Re: IPT (continued) - Avoid cod-liver oil

[Guest guest]

I would definitely recommend AGAINST cod-liver oil. It used to be high in

vitamins A and D, but with recent processing it is high in A and low in D. High

Vitamin A interferes with the effectiveness of vitamin D in helping your immune

system and preventing cancer. From Dr Cannell of VitaminDCouncil:

Proper Vitamin D-Vitamin A Ratio

Dr. Cannell: Can you quote from the paper, telling us why so many experts

condemned cod liver oil? , California

I don't know if copyright laws allow the author to do that, but I will take the

chance. The crux of the problem is that a form of vitamin A, retinoic acid,

weakly activates the vitamin D response element on the gene and perhaps blocks

vitamin D's more robust activation. In fact, the authors of a 1993 study state

" there is a profound inhibition of vitamin D-activated...gene expression by

retinoic acid. " Mac PN, et al. Retinoid X receptors stimulate and 9-cis

retinoic acid inhibits 1,25-dihydroxyvitamin D3-activated expression of the rat

osteocalcin gene. Mol Cell Biol. 1993 Sep;13(9):5907-17. PD, et al.

Heterodimeric DNA binding by the vitamin D receptor and retinoid X receptors is

enhanced by 1,25-dihydroxyvitamin D3 and inhibited by 9-cis-retinoic acid.

Evidence for allosteric receptor interactions. J Biol Chem. 1998 Apr

3;273(14):8483-91.

The key is having the proper ratio of vitamin D to vitamin A in your body. To

obtain this proper D/A ratio, you must make a choice. (1) Either obtain the D/A

ratio Nature intended-that is, the ratio the human genome evolved on-or (2)

assume one knows better and intervene in a closed system, bypass the controls in

the intestine, and inject active A directly into your blood by taking vitamin A

or cod liver oil. Vitamin A production is tightly controlled in the body, the

source (substrate) being carotenoids from vegetables in your intestine. The body

uses these carotenoid substrates to make exactly the right amount of retinol for

your body. That is, it is a closed, tightly regulated, system, one designed to

perfection by Nature. When you take vitamin A as retinol, such as in cod liver

oil, you intervene in this closed system and bypass the controls. Proceed at

your peril.

Vitamin D is also a closed, controlled system and I don't recommend intervening

in that system either. Vitamin D cholecalciferol is a substrate like

carotenoids, it is not the active substance. Taking vitamin A as retinol is like

taking activated vitamin D (calcitriol). Doing so bypasses controls and I have

never recommended anyone take activated vitamin D except patients with renal

failure under the care of a nephrologist. As long as your vitamin D

(cholecalciferol) dose is not excessive, you are not intervening in a closed

system, you are simply providing the vitamin D substrate. The body, if and when

it has enough vitamin D substrate, will use what it needs and dispose of, or

store, the rest.

Thus the goal is to provide all the vitamin A and vitamin D substrate the body

would have obtained in a natural state, so the body can regulate both systems

naturally. This is best done by eating colorful vegetables and by exposing your

naked skin to equatorial sun every day. Since most of us can't do the later, and

won't do the former, we have to take the same amount of vitamin D substrate we

would have obtained living 100,000 years ago-and may want to take beta-carotene

substrate in a multivitamin. As far as I know, low doses of beta-carotene

(1,000-2,000 IU per day) will not do too much harm. The best way to get vitamin

D substrate, as far as I can tell, is to take at least 5,000 IU of vitamin D3

per day in the winter and stop all vitamin D in the summer and sunbathe.

Alternatively, use a tanning bed when the sun is too low on the horizon to

sunbathe. Remember, when you are outside, if your shadow is longer than you are,

you are not making any vitamin D.

Excerpts from our paper

The italicized passages below are from our paper and are the heart of the

reasoning used to issue the warning about vitamin A and cod liver oil. They are

the advice of the 16 experts who co-authored the paper with me, not just mine

alone:

" Although activated vitamin D and vitamin A signal through common cofactors,

they compete for each others function. Retinoic acid antagonizes the action of

vitamin D and its active metabolite. In humans, even the vitamin A in a single

serving of liver impairs vitamin D's rapid intestinal calcium response. In a

dietary intake study, Oh, et al, found that a high retinol intake completely

thwarted vitamin D's otherwise protective effect on distal colorectal adenoma,

and they found a clear relationship between vitamin D and vitamin A intakes, as

the women in the highest quintile of vitamin D intake also ingested around

10,000 IU/d of retinol. " Rohde CM, Deluca HF. All-trans retinoic acid

antagonizes the action of calciferol and its active metabolite,

1,25-dihydroxycholecalciferol, in rats. J Nutr. 2005;135(7):1647-1652. Johansson

S, Melhus H. Vitamin A antagonizes calcium response to vitamin D in man. J Bone

Miner Res. 2001;16(10):1899-1905. Oh K, Willett WC, Wu K, Fuchs CS, Giovannucci

EL. Calcium and vitamin D intakes in relation to risk of distal colorectal

adenoma in women. Am J Epidemiol. 2007;165(10):1178-1186.

" Furthermore, the consumption of preformed retinol even in amounts consumed by

many Americans in both multivitamins and cod liver oil may cause bone toxicity

in individuals with inadequate vitamin D status. Women in the highest quintile

of total vitamin A intake have a 1.5-times elevated risk of hip fracture. "

Feskanich D, Singh V, Willett WC, Colditz GA. Vitamin A intake and hip fractures

among postmenopausal women. JAMA 2002;287:47-54.

