Iron status is associated with worker productivity, independent of physical effort in Indian tea estate workers

Abstract

Iron deficiency is the most common nutrient deficiency in the world, affecting roughly 40% of women in nonindustrialized countries. Iron is the essential element in hemoglobin, the major carrier of blood oxygen and oxidative metabolism that supports physical and cognitive performance. The relationship between iron and physical work capacity suggests that iron deficient individuals could experience reduced work output. Participants were 138 experienced tea pluckers aged 18–55 years from the Panighatta Tea Estate in Darjeeling District of northern West Bengal, India. Hemoglobin, serum ferritin, and soluble transferrin receptor were measured from venous blood. Energy expenditure was estimated from accelerometry and heart rate, and plucking productivity was measured as amount of tea plucked during the morning work session when temperature and rainfall conditions are optimal. At a given level of energy expenditure, iron deficient, anemic, and iron deficient anemic women plucked less tea during a 3-h period. The results warrant further research as to whether interventions providing supplemental iron might improve worker productivity and work efficiency. Further study should examine evidence of economic incentives for policies and programs targeting nutritional deficiencies. Novelty Anemia predicts up to 2.02 kg (9.1%) less tea plucked per 3 h, or 4.0% lower wage per 3 h, compared with nonanemic women, controlling for physical effort. An increase of 1.0 g/L in hemoglobin concentration predicts 0.71 kg (3.3%) more tea plucked over 3 h. An increase of 1.0 g/L in hemoglobin concentration predicts a 1.6% wage increase.