Vitamin A: Essential for Growth and Development

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In my last article on lactation and vitamin A,¹ you learned that infants with low levels of vitamin A can have slowed growth and in­creased susceptibility to respiratory infections. This article will further discuss many of the key ways in which vitamin A is needed for children to grow and develop fully according to their genetic blueprint.

GROWTH

Vitamin A is required for the development and growth of all types of cells, and hence all organs and tissues.² In fact, the earliest symptom of vitamin A deficiency is a loss of appetite and an ensuing decrease of growth.³ This is a pri­mary reason why vitamin A is a very important nutrient for children, especially during phases of accelerated growth.⁴

Clinically, vitamin A supplementation in short children increased nighttime growth hormone secretion; this may be one reason that vitamin A has been shown to increase height and weight for age in children. And when com­pared with growth hormone therapy for young children born small for gestation age, vitamin A, together with zinc and iron supplementation, produced similar improvements in growth.

IMMUNITY AND GUT HEALTH

An equally important role for vitamin A is combating childhood infections.⁵ Compared to their well-nourished peers, vitamin A-deficient children are more susceptible to developing infections, especially those of the respiratory and gastrointestinal tracts. Even milder vitamin A deficiency leads to the keratinization and dis­ruption of the function of the mucosal tissues, potentially allowing opportunistic infections to take hold.⁶

Vitamin A is critical from the earliest stages of life for the proper development and functioning of the immune system. Through its interaction with both the innate and the adaptive immune systems, vitamin A improves defenses against infections. Deficiency, either in utero or early life, decreases the number of immune cells in a child and has the potential to suppress the immune response in the gut.⁶ Deficiency also impairs what is known as “oral tolerance” (the ability of the immune system to not over-respond to ingested antigens), increasing the risk for food allergies.⁷ In a study of neonate mice, giving vitamin A accelerated the development of oral tolerance to an antigenic protein. A similar strategy could prove effective for addressing the increasing rates of food allergies in very young children, especially considering the prevalent low intakes of vitamin A by breastfeeding mothers and in the weaning diets of their babies, which emphasize fruits and vegetables instead of vitamin A-rich animal foods.1,^8,9

Infancy is a crucial period for establish­ing the gut microbiome; proper establishment has short-term as well as long-lasting benefits for infant health.10 Vitamin A is needed for the integrity and functioning of the intestinal barrier and the microbiome that resides in it. Deficiency can impair the development of that barrier because vitamin A is required for the intestinal cells to replicate and differentiate—in other words, to function as they are designed. The mucus produced by these cells also protects the lining of the gut from damage by the resident microbes.

Additionally, vitamin A is needed for the development of the gut mucosal immune system. This involves the development of the various types of cells that regulate adaptive immunity, and most importantly, the cells that produce secretory IgA, which actually “coats” intestinal bacteria, both the beneficial and harmful strains. Thus, vitamin A deficiency (VAD) increases the risk for invasive bacterial infections in the gut. Infants born in developing countries are known to be at high risk for VAD; supplementation in early life reduces the risk of diarrheal disease and other common infections including measles.^10,11

In summary, vitamin A modulates the im­mune system directly through communication with immune cells, or indirectly through its interaction with the microbiome. Deficiency increases susceptibility to infection both at the initial (innate) and second line (adaptive) immune response, impairs oral tolerance and negatively affects the function of lymphocytes (white blood cells that fight off infection and destroy cancer cells).^4,12

MENTAL DEVELOPMENT

Research on the role of vitamin A in the brain is in its early stages. What is currently known is that vitamin A is essential for regu­lating pathways in regions of the brain critical to learning and memory; prolonged deficiency leads to a deterioration of these functions. The actions of vitamin A are crucial for maintaining the balance of neuronal (brain cell) excitation and inhibition. While the brain seems to be able to utilize lower levels of vitamin A more effec­tively than other tissues, the developing brain is particularly sensitive to vitamin A deficiency.¹³ Even a mild deficiency can be a problem when combined with a genetic susceptibility to vita­min A deficiency.¹⁴

Studies in rodents allow scientists to ob­serve the brain changes occurring as a result of prenatal and postnatal vitamin A deficiency, changes that cause deficits in neurodevelopment, notably in spatial learning, memory and social behavior.¹⁵ Vitamin A deficiency reduces the ability of newly formed cells in the hippocampus region of the brain to differentiate into neurons and survive. Following birth, the hippocampus is one of the few regions in the brain where new neurons are made, necessary for certain types of memory formation.¹⁴

