Vitamin K: How to reap the benefits of this essential nutrient

A primer on how vitamin K keeps you healthy, what foods are jam-packed with it and when you need to be careful about how much you ingest

vitamin K

Image, Roberto Caruso.

What it does
When you’ve sliced your hand open, it’s vitamin K that comes to the rescue — creating the proteins that cause our blood to clot when we’re bleeding. This essential nutrient also helps balance calcium levels, prevent fractures, promote cell growth and maintain blood vessels, says Kelly Anne Erdman, a registered dietitian in Calgary.

Are you getting enough?
If you consider yourself even a mildly healthy eater, you’re likely taking in lots of vitamin K. It is found in most leafy green vegetables: kale, spinach, romaine lettuce, collard greens, Swiss chard, turnip greens and mustard greens. “The darker the leaf, the better,” says Erdman. It’s also found in soy beans, broccoli, brussels sprouts, cauliflower, green peas, cabbage.

Health Canada recommends men over the age of 19 take in 120 micrograms (mcg) of vitamin K each day. For women, the baseline is lower at 90 mcg. “If you sit down and have just one cup of kale in your salad, you’re getting more than 500 mcg of vitamin K,” says Lauren Baker, a registered dietitian in Mississauga, Ont. “Your diet will typically cover what you need.” She also notes that there are no risks associated with having more than the recommended amount.

When to supplement
Deficiencies are rare, but can occur in people whose large intestine cannot absorb enough of the vitamin from food, says Erdman. She also suggests those at risk of osteoporosis may want to consult with their doctors about the benefits of vitamin K. “Studies that have looked at bone health,” says Erdman, “show that while it may not help build bones, vitamin K may help reduce fracture risk.”

When to take extra precaution
Anyone on blood thinners should be aware of the negative interaction a vitamin K supplement can have with their medication, cautions Baker. They also need to watch their food-based intake of vitamin K: too much fluctuation in daily intake levels can impact the effectiveness of blood thinners. “If you’re on blood thinners, vitamin K is something you should discuss with your doctor,” says Baker.

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