acid excretion) without affecting blood coagulation.

Ethnic differences in osteocalcin γ-carboxylation, plasma phylloquinone (vitamin K1) and apolipoprotein E genotype

“…The high phylloquinone concentrations in the cohort of Chinese women from Shenyang where osteoporotic fractures are rare (Yan et al, 1999), is compatible with the association of low circulating phylloquinone with a high incidence of osteoporotic fracture in Britain and North America (Hart et al, 1985;Bitensky et al, 1988;Roberts et al, 1996;Booth et al, 2000). Plasma phylloquinone concentration is readily affected by dietary intake and rapidly raises blood concentrations, which then fall within a few hours (Suttie et al, 1988;Ferland et al, 1993;Sokoll et al, 1997;Booth et al, 1999). Plasma phylloquinone also correlates with vitamin K intake in population studies (Booth et al, 1995.…”

The prevalence and risk factors for age-related macular degeneration in rural–urban India, Sankara Nethralaya Rural–Urban Age-related Macular degeneration study, Report No. 1

“…In some cases, higher levels of triglyceride-rich lipoproteins, with advancing age, can account for these higher concentrations. Ferland et al have shown a resistance among older adults in functional measures of vitamin K deficiency when placed on low vitamin K diets (262). This is probably due to greater vitamin K intake among older versus younger adults.…”

Vitamin K Deficiency in the Hospitalized Patient-- Are we Underestimating the Prevalence?

“…Subclinical Vitamin K deficiency has been induced in healthy adults fed a diet providing about 10 micrograms of phyloquinone per day [3]. Vitamin K1 depletion dramatically and significantly decreased plasma vitamin K1 levels (P<0.0001) to values 13-18%.…”