Department of Nutrition, Assuta Medical Center, Tel Aviv, Israel; The Israel Dietetic Association, Herzliya, Israel.
The Israel Dietetic Association, Herzliya, Israel.
Surg Obes Relat Dis. 2019 Aug;15(8):1402-1413. doi: 10.1016/j.soard.2019.05.031. Epub 2019 Jun 5.
Vitamin K, a fat-soluble vitamin, is involved in blood coagulation, bone mineralization, inhibition of vascular calcification, and regulation of numerous enzyme systems. Patients who undergo bariatric surgery (BS), especially procedures that involve a malabsorptive component, are prone to develop vitamin K deficiency (VKD). The causes of VKD include decreased absorptive surface areas, steatorrhea, bacterial overgrowth, marked reduction of carriers of vitamin K, decrease in vitamin K intake, and modifications of gut microbiota. Data on vitamin K status among BS patients are scarce and the strength of evidence supporting vitamin K supplementation is weak. Thus, this systematic review summarized the scientific literature on vitamin K and examined the status among patients before and after BS, as well as among pregnant women with a history of BS. A MEDLINE/Pubmed and Embase electronic search was performed. After a thorough screening of 204 titles, 19 articles were selected by 2 independent reviewers. Five studies on BS candidates (n = 750), 12 studies after BS (n = 1442), and 4 studies on pregnant woman after BS (n = 83, of them n = 7 from case reports) were included. Results of the current review suggest that patients who undergo major malabsorptive surgeries are at a higher risk of developing VKD and should be better monitored. At this point, it is still unclear whether supplementation of vitamin K is required, and what oral dose or vitamer type should be used to normalize serum levels after different types of bariatric procedures. It should be noted that the current protocols for VKD treatment are still experiential in these patients. It is also unknown at what intervals screening tests for vitamin K should be performed and what assay is most appropriate for screening purposes. Future studies are needed to answer these unresolved issues.
维生素 K 是一种脂溶性维生素，参与血液凝固、骨矿化、抑制血管钙化和调节许多酶系统。接受减肥手术（BS）的患者，尤其是涉及吸收不良成分的手术，容易发生维生素 K 缺乏症（VKD）。VKD 的原因包括吸收表面积减少、脂肪泻、细菌过度生长、维生素 K 载体明显减少、维生素 K 摄入量减少以及肠道微生物群的改变。BS 患者的维生素 K 状态数据稀缺，支持维生素 K 补充的证据强度较弱。因此，本系统评价总结了有关维生素 K 的科学文献，并检查了 BS 前后患者以及有 BS 病史的孕妇的维生素 K 状态。进行了 MEDLINE/Pubmed 和 Embase 电子检索。经过对 204 个标题的仔细筛选，由 2 名独立评审员选择了 19 篇文章。纳入了 5 项 BS 候选者研究（n = 750）、12 项 BS 后研究（n = 1442）和 4 项 BS 后孕妇研究（n = 83，其中 n = 7 来自病例报告）。本综述的结果表明，接受主要吸收不良手术的患者发生 VKD 的风险更高，应进行更好的监测。目前尚不清楚是否需要补充维生素 K，以及在不同类型的减肥手术后，应该使用哪种口服剂量或维生素 K 同型来使血清水平正常化。需要注意的是，目前针对这些患者的 VKD 治疗方案仍然是经验性的。目前尚不清楚应该在什么间隔时间进行维生素 K 筛查测试，以及哪种检测最适合筛查目的。需要进一步的研究来回答这些未解决的问题。
