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# Cod Liver Oil and Vitamin A:D Ratios - Clarification?

Created August 14, 2011 at 2:01 AM

I've been reading up a bunch on using cod liver oil to supplement vitamin D in the winter, and I had a question about vitamin A:D ratios. The WAPF states that the ratio of Vitamin A to D in supplements should be around 5:1. Trouble is, no one's said what units that's in. Is it in IUs, RDA percentages, or metric weight?

For example, a tsp of Green Pasture's FCLO has the following stats (roughly):

Vitamin A: 9,500 IU/120% RDA (830mcg)

Vitamin D: 2,000 IU/1000% RDA (50mcg)

If we're going by IU, we have a 4.75:1 A:D ratio. If we're going by RDA, we have a 1:8.5 A/D ratio. In mcg, we have a 17:1 ratio. From this it would seem like the ratio is in IUs, but honestly this whole IU/RDA/mcg thing is confusing (for example, I've seen an UL for Vitamin A [Retinol] listed as 3,000 mcg/10,000 IU, while FCLO has 830mcg/9500 IU - huh?). If FCLO's A:D is around 5:1 I'll take a tsp and be done with it, but I want to make sure before I dive in.

(4493)

on January 11, 2012
at 03:29 AM

i forgot to mention, the sailors in the studies were embarked upon 2-month-long missions in submarines

(4493)

on January 11, 2012
at 03:22 AM

Paul Jaminet made a comment on this under a westonprice post here http://www.westonaprice.org/blogs/cmasterjohn/2010/12/16/is-vitamin-d-safe-still-depends-on-vitamins-a-and-k-testimonials-and-a-human-study/#comment-270

(4493)

on January 11, 2012
at 03:12 AM

copy of my comment under Dragonfly answer; with reference to the half-life of 25(OH)D, i have seen references of anything from weeks to months. This study http://www.ajcn.org/content/69/5/842.full talks about 1 or 2 months. This study http://www.direct-ms.org/pdf/VitDVieth/Vieth%20CHAPTER%2061.pdf talks about a half-life of about 2 months in sailors.

(4493)

on January 11, 2012
at 03:06 AM

with reference to the half-life of 25(OH)D, i have seen references of anything from weeks to months. This study http://www.ajcn.org/content/69/5/842.full talks about 1 or 2 months. This study http://www.direct-ms.org/pdf/VitDVieth/Vieth%20CHAPTER%2061.pdf talks about a half-life of about 2 months in sailors.

(32556)

on August 25, 2011
at 10:56 PM

So Europeans aren't human? Anyway, until you get your D level tested you won't know where your level is.

(1377)

on August 25, 2011
at 09:27 PM

Humans evolved near the equator, but light-skinned Europeans like me evolved further in higher latitudes. Also, peoples such as the Inuit do get a substantial amount of D from their food. Here's the gist of what I'm saying: There were light-skinned cavemen, they got most of their Vitamin D from the sun, some from food, and none from supplements. That's why I'd rather get my D from sun and food, not supplements.

(32556)

on August 25, 2011
at 03:22 PM

Dan~ We got most if not all of our D3 from the SUN, not food and we evolved nearer the equator, so there was no "winter". A light-skinned person will get 10,000-20,000 IUs from 20 min of noonday sun at latitiudes BELOW 38 degrees N.

(1377)

on August 25, 2011
at 12:46 PM

All of that's just speculation, but the big idea for me is staying away from vitamin/mineral supplements and sticking with whole foods/food supplements (fish instead of fish oil, FCLO instead of vit. D, etc.). There's a ton of research for and against vitamin supplements, but food supplements seem to be universally positive (and a little more in line with Paleo logic). In regards to D, a tsp each of FCLO and butter oil gives about 3,000 IU, which is as much as I'd imagine caveman could get from fish guts and such. If we need any more than that, I don't know how we'd have gotten it in the past.

(1377)

on August 25, 2011
at 12:34 PM

If the 2-week half-life is correct (and means we can't store D in our tissues over the winter), how did caveman get his vitamin D? Maybe he didn't - that's a possible alternative, but (as I mused in the other post) that would probably have produced lighter skin tones over generations, which didn't happen in the case of native North Americans. There's also the possibility that the "Vitamin D Winter" isn't nearly as severe as we thought; the WAPF had a post about that lately saying that it might only last a month or two even in higher latitudes (opposed to the 4-6 months in Holick's study).

(32556)

on August 22, 2011
at 09:24 PM

Dan~ With a half-life of 2 weeks, I doubt that your body can store enough D3 to last through the winter and keep your levels above 50 ng/ml (the recommended minimum level by the Vitamin D Council.) Why do you think so many folks get sick at the end of Dec/into Jan/Feb? I keep my levels stable by supplementing 6,000 IUs year-round and haven't been sick in almost 2 years (since I began supplementation.)

(1377)

on August 22, 2011
at 08:00 PM

Great, that answered my question. WAPF isn't a perfect source, but to their credit that 5:1 ratio was listed as ideal for food supplements, not overall intake or blood levels. I('m pretty damn sure I) get enough Vitamin D in the summer to hold me through the winter, so the FCLO is more of a bonus (heard it helps raise testosterone, too).

(32556)

on August 14, 2011
at 02:54 PM

IUs are a measurement. This is what you would use to ascertain a ratio. I wouldn't give the RDA any attention in this case. Unfortunately, those amounts have very little to do with physiologically optimum amounts.

