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Vitamin A for Fetal Development PDF Print E-mail
Written by Mary G. Enig, PhD   
Saturday, 12 November 2005 17:40

True vitamin A is a vitamin that occurs only in animal fats. In primitive societies, pregnant women consumed special foods rich in vitamin A--such as liver, spring butter and fish eggs--in a conscious effort to produce healthy, well-formed children. Modern research completely validates these traditions.

In a recent paper,1 Maija H. Zile, of the Department of Food Science and Human Nutrition, Michigan State University, details the role of vitamin A in fetal development. Working with bird and mouse embryos, she and other researchers have determined that the vitamin A requirement begins at the time of formation of the primitive heart and circulation, and the development of the hindbrain, a period that corresponds to weeks 2-3 in humans. Without vitamin A, the embryo succumbs to gross abnormalities of the heart and is aborted.

Each organ system begins development during a specific window of time. Vitamin A regulates the differentiation of the primitive cells into cells specific to each organ system, in essence signaling to the genes their marching orders so they "know" where to locate themselves and what kind of tissues to become. If vitamin A is lacking during any of these windows, the organs develop abnormally or not at all.

The major target tissues of vitamin A deficiency include the heart, central nervous system, the circulatory, urogenital and respiratory systems, and the development of the skull, skeleton and limbs. Vitamin A deficiencies during the period when any of these systems begin specialization can result in abnormalities and defects.

According to Zile, even partial vitamin A deficiency affects the sensitive developing central nervous system; it plays a key role in the development of the visual system, the retina, the inner ear, the spinal cord, the craniofacial area including the pharyngeal and branchial arches and the thymus, thyroid and parathyroid glands.

During mid-gestation, vitamin A is required for fetal lung development. In vitamin A-deficient animals, congenital malformations in the urogential system occur.
Most interesting is new research on the effect of vitamin A on kidney development. Vitamin A deficiency results in a reduced number of nephrons in the kidney. Lower numbers of nephrons mean the kidneys will not work at optimal levels and may doom the individual to dialysis later in life.2

Another fascinating avenue of research has shown that vitamin A holds the key to what scientists call the "holy grail" puzzle of developmental biology: the existence of a mechanism that ensures that the exterior of our bodies is symmetrical while the inner organs are arranged asymmetrically. Researchers at the Salk Institute have found that vitamin A provides the signal that buffers the influences of asymmetric cues in the early stages of development, and allows these cells to develop symmetrically. In the absence of vitamin A, the exterior of our bodies would develop asymmetrically, with the result being that our right side would be shorter than the left side.3

After the formation of all the organ systems, vitamin A supports their growth. Chronic vitamin A deficiency during pregnancy compromises the liver, heart and kidney and impairs lung growth and development during the last weeks of gestation.4

Unfortunately, FDA and other agencies warn pregnant women to avoid foods like liver and cod liver oil, claiming that too much vitamin A from these foods can cause birth defects. The study usually cited in support of these warnings was carried out in 1995 at the Boston University School of Medicine and published in the New England Journal of Medicine.5 In the study, researchers asked over 22,000 women to respond to questionnaires about their eating habits and supplement intake before and during pregnancy. Researchers found that cranial-neural crest defects increased with increased dosages of vitamin A; but neural tube defects decreased with increased vitamin A consumption, and no trend was apparent with musculoskeletal, urogenital or other defects.

This study is a poor rack on which to hang the myriad warnings that have kept pregnant women from eating liver and taking cod liver oil. Researchers made no distinction between synthetic vitamin A derived from multivitamins and processed food like margarine, and natural vitamin A from food; nor did they take blood samples to determine vitamin A status. Food recall surveys are a notoriously inaccurate method of determining nutrient intake.

Subsequent studies found that high levels of vitamin A did not increase the risk of birth defects. A 1998 study from Switzerland looked at vitamin A in pregnant women and found that a dose of 30,000 IU per day resulted in blood levels that had no association with birth defects.6

A 1999 study carried out in Rome, Italy found no congenital malformations among 120 infants whose mothers consumed an average of 50,000 IU of vitamin A per day.7 Some participants consumed up to 300,000 IU vitamin A daily during pregnancy with no birth defects in the offspring. An average of 50,000 IU vitamin A per day is consistent with our recommendation of cod liver oil to supply 20,000 IU per day plus additional vitamin A in liver, butter, seafood and egg yolks.


