Beta Carotene Cannot Substitute For Real Vitamin A (Retinol)
The National Academy of Sciences says that Vitamin A exhibits toxicity for a few people
at the Lowest Observed Adverse Effect Level of 21,600 IU when taken for long periods
of time
, so some dietary supplement companies are substituting beta carotene for Vitamin A
in their formulas to avoid the possibility of toxicity. This is a scientific mistake.

Beta carotene converts in the body into retinol. However, while it is commonly assumed that
the body can convert beta carotene into real retinol Vitamin A "as needed," efficient conversion
does not happen adequately for over half the population.

Additionally, the conversion of beta carotene into the retinol form of Vitamin A in the body is not efficient.
While beta carotene had previously been thought to convert at a rate of about 6 to 1 into retinol in the body, current
science calculates the conversion to be as little as 21 to 1. (1,2,3,4)

This means that instead of 12,000 IU of beta carotene converting into 2,000 IU of real retinol vitamin A in the body,
it would only convert into about 571 IU.

Since the Daily Value for Vitamin A (retinol) is 5000 IU per day for women and men, it would
take about 105,000 IU of beta carotene per day to produce an RDA amount of retinol in your body -- if
beta carotene conversion happens normally in your body. For many people this is not the case.

Problems arise with Vitamin A deficiency, especially for pregnant women and their babies. Vitamin A
deficiency is associated with 74 percent more chance of premature deliveries(5) and with more incidence of
Chronic Lung Disease and "a lifetime of breathing abnormalities" in the newborn.(6)

The World Health Organization says that all pregnant women should take real retinol Vitamin A and the
International Vitamin A Consulting Group, who advises the World Health Organization, says that
"It is safe to give all fertile women, independent of their Vitamin A status, as much as 10,000 IU 
[of retinol vitamin A] daily at any time during pregnancy."
(7)

Vitamin A supplementation can reduce the potential for the childs' potential for infectious mortality within
the first year of birth by 64 percent and incidence of pneumonia, the leading cause of child death, by 50 percent.(8)

Click here to read the fully referenced details in a 18-page review of this subject.

Michael Mooney
www.michaelmooney.net
mmooney@covad.net

References:

  1. Solomons NW. Plant sources of proVitamin A and human nutriture: How much is still too little? Nutrition Reviews 1999 Nov;57(11):350-361.
  2. Tang G, and associates. Vitamin A equivalence of beta-carotene in a woman as determined by a stable isotope reference method.  European Journal of Nutrition 2002 Feb;39(1):7-11.
  3. Brubacher GB, and associates. The Vitamin A activity of beta-carotene. International Journal of Vitamin and Nutrition Research 1985;55(1):5-15.
  4. Hickenbottom SJ. Dual isotope test for assessing beta-carotene cleavage to Vitamin A in humans. European Journal of Nutrition 2002
  5. Radhika MS, and associates. Effects of Vitamin A deficiency during pregnancy on maternal and child health. British Journal of Gynecology 2002 Jun;109(6):689-93.
  6. Hustead VA, and associates. Relationship of vitamin A (retinol) status to lung disease in the preterm infant. Journal of Pediatrics 1984 Oct;105(4):610-5.
  7. http://ivacg.ilsi.org/publications/pubslist.cfm?pubentityid=16&publicationid=218
  8.  Humphrey J, and associates. Neonatal Vitamin A supplementation: effect on development and growth at 3 years of age. American Journal of Clinical Nutrition 1998;68:109-117.