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Sun exposure for vitamin D may not be reliable for
for everyone.
Vitamin D is a little bit of an imposter; it’s not really a vitamin at all because, technically, it’s not required in the diet. We can make all we need with adequate skin exposure to sunlight.
Theoretically, it doesn’t take much effort to synthesize enough vitamin D. Just 20 to 30 minutes in the sun three times a week can do it for some people. But older people and those with darker skin make vitamin D less efficiently. Smog interferes with vitamin D manufacture as well. So does the use of sunscreen.
It’s become clear that most people need an additional source of vitamin D to avoid deficiency. Vitamin D is needed for healthy bones, but it also may play a role in reducing cancer risk and depression.
Vitamin D in foods
The need for a dietary vitamin D source became clear in the industrial age when jobs took many people, including children, out of the sunlight and into the factory. With few natural dietary sources of this vitamin—it’s generally found only in fatty fish and some eggs—deficiency became widespread. The government responded by requiring vitamin D fortification of milk.
Unless it's added to it, though, milk does not contain vitamin D. And because it is added to large volumes of milk, there has been evidence of quality control problems, with vitamin D not being well mixed in the milk. A series of studies from the 1990s showed that, in some factories, the vitamin D was poorly distributed. Some cartons of milk ended up with no detectable vitamin D while others had extremely high amounts. This raised questions among experts about whether people could depend on milk for meeting vitamin D requirements.
Vegan vitamin D
Most of the vitamin D used to fortify foods is vitamin D3 or cholecalciferol. It’s derived from animals—often from the wool of sheep. An alternative source is vitamin D2, or ergocalciferol, which comes from bacteria. Among vitamin D experts, there has been debate about D2 and whether it works as well as D3. But recent research shows that the vegan vitamin D is just as effective as the type derived from animals.
Most mainstream products—like breakfast cereals—contain vitamin D3. But a growing number of vegetarian foods, including soy and other nondairy milks, are fortified with D2. There are also D2 supplements in nongel caps available now.
The recommended intake (referred to as an Adequate Intake or AI) for vitamin D is 5 micrograms per day for adults, 10 micrograms for those over age 50 and 15 micrograms for people over the age of 70. But there is evidence that these amounts are much too low. In fact, recent research suggests that low vitamin D status is extremely common among all population groups. The growing consensus is that recommendations for vitamin D intake need to be raised.
If you get regular mid-day sun exposure without sunscreen on days when the sun is hot and bright enough to cause sunburn, you are probably making enough vitamin D. But this may not be true for those with more skin pigmentation or for older people. It’s probably prudent for everyone to get 25 micrograms of vitamin D daily, particularly during times of the year when there is no hot sunlight or if you avoid the sun. Vegans can choose supplements of vitamin D2.
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Comments
Hey Virginia!
Just a head's up that there now are *some* (not many) vegan D3 options out there....so it's no longer accurate to say that *all* D3 is animal-based. Do a search on VeganFitness.net - Ryan from VeganEssentials has been highlighting this, surprising to me, but it's good to be informed.
Certainly most D3 will still be animal-derived, but hopefully this shift continues!
Hi Dave,
I'm wondering how this could be possible since vitamin D3 is derived from a cholesterol precursor that is found only in animal cells. Even the synthetic vitamin D is manufactured from cholesterol--and there is no cholesterol in plants!
Heya! You can start reading about it here:
www.veganfitness.net/forum/viewtopic.php?p=310152#310152
Apparently one type is sourced from cottonseed.
If i recall, there is also a type of cholesterol in plants, or maybe it's just phytosterol..maybe that's what converts to D3?
Best contact the companies listed in that thread for the 411... The owner of Vegan Essentials is pretty thorough tho, so i'm willing to take his word for it..
Great column Virginia!
I ordered some Ami's vegan dogfood from Vegan Essentials and noticed that it had d3 listed in the ingredients. I called VeganEssentials and was told that there certainly is a synthetic D3. I didn't trust it and sent it back but that's what I was told.
You have to ask yourself, where does the cow get her vitamin d?
See what happens when veganism becomes dogmatic?
This "L" person is now returning a vegan dog food, which Ryan at Vegan Essentials has gone through the trouble of *ensuring* is vegan, and yet it's just tossed back in his face because of generalizations..doubtless he, and other vegan organizations and companies will be given grief over this subject. This doesn't help the movement!!
Hi all,
If anyone is checking back for more info on this subject, I have been working on it. I've been in contact with a number of vegan experts and vitamin D experts; no one has heard of any plant sources of D3. I still have some emails out.
