Vitamin A derived products such as retinoids are now widely available, both as nutrients and for use in cosmetic products. For the past 15 years, the retinoids have been used to treat
- Sun damaged skin
- Precancerous skin lesions
Isotretinoin or Accutane has been found to be very effective in the treatment of acne.
It is widely believed by many that taking excess or mega doses of nutrient and mineral is essential and beneficial. This is a false myth.
Too much vitamin A can cause toxicity. Taking daily doses which are more than 5-10 times higher than what is recommended can lead to vitamin A toxicity in a few months. Excess vitamin A intake in infants and children can lead to adverse effects on children within 2-4 weeks.
Large amounts of Vitamin A can cause
- coarse hair
- loss of hair
- dry and cracked lips
- rough skin
- vomiting within hours
- Peeling of the skin.
- bone and joint pains
- weakening of bone
In children, pressure within the brain (intracranial pressure) can increase and be associated with severe vomiting. In severe cases of overdose, coma and death may occur unless vitamin A is immediately discontinued
Teratogenic: Vitamin A derivatives are known to cause fetal damage and a variety of congenital malformation when taken during pregnancy. Retinoids are not recommended for women who intend to get pregnant. There is a federal registry of all female users and numerous litigations have occurred over the past decade regarding prescribing the drug to females
Carotenoids can be consumed in foods without causing toxicity. However, when large amounts are consumed, the skin turns a deep yellow (carotenosis), especially on the palms and soles.
According to the 2005 Dietary Guidelines for Americans, "Nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet."
Current recommendation on carotenoids is that beta-carotene supplements are not advisable for the general population. However, they may be appropriate as a provitamin A source for the prevention of vitamin A deficiency in specific populations only