The effects of vitamin K-rich green leafy vegetables on bone metabolism: A 4-week randomised controlled trial in middle-aged and older individuals
Sim M, Lewis JR, Prince RL, Levinger I, Brennan-Speranza TC, Palmer C, Bondonno CP, Bondonno NP, Devine A, Ward NC, Byrnes E, Schultz CJ, Woodman R, Croft K, Hodgson JM, Blekkenhorst LC
Bone reports · 28 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Randomized controlled trial (classified by our AI screen)
- Studied in
- People
- Main outcome
- Health markers and function
- Intake measured by
- Food provided by researchers
Who paid for it
- Funding
- Independent funding
- Nonprofit
- National Heart Foundation of Australia
- University or hospital
- Edith Cowan University
- Government
- Medical Research Council
- Government
- National Health and Medical Research Council
- Grants
- Edith Cowan University (1116973); National Heart Foundation of Australia (G1004431); National Health and Medical Research Council (1084922); National Heart Foundation of Australia (102498); National Heart Foundation of Australia (1172987); Edith Cowan University (G1004441)
Based on 4 listed funder(s) and full-text disclosure statement.
Publication
- Published
- 2020-04-27 · Bone Rep · vol. 12 · p. 100274
- Publisher
- Elsevier BV
- Cited
- 33 citations · more than 87% of similar papers · 2.2× the field average
- References
- 53 works
- Access
- Open access (journal) · CC-BY
- Research areas
- Vitamin K Research Studies · Vitamin C and Antioxidants Research · Antioxidant Activity and Oxidative Stress
- Keywords
- Medicine, Crossover study, Vitamin, Vitamin D and neurology, Vitamin k, Bone remodeling, Osteocalcin, Internal medicine, Food science, Animal science, Chemistry, Biology, Biochemistry, Alkaline phosphatase
16 authors
From AU
- Marc Sim · correspondingEdith Cowan University; Royal Perth Hospital
- Joshua Richard LewisEdith Cowan University; The University of Sydney; Royal Perth Hospital; Children's Hospital at Westmead
- Richard Lewis PrinceThe University of Western Australia; Sir Charles Gairdner Hospital
- Itamar LevingerWestern Health; Australian Institute for Musculoskeletal Science; Victoria University
- Tara C. Brennan‐SperanzaThe University of Sydney
- Claire R. PalmerEdith Cowan University; Royal Perth Hospital
Abstract
Background
High vegetable intake is associated with beneficial effects on bone. However, the mechanisms remain uncertain. Green leafy vegetables are a rich source of vitamin K1, which is known to have large effects on osteoblasts and osteocalcin (OC) metabolism.
Objective
To examine the effects of consumption of two to three extra serves of green leafy vegetables daily on bone metabolism.
Methods
Thirty individuals (mean age 61.8 ± 9.9 years, 67% male) completed three experimental phases in a randomised controlled crossover design, each lasting four weeks, with a washout period of four weeks between phases (clinical trial registration: ACTRN12615000194561). The three experimental phases were: (i) increased dietary vitamin K1 by consuming green leafy vegetables (H-K; ~200 g/d containing 164.3 [99.5-384.7] μg/d of vitamin K1); (ii) low vitamin K1 by consuming vitamin K1-poor vegetables (L-K; ~200 g/d containing 9.4 [7.7-11.6] μg/d of vitamin K1); and (iii) control (CON) where participants consumed an energy-matched non-vegetable control. OC forms, total OC (tOC), carboxylated OC (cOC) and undercarboxylated OC (ucOC), were measured in serum pre- and post-intervention for each experimental phase using a sandwich-electrochemiluminescence immunoassay.
Results
Pre-intervention tOC, ucOC and ucOC:tOC levels were similar between phases (P > .05). Following H-K, but not L-K, tOC, ucOC and ucOC:tOC levels were significantly lower compared to pre-intervention levels (P ≤ .001) and compared to CON (~14%, 31% and 19%, respectively, all P < .05), while cOC remained unchanged.
Conclusions
In middle-aged healthy men and women, an easily achieved increase in dietary intake of vitamin K1-rich green leafy vegetables substantially reduces serum tOC and ucOC suggesting increased entry of OC into bone matrix, where it may improve the material property of bone. In conjunction with previous epidemiological and randomised controlled trial data, these findings suggest that interventions to increase vegetable intake over extended periods should include bone end points including fracture risk.
Abstract via Europe PMC. Copyright remains with the authors or publisher (CC BY).
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