Page 19 - summer2016

While essential throughout the lifespan for growth, immunity, epithe- The IOM set the tolerable upper intake level
lial tissue maintenance, lung and visual function, “[vitamin A’s] influence during pregnancy at 3,000 μg/day RAE (10,000
is particularly critical during periods when cells proliferate rapidly and IU). The upper level only applies to the intake
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differentiate, such as during pregnancy and early childhood.” Deficien- of preformed vitamin A (retinol) not to carot-
1
cies of vitamin A produce a myriad of deleterious outcomes in animals enoids, which are not assigned an upper level.
including defects in the eyes, snout, Although beta-carotene is
dental arches and in the worst case, not limited during preg-
spontaneous abortion or death of RETINOL, RETINAL AND RETINOIC ACID nancy, a high intake can
mother and offspring during labor, cause carotenemia, which
as described by Weston A. Price. has been associated with
2
In humans, even mild deficien- amenorrhea in young veg-
cies during pregnancy can lead to etarian women. Recent
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compromised kidney development research also suggests
in the child. 3 that cleavage products of
Vitamin A’s role in reproduc- beta-carotene can block
tion has been solidly established. vitamin A at its receptor
But questions remain. What is the sites—another possible
optimal amount of vitamin A dur- anti-nutrient?
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ing pregnancy? Are women getting According to USDA
enough to support the health of data, 53 percent of women
their babies? Is it possible to get too ages eighteen to thirty
much? have a usual intake of
vitamin A from diet that
RECOMMENDED DIETARY INTAKES falls below the estimated average requirement
VERSUS ACTUAL POPULATION INTAKES (EAR) of 500 μg RAE/day. An EAR is calcu-
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The National Academy of Sciences Institute of Medicine (IOM) has lated to meet the requirements of 50 percent of
established the recommended dietary allowance (RDA) of vitamin A the individuals in a gender/age group; half of
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for non-pregnant females at 700 μg/day of retinol activity equivalents this group will not have their needs met from
(RAE, explained below), and the RDA for pregnant females at 770 μg/ intakes equal to the EAR. The RDA is set higher
day RAE (2570 IU). This is only 70 μg or just 10 percent more than the in order to include 97.5 percent of the individu-
requirement for a non-pregnant female. The questionable methodology als in the entire gender/age group. In the case of
used to determine the pregnancy RDA has been discussed by Chris vitamin A, 53 percent of women in their prime
Masterjohn, PhD. For newborn infants, an adequate intake is 400 μg/ reproductive years do not even meet this very
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day (1320 IU)—more than half the total RDA during pregnancy. Current low dietary intake of 500 μg (1670 IU). The
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public health guidelines advise that people consume at least 2.5 cups of usual dietary intakes in the lowest fifth and tenth
fruits and vegetables a day to ensure adequate nutrient intake of RAE percentiles of females ages eighteen to thirty are
from carotenoids. However, the U.S. Centers for Disease Control and 210 μg and 257 μg respectively, only one-third or
Prevention (CDC) also states: “fish-liver oils, liver, egg yolks, butter, and less of the RDA. 11,12 The USDA named vitamin
cream are known for their higher content of [preformed] vitamin A.” A one of the “shortfall nutrients,” but did not
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QUANTIFYING VITAMIN A

You may be more familiar with quantifying vitamin A in international units, or IU. Supplement labels report vitamin
A amounts in both IU and % daily value and food labels report just the % daily value, which is based on highest IUs
needed for an adult. (The current “Nutrition Facts” label on foods will no longer require vitamin A to be listed as of July
2018.) According to FDA policy: 100% of the daily value for vitamin A is 5,000 IU for non-pregnant adults and children
four years old or older; in pregnancy the daily value increases to 8,000 IU. The FDA daily values for all nutrients have not
changed since 1995, and are based primarily on the 1968 RDAs which were re-established by the IOM starting in 1997.
In 2001, the IOM set the current RDA at 770 μg/day RAE for pregnant women 19 years and older, equivalent to 2,570
IU. The IOM set the tolerable upper intake level for all adults 19 years and older at 3,000 μg/day RAE which equates to
10,000 IU of preformed vitamin A. You can arrive at IUs by multiplying RAEs by 3.33.

Wise Traditions SUMMER 2016 Wise Traditions 19