No association between vitamin A or retinol intake and the risk of hip or total fractures was observed in postmenopausal women. Only a modest increase in total fracture risk with high vitamin A and retinol intakes was observed in the low vitamin D-intake group.In other words, only women with a low vitamin D intake (less than 440 IU per day) had an increased likelihood of fracture at high vitamin A intakes (more than 8,000 IU per day). This is consistent with the hypothesis that an above-average intake of vitamin A only increases the risk of osteoporosis in the presence of low vitamin D, and that vitamin D deficiency, not vitamin A excess, is the true problem. Hop over to Chris's post for more details.
Vitamin A on Trial: Does Vitamin A Cause Osteoporosis?
Is Vitamin A Toxicity a Concern?
24 comments:
Hopefully you and Chris will continue your endeavors to pursue important research on nutrition and health after you get your Ph.D.s Let's here it for the pre docs!
I found the following post from Chris's blog interesting too.
It suggests that you can suffer vitamin D toxicity if you're deficient in vitmin A+K.
I believe this is the reason I originally had a negative reaction to supplementing vitamin D.
http://blog.cholesterol-and-health.com/2009/04/tufts-university-confirms-that-vitamin.html
These two papers may bring the safety of Vitamin D supplementation into perspective.
The Risk of Additional Vitamin D.Evidence from clinical trials shows, with a wide margin of confidence, that a prolonged intake of 10,000IU/d of vitamin D(3) poses no risk of adverse effects for adults, even if this is added to a rather high physiologic background level of vitamin D.Circulating Vitamin D3 and 25-hydroxyvitamin D in Humans: An Important Tool to Define Adequate Nutritional Vitamin D StatusThe Word Verification for this post is VITUMEN may I suggest the acumen required for the effective the use of vitamin supplements as a possible definition?
An article in the Globe and Mail reports on conference proceedings:
1/3rd Canadian kids deficient in Vitamin D statusWe'll have to wait awhile yet for an publication, hopefully the author's are just using the conference as a trial run for their data and have a manuscript ready.
Yesterday I received the Spring '09 issue of Wise Traditions, the WAPF quarterly journal. Lots o' info about Vit A & D, as well as CLO and WAPF's response to the A & D controversy and disagreements. Anyone else read this yet? Can't wait to learn what everyone here thinks.
Stephan,
I looked over your topics list for your posts that pertain to fertility, esp the fat soluble vitamins (ADEK), but it fertility isn't listed as a key word. Off the top of your head, can you think of a few of the posts that are most useful to someone who wants to enhance fertility with nutrition (no, not me, but I sure wish I had more of this info 15 years ago!)?
Anna,
I don't receive Wise Traditions unfortunately, and it isn't published on line yet.
I would think the posts on fat-soluble vitamins and fat quality would pertain most to fertility.
Thanks Stephan,
I sent her Nina Planck's new book, Real Food for Mother and Baby; The Fertility Diet - Eating for Two and Baby's First Foods. Nina send me a preview copy to review and I skimmed it last night. Not as detailed scientifically as your posts, but it's chock full of very good common-sense advice that parallels traditional nutrition, but iwth a modern context. It's the book I wish I'd had 10-15-20 years ago.
I highly suggest Planck's book for anyone (male or female) who wants or plans children anytime in the future, especially if they don't usually read nutrition stuff.
Anna,
if you understand Danish; there is a book by gynecologist Bjarne Stigsby called 'Spis dig Gravid' (Eat yourself to Pregnancy).
I also want to remember that there has been some posts at the blog Cooling Inflammation on this topic.
Anna & others,
I receive the WAPF's journal -- fascinating stuff for sure. The article that really caught my attention was the article called "Update on Cod Liver Oil Manufacture: Returning to Traditional Production Techniques for the Quintessential Sacred Food."
I found it interesting how one traditional European method of producing cod liver oil consisted of fishermen accumulating cod livers in a barrel over several months beginning in January which they then took home for the summer after putrefying. They then skimmed the oil off the top!
The man who wrote the article is trying to replicate traditional processing techniques (NOT the one above, though) for the modern market. His version of traditional fermented cod liver oil already shows great promise in terms of vitamin content:
"In general, the test totals are substanially higher for vitamin D than one would find in any industrialized cod liver oil. Whereas the high-vitmain cod liver oil contains almost 12,000 IU vitamin A and 1200 IU vitamin D per teaspoon ... the fermented oil contains 4,000-9,000 IU vitamin A per teaspoon and 3,000-4,000 IU vitamin D. The vitamin levels likely test lower because we are only testing for retinol and palmitate, not for all other vitamin A isomers."
Seems that traditional processing techniques balanced out the A & D quite well!
Stephan, you might find the following blip pretty interesting regarding vitamin K2:
"Since this product is a fermented one, we surmise that it would contain vitamin K2 ... What we found was a range of quinones, which include the various forms of K2. The fermentation increases the total quinone count by 700-1600 percent ... We have not identified the specific quinones but I suspect that the K2 category and Co-enzyme Q family will be imporant components ... The fermented cod liver oil tests at 4-8 mg per gram, compared to the high vitamin butter oil at 23-25 mg per gram."
