Sim Marc, Lewis Joshua R, Prince Richard L, Levinger Itamar, Brennan-Speranza Tara C, Palmer Claire, Bondonno Catherine P, Bondonno Nicola P, Devine Amanda, Ward Natalie C, Byrnes Elizabeth, Schultz Carl J, Woodman Richard, Croft Kevin, Hodgson Jonathan M, Blekkenhorst Lauren C
School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
Medical School, Royal Perth Hospital Unit, The University Western Australia, Perth, WA, Australia.
Bone Rep. 2020 Apr 26;12:100274. doi: 10.1016/j.bonr.2020.100274. eCollection 2020 Jun.
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.
To examine the effects of consumption of two to three extra serves of green leafy vegetables daily on bone metabolism.
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.
Pre-intervention tOC, ucOC and ucOC:tOC levels were similar between phases ( > .05). Following H-K, but not L-K, tOC, ucOC and ucOC:tOC levels were significantly lower compared to pre-intervention levels ( ≤ .001) and compared to CON (~14%, 31% and 19%, respectively, all < .05), while cOC remained unchanged.
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.
大量摄入蔬菜对骨骼有益。然而，其作用机制尚不清楚。绿叶蔬菜是维生素K1的丰富来源，已知维生素K1对成骨细胞和骨钙素（OC）代谢有很大影响。
研究每天额外食用两到三份绿叶蔬菜对骨代谢的影响。
30名个体（平均年龄61.8±9.9岁，67%为男性）采用随机对照交叉设计完成三个实验阶段，每个阶段持续四周，阶段之间有四周的洗脱期（临床试验注册号：ACTRN12615000194561）。三个实验阶段分别为：（i）通过食用绿叶蔬菜增加膳食维生素K1摄入量（高维生素K1组；200克/天，含164.3[99.5 - 384.7]微克/天的维生素K1）；（ii）通过食用低维生素K1的蔬菜降低维生素K1摄入量（低维生素K1组；200克/天，含9.4[7.7 - 11.6]微克/天的维生素K1）；以及（iii）对照组（CON），参与者食用能量匹配的非蔬菜对照饮食。在每个实验阶段干预前后，使用夹心电化学发光免疫分析法测定血清中OC形式、总OC（tOC）、羧化OC（cOC）和未羧化OC（ucOC）。
干预前各阶段的tOC、ucOC和ucOC:tOC水平相似（P>0.05）。在高维生素K1组后，但低维生素K1组后未出现，与干预前水平相比，tOC、ucOC和ucOC:tOC水平显著降低（P≤0.001），与对照组相比也显著降低（分别约为14%、31%和19%，均P<0.05），而cOC保持不变。
在中年健康男性和女性中，轻松实现富含维生素K1的绿叶蔬菜膳食摄入量增加，可显著降低血清tOC和ucOC，表明OC进入骨基质增加，这可能改善骨骼的物质特性。结合先前的流行病学和随机对照试验数据，这些发现表明，长期增加蔬菜摄入量的干预措施应包括骨骼相关终点，如骨折风险。
