Daily consumption of Indian spinach (Basella alba) or sweet potatoes has a positive effect on total-body vitamin A stores in Bangladeshi men

Background: Recent evidence suggests that the vitamin A equivalency of β-carotene from plant sources is lower than previously estimated. Objective: We assessed the effect of 60 d of daily supplementation with 750 μg retinol equivalents (RE) of either cooked, puréed sweet potatoes; cooked, puréed Indian spinach (Basella alba); or synthetic sources of vitamin A or β-carotene on total-body vitamin A stores in Bangladeshi men. Design: Total-body vitamin A stores in Bangladeshi men (n = 14/group) were estimated by using the deuterated-retinol-dilution technique before and after 60 d of supplementation with either 0 μg RE/d (white vegetables) or 750 μg RE/d as sweet potatoes, Indian spinach, retinyl palmitate, or β-carotene (RE = 1 μg retinol or 6 μg β-carotene) in addition to a low-vitamin A diet providing ≈200 μg RE/d. Mean changes in vitamin A stores in the vegetable and β-carotene groups were compared with the mean change in the retinyl palmitate group to estimate the relative equivalency of these vitamin A sources. Results: Overall geometric mean (±SD) initial vitamin A stores were 0.108 ± 0.067 mmol. Relative to the low-vitamin A control group, the estimated mean changes in vitamin A stores were 0.029 mmol for sweet potato (P = 0.21), 0.041 mmol for Indian spinach (P = 0.033), 0.065 mmol for retinyl palmitate (P < 0.001), and 0.062 mmol for β-carotene (P < 0.002). Vitamin A equivalency factors (β-carotene:retinol, wt:wt) were estimated as ≈13:1 for sweet potato, ≈10:1 for Indian spinach, and ≈6:1 for synthetic β-carotene. Conclusion: Daily consumption of cooked, puréed green leafy vegetables or sweet potatoes has a positive effect on vitamin A stores in populations at risk of vitamin A deficiency.