I just found a link to the article I referenced above:
Update on Cod Liver Oil Manufacturing
Daniel,
Thanks for the tip on the book. Wish I read Danish, I have at least one felt-making book in Danish, too, but at least it has a lot of photos. My MIL can sort of read Danish, but she's thousands of miles away in London, too far to be practical. Let me know if you ever decide to translate it into English, eh?
I have Cooling Inflammation blog in my google reader, too - thanks - I'll go back and review the posts.
Ryan,
Yeah, I knew there were a lot of changes in modern CLO, particularly with the vitamins, but it was great to read the article and particulars. Gotta admire David Wetzel's determination and daring in attempting this new-old way to make CLO and I wish him a lot of success. In the current era of massive regulations and conventional business/financing plans, etc. it can't be easy with a maverick project like that. I've not had their CLO before but now I'm considering trying the fermented "Viking" version of the fermented CLO. I like supporting mavericks who try to make their ideals realities.
I was amused to note the inset about CLO with the quote from Kurlansky's book Cod: A Biography of the Fish That Changed the World. My husband and I love that book and it comes up in discussion often (great travel book - light, small, and packable, easy to pick up anytime). It's one of those books that sticks to your brain and fills in the gaps from history class, and provides context, as well as insight to the modern fishing issues. Who knew cod had such an interesting and complex history?
Ryan,
I've been taking the Green Pastures fermented CLO all winter. It's expensive per bottle but it's actually cheap per dose. It tastes horrible, I guess that's how you know it works. There is no masking the flavor.
I agree it has a very favorable balance of D to A. It may contain K2 but probably not the MK-4 form.
Stephan --
Wonderful post as usual!!
Like Kiran -- I had a 'negative rxn' to high dose vit A and D once (I was experimenting the WAP theory that one can't get toxic if both A and D are present). You can. But I didn't realize at the time that one needed high dose vitamin K also. Drank a lot of cream but it was not pastured, therefore K2 deficient. (One of the tribes does this pre-marriage...) I had some signs of D toxicity when my blood level exceeded 100 ng/ml x2wks -- rough skin, phlegm (same signs as deficiency).
Ryan -- I really appreciated your INFO and link! Fermentation products (even fish livers) are an amazingly critical part of all ethnic diets (Velveeta cheese in the U.S. doesn't count -- though I LOVED THAT stuff growing up *ahh*). The CoQ10 info is quite curious. Someone else posted about iodine content in CLO -- that's fascinating!
I found out recently that black bean sauce and black soy beans (fermented) in Chinese cooking contain MK-7 like natto (but of course not as much) -- the longer-chain more potent MK7 is associated with greater reduction in coronary artery calcifications in the Rotterdam study.
Stinky tofu and jarred Chinese (fermented) tofu are acquired tastes in China and Taiwan. I've NOT been able to locate MK4 or MK7 content info on these 2food items but I'm certain that they must. Some may argue that these be considered 'food'... like iron-bellied Andrew Zimmerman! When I was growing up, stinky tofu seemed to me a version of 'chinese cheese'.
-G
G,
Do you eat stinky tofu? That is the mother of all acquired tastes. I tried some a while back and it's possibly the first ethnic food that I couldn't stomach. The name is not a misnomer, I'll say that!
I think it took me longer to acquire a taste for durien (the King of fruits) than it did to acquire a taste for fermented tofu which I love. I'm still only lukewarm on the durien, but after you get past the smell it has a lightly sweat flavor and silky texture that is very appealing.
Stephan,
I'd love to see a list of foods you do not tolerate... you eat fermented CLO... !?! I tried some cinnamon tingle-flavored CLO by Blue Ice. Wow. I finished a whole bottle but reluctantly downed w/each spoonful. *GAG* Tasted like cinammon KAAA-KAAA. (greenpasture.org actually has a NEW product... chocolate creme-flavored butter oil+ F E R M E N T E D cod liver oil).
Aaron -- I have new respect for you! Even my kids will clear the room when we order stinky tofu at the restaurant (we can't make it at home obviously *aah*).
-G
G,
Here's the list:
-avocado
-eggplant
-stinky tofu
And I think I'm starting to like avocado and eggplant, so that only leaves stinky tofu! I haven't tried natto yet.
Stephan, if you ever want the Eggplant Caponata recipe that converted me from an longtime eggplant hater, I'm happy to share. Still not wild about other eggplant recipes, but I actually crave this one sometimes (I think the capers are key; I'm a sucker for anything with capers).
Anna,
Thanks, but I'm not quite ready to go out of my way for it.
Just came across this interesting and relevant study: http://dsc.discovery.com/news/2009/05/04/lizard-sunning-vitamin.html. It discusses research showing that chameleons self-regulate the amount of Vitamin D they make through sun bathing.
Hi Stephen:
When it is said that you need vitamin D to absorb calcium, is it dietary vitamin D taken at the same time as calcium that is required, or does simply having an adequate vitamin D status from sufficient sun exposure facilitate calcium absorption? Thanks for the blog.
Olga
Olga,
It's your overall D status that matters. You don't have to take it with the meal. Vitamin D activates calcium absorption in the intestine.
One I read that for many osteoporosis treatments, vitamin D is used along with calcium, but this new researches may prove that using vitamin D may only help patients with high vitamin A intake combined with low vitamin D, and not for all cases. Visit Symposier site, useful videos on osteoporosis and osteoporosis treatments are available, www.symposier.com.
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