23 replies to this topic

[PerfectSeek]

I am curious as to other people's opinions on vitamin a.

I am currently using a fairly high vitamin A cod liver oil (twin labs), along with NOW Brand's 5000 iu vitamin d softgel. Research seems to indicate that Vitamin A and D "balance" each other, but I am unsure of the optimal dose of vit A.

Weston Price also supports a rather high Vitamin A intake. I am currently consuming ~10,000 iu vitamin A, and ~6000-6500 iu vit D.

I imagine anyone following a true paleo (eating organ meats) would have a high vitamin A intake as well.

How much Vitamin A (and vit D) do you consume, and why?

[Skötkonung]

According to CRON-o-meter, my daily intake is around 63,000 IU. That is from a small portion of carrots, lots of kale, spinach, broccoli, and blueberries (amongst other things). I don't see a need to supplement given a correctly organized diet.

I supplement 4,000 IU of Vitamin D3 because I get little sun. The almond milk I drink is fortified with Vitamin D2.

Edited by Skotkonung, 04 December 2009 - 05:04 AM.

[PerfectSeek]

We should distinguish between pro-vitamin A (beta-carotene) and Vitamin A (retinol). I believe pro-vitamin A is only converted when it is necessary and cannot cause toxicity.

[JackChristopher]

According to CRON-o-meter, my daily intake is around 63,000 IU.

I'm in the multiple tens of thousands range too—mainly from animal foods. That's almost entirely from food. But I do take 5000IU of D3, and get incidental D3 (and K2-mk4) from food.

Edited by JackChristopher, 04 December 2009 - 11:13 PM.

[pycnogenol]

I take 2,500 IU of retinol (vitamin A)*

*Solgar brand [1/2 tab]

Edited by pycnogenol, 04 December 2009 - 11:48 PM.

[Skötkonung]

According to CRON-o-meter, my daily intake is around 63,000 IU.

I'm in the multiple tens of thousands range too—mainly from animal foods. That's almost entirely from food. But I do take 5000IU of D3, and get incidental D3 (and K2-mk4) from food.

Exactly, I think when beta-carotene is so readily available in the diet, issues with deficiency do not arise. Likely it is an evolved defense to protect against toxicity. It is only now that people have switched to eating more nutrient depleted processed food rather than whole foods that vitamin A absorption is becoming a hot issue. My suggestion is that if you are needing to take retinol supplements to meet your RDI of vitamin A, then you probably should reconfigure your diet as you are probably deficient in other nutrients as well (minerals, vitamins, phytonutrients).

I'm sure the societies Weston A Price was studying weren't taking retinol, they were getting plenty of beta-carotene through plant and animal foods.

[ajnast4r]

According to CRON-o-meter, my daily intake is around 63,000 IU.

of bc or retinol? youre not worried about intakes that high?

[rwac]

Exactly, I think when beta-carotene is so readily available in the diet, issues with deficiency do not arise. Likely it is an evolved defense to protect against toxicity. It is only now that people have switched to eating more nutrient depleted processed food rather than whole foods that vitamin A absorption is becoming a hot issue. My suggestion is that if you are needing to take retinol supplements to meet your RDI of vitamin A, then you probably should reconfigure your diet as you are probably deficient in other nutrients as well (minerals, vitamins, phytonutrients).

I'm sure the societies Weston A Price was studying weren't taking retinol, they were getting plenty of beta-carotene through plant and animal foods.

You're confused. Atleast some people are unable to convert bc to retinol, and there is significant variability in the conversion rate.
Getting sufficient bc is not a guarantee of retinol sufficiency.

Beta-Carotene comes from plant sources, while Retinol comes from animal sources, mainly liver.

[pamojja]

Research seems to indicate that Vitamin A and D "balance" each other, but I am unsure of the optimal dose of vit A.

Weston Price also supports a rather high Vitamin A intake. I am currently consuming ~10,000 iu vitamin A, and ~6000-6500 iu vit D.

