GLV supplements increased plasma β-carotene, vitamin C, zinc and hemoglobin in young healthy adults

Background Green leafy vegetables (GLV) are rich sources of beta-carotene, iron and other micronutrients. Our in vitro studies have demonstrated good antioxidant potential in GLV. Moreover linkages of GLV intakes with plasma retinol and ascorbic acid were seen in apparently healthy Indians. Aim of the study To investigate the effect of GLV as a natural fortificant of multiple micronutrients through a prospective human trial. Methods Short-term (0-4 h) response (AUC) of single dose of 7.9 mg beta-carotene and 130 mg ascorbic acid through a spinach-carrot meal against the standard meal without GLV plus 10 mg beta-carotene and 150 mg ascorbic acid tablets was studied in two groups of 4 young volunteers each. In the second trial of 3 weeks' supplementation, 5 groups of young adults (n=40) were given either 100 g GLV/day alone or with tablets of vitamin E (100 mg/day), or C (100 mg/day) or more oil (5 g/day) or non-GLV meal with tablet of beta-carotene (10 mg/day). Hemoglobin (Hb), plasma beta-carotene, zinc, vitamin C, glucose, and triglycerides were measured. Results In a postprandial response, AUC were comparable in both GLV and standard meals for beta-carotene and ascorbic acid. In case of triglycerides and glucose AUC the GLV meal showed a better recovery to the baseline value after 4 hours than the standard meal. Three weeks' supplementation of GLV with more oil resulted in significant increase of plasma beta-carotene (51%) and Hb (9%). GLV with vitamin E showed a significant increase in plasma beta-carotene (40%), Hb (8%) and plasma vitamin C (6%). Supplementing beta-carotene without GLV significantly increased Hb (11%), plasma zinc (14%) in addition to beta-carotene. Multiple regression analyses weighted for energy intake indicated a significant association of percent increase in Hb with intakes of iron, riboflavin, folic acid, beta-carotene, copper, phytate and fiber (p < 0.01), percent change in plasma zinc with intakes of zinc, beta-carotene, vitamin C, riboflavin, copper, iron, and thiamin (p < 0.01), percent change in vitamin C with intakes of vitamin C, vitamin E, niacin, riboflavin, thiamin, beta-carotene, zinc, phytate and fiber (p < 0.05) and percent change in plasma beta-carotene with intakes of beta-carotene, thiamin, folic acid, zinc, phytate and tannins (p < 0.05). Conclusion Using 100 g GLV/day with 10 g oil could be a single moderate strategy for supplementation of iron, beta-carotene, ascorbic acid and zinc.