Vitamin A 10,000 IU is delivered as all-trans-retinyl palmitate for increased efficacy. The 10,000 IU per capsule dosage can be used short-term to boost immune activity and support the aging eye.
- Supports Normal Eyesight
- Supports the Aging Eye
- Boosts Immune Activity
- Supports Skin Growth and Repair
- Plays a Role in Red Blood Cell Production
Vitamin A refers to a range of fat-soluble nutrients, some referred to as “preformed,” which includes retinol and its derivatives, and those deemed “vitamin A precursors or provitamins,” including beta-carotene and other carotenoids. The final bioactive form of vitamin A is retinoic acid. Research highlights the importance of vitamin A in many physiological processes. Most notably, vitamin A supports the retina and normal eyesight, especially night vision. It also plays a vital role in immune response, skin function, and red blood cell production.
Natural sources of preformed vitamin A include milk, eggs, cheese and liver. The most common type of pro-vitamin A is beta-carotene, a carotenoid that produces dark pigments in plant foods. Food sources for carotenoids include sweet potatoes, carrots, dark green leafy vegetables, broccoli and cantaloupes. Due to the Standard American Diet, few of these food sources are consumed on a regular basis, thus making it important to supplement with high-quality vitamin A.
Vitamin A 10,000 IU is designed for short-term use only. Take one capsule per day as directed by your health care practitioner.
According to the World Health Organization, vitamin A deficiency is most often seen in developing nations in Africa and South Asia. The most common cause of deficiency is lack of dietary intake. However, other causes include iron deficiency, pancreatic and liver insufficiency, and bowel problems.
The following information highlights the physiological effects of normal vitamin A levels. Retinol is transported to the retina and accumulates in the retinal pigment epithelial cells. It is esterified back to retinyl esters and stored. Retinyl esters are hydrolyzed to a usable form, 11-cis-retinal. 11-cis-retinal is used for low-light conditions and movement in rod receptors within the retina. It binds to a protein receptor known as opsin in the rod cell to form visual pigment called rhodopsin. Absorption of a photon of light catalyzes this combination to form all-trans-retinal which, in turn, leads to a generation of a nerve impulse from the optic nerve to the visual cortex in the brain for interpretation. The all-trans-retinal is converted to all-trans-retinoland transported back to the retinal pigment epithelial cells completing the visual cycle. The all-trans-retinol is further converted back to retinyl esters for storage until it is needed again. It is also important for cell differentiation and function of the cornea. Vitamin A supplementation along with zinc has been shown to support the aging eye.
Mucosal linings of the digestive tract are active areas of immunity. Dendritic macrophages send extensions through the gap junctions to sample the contents of the lumen, examining for antigens. Once a sample of the antigen is taken, the dendritic cells convey the specific antigen to virgin T4 lymphocytes to convey an antigenic response by the now mature lymphocytes. Retinoic acid is involved in two parts of this process. First, it supports differentiation, migration and antigen-presenting capacity. Secondly, retinoic acid used by antigen-presenting cells supports differentiation of naïve CD4 lymphocytes into induced regulatory T lymphocytes.
Red Blood Cell Development
Red blood cell production, or erythropoiesis, occurs in the marrow. Research suggests that vitamin A supports immature stem cells as they differentiate to red blood cells. Vitamin A supplementation supports a rise in hemoglobin concentration as well as facilitates iron transportation into hemoglobin. Vitamin A deficiency affects iron movement and can affect hemoglobin synthesis.
Vitamin A has been used to address skin conditions. Skin contains retinoic acid receptors and retinoic X receptors found in the dermis and epidermis. In the skin, retinol is converted into retinoic acid. Retinoic acid modulates gene expression in both the dermis and epidermis. Ultraviolet B can activate transcription factor AP-1, which increases the production of metalloproteinases in the skin and causes degradation of collagen and fibrillin.
Topical retinoid application has been used as a first line of defense to support healthy skin due to its few side effects. The use of oral retinoid does not induce bacterial resistance and can be used for maintenance.
Topical and supplemental vitamin A are important in wound healing. Vitamin A deficiency has been shown to slow wound healing rates.
Vitamin A is involved with thyroid function in numerous ways. It modulates thyroid gland metabolism, peripheral metabolism of the thyroid hormones and the production of thyroid stimulating hormone. In fact, iodine deficiency is often found in tandem with vitamin A deficiency. Adding vitamin A with iodine supplementation may be used to maintain healthy thyroid function.