I'm not so sure if research indicates a A and D 'balance', but rather an antagonism as the VitaminDCouncil strongly suggests (http://www.vitamindc...-december.shtml) where it is advised to refrain from high vit A intake (less than 2000 IU) together with vit D due to its ability to block vit D receptors.

Weston Price recommends a strange vit A to vit D ratio of 10:1. If one considers that many need to take 5.000 IU of vit D3 to reach optimal 25(OH) levels during winter, that would mean 50.000 IU of vit A - and with much sunshine in the summer at least 100.000 IU of Retinol - daily!!!

I yet have to meet someone who uses such huge doses following Dr. Price advise in this respect.

However, since there are many here using D3 while regularly checking their 25(OH)D - maybe has someone additionally tried vitamin A in doses above 20.000 IU daily? - and with what kind of effect to D levels?

According to CRON-o-meter, my daily intake is around 63,000 IU. That is from a small portion of carrots, lots of kale, spinach, broccoli, and blueberries (amongst other things). I don't see a need to supplement given a correctly organized diet.

I think I found a serious flaw with Cron-o-meter - where I hope someone here is able to verify.

I first checked my daily vitamin intake with a self-made excel table with vitamin data from german online vitamin data bases. When I first encountered Cron-o-meter I was really shocked about the high vitamin A content it assumes!

Lets take for example carrots, raw - for their highest vit A content - from 'the USDA National Nutrient Database for Standard Reference' (where I think the data for cron-o-meter was taken):

CARROTS, RAW, 100 GRAMS:
835 mcg_RAE Vitamin A, RAE
0 mcg Retinol
8.285 mcg Carotene, beta
3.477 mcg Carotene, alpha
0 mcg Cryptoxanthin, beta
16.706 IU Vitamin A, IU

Compared with:
http://lpi.oregonsta...amins/vitaminA/
Carrot (raw) 1/2 cup= 64 grams
538 mcg_RAE Vitamin A, RAE
1.798 Vitamin A, IU
0 mcg Retinol
0 mcg Retinol, IU

Or http://en.wikipedia.org/wiki/Carrot:
per 100g
835 mcg Vitamin A equiv
8285 mcg beta-carotene

According to http://en.wikipedia....wiki/Vitamin_A:
Newer research has shown that the absorption of provitamin-A carotenoids is only half as much as previously thought, so in 2001 the US Institute of Medicine recommended a new unit, the retinol activity equivalent (RAE). 1 mcg RAE corresponds to 1 mcg retinol, 2 mcg of ?-carotene in oil, 12 mcg of "dietary" beta-carotene, or 24 mcg of the three other dietary provitamin-A carotenoids.[5]

And if I take this newer scheme of calculating from carotenes I indeed get values from http://www.nal.usda....oodcomp/search/ more close to my excel's, and the alleged - for me unbelieveable high intake of Vitamin A from vegetables (meat is a different story) - as some report here, is in reality very likely more around 2.000 IU daily, as it has for me with loads of raw carrots, dried fruids, greens.. till it grew out of my ears!
I surrendered to this difficulty to get enough vitamin A as a vegetarian - and started with a similar amounts from a multi.

Kind regards..

[rwac]

However, since there are many here using D3 while regularly checking their 25(OH)D - maybe has someone additionally tried vitamin A in doses above 20.000 IU daily? - and with what kind of effect to D levels?

I've taken 15,000 IU, and it doesn't seem to have affected my D3 levels.
5000IU of D3 pushed my level to 55 ng/ml anyway

Edited by rwac, 05 December 2009 - 02:26 AM.

[Skötkonung]

According to CRON-o-meter, my daily intake is around 63,000 IU.

of bc or retinol? youre not worried about intakes that high?

Why should I be? I am eating "normal" amounts of leafy greens and to a lesser extent, animal products. It isn't like I'm drinking copious amounts of carrot juice mixed with some fat source.

Edited by Skotkonung, 05 December 2009 - 08:42 AM.

