The Study
Vitamin K Supplementation to Improve Vascular Stiffness in CKD: The K4Kidneys Randomized Controlled Trial.
This study gave one group of people with kidney disease a vitamin pill and another group a fake pill, then checked if their blood vessels got stiffer over a year. It found no difference, so we can say this vitamin didn't help their blood vessels in this case. But it doesn't mean all vitamins or all people would be the same.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists gave people with bad kidney disease a daily vitamin K2 pill for a year to see if it would make their arteries less stiff and reduce heart risks.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 584 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Even though vitamin K2 helps stop calcium buildup in arteries in theory, this study shows it doesn't work in people with advanced kidney disease under these conditions.
- 2159 people took either vitamin K2 (400 mcg) or a placebo daily for 12 months.
- 3No difference was found in artery stiffness, blood pressure, or heart markers between the two groups.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of the American Society of Nephrology : JASN
Year
2020
Authors
M. Witham, J. Lees, Myra White, Margaret M Band, Samira Bell, D. Chantler, Ian Ford, Roberta L. Fulton, G. Kennedy, Roberta Littleford, I. McCrea, D. McGlynn, Maurizio Panarelli, M. Ralston, E. Rutherford, Alison Severn, Nicola Thomson, J. Traynor, A. D. Struthers, K. Wetherall, Patrick B. Mark
Related Content
Claims (6)
Taking 400 micrograms of vitamin K2 every day for a year does not change augmentation index, abdominal aortic calcification, blood pressure, B-type natriuretic peptide levels, or physical function in adults with moderate to severe chronic kidney disease.
Vitamin K2 does not reduce vascular stiffness in people with chronic kidney disease, but this does not mean other types of vitamin K, higher doses, longer use, or different patient groups also have no effect.
Taking 400 micrograms of vitamin K2 daily for one year does not change arterial stiffness in adults with moderate to severe chronic kidney disease.
Taking vitamin K supplements does not change the stiffness or calcification of blood vessels in people with chronic kidney disease.
Taking vitamin K2 supplements for 12 months does not change levels of blood markers related to mineral balance or heart health in adults with moderate to severe chronic kidney disease.
Taking vitamin K2 supplements is associated with a lower rate of calcium buildup in the arteries.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.