GOMAD, multivitamins, and Vitamin A toxicity

[Rich_S]

Coach - Just curious what you think about this.

The multivitamin I take every night has 10,000 IU Vitamin A. A gallon of 2% milk has 8,000 IU. I probably get another 2,000 IU or so from my diet. That's a total of 20,000 IU.

US RDA is 5,000 IU. In Strongest Shall Survive, Starr recommends 25,000 IU. In PP, you seem to agree with Starr and note that vitamin toxicity is uncommon.

So I should be good. But I just read a series of studies stating while levels required for acute toxicity are much higher, that osteoporosis can set in at levels around 10,000IU. Then I read another study saying that Vitamin A toxicity is actually Vitamin D deficiency and that so long as Vit D intake is increased, you can tolerate much more Vit A.

Thoughts? I don't want my femurs to turn to dust one day while squatting.

[Mark Rippetoe]

Gosh, neither do I. When will I know if this happens? Will I fall? Jesus Christ On A Fucking Green Skateboard. From where does this absurd shit drip?

[lukeBW]

Coach - Just curious what you think about this.

The multivitamin I take every night has 10,000 IU Vitamin A. A gallon of 2% milk has 8,000 IU. I probably get another 2,000 IU or so from my diet. That's a total of 20,000 IU.

US RDA is 5,000 IU. In Strongest Shall Survive, Starr recommends 25,000 IU. In PP, you seem to agree with Starr and note that vitamin toxicity is uncommon.

So I should be good. But I just read a series of studies stating while levels required for acute toxicity are much higher, that osteoporosis can set in at levels around 10,000IU. Then I read another study saying that Vitamin A toxicity is actually Vitamin D deficiency and that so long as Vit D intake is increased, you can tolerate much more Vit A.

Thoughts? I don't want my femurs to turn to dust one day while squatting.

One of the most distinctive signs of vitamin A overdose is yellowish to orange skin
Vitamin A overdose is also associated with nausea, vomiting, dizziness, blurred vision, an upset stomach, exhaustion, irritability, dry or cracking skin, hair loss, and damage to internal organs, particularly the liver.

You have any of those symptoms ? shoot yourself before you crumble away

[Tiburon]

If you want to see which studies the Institute of Medicine used to set the Tolerable Upper Intake Level (UL) for Vitamin A, see page 125 of the 2000 "Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc"

http://www.nap.edu/openbook.php?reco...10026&page=125

The biggest concern is for birth-defects, and I assume, Rich, that you aren't pregnant.

[Rich_S]

One of the sources of the absurd shit drip:

http://www.ajcn.org/cgi/content/abstract/83/2/191

"Osteoporosis and hip fracture are associated with preformed vitamin A intakes that are only twice the current RDA."

And here's the study indicating the real issue is an imbalance between Vitamin A and D, not excess Vitamin A:

http://www.westonaprice.org/basicnut...ina-osteo.html

[Tiburon]

One of the most distinctive signs of vitamin A overdose is yellowish to orange skin

Technically, you can't get orange skin from Vitamin A -- only from the carotenoids, like beta-carotene, which are precursors to Vit A. See attached structure.

[Tiburon]

One of the sources of the absurd shit drip:

http://www.ajcn.org/cgi/content/abstract/83/2/191

"Osteoporosis and hip fracture are associated with preformed vitamin A intakes that are only twice the current RDA."

When looking at the medical literature, it is important to determine whether a study is crap, or whether it has solid internal validity but might not apply to you. There are four studies which led to the above conclusion (which Rich linked to in a review paper). The four populations were postmenopausal American women, Swedish men aged 49-51, Americans between the ages of 55-92, and another sample of postmenopausal women:

-Vitamin A intake and the risk of hip fracture in postmenopausal women: the Iowa women?s health study.
http://www.springerlink.com/content/xre4gmj681jqmnr7/

-Serum Retinol Levels and the Risk of Fracture
http://content.nejm.org/cgi/content/abstract/348/4/287

-Retinol intake and bone mineral density in the elderly: the Rancho
Bernardo study.
http://www.jbmronline.org/doi/abs/10...2002.17.8.1349

-Vitamin A intake and hip fractures among postmenopausal women.
http://jama.ama-assn.org/cgi/content/abstract/287/1/47

[Mark Rippetoe]

And no studies of hard-training athletes. Yet this recommendation is extrapolated across the entire population.

[TravisRussellDC]

Hard training athletes are a special population. The vast majority of "studies" out there unfortunately do not apply. At the same time, when reading a "study" there are a few questions you must ask yourself. Who performed the study? Who funded the study? What were they looking for in the first place? What do the conclusions really mean? How did they manipulate the statistics to match what they were looking for in the first place?

I'm not going to say that all medical studies out there are crap. But I will say this, a controlled lab setting and the real world are two extremely different things. There are so many uncontrolled variables in the outside world that many things that are true in the lab setting are false outside of the lab setting. I prefer to do what works in practice, not what works in a lab.

[Mark Rippetoe]

Controlled, peer-reviewed studies are useful. So is anecdotal evidence, and the lessons of experience. There are problems when the academic establishment pretends that the first kind is the only one that is credible.