Vitamin A – Reduced Cancer Risk
In epidemiological studies, a low intake intake of vitamin A has consistently been associated with increased risk of developing certain cancers.
However, the role vitamin A in cancer etiology is confused by the failure, in many studies to differentiate between preformed vitamin A (retinol) and carotenoids, which may have anticancer effects unrelated to their provitamin A function.
Another difficulty in interpreting epidemiological data on vitamin A is that serum retinol and RBP (retinol binding protein) do not necessarily reflect vitamin A status or intake.
In addition, retinol status can be affected by protein malnutrition, liver diseased and infection.
There are several theorized mechanisms to explain cancer risk reduction by vitamin A. It is well established that vitamin A is required for the maintenance of epithelial tissues, where man cancers are seen.
Vitamin A status must therefore be adequate to allow normal epithelial growth.
Immune system function, including tumor surveillance has also been shown in animal models to depend on sufficient levels of vitamin A.
In addition, vitamin A and retinoid (vitamin A derivatives) may directly influence gene expression.
Vitamin A – Reduced Cancer Risk
In epidemiological studies, a low intake intake of vitamin A has consistently been associated with increased risk of developing certain cancers.
However, the role vitamin A in cancer etiology is confused by the failure, in many studies to differentiate between preformed vitamin A (retinol) and carotenoids, which may have anticancer effects unrelated to their provitamin A function.Another difficulty in interpreting epidemiological data on vitamin A is that serum retinol and RBP (retinol binding protein) do not necessarily reflect vitamin A status or intake.
In addition, retinol status can be affected by protein malnutrition, liver diseased and infection.
There are several theorized mechanisms to explain cancer risk reduction by vitamin A. It is well established that vitamin A is required for the maintenance of epithelial tissues, where man cancers are seen.
Vitamin A status must therefore be adequate to allow normal epithelial growth.
Immune system function, including tumor surveillance has also been shown in animal models to depend on sufficient levels of vitamin A.
In addition, vitamin A and retinoid (vitamin A derivatives) may directly influence gene expression.
Vitamin A – Reduced Cancer Risk