15 Nutritional Deficiencies That Develop Slowly and Are Frequently Missed

10. Vitamin A Deficiency - More Than Just Night Vision

Vitamin A deficiency affects millions of people worldwide and remains a leading cause of preventable blindness in children, yet subclinical deficiency in developed countries often goes unrecognized. This fat-soluble vitamin is essential for vision, immune function, cell differentiation, and reproduction. The deficiency typically develops slowly, with night blindness being one of the earliest and most specific symptoms. However, before vision problems become apparent, individuals may experience increased susceptibility to infections, dry skin, poor wound healing, and reproductive issues. Vitamin A exists in two forms: preformed vitamin A (retinol) found in animal products, and provitamin A carotenoids found in colorful fruits and vegetables. The conversion of carotenoids to active vitamin A is influenced by various factors including genetic variations, fat intake, and overall nutritional status. Risk factors for deficiency include inadequate dietary intake of vitamin A-rich foods, malabsorption disorders, liver disease, and chronic alcoholism. Certain populations are at higher risk, including children, pregnant women, and individuals following very low-fat diets that impair absorption. The assessment of vitamin A status involves measuring serum retinol levels, though this may not reflect tissue stores in cases of mild deficiency. Subclinical vitamin A deficiency can compromise immune function and increase susceptibility to infectious diseases, making it a significant public health concern.