Re: Vitamin A repletion in rats with concurrent vitamin A and iodine deficiency

[Guest guest]

That is very interesting, . Pretty complicated stuff!

Earlier today I found an article on Vit A and the immune system while

going through the selenium stuff. I only read it briefly and didn't

save it unfortunately...wish I had now.

Here's the part of that article you posted that is very intriguiing.

It would be good to find out more about this.

(PS - I lost the email you sent me last week - could you resend it

again? Thx)

Val

----------

" Because the cells originate without specialized abilities to fight

specific diseases, they are known as T-zero helper cells, or Th0 for

short. Later, in response to invasion by specific diseases, they

become either Th1 or Th2 cells, but we don't know all the details

about that specialization. In general, Th1 cells seem to be of most

use in fighting viral infections, such as HIV. Th2 cells apparently

have the lead role in defending against certain bacteria or

intestinal parasites, like roundworms. "

sen's group demonstrated—for the first time—that retinoic acid

promotes development of Th0 cells into Th2 cells rather than Th1

cells. sen and colleagues plan to repeat the experiment in

laboratory mice—not just in samples of their cells. Depending on

those findings, the scientists will follow up with studies of human

volunteers.

---------------------------------------------------

Here's more about the Th1/Th2 from that earlier article:

http://64.233.167.104/search?

q=cache:p32BCCbFJocJ:www.jbrha.com/archives/2004_subs/vol18no1/11colin

..pdf+TPOab,+inflammation,+lymphocytes,+destruction & hl=en & ct=clnk & cd=7 &

gl=us

Accumulated evidence over the recent years suggests that destructive

thyroiditis results from T cell-mediated activation, especially

originating from CD4+T cells (2).

Two different functionally defined T cell clones have been identified

so far, namely Th1 and Th2 cells. The Th1 subpopulation secrete

proinflammatory cytokines, such as interleukin-2, interferon-ã (IFN-

ã), tumournecrosis factor-á (TNF-á), and plays a major role invarious

destructive endocrine autoimmune diseases, such as in type I

diabetes, but also in HT. Th1 cytokine-mediated biological actions

are counter-balanced by Th2 cells that secrete anti-inflammatory

cytokines, such as interleukin-4 (IL-4), IL-5, IL-6, IL-10, or IL-13

(3).

The main hypothesis of the present study is based on the idea that

the proportion of the Th1/Th2 subsets of T cells in the peripheral

blood could be altered in HT (Hashi) patients when compared to a

group of control subjects.

>

> More on Vit A

>

>

> http://www.ncbi.nlm.nih.gov/pubmed/17311942?

ordinalpos=16 & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.P

ubmed_RVDocSum

>

> Vitamin A repletion in rats with concurrent vitamin A and iodine

> deficiency affects pituitary TSHbeta gene expression and reduces

> thyroid hyperstimulation and thyroid size.

> Biebinger R, Arnold M, Langhans W, Hurrell RF, Zimmermann MB.

>

> Human Nutrition Laboratory, Institute of Food Science and Nutrition,

> ETH Zurich, Switzerland. ralf.biebinger@...

>

> Concurrent vitamin A (VA) deficiency (VAD) and iodine deficiency

(ID)

> are common in developing countries. VAD has effects on thyroid

> metabolism that may be dependent on iodine status. The aim of this

> study was to investigate the effect of VA supplementation (VAS)

and/or

> dietary iodine repletion, alone and in combination, on the

> thyroid-pituitary axis in rats with concurrent VAD and ID. Weanling

> rats (n = 96) were fed diets deficient in VA and iodine or

sufficient

> in both (control), for 30 d. Subsequently, deficient rats were

> repleted with iodine and/or single VAS or remained deficient for 10

d.

> Serum retinol (SR), thyroid hormones, serum thyrotropin (TSH),

> pituitary TSHbeta mRNA expression level, and thyroid weight were

> measured. High-dose VAS restored SR concentrations to normal in both

> iodine-deficient and iodine-sufficient rats. Despite continuing VAD,

> provision of the iodine-sufficient diet entirely reversed the

> abnormalities of the pituitary-thyroid axis produced by VAD and ID.

