GENERAL DESCRIPTION:
Found only in animal sources; particularly
fish liver oils (as in cod liver oil), liver, milk,
cream, cheese, butter, and eggs.
ROLE IN ANTI-AGING:
Vitamin A is essential for healthy eyes and good vision, especially night vision. It is required for the
proper growth and maintenance of the
skin, bones, and reproductive organs,
and helps in building resistance to respiratory infections and boosting immunity.
Vitamin A may also protect against cancer, and is useful in the treatment of skin conditions such as acne.
DEFICIENCY SYMPTOMS:
Night blindness or loss of adaptation to the
dark; dry eye disease; sty in the eye; increased susceptibility to infection; sinus and
bronchial infections; drying out of skin and mucous
membranes; loss of taste and smell which leads to loss of
appetite; loss of vigor; defective teeth and gums; slowed
growth.
THERAPEUTIC DAILY AMOUNT:
7,000 – 10,000 I.U. RDA is 3,000 I.U (900mcg)
for men, and 2,300 I.U. (700mcg) for women. The European RDA is 800mcg.
MAXIMUM SAFE LEVEL:
2300mcg (long-term usage), 7500mcg (25,000
I.U.) (short-term usage). People over the age of 65 and those with liver disease are advised to
take no more than 15,000IU of Vitamin-A. Vitamin A toxicity
can be serious, thus, it is important to ensure that the
recommended dose is not exceeded.
SIDE EFFECTS/CONTRAINDICATIONS:
Women who are planning to become pregnant
or those who are in the first three months of pregnancy should not eat liver, or take
vitamin A supplements which contain more than the 800mcg,
unless under medical supervision as too much vitamin A can
cause birth defects. However, adequate vitamin A is
essential during pregnancy. Results of a
clinical trial published in 1999 revealed that people who
took 25,000 IU of vitamin A each day for approximately four
years experienced an 11% increase in triglycerides, a 3% increase in total cholesterol and
a 1% decrease in “good” HDL cholesterol, suggesting that
people at high risk of developing heart disease should be
cautious when thinking about taking supplementary
vitamin-A. Meanwhile another study published in 1998 linked a daily intake of just 5,000 I.U. of
vitamin-A (the US RDA) with a significant reduction in bone
mineral density.
The decrease in bone mineral density was so
great that it approximately doubled the risk of hip fracture. Based on these findings, people at high
risk of developing osteoporosis – in particular menopausal
and postmenopausal women – may benefit from taking
betacarotene supplements instead of vitamin-A. Vitamin-A should not be taken by people using the
acne medications isotretinoin, resorcinol, topical sulfur,
and tazarotene.
SOLUBILITY:
soluble
