The evidence is piling up for including Vitamin K2 in your diet. Studies indicate that it can improve cardiovascular health by reducing arterial calcification and stave off osteoporosis by helping get calcium where it's needed in the body, in the bones.
It appears that Vitamin K2 (which is not much like it's cousin K1 at all) could help inhibit cancer cell growth in prostate and lung cancer and leukemia, providing a boost to traditional treatments for these diseases.
This little understood vitamin may even help people keep their rosy faces less wrinkled for longer.
But getting wondrous K2 into your diet (let's always look to food before supplements) may not easy if you are pursuing a humane and sustainable approach to food.
For instance, one of the "best" sources of K2 is goose liver pate, which would also top the list of most inhumanely obtained animal proteins. Do we even need to review how geese (and also ducks) are force fed for weeks to enlarge their livers, essentially sickening them, to obtain this sinfully bad cracker spread?
Luckily, there are many better sources of K2, also called menaquinone, with two component parts, MK-4 and MK-7 (and some debate which is better MK-4 or MK-7). Among the foods that provide K2 are simple butter and certain cheeses.
And the early research suggests that keeping sustainability in mind will serve you well in finding the best sources of Vitamin K2. Butter from the grain-fed, CAFO-production machine does not provide this vitamin. However, grass-fed butter does deliver K2, according to several sources, among them a man who will be familiar to natural/organic dairy-eating adherents, Dr. Weston A. Price.
Dr. Price, who praised the value of full-fat and unpasteurized dairy products, apparently experimented on butters to find which carried an element he identified as "Activator X" (which people believe was K2 – a story too long for here). He found that pastured butter contained this health-conferring ingredient, aka Vitamin K2, but commercial butter, not so much.
Cheeses are a different story; it's not the grass feeding but the bacteria used in making them that's key. Thus Gouda and Brie are high in K2, but not necessarily other cheeses, according to Dr. Kate Rheaume-Bleue, who wrote Vitamin K2 and the Calcium Paradox: How a Little Known Vitamin Could Save Your Life.
Another great source of Vitamin K2, it turns out, is natto, often described as a foul-smelling, stringy soybean-derived food that Japanese people eat. So natto’s not got the best PR story. It’s not exactly upending the Western diet. Still, if you like fermented foods, which have the added benefit of keeping your gut bacteria in shape, natto provides both a direct source of K2 and a way to assist your gut bacteria ing converting Vitamin K1 into K2 (yes your good bugs can do that – what a relief it is).
So you may want to try natto; maybe even make some at home.
Hold your nose while its fermenting and you’ll discover it’s actually offers more than its PR advance team suggests. Natto's a protein food. It’s affordable and lower on the food chain, which is great for vegetarians, vegans and anyone factoring in sustainability.
Natto, according to "The Healthy Home Economist" contains 1,103 mcg of K2 per 3.5 oz portion, making it the richest K2 food you can find, and hopefully, eat. (Goose liver pate contains about 1/3 as much.)
Not sure about Natto? It's back to Brie and Gouda cheese and also fermented vegetables, though the amount of K2 generated can vary greatly, according to Dr. Rheame-Bleue.
So here's the short list, with the amount of Vitamin K2 per 3.5 oz. serving:
Natto …………………………………….….1,103 mcg
Fermented vegetables………………………50 to 500 mcg (according to Dr. Rheame-Bleue much depends on the starter sauce).
Sauerkraut (also fermented veggie)……..4.8 mcg per 3.5 oz. serving (this is much lower than the doctor's range, and we're not sure why)
Gouda…………………………………………..75 mcg per 3.5 oz. serving
Brie……………………………………………..57 mcg per 3.5 oz. serving
Pastured egg yolks……………………………15 mcg per 3.5 oz. serving
Pastured butter……………………………….15 mcg per 3.5 oz.
Chicken liver, breast, legs…………………….12.6 to 8.5 per 3.5 oz.
In addition to chicken, assorted other meats, including some you wouldn't want to eat, like hot dogs, and some you might, like calf or chicken liver, contain significant, but smaller amounts of K2.
The studies looking at grass-fed meat vs. grain-fed animals haven't been done (and don't hold your breath) but one could reasonably guess that the same chemistry that raised K2 levels in pastured butter and eggs works here too.
Finally, if you supplement, don't get crazy. While neither K1 nor K2 has not been shown to carry any toxicity (such as one finds with excess Vitamin A consumption for example), the human body can only absorb so much. Also, while some people may be deficient in K2 because of a chronic health condition (liver disease, inflammatory bowel disorders or bariatric surgery), regular folks without special dietary issues may not be.
A final note: If natto proves to be, in your book, just nasty-o, remember, your own healthy digestive system can make K2, using K1, and that is easy to get on the menu. You'll find K1 in kale, spinach, mustard greens, broccoli, Brussels sprouts, cabbage and other green leafies, proving once again that it's never wrong to eat your veggies. (Don't put Kale in every smoothie, though, you might overdose on Vitamin A!)
(Photo of natto at top: Kinchan 1, Wikimedia Commons)
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