Vitamin K2 May Ease Nighttime Leg Cramps

New research suggests that people experiencing sleep-robbing "Charley horses" at night may benefit from taking vitamin K2.

Nocturnal leg cramps or sudden uncontrollable muscle spasms in the thigh, calf, or foot are a frustrating phenomenon that can disrupt even the most blissful night's sleep. Statistics suggest that up to 60% of adults and 40% of children and teens experience leg cramps at night and nearly every adult over 60 will endure them at least once.

Managing leg cramps, AKA Charley horses is challenging since few effective treatments are available. The American Academy of Family Physicians (AAFP) recommends that people with leg cramps use deep stretching and deep tissue massage to help alleviate the problem.

Medications, such as carisoprodol, diltiazem, gabapentin, orphenadrine, and verapamil, and magnesium and vitamin B12 supplements may be helpful for some people. Still, the AAFP says quinine, an antimalarial drug that's sometimes prescribed for nocturnal leg cramps, should not be used to treat the condition due to its adverse health effects.

In addition to vitamin B12 and magnesium, a recent study found that a lesser-known nutrient — vitamin K2 — may be a proven winner when it comes to treating nighttime leg cramps.

The results of the investigation showed that people who took K2 had significantly fewer cramps during the night, and less painful cramps than those not taking the vitamin.

Vitamin K2's impact on nighttime leg spasms

The latest research, published in JAMA Internal Medicine, was based on the scientist's previous investigation, which found that vitamin K2 helped relieve dialysis related leg cramps in people with kidney disease.

This more recent study included 199 male and female participants with an average age of 73 who had a similar number of leg cramp episodes, around 2.60 to 2.71, per week.

For 8 weeks, the participants received a daily dose of either 180 micrograms of vitamin K2 or a placebo capsule.

After the 8-week trial concluded, participants who took vitamin K2 said they experienced fewer leg cramps, down to less than one per week. In contrast, individuals taking a placebo reported more leg cramps, up to 3.63 per week.

In addition, the pain level and duration of the leg cramps lessened in the vitamin K2 group.

The participants also reported no adverse effects while taking the fat-soluble nutrient.

"Our results demonstrated that daily vitamin K2 supplementation alleviates muscle cramps in older individuals affected by NLCs, manifested by decreased frequency, shortened duration, and weakened intensity," the study's authors wrote. "Notably, cramping frequency was significantly reduced compared with the placebo group, starting from the first week of intervention with vitamin K2."

Despite the favorable safety profile of vitamin K, it can interfere with the anticoagulant actions of warfarin, a blood thinner often prescribed for older individuals. Therefore, the scientists note that vitamin K2 is not recommended for people taking warfarin.

Sources of vitamin K2

According to the National Institutes of Health (NIH), since it has a low potential for toxicity, there are no established upper limits for vitamin K, which includes K1 and K2.

Daily recommended allowances for vitamin K in adults 19 years and older is 120 micrograms for men and 90 micrograms for women. Foods that contain 20 or more micrograms of vitamin K include:

• Natto
• Collard greens
• Turnip greens
• Spinach
• Kale
• Broccoli
• Soybeans
• Carrot juice
• Soybean oil
• Edamame
• Pumpkin

K2 is also available as a dietary supplement. However, since it can interact with some medications, including warfarin and specific antibiotics, it's best to consult with a healthcare provider before taking vitamin K2 supplements.