  1. J Nutr. 2001;131:705-708.
  2. Nephr Dial Trans. 2002 Sept;17(Suppl9):78-80.
  4. Brit J Nutr. 2000 July;84(1):125-132.
  5. NEJM. 1995 Nov 23;333(21):1414-5.
  6. Int J Vit Nutr Res 1998;68(6):411-6.
  7. Teratology. 1999 Jan;59(1):1-2.
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Summer 2005.

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Comments (5)Add Comment
Reply to Grace
written by DianaG, Apr 19 2012
Hi Grace. I have a very healthy little man who is about to turn 2. I give him FCLO/BO (the unflavoured liquid via syringe) every day. He is so healthy in comparison to his peers, my husband and I are very pleased we've chosen to follow the WAPF principles for him. He's been taking the combination since he was six months.

Go for it smilies/grin.gif

Also, check out (videos section) to see how to give the cod oil - not that we have followed it, but for someone new to it it'll be helpful - and it's a fabulous blog as well. Sarah Pope, the lady whose blog it is, is a chapter leader for the WAPF.
written by Grace Hood, Mar 31 2012
Should I give my 2 year old daughter butter oil/Fermented CLO Blend - Cinnamon Gel from Radiant Life? Is she old enough?
written by Amber, Mar 04 2012
My daughter was also born with a kidney issue. A UPJ blockage of her left ureter with hydronephrosis of the left kidney. it is functioning but draining slowly. I was unfortunately on the SAD diet throughout my pregnancy with her and blame that on her kidney issue. Doctor just say it's a fluke. Very thankful it's not worse but wish I would have found this site and information sooner for her sake. dr wants to do surgery to correct it but I'm refusing since she has had no complications from the blockage and still has time to outgrow it and fix itself. Anyway, thanks or info, I'm now taking cod liver oil everyday and in my second pregnancy.
Still confused
written by Sasha, Dec 09 2010
I'm still really confused about Vitamin A. I'm pregnant with my second child and have been a vegetarian for 20 years. I'm currently learning more and reevaluating this, so I'm open to animal foods (I eat dairy and eggs anyway). My midwife (I'm in the UK) and all the government information say to avoid too much vitamin a, specifically animal-based sources. I have read 'The Vitamin A saga' and I understand the distinction between beta carotenes and vitamin A, but I still don't really understand why some research seems to clearly indicate that I should avoid vitamin A.
written by Dana, Jan 25 2010
Although I was taking a prenatal vitamin during my second pregnancy, in hindsight I would not have been getting enough natural vitamin A. Additionally, I tested high enough on my glucose levels at prenatal appointments that they ran me through the glucose tolerance test not once but twice. So I wasn't suffering from gestational diabetes but I was pretty close.

My daughter was diagnosed at four months with vesicourinary or vesicoureteral reflux. Additionally, the doctor found from the scans they did of her urinary system that her right kidney was significantly smaller than her left. Eventually the left side corrected itself without surgery but she required a procedure to reinsert the ureter on the right side.

I'm very suspicious that my diet during my pregnancy is the culprit. But what they tell us when our child is diagnosed with this thing is that they think it's genetic. They say it runs in families and that if one child has it there is a thirty percent chance other children in the family will have it.

I wonder. Dr. Price noticed a relationship between birth order and stunted development due to poor nutrition. I wouldn't be surprised if this were related too. If a first child were to suffer from VUR due to poor nutrition, it only stands to reason the subsequent children have a greater chance of it if the mother doesn't correct her nutrition.

I wish your work were more widely known. Kidney failure is so common in our country that the need for dialysis is one of the major trigger events that qualifies an American citizen for Medicare. Imagine all the money and pain and sorrow and shortened lives we would spare if people would just eat more liver.

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Last Updated on Thursday, 07 October 2010 17:46