[Skötkonung]

Exactly, I think when beta-carotene is so readily available in the diet, issues with deficiency do not arise. Likely it is an evolved defense to protect against toxicity. It is only now that people have switched to eating more nutrient depleted processed food rather than whole foods that vitamin A absorption is becoming a hot issue. My suggestion is that if you are needing to take retinol supplements to meet your RDI of vitamin A, then you probably should reconfigure your diet as you are probably deficient in other nutrients as well (minerals, vitamins, phytonutrients).

I'm sure the societies Weston A Price was studying weren't taking retinol, they were getting plenty of beta-carotene through plant and animal foods.

You're confused. Atleast some people are unable to convert bc to retinol, and there is significant variability in the conversion rate.
Getting sufficient bc is not a guarantee of retinol sufficiency.

Beta-Carotene comes from plant sources, while Retinol comes from animal sources, mainly liver.

I have not seen any literature stating that some people cannot convert beta-carotene to retinol. I have seen research showing that the rate of conversion is variable.
My speculation is that having a high level of dietary beta-carotene from a variety of sources will cover any potential issues with conversion. It isn't like my skin is turning orange, nor am I suffering problems with night blindness.

Honestly, I think if you have a vitamin A deficiency, you may need to rethink your diet. Again, the only reason we are seeing these reports of deficiency is because consumption of fresh fruits / vegetables (which constitute 80% of vitamin A sources) are on a steep decline in western populations.

Edited by Skotkonung, 05 December 2009 - 08:41 AM.

[rwac]

I have not seen any literature stating that some people cannot convert beta-carotene to retinol. I have seen research showing that the rate of conversion is variable.

This may be pretty unusual.
http://archpedi.ama-...tract/121/4/278

Failure of Enzymic Cleavage of β-CaroteneThe Cause of Vitamin A Deficiency in a Child



Donald S. McLaren, MD, PhD; Beatrice Zekian


Am J Dis Child. 1971;121(4):278-280.


Abstract
A 10-year-old Lebanese Arab girl had vitamin A deficiency as evidenced by night blindness, bilateral Bitot's spots, and very low plasma vitamin A concentration (7µg/100 ml). Total plasma carotenoid values were high with about 50% as β-carotene. Repeated blood sampling after large doses of β-carotene failed to produce any retinyl ester in the plasma whereas there was significant rise of ester levels in three control subjects. Preformed vitamin A cured the clinical condition and caused retinyl ester to appear in the plasma. There was no malabsorption, hypothyroidism, or liver dysfunction. The evidence suggests failure of enzymic conversion of β-carotene to retinal in the intestine as the cause of vitamin A deficiency.

[pamojja]

According to CRON-o-meter, my daily intake is around 63,000 IU.

of bc or retinol? youre not worried about intakes that high?

Why should I be? I am eating "normal" amounts of leafy greens and to a lesser extent, animal products. It isn't like I'm drinking copious amounts of carrot juice mixed with some fat source.

If your eating normal amounts of leafy greens than you vit A intake is more likely closer to 1.000 IU than 63.000 IU.

[pamojja]

However, since there are many here using D3 while regularly checking their 25(OH)D - maybe has someone additionally tried vitamin A in doses above 20.000 IU daily? - and with what kind of effect to D levels?

I've taken 15,000 IU, and it doesn't seem to have affected my D3 levels.
5000IU of D3 pushed my level to 55 ng/ml anyway

Thanks rwac, for your interesting observation. For how long do you take these amounts?

[ajnast4r]

According to CRON-o-meter, my daily intake is around 63,000 IU.

of bc or retinol? youre not worried about intakes that high?

Why should I be? I am eating "normal" amounts of leafy greens and to a lesser extent, animal products. It isn't like I'm drinking copious amounts of carrot juice mixed with some fat source.

63000iu is not from a normal amounts of leafy greens... the failed bc/lung cancer trial used 25,000iu, albeit synthetic bc, i still wouldnt go much above 10-15,000 daily just to be safe. anecdotally, i feel my asthma worsens when i have high bc intakes, ie: drinking lots of carrot juice.

