Vitamin A and Carotenoids

Vitamin A is an important fat-soluble vitamin that plays a role in vision, growth and development, reproduction, and immune system function.  Vitamin A, along with carotenes, also function as important antioxidants.

 

Major Functions of Vitamin A:

– Promotes good vision and counteracts night blindness and eye disorders
– Aids in proper function of immune system
– Necessary for normal cell growth and development
– Needed for maintenance and repair of epithelial tissue
– Antioxidant that protect cells from free-radical damage

 

Vitamin A plays a role in skin health because it is needed for the maintenance and repair of epithelial tissue, of which the skin and mucous membranes are composed.  Vitamin A stimulates growth of the base layer of the skin cells.  It also helps cells to differentiate normally and gives them their structural integrity.  Due to its importance to epithelial tissue, a deficiency of this vitamin can cause dry hair and skin.

 

Food Sources

Animal Sources (retinyl palmitate):  liver, kidney, egg yolks, butter, whole milk and cod liver oil.  Non-fat milk products as well as some packaged foods (e.g., cereal) are fortified with vitamin A.

 

Plant Sources (carotenoids):  apricots, melon, red peppers, carrots, cantaloupe, chives, parsley, shallots, sweet potato, broccoli, kale, dandelion greens, spinach, squash (winter or butternut), mustard greens, and pink grapefruit.

 

Two Forms

Vitamin A occurs in two forms – preformed vitamin A and provitamin A.

 

Preformed vitamin A is found in foods of animal origin and typically occurs as retinyl palmitate.  The body then converts this compound into three active forms: retinol, retinal and retinoic acid.

 

Provitamin A refers to a family of fat-soluble compounds called carotenoids.  The carotenoid family includes not only beta-carotene but alpha-carotene, cryptoxanthin, lycopene, lutein and zeaxanthin.  Fruits and vegetables that are deeply colored yellow, orange, red, blue, and purple indicate that these plants are high in carotenoids.

 

Unlike preformed vitamin A, carotenoids convert into vitamin A only as the body requires.  The conversion to vitamin A decreases when stores of vitamin A are full.  However, not all carotenes convert into vitamin A.  Since beta-carotene converts the most readily, this form is often used in nutritional supplements.  But, some carotenoids such as lycopene, zeaxanthin and lutein do not have any provitamin A activity (do not convert into vitamin A).  Instead, they exert potent antioxidant protective benefits.

 

Recommended Dietary Allowance

The Recommended Dietary Allowance (RDA) for vitamin A is 2,310 IUs for adult women and 3,000 IUs for adult men.  Keep in mind that the RDA applies only to vitamin A from retinyl palmitate.  It does not apply to a carotenoid source because no toxicity issues have been found with these compounds.  For this reason, the Institute of Medicine has not established an RDA or a Tolerable Upper Intake Level for carotenoids.

 

If you look on a nutritional supplement facts panel, you’ll notice the Amount Per Serving for vitamin A and the % Daily Values is at located at the top of the panel.  The Amount Per Serving is based on the Reference Daily Intake (RDI) for this nutrient which is considered to be sufficient to meet the requirements of nearly all (97–98%) healthy individuals in each life-stage and sex group.

 

The Reference Daily Intake for vitamin A is 5,000 IUs which represents 100% of the Daily Values.  At this time, the FDA requires that a carotenoid with any provitamin A activity must be listed under the vitamin A section of the supplement facts panel.  However, if the carotenoid blend does not have any provitamin A activity (e.g, a lutein or lycopene) then the nutrient can be listed in the section of the panel where Daily Values have not yet been established.

 

Precautions

Antibiotics, laxatives, some cholesterol lowering drugs and excess alcohol intake can interfere with vitamin A absorption.

 

Pregnant women should be careful of their vitamin A intake as excess is associated with birth defects like spina bifida and cleft palate.

 

Menopausal women should be careful to not exceed the RDA for vitamin A.  The Nurses Health Study, a large study funded by the National Institutes of Health, found women with high vitamin A intake from both dietary and supplement sources, greatly increased their risk of developing an osteoporotic hip fracture as compared to women who consumed the least amount.  Current evidence does not point to this risk from carotenoid sources.

 

VitaMedica Products

VitaMedica nutraceuticals are formulated with retinyl-palmitate, carotenoids or a combination of both.  The form that we use depends on the purpose of the supplement.

 

Our Recovery Products are formulated with a combination of retinyl-palmitate and beta-carotene.  After surgery or trauma, the body requires higher levels of macro and micro nutrients to repair injured tissue.  After trauma, the immune system can be weakened thereby increasing the chance of infection.  Given the importance of vitamin A to healing and the immune system, obtaining higher levels of this vitamin during the peri-operative period is beneficial.  That’s why VitaMedica’s Recovery Support Program and Clinical Support Program contain 25,000 IUs of vitamin A.  This amount is quite safe because it combines 10,000 IUs of retinyl palmitate and 15,000 IUs of beta-carotene.  Additionally, our Recovery Products are used for a limited duration of time.

 

Our Anti-Aging and Acne products are formulated with Betatene, a naturally occurring blend of carotenes including beta-carotene, alpha-carotene, cryptoxanthin, zeaxanthin and lutein.  Betatene is extracted from Dunaliella salina algae, which is grown on the world’s largest cultivated algae farm, located in Whyalla, Australia.

 

Given that most adults obtain the Recommended Dietary Intake of vitamin A from foods, taking extra in a supplement is not required.  However, taking extra carotenoids like Betatene for their antioxidant, anti-inflammatory and other health benefits is prudent.  Our daily supplements like Anti-Aging Formula, Bone Support, Energy Support and Multi-Vitamin & Mineral are formulated with this nutrient.

 

Our two acne supplements, Healthy Skin Formula and Clear Skin Formula, include a combination of retinyl palmitate plus Betatene.  Given the importance of vitamin A to skin health, including some vitamin A as retinyl palmitate is beneficial in patients who have acne, psoriasis or eczema.  Given their daily use, the amount of retinyl palmitate formulated in our acne supplements (7,500 IUs) is lower than in our Recovery Products (10,000 IUs).

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