In an observational study of children with autism spectrum disorder (ASD), the lower their vitamin A levels were, the more severe their ASD was. A pilot study providing higher-dose vitamin A to Chinese children with autism significantly improved their scores on the Childhood Autism Rating Scale six months after administration.¹³ Unfortunately, there have been increasing reports of vitamin A deficiency among children with ASD in developed na­tions.¹⁶

In the United States, Dr. Mary Megson has improved the cognitive and behavioral health of thousands of children diagnosed with autism using a protocol that includes the “natural lipid soluble concentrated cis form of vitamin A in cod liver oil.”¹⁷ She reports that these chil­dren also require another form of vitamin A, 14-hydroxy retro-retinol, naturally present in cod liver oil, to activate their immune systems, which then improves their physical health. I would encourage readers to share Dr. Megson’s detailed description of her therapy with parents who are looking for answers to their child’s ASD symptoms.¹⁷ (Also according to Megson, Bos­ton University pediatric neurologist Margaret Bauman has described “a lack of cell growth and differentiation in the hippocampus seen on autopsy in autistic children.”¹⁷ The frontal lobe is the seat of attention, inhibition of impulse, social judgment and all executive function.) Cod liver oil use in young children is also associated with a significantly lower risk of type 1 diabetes and upper respiratory tract infections.^18,19

SEXUAL MATURATION

Vitamin A has an important role in the sexual development of both females and males, although, like brain development, it is not completely understood. Deficiency can delay puberty and restrict the rapid growth that nor­mally accompanies this stage of life. In a group of teenage boys with low intake, supplementa­tion with vitamin A and iron worked as well as testosterone therapy in inducing normal pubertal growth and maturation.²⁰ In well-nourished girls, an increase in the carrier protein for vitamin A occurs during the latter stage of puberty, suggesting a higher demand for sexual maturation.²¹ In another study, painful men­strual periods with excessive blood loss were alleviated with vitamin A therapy.²² Adolescent and teenage girls suffer physically, socially and emotionally when periods are heavy and pain­ful; increasing the intake of vitamin A should be considered a first-line therapy. Looking to the future, abundant vitamin A is needed to support growth of the skeletal structure, including the pelvic region.

BONES AND TEETH

Vitamin A is important in controlling the activity of skeletal bone formation, orchestrat­ing the balance between the bone-forming cells (osteoblasts) and the bone “breaking down” cells (osteoclasts). Without this balance, bone growth is unregulated, and bones become overly dense—cranial bones do not expand properly to accommodate the growing tissues, causing nerve damage due to compression.^23,24

In the mouth, vitamin A is needed to form teeth of the proper shape, size, spacing and structure.²⁵ M ore s pecifically, v itamin A is needed by cells called odontoblasts to form the dentin properly, by cells called ameloblasts to create the strong enamel coating and by the glands producing saliva that moistens the mouth and neutralizes the acids that are produced by oral bacteria.²⁶ Without enough vitamin A dur­ing development, teeth are weaker, don’t line up properly in the mouth and are more prone to cav­ities and chipping. They also may come in later than normal, contributing to difficulty chewing solid foods.²⁷ All of these dental problems are common among children today, unfortunately. Dr. Weston A. Price, a pioneer in the field of nutrition, recorded the same dental problems in children raised in communities who adopted “modern” diets devoid of nutrients, including vitamin A and the other fat-soluble vitamins.

WHY DO CHILDREN BECOME DEFICIENT?

In developing nations, VAD is prevalent among children, especially after weaning due to the problems of widespread malnutrition compounded by frequent infections, which lower vitamin A levels. VAD is considered a “public health problem” when the prevalence of Bitot spots (foamy white or grayish patches that appear on the surface of the eye) is 0.5 percent or more in preschool children and more than 5 percent of a population has low serum retinol levels^.6,28 While the incidence of severe VAD has not been seen in developed countries for several decades (Bitot spots are very rare),²⁹ there is evidence of decreased dietary vitamin A intake and marginal deficiency in populations that were previously considered to have adequate vitamin A status.^30,31 Even in “food-secure” developed nations, inappropriate feeding patterns and re­strictive diets have created the hidden problem of vitamin A deficiency in children.^34,45 There are numerous reports of low vitamin A levels (measured in the serum and livers) of “healthy” newborns, infants and children from countries that continue to be considered as having a vita­min A-sufficient food supply.⁸

