Page 80 - Special Issue: Healthy Baby
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A study of the risk of birth defects. This belief can be of the third trimester. One study conducted in
over 10,000 traced to a single study published in 1995 that Britain showed that 36 percent of new mothers
purportedly found an increase in the risk of birth and 32 percent of newborn infants had no detect-
infants in defects among mothers consuming more than able vitamin D in their blood; another showed
Finland 10,000 IU per day. As discussed in the sidebar that 60 percent of infants born to white mothers
below, there are several important flaws in in the spring and summer had levels under 8
showed this study. Every other published study on this nanograms per milliliter (ng/mL), a level that is
that direct subject shows this amount of vitamin A to be overtly deficient. 32
supplemention safe—indeed, one major study of over 25,000 In 1963, the American Academy of Pediatrics
births showed that daily doses of vitamin A up acknowledged the increased need for vitamin
of 2,000 IU to 40,000 IU cut the risk of birth defects in half. D during the third trimester of pregnancy. The
vitamin D Considering the ubiquitous role of vitamin Academy lamented the lack of data elucidating
per day to A in the development of every organ system of the precise amount of this need and suggested that
the body and how tightly the body regulates the 400 IU per day would cover the requirements of
infants in the level of the activated form, we should expect a mother and fetus. 28
first year of generous helping of vitamin A-rich organs and In 1997, however, the Institute of Medicine
animal fats to help perfect fetal development, not declared that the transfer of vitamin D from the
life virtually to throw it off course. The preponderance of the mother to the fetus is so small that the mother’s
eradicated the evidence suggests that this is the case. vitamin D status is not affected. Citing a 1978
risk of type 1 VITAMIN D study showing that the average vitamin D level
of pregnant women consuming small amounts
diabetes Late in the third trimester, the fetal skeleton of vitamin D at high latitudes was 9.1 ng/mL
over the next enters a period of rapid growth that requires calci- (25 percent under the level required to protect
um, phosphorus and vitamin D. An infant born six against overt deficiency) the Institute concluded
30 years. weeks prematurely has laid down only half the cal- that “there is no additional need to increase the
cium into its bones as an infant carried to term.28 vitamin D age-related [adequate intake] during
There is evidence that vitamin D plays a role in pregnancy above that required for non-pregnant
lung development, and it probably plays a much women.” This conclusion is strange, not only
29
larger role in fetal development in general due to because many of the mothers in this study must
vitamin D’s interaction with vitamin A. At birth, have had vitamin D levels below the average, but
the infant’s blood level of vitamin D is closely because the average level itself was already defi-
correlated to that of the mother. 30,31 Adequate cient. The Institute set the recommended intake
levels of vitamin D protect the newborn from at 200 IU, which it rather dubiously supposed
tetany, convulsions and heart failure. 29 “may actually represent an overestimate of true
The rapid skeletal growth that occurs in late biological need.” 33
pregnancy taxes the vitamin D supply of the In 2003, the American Academy of Pediat-
mother and her blood levels drop over the course rics’ Committee on Nutrition and its Section on
IS THE PREGNANCY RDA FOR VITAMIN A ADEQUATE?
The RDA of vitamin A for pregnant women is only 2,600 IU—just 300 IU more than the RDA for women who are
not pregnant. To obtain this figure, the scientists at the Institute of Medicine (IOM) made the following calculation: first,
they ascertained from previous reports the amount of vitamin A stored in the livers of fetuses that were spontaneously or
voluntarily aborted between 37 and 40 weeks; second, they doubled this figure, assuming that half of the fetal vitamin
A stores exist in the liver; and third, they divided this amount over the number of days in the last trimester, during which
they presumed this vitamin A would accumulate. 20
There are several problems with this calculation. Since the fetuses were aborted, we have no idea what their future
health would have been like—their visual acuity, their hearing, their intelligence, their facial and dental features, their
reproductive health, or their length of life. And the function of vitamin A, of course, is not to be stored but to be used.
The fetus does not simply hold on to vitamin A to use it after birth, but rapidly uses and metabolizes it to regulate the
entirety of its growth and development. Granted, the IOM acknowledges that it has only used this data because better
data do not exist—yet it is important to emphasize just how little the data tell us.
78 Wise Traditions