My speculation is that having a high level of dietary beta-carotene from a variety of sources will cover any potential issues with conversion. It isn't like my skin is turning orange, nor am I suffering problems with night blindness.

Honestly, I think if you have a vitamin A deficiency, you may need to rethink your diet. Again, the only reason we are seeing these reports of deficiency is because consumption of fresh fruits / vegetables (which constitute 80% of vitamin A sources) are on a steep decline in western populations.

agree and agree

Edited by ajnast4r, 05 December 2009 - 03:08 PM.

[Skötkonung]

According to CRON-o-meter, my daily intake is around 63,000 IU.

of bc or retinol? youre not worried about intakes that high?

Why should I be? I am eating "normal" amounts of leafy greens and to a lesser extent, animal products. It isn't like I'm drinking copious amounts of carrot juice mixed with some fat source.

If your eating normal amounts of leafy greens than you vit A intake is more likely closer to 1.000 IU than 63.000 IU.

Hardly, according to CRON-o-meter:

- 4 cups of broccoli flowerets is 8520 IU
- 2.5 cup of raw spinach is 7032 IU
- 1 cucumber raw with peel is 316 IU
- 4 cups chopped kale is 41207 IU
- 1/4 cup chopped carrots is 5345 IU

This is not a massive amount of vegetables. Even the broccoli alone exceeds your "normal" estimate. Maybe the software is off, but I haven't seen anything to indicate this is the case.

According to WHFood, broccoli has 2280.72 IU per cup, which is more of less in line with the numbers provided by CRON-o-meter. Kale has 9620 IU per cup (when boiled).

You guys a re crazy Maybe the only reason I'm not dead with my high bc intake is that I have some issue with conversion, hah!

Edited by Skotkonung, 05 December 2009 - 10:07 PM.

[pamojja]

Hi Skotkonung,

trying to clear up the confusion I might have contributed too.. The software isn't 'off' by it self, it just uses an older model to calculate vitamin A content.

Quotes from wikipedia:

As some carotenoids can be converted into vitamin A, attempts have been made to determine how much of them in the diet is equivalent to a particular amount of retinol, so that comparisons can be made of the benefit of different foods. Unfortunately the situation is confusing because the accepted equivalences have changed. For many years, a system of equivalencies was used in which an international unit (IU) was equal to 0.3 mcg of retinol, 0.6 mcg of beta-carotene, or 1.2 mcg of other provitamin-A carotenoids.[4]

Later, a unit called retinol equivalent (RE) was introduced. 1 RE corresponded to 1 mcg retinol, 2 mcg beta-carotene dissolved in oil (it is only partly dissolved in most supplement pills, due to very poor solubility in any medium), 6 mcg beta-carotene in normal food (because it is not absorbed as well as when in oils), and 12 mcg of either alpha-carotene, gamma-carotene, or beta-cryptoxanthin in food (these molecules only provide 50% of the retinol as beta-carotene, due to only half the molecule being convertible to usable vitamin).

Newer research has shown that the absorption of provitamin-A carotenoids is only half as much as previously thought, so in 2001 the US Institute of Medicine recommended a new unit, the retinol activity equivalent (RAE). 1 mcg RAE corresponds to 1 mcg retinol, 2 mcg of beta-carotene in oil, 12 mcg of "dietary" beta-carotene, or 24 mcg of the three other dietary provitamin-A carotenoids.[5]
..

The conclusion that can be drawn from the newer research is that fruits and vegetables are not as useful for obtaining vitamin A as was thought; in other words, the IU's that these foods were reported to contain were worth much less than the same number of IU's of fat-dissolved oils and (to some extent) supplements. This is important for vegetarians. (Night blindness is prevalent in countries where little meat or vitamin A-fortified foods are available.)

A sample vegan diet for one day that provides sufficient vitamin A has been published by the Food and Nutrition Board (page 120[5]). On the other hand, reference values for retinol or its equivalents, provided by the National Academy of Sciences, have decreased. The RDA (for men) of 1968 was 5000 IU (1500 mcg retinol). In 1974, the RDA was set to 1000 RE (1000 mcg retinol), whereas now the Dietary Reference Intake is 900 RAE (900 mcg or 3000 IU retinol). This is equivalent to 1800 mcg of beta-carotene supplement (3000 IU) or 10800 mcg of beta-carotene in food (18000 IU).

