Background   

Green leafy vegetables (GLV) are rich sources of β–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 β–carotene and 130 mg ascorbic acid through a spinach–carrot meal against the standard meal without GLV plus10 mg β–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 β–carotene (10 mg/day). Hemoglobin (Hb), plasma β–carotene, zinc, vitamin C, glucose, and triglycerides were measured.

Results   

In a postprandial response, AUC were comparable in both GLV and standard meals for β–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 β–carotene (51%) and Hb (9%). GLV with vitamin E showed a significant increase in plasma β–carotene (40%), Hb (8%) and plasma vitamin C (6%). Supplementing β–carotene without GLV significantly increased Hb (11%), plasma zinc (14%) in addition to β–carotene. Multiple regression analyses weighted for energy intake indicated a significant association of percent increase in Hb with intakes of iron, riboflavin, folic acid, β–carotene, copper, phytate and fiber (p < 0.01), percent change in plasma zinc with intakes of zinc, β–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, β–carotene, zinc, phytate and fiber (p < 0.05) and percent change in plasma β–carotene with intakes of β–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, β–carotene, ascorbic acid and zinc.