(1377)

on August 14, 2011
at 12:59 PM

Thanks, and I agree that it makes a lot more sense to have more vitamin D than A, which is why I was wondering how you measure "more." If we go by IUs, we have "more" vitamin A. If we go by RDA, we have "more" vitamin D. This is why I'm still confused about all this.

(32556)

on August 14, 2011
at 03:14 AM

And here's another link to a previous discussion here: http://paleohacks.com/questions/1096/cod-liver-oil-and-vitamin-a-are-toxic#axzz1Uy7pTws4

(1377)
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(32556)

on August 14, 2011
at 02:53 AM

I understand where you are coming from, but I'm not so sure about those ratios (5:1).

I've read both WAPF's stance and the Vitamin D Council's and it just does not make any sense to me that we would have evolved with a higher daily A to D ratio. Liver is one per animal, shared amongst the tribe--not a daily thing, either. Sunshine = 10,000 to 20,000 IUs D3/day.

Katherine has commented on this as well in some previous posts.

Personally, I go for liver once a week and 1000 IUs of D3 per 25 lbs of body weight (Vitamin D Council recs.)

(1377)

on August 14, 2011
at 12:59 PM

Thanks, and I agree that it makes a lot more sense to have more vitamin D than A, which is why I was wondering how you measure "more." If we go by IUs, we have "more" vitamin A. If we go by RDA, we have "more" vitamin D. This is why I'm still confused about all this.

(32556)

on August 14, 2011
at 03:14 AM

And here's another link to a previous discussion here: http://paleohacks.com/questions/1096/cod-liver-oil-and-vitamin-a-are-toxic#axzz1Uy7pTws4

(32556)

on August 14, 2011
at 02:54 PM

IUs are a measurement. This is what you would use to ascertain a ratio. I wouldn't give the RDA any attention in this case. Unfortunately, those amounts have very little to do with physiologically optimum amounts.

(1377)

on August 22, 2011
at 08:00 PM

Great, that answered my question. WAPF isn't a perfect source, but to their credit that 5:1 ratio was listed as ideal for food supplements, not overall intake or blood levels. I('m pretty damn sure I) get enough Vitamin D in the summer to hold me through the winter, so the FCLO is more of a bonus (heard it helps raise testosterone, too).

(32556)

on August 22, 2011
at 09:24 PM

Dan~ With a half-life of 2 weeks, I doubt that your body can store enough D3 to last through the winter and keep your levels above 50 ng/ml (the recommended minimum level by the Vitamin D Council.) Why do you think so many folks get sick at the end of Dec/into Jan/Feb? I keep my levels stable by supplementing 6,000 IUs year-round and haven't been sick in almost 2 years (since I began supplementation.)

(1377)

on August 25, 2011
at 12:34 PM

If the 2-week half-life is correct (and means we can't store D in our tissues over the winter), how did caveman get his vitamin D? Maybe he didn't - that's a possible alternative, but (as I mused in the other post) that would probably have produced lighter skin tones over generations, which didn't happen in the case of native North Americans. There's also the possibility that the "Vitamin D Winter" isn't nearly as severe as we thought; the WAPF had a post about that lately saying that it might only last a month or two even in higher latitudes (opposed to the 4-6 months in Holick's study).

(32556)

on August 25, 2011
at 10:56 PM

So Europeans aren't human? Anyway, until you get your D level tested you won't know where your level is.

(32556)

on August 25, 2011
at 03:22 PM

Dan~ We got most if not all of our D3 from the SUN, not food and we evolved nearer the equator, so there was no "winter". A light-skinned person will get 10,000-20,000 IUs from 20 min of noonday sun at latitiudes BELOW 38 degrees N.

(1377)

on August 25, 2011
at 12:46 PM

All of that's just speculation, but the big idea for me is staying away from vitamin/mineral supplements and sticking with whole foods/food supplements (fish instead of fish oil, FCLO instead of vit. D, etc.). There's a ton of research for and against vitamin supplements, but food supplements seem to be universally positive (and a little more in line with Paleo logic). In regards to D, a tsp each of FCLO and butter oil gives about 3,000 IU, which is as much as I'd imagine caveman could get from fish guts and such. If we need any more than that, I don't know how we'd have gotten it in the past.

(1377)

on August 25, 2011
at 09:27 PM

Humans evolved near the equator, but light-skinned Europeans like me evolved further in higher latitudes. Also, peoples such as the Inuit do get a substantial amount of D from their food. Here's the gist of what I'm saying: There were light-skinned cavemen, they got most of their Vitamin D from the sun, some from food, and none from supplements. That's why I'd rather get my D from sun and food, not supplements.

(4493)

on January 11, 2012
at 03:06 AM

with reference to the half-life of 25(OH)D, i have seen references of anything from weeks to months. This study http://www.ajcn.org/content/69/5/842.full talks about 1 or 2 months. This study http://www.direct-ms.org/pdf/VitDVieth/Vieth%20CHAPTER%2061.pdf talks about a half-life of about 2 months in sailors.

1

(678)

on August 22, 2011
at 08:23 PM

I know Paul Jaminet of perfecthealthdiet.com wrote that the ideal ratio is 3:1 A to D. Gotta have your vitamin K as well.

(4493)

on January 11, 2012
at 03:22 AM

Paul Jaminet made a comment on this under a westonprice post here http://www.westonaprice.org/blogs/cmasterjohn/2010/12/16/is-vitamin-d-safe-still-depends-on-vitamins-a-and-k-testimonials-and-a-human-study/#comment-270

-1

(1533)

on August 14, 2011
at 06:08 PM

Caveman did not spend time worrying about ratios - Just eat like an animal.