In other words, your example meal of 63.000 IU calculated the old way is actually (taken from the same database):

426 RAE - of 4 cups of broccoli flowerets (8520 IU)
352 RAE - of 2.5 cup of raw spinach (7032 IU)
15 RAE - of 1 cucumber raw with peel (316 IU)
2061 RAE - of 4 cups chopped kale (41207 IU)
Total = 2854 RAE

I doubt you eat such amounts raw daily - so if you:
freeze -5%
dry -50%
cook -25%
cook + drain -35%
reheat -10%
.. loss of the vit A contents in the veggies.

With such a daily diet you get more than enough according to the currently Recommended Dietary Allowence of 900 RAE - and actually getting close at its tolerable upper intake levels of 3000 mcg RAE - given your body converts carotenes as science says it should..

My shock of seeing such a discrepancy between CRON-o-meter and my self-made excel calculation came from assuming that nowadays IUs would actually have been adapted to Retinoic Activity Equivalent 1 : 1. So I assumed you would get only about 1.000 IU while I actually had RAE in mind. My fault.

At least you really don't have to worry about getting too much beta-carotenes - but could be congratulated if you really are able to eat these amounts of raw broccoli and kale each and every day!

I rather stay with RAEs in my excel - than using confusing and arbitrary calculated IUs.

Kind regards..

Edited by pamojja, 06 December 2009 - 03:51 PM.

[rwac]

Thanks rwac, for your interesting observation. For how long do you take these amounts?

I took the vit A for over a year, at one point it was 20K IU.
I stopped when I started develping generalized itching.

I've taken the 5K IU vit D for 8 months and continue to take it.

[pamojja]

If I assume that you took 20.000 IU of Retinol - that would mean about 6000 RAE - or double the upper tolerable limit, causing generalized itching in your case.

And 6000 RAE wouldn't antagonize the absorbtion of 5000 IU of vit D started later - contrary to the findings of the vitamin D council.

Thanks again..

[Skötkonung]

Hi Skotkonung,

trying to clear up the confusion I might have contributed too.. The software isn't 'off' by it self, it just uses an older model to calculate vitamin A content.

Quotes from wikipedia:

As some carotenoids can be converted into vitamin A, attempts have been made to determine how much of them in the diet is equivalent to a particular amount of retinol, so that comparisons can be made of the benefit of different foods. Unfortunately the situation is confusing because the accepted equivalences have changed. For many years, a system of equivalencies was used in which an international unit (IU) was equal to 0.3 mcg of retinol, 0.6 mcg of beta-carotene, or 1.2 mcg of other provitamin-A carotenoids.[4]

Later, a unit called retinol equivalent (RE) was introduced. 1 RE corresponded to 1 mcg retinol, 2 mcg beta-carotene dissolved in oil (it is only partly dissolved in most supplement pills, due to very poor solubility in any medium), 6 mcg beta-carotene in normal food (because it is not absorbed as well as when in oils), and 12 mcg of either alpha-carotene, gamma-carotene, or beta-cryptoxanthin in food (these molecules only provide 50% of the retinol as beta-carotene, due to only half the molecule being convertible to usable vitamin).

Newer research has shown that the absorption of provitamin-A carotenoids is only half as much as previously thought, so in 2001 the US Institute of Medicine recommended a new unit, the retinol activity equivalent (RAE). 1 mcg RAE corresponds to 1 mcg retinol, 2 mcg of beta-carotene in oil, 12 mcg of "dietary" beta-carotene, or 24 mcg of the three other dietary provitamin-A carotenoids.[5]
..

