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

Am J Clin Nutr. 2004 Sep;80(3):705-14. doi: 10.1093/ajcn/80.3.705.


Background: Recent evidence suggests that the vitamin A equivalency of beta-carotene from plant sources is lower than previously estimated.

Objective: We assessed the effect of 60 d of daily supplementation with 750 microg retinol equivalents (RE) of either cooked, puréed sweet potatoes; cooked, puréed Indian spinach (Basella alba); or synthetic sources of vitamin A or beta-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 microg RE/d (white vegetables) or 750 microg RE/d as sweet potatoes, Indian spinach, retinyl palmitate, or beta-carotene (RE = 1 microg retinol or 6 microg beta-carotene) in addition to a low-vitamin A diet providing approximately 200 microg RE/d. Mean changes in vitamin A stores in the vegetable and beta-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 beta-carotene (P < 0.002). Vitamin A equivalency factors (beta-carotene:retinol, wt:wt) were estimated as approximately 13:1 for sweet potato, approximately 10:1 for Indian spinach, and approximately 6:1 for synthetic beta-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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Antioxidants
  • Bangladesh
  • Biological Availability
  • Deuterium
  • Dietary Supplements
  • Humans
  • Indicator Dilution Techniques
  • Intestinal Absorption
  • Ipomoea batatas* / chemistry
  • Magnoliopsida* / chemistry
  • Male
  • Nutritional Status
  • Vitamin A / administration & dosage*
  • Vitamin A / metabolism
  • Vitamin A / pharmacokinetics*
  • Vitamin A Deficiency / blood
  • Vitamin A Deficiency / prevention & control*
  • beta Carotene / blood*
  • beta Carotene / metabolism


  • Antioxidants
  • beta Carotene
  • Vitamin A
  • Deuterium