I really like Jack Norris's blog: http://jacknorrisrd.com/, which I find to be less biased and more accurate than other sites.
You find all kinds of crazy shizzle on the internet...
I've read a lot of inaccurate information about nutrition from various sources (regardless of their stance on vegetarianism), though. For example, I've read on a few sites (and even in a book) that nettles and sunflower seeds are a great source of vitamin D, but I have yet to find any actual sources to back this up (the sites never seem to cite any sources relevant to this). I have, however, read amazing tales of vitamin D being present in mushrooms that have been exposed to UV rays and these tale-tellers pretty much always cite their sources.
What I'm saying is it's always a good idea to double-check your 'facts' -- you don't want to get pwnd in a nutritional debate....
I consulted my favorite vegetarian reference book, _Laurel's Kitchen_ by Laurel Robertson (I got my copy used, from Old Friends books store). They have a lot of nutritional tables that are quite handy. They mention that human milk has Vitamin D, and that nursing mothers should sunbathe with their infants. But nothing about sunflower seeds...
ReplyDeletei also feel as if there is so much we still don't know about nutrition. how food works. the synergies. for instance, take D2 (vegan for of vitamin D) and D3 (non-vegan form). Are they the same? Is one nutritionally inferior? What about absorption? I can't find any information giving a definite answer.
ReplyDeleteKathleen, I've read a TON about vitamin D lately (for various reasons). So, I'll blah blah blah about it a little here (I've cited a couple sources, but if you'd like, I can go back and cite some more):
ReplyDeleteFrom what I gather, they are both converted into the same chemical, but D3 has a longer half-life than D2. In large single-doses, D2 (ergocalciferol) doesn't hang around as long as D3 (cholecalciferol -- vitamin D3 is made from cholesterol -- I read when your body makes it, it cannibalises a molecule of cholesterol for every molecule of D made!), but if you are taking a daily dose, they are equally effective:
http://www.veganhealth.org/articles/bones#d2d3
(This is an article by Jack Norris -- I like him because he always cites his sources.)
This is a very long paper that says D3 is still more effective and potent and discusses a wide variety of reasons (although it seems to indicate in some cases they are equally effective):
http://www.ajcn.org/content/84/4/694.full
The biggest problem is that more and more people lead predominantly indoor lifestyles and don't make enough of their own D3 from the sun -- it is incredibly difficult to get enough vitamin D from diet alone (whether from fortified foods or non-vegan sources).
The second biggest problem (which is not applicable to people in more equatorial regions) is that it is incredibly difficult (some say impossible) to get enough UVB exposure in the winter -- from what I gather, once you are further north (south for our antipodean* friends) than a certain latitude, the sun's rays are coming in at too low an angle.
* And everyone else in the southern hemisphere...
Some people say it kind of sucks having to rely on supplements to get enough vitamin D, and I see where they're coming from. However, I think it's pretty cool that we are advanced enough to have supplements and are able to lead predominantly indoor lives without compromising our health. (I still try to spend time outdoors in the summer, though!) :D
Gosh, this is such a long comment, I ought to put in more citations and make it into a post! ;p