Researchers Assess the Role of Vitamin K2 in Managing Nocturnal Leg Cramps

Published in JAMA Internal Medicine, researchers assessed the role of vitamin K2 in reducing the frequency, duration, and severity of nocturnal leg cramps (NLCs) among older individuals. The researchers conducted a randomized clinical trial that compared vitamin K2 to a placebo, which suggested that vitamin K2 could be effective in managing NLCs.¹

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NLCs, also known as night leg cramps, are agonizing, involuntary contractions of leg muscles that occur during sleep, which commonly impact the calf muscles, feet, or thighs.² While the specific cause remains unknown, researchers suggest that sitting for long periods of time, overusing the muscles, standing or working on concrete floors, having poor posture during the day, kidney failure, diabetic nerve damage, mineral deficits, and issues with blood flow are all possible causes.²

Vitamin K2 is a fat-soluble vitamin that is involved in blood clothing and aids bone and heart health. The vitamin can be found in animal-based foods, which include beef liver and cheese.³ While it is known that vitamin K2 relates to bone and cardiovascular health, its impact in muscles remains limited, according to study authors.¹

The study authors noted that around 50% to 60% of individuals experience NLCs throughout their lifetime. Among the individuals impacted, around 20% experience levels of distress and insomnia connected to the cramps that leads them to seek medical attention. Despite its large prevalence, there is limited research that highlight which medication could effectively treat NLCs. Quinine, which was once deemed as an effective treatment, is no longer recommended as it relates to severe adverse events.¹

The multicenter, double-blind, placebo-controlled randomized clinical trial included 199 individuals 65 years and older with 2 or more documented episodes of NLCs during 2 weeks of screening. The individuals were selected through recruitment advertisements in Third People’s Hospital of Chengdu and Affiliated Hospital of North Sichuan Medical College between September 2022 and December 2023, according to study authors.¹

Individuals were randomly assigned to receive vitamin K2 180 μg or a similar placebo capsule every day for 8 weeks in a 1:1 ratio, with 103 individuals in the vitamin K2 group and 96 individuals in the placebo group. The primary outcome of the study was the mean number of NLCs per week in the vitamin K2 and placebo arms. The secondary outcome was the duration of muscle cramps measured in minutes and the severity of muscle cramps evaluated, using an analog scale which ranged from 1 to 10, according to study authors.¹

“The baseline characteristics of the participating individuals, including their concomitant chronic diseases, were similar between the treatment groups. At baseline, the mean (SD) number of NLCs was comparable in both the vitamin K2 group (2.60 [0.81]) and the placebo group (2.71 [0.80]),” said the study authors.¹

The results displayed that over the 8-week period, individuals in the vitamin K2 group displayed a marked reduction in cramp frequency, with a mean of 0.96, as individuals in the placebo group displayed a mean of 3.63. Additionally, the duration of pain intensity decreased in the intervention phase for both vitamin K2 and the placebo, but vitamin K2 had a greater mean reduction in NLC severity. The study authors noted that no adverse events were reporting among individuals in the vitamin K2 group.¹

“Due to the safety profile of vitamin K2, clinical trials are encouraged to confirm the efficacy of cramping management and its impact on the quality of life and sleep in patients with NLCs,” said the study authors.¹

REFERENCES

1. Tan J, Zhu R, Li Y, et al. Vitamin K2 in Managing Nocturnal Leg Cramps: A Randomized Clinical Trial. JAMA Intern Med. Published online October 28, 2024. doi:10.1001/jamainternmed.2024.5726

2. Leg Cramps. Cleveland Clinic. News release. June 5, 2023. Accessed November 8, 2024. https://my.clevelandclinic.org/health/diseases/14170-leg-cramps

3. Vitamin K2: Everything You Need to Know. Healthline. March 5, 2024. Accessed November 8, 2024. https://www.healthline.com/nutrition/vitamin-k2