Hi All, I am wondering if it is a good idea to supplement with synthetic vitamin d (it can be more convenient than sunlight depending on time of year and activities--indoor or outdoor, etc.--), and more so than cod liver oil (which can be expensive for some not to mention the PUFAs). If so, what would the limit be for the average young male from a northerly climate? What problems would one encounter with synthetic vitamin d (the kind allegedly containing 'cholecalciferol'/D3)? How would he overcome these problems(eg. by NOT taking it or combining it with other vitamins A and K, etc.). Any advice would be appreciated.
Cholecalciferol IS natural vitamin D. Specifically, vitamin D3. It's what your skin makes from cholesterol when exposed to the sun, and then the cholecalciferol goes to your liver and is converted to calcidiol and later into calcitriol. D2 is the one you pretty much have no use for, since it's the fungal form and your body would have to convert it and frankly, from everything I've read, our track record for converting fat-soluble vitamin precursors from plants or fungus is pretty poor.
If you look at Weston Price's work you find that even indigenous people who did not live in the Arctic tended to procure sea foods wherever they could, and some of those are pretty good sources of D3. Salmon is the best; shrimp also contains some and there are a few other sources, at least in terms of what we would recognize as food and want to eat. There is no guarantee that we'll make the vitamin in sunlight, especially if coming off a poor diet (Green Pastures tells me you only make enough vitamin D if you have enough saturated fat in your cell membranes--that pretty much rules out most SAD eaters) or if you live too far north (or too far south in the Southern Hemisphere). So having the vitamin D-containing foods is a smart backup in case sun exposure fails you. Nature may abhor a vacuum but it loves redundancy.
If you really can't do the vitamin D foods thing because you're trying to avoid PUFA as much as possible, NOW Foods makes a D3 supplement in an olive oil capsule. Yeah, I was surprised too. Most vitamin sellers use soybean oil in their oil capsules. You don't have the inflammatory issues with monounsaturated oil that you have with PUFA and it is a lot more stable (takes longer to go rancid).
I would get sun anyway, whether or not you're making D. It's good for keeping your circadian rhythm working correctly (as Kaz pointed out with all those big words), and if you stay out of the sun too much, all it takes is one day at a summer festival to leave you feeling like crap on into the evening. Speaking from experience... I have a bad habit of staying indoors too much and then I go to some festival in town and feel poisoned by the end of the day, and I'm not even sunburned. It's something you have to build up a tolerance to if you're a homebody like me--but it's really good for you, so it's worth the effort. And the nice thing about your skin in relationship to the sun is it will tell you when it's had enough. The same UVB rays that help you make vitamin D are also the rays that give you a sunburn when you have been out too long.
Oh and yes, definitely make sure you get A and K in your diet as well, or at least supplement them some way. Retinol is the usual preformed vitamin A I see; you want it in a 10 to 1 ratio or better to vitamin D (9:1, 8:1, etc.). A keeps D honest in terms of what it does with calcium and D is protective against A toxicity.
With K you want vitamin K2, not K1 (menaquinone, not phylloquinone), and you want analog mk-4, not mk-7. mk-4 is found in animal foods; mk-7 is found in natto. As I understand it the mk-4 form can cross the placenta in a pregnant woman while mk-7 can't, and to me that speaks volumes about which version is important in adults as well. K2 is awesome. Along with the usual stuff people blather about blood clotting, it's also instrumental in the production of osteocalcin, which not only strengthens bone and dentin (which is why some people on WAPF protocol halt cavity production in their teeth) but also signals your fat cells to release adiponectin. And that is a nifty chemical that increases your insulin sensitivity. :) I don't know what the recommended ratio is of A and D to K, not sure whether anyone's even worked that out, but you could probably Google it. I should have been in bed hours ago. >_<
Supplementation with Vit D3 is great to fortify ones immune system. http://paleohacks.com/questions/28750/do-you-know-how-vit-d-assists-the-body-in-warding-off-diseases#axzz1I268CJRi
Most people living in the cold north latitudes are D3 deficient. It does aid in transporting calcium to the bones. Over supplementing can lead to hyper calsification (others can fill in the correct name).
I have seen a map of the US that shows the incidence of colon cancer and the incidence gets more profound in the populations going north. I wish I could find that map again. It is thought that less sunlight in the north allows colon cancer to develop.
Many of us start at 10000IU Vit D3 for three to six months then back down to 5000IU per day. After a year, get checked. Dr. K wants his patients in NYC to have 70-100ng/mL in their blood.
I take Now Brands D3 5000IU because the carrier is olive oil. Many brands use soybean oil as the carrier.
I don't think I have ever read of anyone having difficulty supplementing with Vit D3.
I think it's likely that any downsides are vastly outweighed by the advantages of not being deficient. What I wonder is if it might actually be safer to take synthetic vitamin D instead of receiving UV exposure.
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