Comparative evaluation of minerals content of common green leafy vegetables consumed by the Asian populations in Singapore

Many green leafy vegetables (GLV) are native to Southeast Asia but information on their minerals content remains limited. Minerals content of 31 types of GLV, including 26 from conventional farming consumed by three ethnic groups in Singapore and five from indoor vertical farming, were studied using ICP OES. Mineral contents (mg/100 g fresh weight (FW)) of 26 GLV were diverse for the nine elements: Ca (6.55-394), K (163-771), Na (0.40-106), P (18.3-119), Mg (9.30-131), Cu (0.02-0.30), Fe (0.09-5.25), Mn (0.06-6.42), and Zn (0.10-3.60). GLV consumed by Malay and Indian ethnic groups contained significantly higher levels (p < 0.05) of microelements (Cu, Fe, Mn, and Zn) and macroelements (Ca, K, Na, P, and Mg) than GLV consumed by Chinese ethnic group. GLV from indoor vertical farming contained significantly (p < 0.05) lower Fe (0.57 mg/100 g FW), Zn (0.21 mg/100 g FW), and Na (3.63 mg/100 g FW) than conventional farming (Fe: 0.87, Zn: 0.47, Na: 18.0 mg/ 100 g FW). Overall, these data will be useful to identify promising sources of GLV for improved dietary minerals intake, nutritional education and agricultural research in the region for better health outcomes.