In the United States, large national surveys of dietary intake by children report inadequate intakes of multiple key nutrients, including vitamin A.³² According to data collected be­tween 2001 and 2020, almost half of teenagers and about one quarter of adolescents had low vitamin A intakes, below the Estimated Aver­age Requirement (EAR). (The EAR is already low—set to meet the needs of just half of the individuals in a given age and sex category.) Yet less than 1 percent had low serum retinol levels, seeming to indicate that vitamin A deficiency among children is not a concern in the U.S. Children eight years old and younger were not found to have low vitamin A intakes; however, those intakes also include the vitamin A precur­sor, beta carotene, which is very inefficiently converted to retinol in very young children.³³ In the special case of infants, when setting the Dietary Reference Intakes, the Institute of Medicine (IOM) did not consider the contribu­tion of carotenoids in breastmilk because in infants, their conversion to retinol is unknown (and likely very inefficient according to earlier studies).³³ In addition, the EAR for children was extrapolated from a study of adult men, using a downward scaling factor based on body weight, again due to the absence of data.³⁴

Researchers from Iowa State University used a sensitive blood test (the modified rela­tive dose response test or MRDR) to evaluate the vitamin A status of a group of socioeco­nomically disadvantaged American preschool children.³⁵ The MRDR test can detect marginal vitamin A status, whereas the much more com­monly utilized test, serum retinol, cannot. The true status of vitamin A cannot be adequately determined by measuring plasma retinol, since it is homeostatically maintained across a range of intakes except at the extremes of the continuum.6,36 In this group of preschoolers, who were determined to be in “general good health,” 32 percent had inadequate vitamin A status according to the MRDR test, but only 3.9 percent had low serum retinol levels. The researchers concluded, “Vitamin A inadequacy must consequently be considered as a major nutritional problem among socioeconomically disadvantaged segments of our population, as it is in other cultures” (emphasis added).

Considering the typical diets of American children, marginal vitamin A levels are likely prevalent across all socioeconomic groups. Notably, ³⁵ percent of pregnant women of the same socioeconomic group also were found to be low in vitamin A per the MRDR test.

FACTORS BEHIND THIS DECLINE

As recently as the 1960s, it was considered important to include a weekly serving of liver in the diets of growing children and/or a daily spoonful of cod liver oil.^19,37 Commercial baby food companies sold strained liver in jars for convenience.

Today, American children are no longer introduced to this supremely nutrient-dense food. When prepared properly, infants enjoy eating liver (I have seen this firsthand in my own grandchildren), and as they grow, they will continue to enjoy it if offered routinely.

There has also been a decline in dairy in­takes by American children, and less than one in five eat egg(s) on any given day, further con­tributing to the decline in vitamin A intakes.^32,38 Raw carrots are a popular childhood vegetable and are widely believed to be rich in vitamin A, yet they are a very poor source of vitamin A for children.^33,39 Infant and toddler vitamins containing vitamins A, C and D have been re­placed by vitamin D-only recommendations; I suspect that this is due to the belief that young children are at risk for getting too much vitamin A. While the Weston A. Price Foundation does not recommend synthetic vitamins, this does illustrate the general lack of knowledge among pediatricians about the importance of vitamin A.

Another problem that I suspect is reducing the levels of vitamin A in children is their con­sumption of commercially fried foods. Chicken fingers and nuggets fried in industrial seed oils are one of the most popular processed foods for young children. (For a healthy alternative, see “Homemade Chicken Nuggets” at the WAPF website.⁴⁰) Toxic aldehydes produced in frying oils not only create a cell-localized deficiency of vitamin A in the body; they require the body to use a lot of vitamin E to limit their damaging oxidation.^41-45

Studies on animals published in 1940 indicate that vitamin E is needed to protect the liver’s stores of vitamin A.^33,46 A study published in 2025 examining the relationship of vitamins A and E levels in children highlighted the “importance of maintaining optimal Vita­min E status to support Vitamin A status” and “their implications for public health interven­tions.”⁴⁷

In conclusion, the problem of low vitamin A intakes puts our children at risk for compro­mised mental and physical growth. Children’s meals should not consist of overly processed foods like chicken fingers and cold cereals. Wise parents know that including liver, eggs, full-fat dairy, butter and fish liver oil in their regular family meals, beginning with the intro­duction of solid foods, will give their children the best opportunity to develop to their fullest genetic potential.

REFERENCES

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