Vitamin A & D use same receptor

[lyndacarol]

Vitamin D Prevents Cancer: Is It True? (30 min) 2009
Carole Baggerly & Cedric F Garland, Dr.P.H., FACE, UC, San Diego, Moores Cancer Center


Baggerly speaks first; Garland begins @18:53 ( )

@24:58 Slide: Unfortunately, Vitamin A and D use the same receptor, it's known as the vitamin A and D heterodimer receptor. And if vitamin A gets on board, vitamin D has a hard time getting on board and the effect of vitamin D is diminished. It's competition at the receptor level so you want to keep your vitamin A intake below 6000 IU/day. It's just not necessary to take a high amount of vitamin A and actually is counterproductive. Cod liver oil, unfortunately, contains both vitamin A and D so you can't really get to affective levels for cancer prevention, or it's nearly impossible, with vitamin A interfering with the effect of vitamin D which occurs in cod liver oil, so you're looking for something that contains only vitamin D3, cholecalciferol, as long as you're at the usual intake level of vitamin A. A thousand\ international units a day really would meet those requirements.

@27:29 We metabolize, according to Dr. Robert Heaney and his colleagues, almost 5,000 international units a day of vitamin D, so we go through it quite rapidly and we’re very depleted by March.