American Journal of Clinical Nutrition, Vol 23, 231-241, Copyright © 1970 by The American Society for Clinical Nutrition, Inc.

Hypovitaminosis A in the Americas

Technical Group on Hypovitaminosis A in the Americas

Hypovitaminosis A attracted attention as a public health problem in Latin America and the Caribbean area at the first and second Pan American Health Organization Technical Advisory Committee Meetings on Nutrition, 1962 and 1968, and as a result of the worldwide survey of xerophthalmia sponsored by the World Health Organization in 1962.

Results of many nutrition surveys show that a low dietary intake of vitamin A is widespread in sectors of the population in many parts of this hemisphere. Clinical and biochemical studies also indicate that hypovitaminosis A exists in certain portions of the population. Partial and total blindness resulting from severe vitamin A deficiency, in association with protein-calorie malnutrition, has been reported often in relation to high case-fatality rates. It may be concluded that hypovitaminosis A represents a public health problem in this hemisphere.

It was considered important that the Pan American Health Organization provide some guidelines to the control and prevention of this condition and a technical group was convened for this purpose in 1968.

The following definition was proposed for hypovitaminosis A, as it may be applied to human populations in the context of public health practice:

The presence of depleted tissues stores and low serum levels of vitamin A which may result from a prolonged deficient dietary intake and lead to serious clinical lesions of the eye.

Criteria for diagnosis should include clinical, biochemical, and dietary measurements. Any one indication by itself is not sufficient proof of vitamin A deficiency, but should arouse suspicion. Many factors, nutritional, physiological, and pathological, can influence vitamin A status and must be taken into account.

From available data, it was evident that xerophthalmia is generally found in those parts of the Caribbean and Central and South American areas where living standards for the majority of people are low. The preschool children, or more specifically those from 6 months to 4 years of age, represent the most vulnerable group in the socially deprived sectors and are also the most difficult to reach and protect.

The biochemical data from ICNND surveys in Latin America and the West Indies showed that from 5 to 45% of the overall population surveyed had serum vitamin A levels under 20 µg/100 ml. Vulnerable groups including children and pregnant women had even higher proportions of low or deficient values. Using the standards of the FAO/WHO expert committee, the intake was also deficient for a large majority, judging from the vitamin A content of the diets.

Based on the available information, the committee made specific recommendations for the treatment and prevention of vitamin A deficiency and defined areas in which PAHO should encourage research.