Daily consumption of Indian spinach (Basella alba) or sweet potatoes has a positive effect on total-body vitamin A stores in Bangladeshi men1–3 Marjorie J Haskell, Kazi M Jamil, Ferdaus Hassan, Janet M Peerson, M Iqbal Hossain, George J Fuchs, and Kenneth H Brown Downloaded from https://academic.oup.com/ajcn/article/80/3/705/4690550 by guest on 27 September 2021 ABSTRACT Ȃ44% (3). The World Health Organization recommends sup- Background: Recent evidence suggests that the vitamin A equiv- plementing infants and children 5 y of age with high doses of alency of ␤-carotene from plant sources is lower than previously vitamin A to improve their vitamin A status (4). However, be- estimated. cause vitamin A is potentially teratogenic, high-dose vitamin A Objective: We assessed the effect of 60 d of daily supplementation supplements can be given safely to women of childbearing age ␮ with 750 g retinol equivalents (RE) of either cooked, puréed sweet only within the first 6 wk postpartum, when the likelihood of potatoes; cooked, puréed Indian spinach (Basella alba); or synthetic becoming pregnant is very low. ␤ sources of vitamin A or -carotene on total-body vitamin A stores in The provision of small daily doses of vitamin A from food may Bangladeshi men. be an alternative strategy for improving vitamin A status in pop- Design: Total-body vitamin A stores in Bangladeshi men (n ҃ ulations at risk of deficiency. Appropriate foods provide safe 14/group) were estimated by using the deuterated-retinol-dilution amounts of vitamin A and can be given to all population groups technique before and after 60 d of supplementation with either 0 ␮g at risk of deficiency, including women of childbearing age. An- RE/d (white vegetables) or 750 ␮g RE/d as sweet potatoes, Indian spinach, retinyl palmitate, or ␤-carotene (RE ҃ 1 ␮g retinol or 6 ␮g imal source foods, such as dairy foods, eggs, and liver, contain ␤-carotene) in addition to a low–vitamin A diet providing Ȃ200 ␮g preformed retinol, which is readily absorbed in the human intes- RE/d. Mean changes in vitamin A stores in the vegetable and tine; however, these foods are generally not affordable for pop- ␤-carotene groups were compared with the mean change in the ulations at risk of deficiency (5). In less-industrialized countries, retinyl palmitate group to estimate the relative equivalency of these 65–85% of vitamin A in the diet is estimated to be supplied by vitamin A sources. provitamin A carotenoids in vegetables and fruit (5). However, Results: Overall geometric mean (ȀSD) initial vitamin A stores recent evidence indicates that the bioavailability of provitamin A were 0.108 Ȁ 0.067 mmol. Relative to the low–vitamin A control carotenoids from plant sources is lower than previously assumed group, the estimated mean changes in vitamin A stores were 0.029 and suggests that plant sources of vitamin A may not be ef- mmol for sweet potato (P ҃ 0.21), 0.041 mmol for Indian spinach ficacious for improving vitamin A status (6, 7). In the most recent (P ҃ 0.033), 0.065 mmol for retinyl palmitate (P 0.001), and 0.062 edition of the Dietary Reference Intakes (8), the vitamin A mmol for ␤-carotene (P 0.002). Vitamin A equivalency factors equivalency factors for provitamin A carotenoids from foods (␤-carotene:retinol, wt:wt) were estimated as Ȃ13:1 for sweet po- were increased from 6:1 to 12:1 for ␤-carotene [12 ␮g tato, Ȃ10:1 for Indian spinach, and Ȃ6:1 for synthetic ␤-carotene. ␤-carotene ҃ 1 ␮g retinol ҃ 1 retinol acitivity equivalent (RAE)] Conclusion: Daily consumption of cooked, puréed green leafy veg- and from 12:1 to 24:1 for ␣-carotene, ␥-carotene, and etables or sweet potatoes has a positive effect on vitamin A stores in ␤-cryptoxanthin (24 ␮g other provitamin A carotenoids ҃ 1 ␮g populations at risk of vitamin A deficiency. Am J Clin Nutr 2004;80:705–14. 1 From the Program in International Nutrition, Department of Nutrition, University of California, Davis (MJH, JMP, and KHB), and the International KEY WORDS Deuterated retinol dilution, stable isotope, bio- Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B): Centre for availability, vitamin A status, ␤-carotene, vitamin A stores, green Health and Population Research, Dhaka, Bangladesh (KMJ, FH, MIH, and leafy vegetables, sweet potatoes, Bangladesh GJF). 