" Indeed, a recent Cochrane Review found that vitamin A supplements increased

total mortality rate by 16%, perhaps through antagonism of vitamin D. "

Bjelakovic G, et al. Antioxidant supplements for prevention of mortality in

healthy participants and patients with various diseases. Cochrane Database Syst

Rev 2008 Apr 16;(2):CD007176.

" Another recent Cochrane meta-analysis concluded that although vitamin A

significantly reduced the incidence of acute lower respiratory tract infections

in children with low intake of retinol, as occurs in the Third World, it appears

to increase the risk and/or worsen the clinical course in children in developed

countries. " Chen H, Zhuo Q, Yuan W, Wang J, Wu T. Vitamin A for preventing acute

lower respiratory tract infections in children up to seven years of age.

Cochrane Database Syst Rev 2008.

" As early as 1933, Alfred Hess, who discovered that sunlight both prevented and

cured rickets Hess A. The Prevention and Cure of Rickets By Sunlight. [PDF

download] American Journal of Public Health, 1921. warned about vitamin A

consumption, concluding, ...as to a requirement of thousands of units of vitamin

A daily, the unquestionable answer is that this constitutes therapeutic

absurdity, which, happily, will prove to be only a passing fad (p 662). " Hess

AF, JM, Barenberg LH. Does our dietary require vitamin A supplement? JAMA.

1933;101:657-663.

" Unfortunately, Hess's prophecy of a passing fad proved premature and Americans

continue consuming multivitamins and/or cod liver oil containing small amounts

of vitamin D but undesirable quantities of vitamin A. For example,

multivitamins, until recently, had small amounts of vitamin D (200 to 400 IU)

but high amounts of preformed retinol (5,000 to 10,000 IU). This pales in

comparison to a tablespoon of modern cod liver oil, most of which contains

sub-physiological amounts of vitamin D (400 to 1200 IU) but supra-physiological

amounts of completely preformed retinol (5,000 to 15,000 IU or, in some cases,

30,000 IU). " Penniston KL, Tanumihardjo SA. The acute and chronic toxic effects

of vitamin A. Am J Clin Nutr. 2006;83(2):191-201.

" Clinical lore holds that Vitamin A is an anti-infective. We suggest that lore

exists because of old cod liver oil studies. Semba reviewed early literature on

vitamin A, usually given as cod or halibut liver oil, as a successful

anti-infective. For reasons that are not entirely clear, fish liver oils of the

time contained much higher amounts of vitamin D then does modern cod liver oil,

perhaps because modern processing removes the vitamin D during distillation and

then replace it at lower doses. Furthermore, a meta-analysis concluded that

vitamin A, when given alone, increases the incidence of respiratory tract

infections. If vitamin A increases the risk of respiratory infections, its high

content in modern cod liver oils will only mask the full benefit of adequate

vitamin D nutrition. " Semba RD. Vitamin A as " anti-infective " therapy,

1920-1940. J Nutr 1999;129:783-791. Grotto I, Mimouni M, Gdalevich M, Mimouni D.

Vitamin A supplementation and childhood morbidity from diarrhea and respiratory

infections: a meta-analysis. J Pediatr 2003;142:297-304.

" As the prevalence of vitamin A deficiency in the United States is apparently

much lower than the prevalence of subclinical vitamin A toxicity, we cannot

recommend cod liver oil for either adults or children. (We exclude fish body oil

from our warning, as it contains no vitamin A or vitamin D but is a very

important source of omega-3 fatty acids.) For example, in a recent assessment of

serum retinyl esters in a group of obese individuals, four percent had levels

>10% of total retinol which usually indicates hypervitaminosis A. Instead, a

diet rich in carrots, sweet potatoes, cantaloupe, and other orange fruits and

vegetables will supply all the carotenoids the body needs to make retinol

without the potential for hypervitaminosis A, especially when additional

preformed retinol already exists in dairy products, eggs, and fortified cereal.

We wish our diet were as rich in vitamin D. With the exception of infants on

formula or toddlers drinking large amounts of milk or fortified juice, adequate

amounts of vitamin D are virtually impossible to obtain from diet. " Hathcock JN,

Hattan DG, MY, Mc JT, Sundaresan PR, Wilkening VL. Evaluation of

vitamin A toxicity. Am J Clin Nutr. 1990;52:183-202. Mills JP, Furr HC,

Tanumihardjo SA. Retinol to retinol binding protein (RBP) is low in obese adults

due to elevated apo-RBP. Exp Bio Med. In press. Tanumihardjo SA. Food-based

approaches for ensuring adequate vitamin A nutrition. Comp Rev Food Sci Food

Safety. In press.

Long story short, don't take cod liver oil or vitamin A as a retinol.

[Guest guest]

I think the concerns about cod liver oil (in particular) and vit. A are

exaggerated and that the pros of cod liver oil far outweigh the cons.

A doctor told me more research has been done on cod liver oil than on any other

supplement. It's also a good source of omega 3.

I simply use a high-quality brand (e.g., NordicNaturals.com or Carlsons.com)

that has lot of vit. D.

Also, I think it's a good idea for almost all cancer patients (and most people

w/o cancer to take at least 4,000 IU of D3 (unless they're getting a lot of

sunlight) anyway.

Vit. A " toxicity usually occurs with doses in excess of 100,000 units a day for

periods in excess of a year....emulsified vitamin A products are widely used in

cancer clinics; these forms have less liver toxicity....Large doses need to be

given to attain an anticancer effect. " ( , M.D.

[www.ivanhoe.com]

Some cancer practitioners have given up to 3 million IU of emulsified vit. A

daily, but I would NOT take even 1/100th of that w/o medical supervision.

" vitamin A is a mixed blessing....Use Acutane whenever possible. " ,

7/21/08

Any other general guidelines re: vit. A, ?

Leonard