The conclusion that can be drawn from the newer research is that fruits and vegetables are not as useful for obtaining vitamin A as was thought; in other words, the IU's that these foods were reported to contain were worth much less than the same number of IU's of fat-dissolved oils and (to some extent) supplements. This is important for vegetarians. (Night blindness is prevalent in countries where little meat or vitamin A-fortified foods are available.)

A sample vegan diet for one day that provides sufficient vitamin A has been published by the Food and Nutrition Board (page 120[5]). On the other hand, reference values for retinol or its equivalents, provided by the National Academy of Sciences, have decreased. The RDA (for men) of 1968 was 5000 IU (1500 mcg retinol). In 1974, the RDA was set to 1000 RE (1000 mcg retinol), whereas now the Dietary Reference Intake is 900 RAE (900 mcg or 3000 IU retinol). This is equivalent to 1800 mcg of beta-carotene supplement (3000 IU) or 10800 mcg of beta-carotene in food (18000 IU).

In other words, your example meal of 63.000 IU calculated the old way is actually (taken from the same database):

426 RAE - of 4 cups of broccoli flowerets (8520 IU)
352 RAE - of 2.5 cup of raw spinach (7032 IU)
15 RAE - of 1 cucumber raw with peel (316 IU)
2061 RAE - of 4 cups chopped kale (41207 IU)
Total = 2854 RAE

I doubt you eat such amounts raw daily - so if you:
freeze -5%
dry -50%
cook -25%
cook + drain -35%
reheat -10%
.. loss of the vit A contents in the veggies.

With such a daily diet you get more than enough according to the currently Recommended Dietary Allowence of 900 RAE - and actually getting close at its tolerable upper intake levels of 3000 mcg RAE - given your body converts carotenes as science says it should..

My shock of seeing such a discrepancy between CRON-o-meter and my self-made excel calculation came from assuming that nowadays IUs would actually have been adapted to Retinoic Activity Equivalent 1 : 1. So I assumed you would get only about 1.000 IU while I actually had RAE in mind. My fault.

At least you really don't have to worry about getting too much beta-carotenes - but could be congratulated if you really are able to eat these amounts of raw broccoli and kale each and every day!

I rather stay with RAEs in my excel - than using confusing and arbitrary calculated IUs.

Kind regards..

Thanks for the clarification. I do in fact consume that much greens, and I am neglecting to mention the small amounts of other vegetables, fruits, berries, and meats that are also compose my diet, so that likely explains the discrepancy between the numbers I provided and the full 63,000 IU I presented earlier. My total dietary energy intake is about 2,800 calories daily, and as I am very active, it makes consuming high levels of these foods possible (the caloric density is low, but the dietary bulk is high). As for how they are consumed, the kale (sometimes alternated with chard) is blended raw into smoothies. The broccoli is lightly steamed, and the spinach and cucumber are also raw. Foods are consumed like this to reduce the presence of glycotoxins. The large amount of food caloric density (830 calories) comes from the 340g of meat I eat daily, baking chocolate, and quinoa.

For what its worth, I've always enjoyed good health when consuming green vegetables for the bulk of my carbohydrate intake.

[niner]

Did you guys see this thread? It concerns the study where 47% of a sample of women in the UK had one or both SNPs that confer a reduced ability to convert beta carotene to retinol. This defect appears to be pretty common.

[PerfectSeek]

I should have rephrased my original post to include the question: "what is the optimal intake of vitamin A/vitamin D?"

Weston Price has recommended a 10:1 A:D ratio, but that would mean I should consume 50,000 iu of Vitamin A with my 5,000 iu of D... which seems high to me.

Any thoughts?

[rwac]

I should have rephrased my original post to include the question: "what is the optimal intake of vitamin A/vitamin D?"

Weston Price has recommended a 10:1 A:D ratio, but that would mean I should consume 50,000 iu of Vitamin A with my 5,000 iu of D... which seems high to me.

Any thoughts?

Your intake from cod liver oil should have a 10:1 A:D ratio. But, you can always add extra D, to mimic sunlight.
So you should take atleast 1/10 of the A as D3.

Make sense ?

Edited by rwac, 17 December 2009 - 04:26 PM.