In

> iodine-sufficient rats, VAS had no discernible effects on the

> pituitary-thyroid axis; in iodine-deficient rats, VAS reduced

> pituitary production of TSH and thyroid stimulation but had no

> discernible effects on circulating thyroid hormone concentrations.

> Primary hypothyroidism in rats with concurrent VAD and ID does not

> reduce the efficacy of VAS, nor does VAD reduce the efficacy of

> dietary iodine to correct pituitary-thyroid axis dysfunction due to

> ID. In concurrent VAD and ID, VAS, independent of iodine repletion,

> reduces thyroid hyperstimulation and size, an effect likely mediated

> through the effects of VA on pituitary TSHbeta gene expression.

>

>

>

[Guest guest]

Val,

Yes, I find it fascinating to study the role of nutrients and health.

Here's a page from the iThyroid website on Vit A and thyroid:

http://www.ithyroid.com/vitamin_a.htm

I saved several other studies about Vit A. It's important to note

that beta carotene will not work, it must be retinol from fish oil,

which is safe and doesn't need to be converted. I've always used the

Carlson brand of Vit A from fish oil--25,000 IU. I discovered many

years ago that I was chronically deficient--was always told I had a

yellow cast to my skin. Maybe I've had thyroid problems from childhood.

Once I started taking it I no longer suffered from the frequent ear

infections and bronchitis that had plagued me for years.

> >

> > More on Vit A

> >

> >

> > http://www.ncbi.nlm.nih.gov/pubmed/17311942?

> ordinalpos=16 & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.P

> ubmed_RVDocSum

> >

> > Vitamin A repletion in rats with concurrent vitamin A and iodine

> > deficiency affects pituitary TSHbeta gene expression and reduces

> > thyroid hyperstimulation and thyroid size.

> > Biebinger R, Arnold M, Langhans W, Hurrell RF, Zimmermann MB.

> >

> > Human Nutrition Laboratory, Institute of Food Science and Nutrition,

> > ETH Zurich, Switzerland. ralf.biebinger@

> >

> > Concurrent vitamin A (VA) deficiency (VAD) and iodine deficiency

> (ID)

> > are common in developing countries. VAD has effects on thyroid

> > metabolism that may be dependent on iodine status. The aim of this

> > study was to investigate the effect of VA supplementation (VAS)

> and/or

> > dietary iodine repletion, alone and in combination, on the

> > thyroid-pituitary axis in rats with concurrent VAD and ID. Weanling

> > rats (n = 96) were fed diets deficient in VA and iodine or

> sufficient

> > in both (control), for 30 d. Subsequently, deficient rats were

> > repleted with iodine and/or single VAS or remained deficient for 10

> d.

> > Serum retinol (SR), thyroid hormones, serum thyrotropin (TSH),

> > pituitary TSHbeta mRNA expression level, and thyroid weight were

> > measured. High-dose VAS restored SR concentrations to normal in both

> > iodine-deficient and iodine-sufficient rats. Despite continuing VAD,

> > provision of the iodine-sufficient diet entirely reversed the

> > abnormalities of the pituitary-thyroid axis produced by VAD and ID.

> In

> > iodine-sufficient rats, VAS had no discernible effects on the

> > pituitary-thyroid axis; in iodine-deficient rats, VAS reduced

> > pituitary production of TSH and thyroid stimulation but had no

> > discernible effects on circulating thyroid hormone concentrations.

> > Primary hypothyroidism in rats with concurrent VAD and ID does not

> > reduce the efficacy of VAS, nor does VAD reduce the efficacy of

> > dietary iodine to correct pituitary-thyroid axis dysfunction due to

> > ID. In concurrent VAD and ID, VAS, independent of iodine repletion,

> > reduces thyroid hyperstimulation and size, an effect likely mediated

> > through the effects of VA on pituitary TSHbeta gene expression.

> >

> >

> >

>