Vitamin A Deficiency Disorders: International Efforts to Control A Preventable Pox

January 24, 2004

January 2004

Supplement: Proceedings of Symposium to Honor the Memory of James Allen

OlsonVitamin A Deficiency Disorders: International Efforts to Control A

Preventable " Pox " 1 Barbara A. Underwood2

Institute of Medicine, National Academies, 2101 Constitution Ave., NW,

Washington, D.C. 20418

2To whom correspondence should be addressed. E-mail: e-mail: bunderwo.

Visual symptoms (night blindness) of vitamin A deficiency (VAD) were among the

earliest diet-related deficiencies documented. Knowledge of vitamin A chemistry,

metabolism and deficiency consequences accrued rapidly during the first eight

decades of the 20th century. A series of disorders were described in animals,

including impaired growth, reproduction, epithelial integrity, and disease

resistance that were relieved by consumption of both animal and plant sources of

the vitamin. Identification of the intestinal beta-carotene cleavage enzyme in

the laboratory of James Allen Olson was seminal to understanding the mechanism

for formation of vitamin A from ingested carotenoids. WHO’s 1990 estimate of

about 40 million children annually with clinical eye signs of VAD was revised

upward to 140–250 million at risk of vitamin A deficiency disorders (VADD) when

epidemiological and clinical trials demonstrated morbidity and mortality risk

even in the absence of ocular signs. Alternative

methods for VAD status assessment and more reliable analytical techniques were

developed, several in Dr. Olson’s laboratory. The last decade has seen global

progress in VADD control by expanding distribution of medicinal supplements,

fortification of foods and dietary diversification through horticulture and

education programs. Experience shows that achievements gained through narrowly

focused interventions are fragile and vulnerable to national political and

economic instability. Contextually relevant, community-centered strategies that

improve household food and nutrition security and self-reliance are critical to

sustaining international efforts to control the VADD " pox. "

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