Subclinical vitamin A deficiency: a potentially unrecognized problem in the United States.

Vitamin A deficiency in its subclinical form is a world health problem in young children. The problem is probably under recognized in the United States and other developed countries who do not normally consider their citizens to be malnourished. Lack of a simple screening test to measure subclinical deficiency adds to this problem. Consequently, focused dietary assessment of vitamin A intake by a Food Frequency Questionnaire (FFQ) is a necessary component of health care maintenance, especially for toddlers and preschool age children. Dietary counseling and vitamin supplementation for high risk children is a necessary health promotion intervention.