Vitamin A Deficiency: Causes, Symptoms, and Testing Options

Written by Kristy Beard, MSN, APRN, FNP-C — Board-Certified Family Nurse Practitioner and Founder of Elevate Health and Wellness, serving patients across the Gulf Coast in Gautier, MS and Foley, AL.

What Is Vitamin A and Why Does the Body Need It?

Vitamin A is a fat-soluble vitamin that exists in two primary forms in the diet: preformed vitamin A (retinol and retinyl esters) found in animal products including liver, dairy, and eggs, and provitamin A carotenoids (primarily beta-carotene) found in colorful fruits and vegetables that the body converts to retinol. Vitamin A plays critical roles in vision — particularly dark adaptation and the maintenance of the corneal epithelium; immune function — supporting the differentiation and activity of multiple immune cell populations; cellular differentiation and growth — regulating gene expression in virtually every tissue; reproductive health — particularly fetal development and placental function; and skin and mucosal barrier integrity — maintaining the epithelial surfaces that protect against pathogen entry.

Who Is at Risk for Vitamin A Deficiency in the United States?

Severe vitamin A deficiency — characterized by night blindness and xerophthalmia — is primarily a developing world problem. In the United States, overt deficiency is rare but subclinical insufficiency is more common than generally recognized, particularly in specific populations. Patients with fat malabsorption due to conditions including Crohn's disease, cystic fibrosis, celiac disease, short bowel syndrome, and following bariatric surgery cannot absorb fat-soluble vitamins adequately regardless of dietary intake. Alcoholism impairs vitamin A metabolism and storage. Zinc deficiency — which is common in Gulf Coast populations — impairs vitamin A transport and utilization because the carrier protein for vitamin A (retinol-binding protein) requires zinc for synthesis. Very low-fat diets impair absorption of fat-soluble vitamins. And patients with chronic liver disease have impaired vitamin A storage capacity.

Recognizing Vitamin A Insufficiency

The symptoms of vitamin A insufficiency in American adults are subtle and nonspecific — frequently attributed to other causes without testing. Difficulty with night vision or dark adaptation is the most specific early symptom of vitamin A deficiency. Dry, rough skin and keratosis pilaris can reflect vitamin A insufficiency. Recurrent infections — particularly respiratory and gastrointestinal — may indicate impaired mucosal immunity from vitamin A deficiency. Dry eyes and increased susceptibility to corneal abrasions reflect the role of vitamin A in maintaining ocular surface epithelia. And impaired wound healing has been documented in vitamin A deficient patients.

Testing and Treatment at Elevate

Serum retinol measurement is the standard clinical test for vitamin A status. At Elevate Health and Wellness, Kristy Beard, MSN, APRN, FNP-C includes vitamin A assessment in comprehensive nutritional panels for patients with fat malabsorption conditions, significant dietary restrictions, chronic liver disease, or unexplained symptoms that may reflect nutritional deficiency. When deficiency is identified, treatment is individualized based on the severity of deficiency and its underlying cause — ranging from dietary counseling and oral supplementation to higher-dose therapeutic supplementation for malabsorption-related deficiency. It is important to note that vitamin A toxicity (hypervitaminosis A) is a real risk with excessive supplementation — testing before supplementing is always the safest approach.

Want to assess your nutritional status comprehensively? Learn about our nutritional health and lab services at Elevate in Gautier, MS and Foley, AL.

Sources: NIH Office of Dietary Supplements. Vitamin A Fact Sheet. ods.od.nih.gov. | WHO. Vitamin A Deficiency. who.int.

This article is written by Kristy Beard, MSN, APRN, FNP-C, board-certified Family Nurse Practitioner and founder of Elevate Health and Wellness. Information provided is for educational purposes only and does not constitute medical advice. Please consult a licensed healthcare provider for personalized care.