When you think of vitamin C you probably automatically picture oranges (though capsicum, dark leafy greens, kiwifruit, broccoli and berries also boast high vitamin C levels), but what comes to mind when you think of vitamin K?
While it's not the most talked about, vitamin K is hugely important.
"Vitamin K is a fat-soluble vitamin that we need every day for good health. There are two forms of vitamin K. There is vitamin K1, and our main dietary source of it comes from from plant sources. Then there is vitamin K2, found in fermented foods and some meats and cheeses, and can be converted from vitamin K1 in our bodies," Chloe Phillips, Accredited Practising Dietitian told The Huffington Post Australia.
Green leafy vegetables are our main source of Vitamin K. The darker the better!
"Vitamin K's main role in our body is in blood coagulation (clotting), but it is also involved in bone metabolism, cell growth and vascular health, which is the health of our arteries and veins."
And like so many of the other vitamins, the main source is the green leafy stuff. Popeye was really onto something.
"Green leafy vegetables are our main source of Vitamin K. The darker the better! For example kale, spinach, collard greens, swiss chard and parsley. The vitamin K from plant-based foods is in the form of vitamin K1. Fermented foods such as the Japanese fermented soybean Natto are great sources of vitamin K2, and there are small amounts of K2 in meats and dairy foods," Phillips said.
Said meat and dairy food include foie gras (though eating it comes with its own ethical dilemma), aged and curd cheeses, and grass-fed butter and organ meats.
To gain benefit from these foods in terms of vitamin K, it's best to combine them with a fat source.
A big bowl of blitva, anyone?
"The bioavailability (how easily our bodies access a nutrient) of Vitamin K from food sources, however, is low -- but because vitamin K is fat soluble we can improve this by consuming these foods with a fat source. For example, kale or spinach salad sautéed with a little olive oil or a leafy green salad with some cheese or dry roasted nuts," Phillips said.
The good news is that freezing and cooking these leafy greens does not affect the vitamin K.
"People may have heard about vitamin K in regards to Warfarin, as those on this blood thinning medication need to keep their intake of vitamin K rich foods consistent as to not affect their INR (blood clotting rate)," Phillips said.
Vitamin K can also be supplemented, with brands such as Blackmores, Bioceuticals and Nutrition Care offering oral forms. Speak to your doctor before taking any form of vitamins or supplements.