Vitamin A deficiency

Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of <a href="/facts/Vitamin_A/5ewDf9LF">vitamin A</a> in <a href="/facts/Blood/03zEulkj">blood</a> and <a href="/facts/Tissue_(biology)/H7CpML7A">tissues</a>. It is common in poorer countries, especially among children and women of reproductive age, but is rarely seen in more developed countries. Vitamin A plays a major role in phototransduction, so this deficiency impairs vision, often presenting with <a href="/facts/Nyctalopia/YnamXaB5">nyctalopia</a> (night blindness). In more severe VAD cases, it can progress to <a href="/facts/Xerophthalmia/5nsT0hp7">xerophthalmia</a>, <a href="/facts/Keratomalacia/45hRTI47">keratomalacia</a>, and complete blindness.
Vitamin A deficiency is the leading cause of preventable <a href="/facts/Childhood_blindness/B193RNwK">childhood blindness</a> worldwide and is a major cause of childhood mortality. Each year, approximately 250,000 to 500,000 malnourished children in the developing world go blind from a VAD, with about half of whom dying within a year of losing their sight. Addressing VAD has been a critical focus of global health initiatives, including <a href="/facts/Sustainable_Development_Goal_2/mV584m7j">Sustainable Development Goal 2</a>: to end hunger, achieve food security and improved nutrition and promote sustainable agriculture.
In pregnant women, VAD is associated with a high prevalence of night blindness and poor maternal health outcomes including an increased risk of <a href="/facts/Maternal_mortality/UquTVxdf">maternal mortality</a> and complications during <a href="/facts/Pregnancy/vEKYGpep">pregnancy</a> and <a href="/facts/Lactation/0w1HoW27">lactation</a>. VAD also affects the immune system and diminishes the body's ability to fight infections. In countries where children are not <a href="/facts/Immunization_(medicine)/f2NLoleW">immunized</a>, VAD is linked to higher fatality rates from infectious diseases such as <a href="/facts/Measles/tepQCUIG">measles</a>. Even mild, subclinical deficiency can also be a problem, as it may increase children's risk of developing respiratory and diarrheal infections, decrease growth, impair bone development, and reduce their likelihood of surviving serious illnesses.
Globally, VAD is estimated to affect about one-third of children under the age of five, causing an estimated 670,000 deaths in children under five annually. It is most prevalent in sub-Saharan Africa (48 percent) and South Asia (44 percent). Although VAD is well-managed in many high income nations, it remains a significant concern in resource-poor settings. Public health interventions, such as vitamin A supplementation, reached 59% of targeted children in 2022, highlighting the ongoing need for comprehensive efforts to combat VAD.

Vitamin A deficiency open-in-new

Vitamin A deficiency