Vitamin A is so named, as it was the first vitamin discovered.  The major functions of Vitamin A in the body include:

·      Promoting vision.  It is especially noted for decreasing night blindness as night blindness is considered one of the first detectable signs of a deficiency.

·      Maintaining the integrity of the skin, lining of the mouth and intestines.  Vitamin A can be used for the treatment of psoriasis, acne and sun damaged skin.

·      Promoting bone growth. 

·      Supporting the immune system.

Vitamin A is available in two forms.   These are:

• Beta-carotene is found in many plant foods.  Beta-carotene is converted into Vitamin A when the body has a need. It is not toxic.  The RDA for this form of Vitamin A is equivalent to 8000-10,000 IU.    Beta Carotene is an antioxidant and is therefore a healthy addition to the diet in its own right
• The Retinoids (Retinol, Retinal and Retinoic Acid) are pre-formed Vitamin A found in animal products   The RDA for this form of Vitamin A is equivalent to 2664-3333 IU.   Amounts greater then 10-15 times the RDA can cause toxic symptoms such as: nausea, vomiting, and abdominal pain, diarrhea, and weight loss.   Birth defects have been known to result from excess Vitamin A.  This toxicity is unlikely if a person relies on foods but can be reached through the use of supplements.  (Eating liver every night also has the potential of reaching toxic levels) 

Significant food sources for retinol include: fortified milk, cheese, cream, butter, fortified margarine, eggs, and liver.  Significant sources for Beta Carotene include: dark, leafy greens, broccoli, and deep orange fruits and vegetables such as apricots, cantaloupe, carrots, squash, pumpkin and sweet potatoes.

Most multivitamins contain both Beta-carotene and a pre-formed Vitamin A.   The multivitamin complex usually has 100% of the RDA, which is listed on the package as Percent Daily Value.   Vitamin A can also be included in other vitamin complexes especially those claiming to be of benefit to the eyes.   Read the Labels and don’t double and triple up!

Vitamin D is the sunshine vitamin.    The body can make Vitamin D from exposure of bare skin to the ultraviolet rays of the sun.  (Sunscreen can prevent the synthesis of Vitamin D)  The main function of vitamin D is to aid in the absorption and retention of calcium.  Low intakes of vitamin D result in calcium deficiency and abnormal bone mineralization.   Vitamin D supplementation can be recommended for:

·        The elderly as their skin is less efficient in converting sunlight into Vitamin D.

·        Those with a minimal exposure to the sun.

·        Dark skinned people

·        Those who live where there is very little natural sunlight or a great deal of smog.

Significant food sources of Vitamin D are:  fortified milk and margarines, egg yolk, liver and fatty fish.

The RDA is equal to 400 IU.  A multivitamin usually has 400 IU, which is adequate for most adults.  (Those over 70 could benefit from 600 IU if they do not drink milk)  Many calcium preparations and other vitamin formulas also include a vitamin D in various amounts.   Toxicity of Vitamin D can begin at about four times the RDA.    Be careful if you are taking several vitamin complexes that include this vitamin.