Do you bruise easily? Did you suffer from "shin splint" bone pain as an adolescent? Were you or your children born by caesarian section due to cephalopelvic disproportion (baby's head too big for mother's pelvis)? Trying to conceive (maybe having trouble)? Are you dark-skinned and diabetic? At risk for osteoporosis or hardened arteries? Get your vitamin D levels checked.
I'm going to cheat and send you straight to someone who knows way
more about vitamin D than pretty much anyone. It's a long video, and I
figured I'd watch the first bit and start skimming, but it's fascinating
- check it out and tell me what surprised you, or what you'd like to
follow up on a little more (for me, that's suitable holiday destinations below the 29th parallel). He gives the officially-recommended levels and then his revised suggestions, really fast and in various units measurements, so have your pen ready!
The bottom line is that the majority of light-skinned people are deficient in vitamin D, and nearly all dark-skinned people are. The recommended daily allowance is pitifully low, and still fosters signs of deficiency, so skip the measly 400 units They're recommending and aim for 2000 a day plus smart sunshine. The good news is that the body can store it for a while, so a good dose once a week should keep you happy, robust, and lean.
But that stuff's moderately common knowledge. What about D's buddies in the fat-soluble vitamin line-up?
We know that A and D work in synergy, and that as long as they're taken from natural sources the alarmist reports of vitamin A toxicity are not an issue. We know that E is an antioxidant most famous for raising the price of facial moisturisers and fake-food salad dressings. But what the heck is vitamin K?
From RealMilk.com: K2 "is a
powerful catalyst which helps the body absorb and utilize minerals...
has almost completely disappeared from the modern western diet. Sources
include organ meats from cows eating green grass, fish eggs and
shellfish.[Pastured] butter [from calcium-sufficient soil] can be an especially rich source ... It
disappears in cows fed cottonseed meal or high protein soy-based feeds.
Fortunately, it is not destroyed by pasteurization."
WAPF: "Vitamin K2 is produced by animal tissues from vitamin K1, which
occurs in rapidly growing green plants... it acts in synergy with the
other fat-soluble vitamins: A and D vitamins command cells to make
proteins, but vitamin K brings these proteins to life. K2 is important
for the utilization of minerals, protects against tooth decay, supports
growth and development, is involved in normal reproduction, protects
against calcification of the arteries leading to heart disease, and is a
major component of the brain." It seems to 'activate digestive enzymes,
regulate blood sugar, and prevent kidney stones'.
Polyunsaturated oils reduce K2 and D absorption. Aspirin and sulfa drugs destroy vitamin K. Large doses of vitamin E block K absorption. The heart
medication Kumadin (aka Warfarin = rat poison) blocks K2 reception;
children born to women taking this drug have dangerous facial malformations.
A rarely-mentioned source of K2 is bacteria - in your gut or in your sauerkraut. For those with fat metabolism problems, (people with gall stones or who have had their gallbladder removed, for example,) focus on sources of K1 and try to get creative with lactofermentation. If you tolerate dairy, stir a tablespoon of raw whey through room-temperature condiments and leave them on the counter for a few hours before refrigerating and using as usual. Otherwise, it's off to the library/interwebs for Wild Fermentation for you!
I've been trying for years to get more fermented foods in my diet. It's not really working - at least, not to the level I'd need to satisfy these guidelines. But unless you're pregnant or trying to be, as long as you have your gallbladder, and providing you're not a vegetarian, if you eat well you should be fine for K2. So you know what? I'll think about supplements but, until then, I'm going tanning until the sun starts to shine again.