Compliments, Virginia! I'm happy to see that it is a vegan who is posting the first article on the issue that is spot on in all respects.
Ginny <<Even the synthetic vitamin D is manufactured from cholesterol--and there is no cholesterol in plants>>
Ergocalciferol, or Vitamin D2 is vegan and often made from yeasts, fungi or bacteria. If you sun-dry mushrooms they also will generate large quantity of Vitamin D2 from UVB radiation. Many plants or plant products are Vitamin D2 active upon UVB exposure, like olive oil or cassava. Obviously there's a route for building Vitamin D which does not rely on (animal based) cholesterol.
There ARE two plants which naturally contain even Vitamin D3, one is Golden Oat Grass which frequently causes -difficult to achieve- Vitamin D overdoses in horses and cows. The other is Solanum Glaucophyllum, or Waxyleaf Nightshade.
The question is, do the producers of products which claim to contain vegan D3 really go through a route of harvesting a di
continued from post below (read older post below first)
... of harvesting a difficult route of a rather esoteric source a vegan Vitamin D3, when a) with Vitamin D2 a valid alternative which is known to be able to be produced in a vegan manner is available. In fact, it would be difficult if not impossible to produce D2 from animal sources, however supplements may be pressed with lactose or gelatin or whatnot. b) animal based Vitamin D3 is *very cheap and abundantly available*.
I've had contact with Amicat myself, and they were very happy to give information until I brought up the issue of D3. Suddenly it was all about "trade secret" and communication stopped.
I found this to be a very weird justification, because what loss would Amicat have if their "trade secret" about the mysterious and supposedly vegan Vitamin D3 was out on the table? They would gain more vegan customers I'd think.
continued from older post below, (read older post below first)
Wow, this character limitation is really crippling my urge to disseminate good information.
Dave, please don't defame critical thinking and the desire to have vegan products to be what they claim, namely vegan (that's what customers of vegan shops pay them for....vegan products) as "dogmatic". You are in no position whatsoever to control or define what "hurts the movement", when you're positioning yourself against vegan interests. This rhetorical method of denigration reeks of welfarist propaganda and exposes an attitude problem to boot.
The question if Vitamin D3 is vegan or not is completely legitimate, especially since no one has provided valid evidence that it exists. It's really a mythical substance and with all myths, some just want to believe. However customers not so much inclinded towards religion are certainly in her or his right to return the product which does not meet *her or his* standard.
<<II've been in contact with a number of vegan experts and vitamin D experts; no one has heard of any plant sources of D3.>>
Which kind of shows the limits of "expertism".
But anyway, why go the experts when the experts come to you?:-) As I mentioned in another post, there are at least two plants known to contain Vitamin D3. This however doesn't mean that the companies claiming vegan D3 in their products know nor utilize these sources. Their source is even more mysterious. The biggest doubt being: Why jump through hoops when D2 is valid, vegan, cheap and abundant? A "special vegan D3" produced in tiny quantities would be gloriously expensive to manufacture. It just doesn't make any sense.
Ava, thanks for your comments. If synthetic vegan vitamin D3 is being manufactured, it is being made--I assume--from plant sterols. So my real question (since my biochem background is a little weak!) is: can vitamin D3 be created from plant sterols? If there is active D3 in the two plants you mentioned, then it seems that this occurs in nature so could possibly also be done in a lab? The vitamin D nutritionists and biochemists I spoke with were not aware that this has ever been done. I agree that, given the sort of esoteric nature of this mythical vegan D3, it is hard to imagine that a small cat food company could afford to get their hands on something like this. And as you noted, why would they when D2 is just as good? So I'm open to all the possibilities here, but not convinced about any of them.
Tropical humans seem to compensate by converting more vitamin D into its active form. Although a single UV-B exposure produces less vitamin D3 in black subjects than in whites, the difference narrows after liver hydroxylation to 25-OHD and disappears after kidney hydroxylation to 1,25-(OH)2D. The active form of vitamin D is thus kept at a constant level, regardless of skin color (Matsuoka et al., 1991, 1995).
Robins (2009) notes that nearly half of all African Americans are classified as vitamin-D deficient and yet show no signs of calcium deficiency, which would be a logical result of vitamin D deficiency. Indeed, they “have a lower prevalence of osteoporosis, a lower incidence of fractures and a higher bone mineral density than white Americans, who generally exhibit a much more favourable vitamin D status.” He also cites a survey of 232 black (East African) immigrant children in Melbourne, Australia, among whom 87% had levels below 50 nmol/L and 44% below 25 nmol/L. None had rickets
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