How VAD Causes Blindness

By Aderinoye Adegboyega

Vitamin A deficiency (VAD) is the leading cause of preventable blindness in children and raises the risk of disease and death from severe infections. In pregnant women, VAD causes night blindness and may increase the risk of maternal mortality.

• Between 100 and 140 million children are vitamin A deficient.

• An estimated 250 000 to 500 000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight.

• Nearly 600 000 women die from childbirth-related causes each year, the vast majority of them from complications which could be reduced through better nutrition, including provision of vitamin A.

Vitamin A deficiency is a public health problem in 118 countries, especially in Africa and South-East Asia , once again hitting hardest young children and pregnant women in low-income countries. Crucial for maternal and child survival, supplying adequate vitamin A in high-risk areas can significantly reduce mortality. Conversely, its absence causes a needlessly high risk of disease and death.

For children, lack of vitamin A causes severe visual impairment and blindness, and significantly increases the risk of severe illness, and even death, from such common childhood infections as diarrhea disease and measles.

For pregnant women in high-risk areas, vitamin A deficiency occurs especially during the last trimester when demand by both the unborn child and the mother is highest. The mother’s deficiency is demonstrated by the high prevalence of night blindness during this period. VAD may also be associated with elevated mother-to-child HIV transmission.
The response: planting the seeds, cultivating the garden

WHO’s goal is the worldwide elimination of Vitamin A Deficiency (VAD) and its tragic consequences, including blindness, disease and premature death. To successfully combat VAD, short-term interventions and proper feeding in infancy must be backed up by long-term sustainable solutions. The arsenal of nutritional “well-being weapons” includes a combination of breastfeeding and vitamin A supplementation, coupled with enduring solutions, such as the promotion of vitamin A-rich diets and food fortification.
Planting the seeds. The basis for lifelong health begins in childhood. Vitamin A is a crucial component:

Breastfeeding. Breast milk is a natural source of vitamin A. Promoting breastfeeding is the best way to protect babies from VAD.

Vitamin A supplementation. For deficient children, the periodic supply of high-dose vitamin A in swift, simple, low-cost, high-benefit interventions has also produced remarkable results, reducing mortality by 23% overall and by up to 50% for acute measles sufferers.

“Planting these seeds” between six months and six years of age can reduce overall child mortality by a quarter in areas with significant VAD. However, because breastfeeding is time-limited and the effects of vitamin A supplementation capsules last only four to six months, neither are long-term solutions. Rather, they should be seen as initial steps towards better overall nutrition.

Cultivating the garden. Both literally and figuratively, the next phase is necessary for long-term results: Food fortification. Taking over where supplementation leaves off, food fortification (e.g. sugar in Guatemala ) maintains vitamin A status, especially for high-risk groups and needy families.

Home gardens. For vulnerable rural families (e.g. in Africa and South-East Asia ), growing fruits and vegetables in home gardens complements dietary diversification and fortification and contributes to better lifelong health.

- Adegboyega writes from University of Ibadan.