A new study finds that vitamin K2 may be helpful for nighttime leg cramps. What else can it do for us?
A new study finds that vitamin K2 may be helpful for nighttime leg cramps. What else can it do for us?
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The truth about magnesium and muscle cramps (Nutrition Diva #769)
Welcome to the Nutrition Diva Podcast, where we take a closer look at nutrition research, trends, and claims, so that you can feel more confident about your food and nutrition choices. I’m your host, Monica Reinagel, and today, we’re taking a look at a new study on Vitamin K2 as a potential preventive therapy for leg cramps.
These are more common than you might realize. It’s estimated that about half of us will experience them at some point during our lives. But as we get older, they often get more common, for reasons that I talked about in my episode on magnesium as a treatment for leg cramps. Other things that can make leg cramps more likely are are dehydration, prolonged sitting or standing, and certain medications, including some that are commonly prescribed for high blood pressure, or high cholesterol.
Magnesium is probably the most commonly suggested remedy for this vexing condition–along with strategies like stretching before bed. And while it does seem to work for some, it’s not universally effective–which is why there is bound to be some excitement about this new research.
Before we get into the details of this latest study, let me clarify how nocturnal leg cramps differ from Restless Leg Syndrome, another very frustrating condition that can seriously ruin a good night’s sleep.
Nocturnal leg cramps are a sudden, involuntary contraction of the muscles, causing intense pain–usually in the muscles of the calf or foot. While they usually don’t last very long, they can be enough to jolt you out of sleep and will often leave you sore the next day.
Restless Leg Syndrome, on the other hand, is actually a neurological condition that creates an irresistible urge to move the legs. You might experience this as an uncomfortable tingling or crawling sensation that can only be relieved by moving your legs.
Unlike leg cramps, which are sudden and painful, RLS is more of an ongoing, nagging discomfort that tends to get worse when you’re resting—especially at night. And unlike cramps, which tend to go away after a few seconds or minutes, the only way to relieve RLS is to move your legs, which, of course, isn’t great for getting a good night’s sleep.
So, while both conditions can mess with your sleep and cause frustration, they have different causes and usually require different solutions.
With that, let’s talk about this new research on vitamin K2.
A recent study published in JAMA Internal Medicine tested the effects of vitamin K2 on 200 people who frequently experience nighttime leg cramps. All of the folks in this particular study were 65 or older and they either took 180 mcg of vitamin K2 or a placebo for eight weeks.
And the results were pretty compelling. The group taking vitamin K2 saw a significant reduction in the frequency of their leg cramps—going from more than two incidents per week to less than one (on average). Even better, they reported that their cramps were less severe and didn’t last as long. The placebo group, on the other hand, saw no meaningful change.
There were also no reported adverse effects in the group that were taking vitamin K2. That’s always an important consideration when evaluating a potential treatment—especially for something like leg cramps, where the main issue is discomfort rather than a serious health threat. In fact, there may well be some collateral benefits to K2 supplementation, as it has also been found to increase bone mineral density.
So how do researchers think that K2 works to reduce leg cramps? It might have to do with K2’s role in regulating calcium metabolism. It helps activate the proteins that steer calcium into the bones. And one theory is that this action also serves to direct calcium away from soft tissues—like muscles, which might reduce the likelihood of these involuntary muscle contractions.
While this is just one study, and we’d ideally like to see this confirmed by further studies in other populations, it does suggest a promising new option for people who struggle with nighttime leg cramps—especially if other approaches, like stretching or magnesium, haven’t been effective.
Now, if you know me, you know that I always encourage you to get your nutrients from foods instead of supplements, whenever possible. So, how hard would it be to get 180 mcg of vitamin K2 (the dosage used in the study) from your diet? Actually, it might be pretty challenging.
The average American adult gets about 120 mcg of vitamin K from their diet. But most of this is vitamin K1 (or phylloquinone), which is found in leafy greens and other vegetables. But the form of the vitamin used in this study was K2, or menaquinone. This form of vitamin K is found mostly in fermented foods, particularly natto, a traditional fermented soybean dish that is commonly eaten in Japan. If you are not eating natto on a regular basis, I think you’d be hard pressed to get anywhere close to the 180 mcg of K2 that they used in the study.
In other words, if you are interested in the therapeutic benefits of K2 for leg cramps (or, for that matter, bone health), a supplement is probably your best option. Fortunately, K2 supplements have a very good safety profile. Even so, you’d want to check with your doctor or pharmacist before adding this to your regimen–especially if you are on any type of anticoagulant or blood-thinning medication, as vitamin K plays a key role in blood clotting.
If you do decide with your doctor to add K2 to your regimen, you might want to take it with a meal. Vitamin K is a fat soluble vitamin and may be better absorbed if taken with some fat. And if you find it makes a difference for you in terms of leg cramps, let me know!
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Nutrition Diva is a Quick and Dirty Tips podcast. Our team includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, Morgan Christianson and Nathaniel Hoopes.
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