Abstract
To determine if double-fortified salt improved the haemoglobin levels and productivity of tea pickers, a double-blind, randomized, placebo-controlled trial was conducted on 793 tea pickers. The subjects in the experimental households (n = 385) received salt fortified with iron and iodine, and the subjects in the control households (n = 408) received common unfortified salt. Fingerprick blood analysis for haemoglobin by the cyanmethaemoglobin method was performed three times during a period of one year. The productivity data were also analysed for 450 tea pickers. At the end of the year, their average haemoglobin level had increased from 8.9 to 10.2 g/dl and their corresponding picking average had increased from 24.8 kg to 26.2 kg, which could increase annual tea production by 330 tonnes.