2 Supported by the US Department of Agriculture (grant no. 98-35200- 6099) and the Micronutrient Initiative (grant no. 5600-0001-04-300. Retinyl INTRODUCTION palmitate and ␤-carotene were donated by Roche Vitamins (Parsippany, NJ), Vitamin A deficiency is a serious public health problem in and sweet potatoes were donated by the Allen Canning Company (Siloam low-income populations in less-industrialized populations (1). Springs, AR). 3 Reprints not available. Address correspondence to MJ Haskell, Univer- Young children and women of childbearing age are considered to sity of California, Program in International Nutrition, 3217A Meyer Hall, be at greatest risk of deficiency. In these populations, supple- One Shields Avenue, Davis, CA 95616. E-mail: [email protected]. mentation with vitamin A has been shown to reduce childhood Received September 12, 2003. mortality by Ȃ23% (2) and to reduce maternal mortality by Accepted for publication March 25, 2004. Am J Clin Nutr 2004;80:705–14. Printed in USA. © 2004 American Society for Clinical Nutrition 705 706 HASKELL ET AL retinol ҃ 1 RAE). The equivalency factors were increased be- cause recent evidence indicates that the efficiency of absorption of ␤-carotene from foods is lower than previously estimated (Ȃ16% compared with Ȃ33%) (8–10). The effect of supplementation with plant sources of vitamin A on vitamin A status in humans has been assessed in placebo- controlled trials by examining changes in plasma retinol concen- tration in response to supplementation with plant or synthetic sources of vitamin A (6, 7). However, because of homeostatic regulation, plasma retinol concentrations are not likely to change in response to supplementation, unless subjects are moderately FIGURE 1. Study protocol. or severely vitamin A deficient at the onset of the intervention. Even when plasma retinol concentrations respond to supplemen- greater risk of vitamin A deficiency than are men, enrollment of tation in depleted persons, the magnitude of increase may not be Downloaded from https://academic.oup.com/ajcn/article/80/3/705/4690550 by guest on 27 September 2021 directly proportional to the vitamin A bioavailability from a women into the study was not possible because it is not culturally particular food source. In contrast, the deuterated-retinol- acceptable in Bangladesh for women to spend the time required dilution (DRD) technique is an indirect method for quantitatively to complete the study protocol (Ȃ12 h/d for 113 d) at the study estimating total body stores of vitamin A in humans (11), and the facility. Preschool-aged children were not enrolled because at the 2 technique has been validated in 2 sets of surgical patients with time the study was conducted the plasma kinetics of [ H4]retinol adequate to large (11) or small to adequate hepatic vitamin A had not been described in young children, and it was not known reserves (12). Moreover, the paired-DRD technique (estimation whether the isotope dilution equation that is used for estimating of vitamin A pool size before and after supplementation) pro- total-body vitamin A stores in adults would be appropriate for use vides expected quantitative estimates of change in total-body in that age group. Moreover, children in Bangladesh are sched- vitamin A stores in response to supplementation with different uled to receive periodic large-dose supplementation as part of a amounts of vitamin A (13). The purpose of the present study was national intervention program. to assess quantitative changes in total body stores of vitamin A by The subjects were ranked according to their initial plasma using the paired-DRD technique before and after 60 d of supple- retinol concentration and randomly assigned in blocks of 5 to 1 mentation with an orange tuber (sweet potatoes), a green leafy of 5 treatment groups. The subjects in each treatment group vegetable [Indian spinach (Basella alba); local name: pui sak], or received a low–vitamin A diet that was supplemented twice per an equivalent amount of synthetic vitamin A, which was pro- day, at the noon and evening meals, with either 1) low–vitamin vided as either retinyl palmitate or ␤-carotene in oil, to determine A vegetables (white potato, cauliflower) and a corn oil capsule [0 the relative efficacy of plant sources of vitamin A for improving ␮g retinol equivalents (RE)/d], 2) sweet potato (80 g to provide vitamin A status. 2.25 mg ␤-carotene, or 375 ␮g RE/meal) and a corn oil capsule, 3) Indian spinach (75 g to provide 2.25 mg ␤-carotene, or 375 ␮g RE/meal) and a corn oil capsule, 4) low–vitamin A vegetables SUBJECTS AND METHODS and a vitamin A capsule (375 ␮g RE/meal as 685 ␮g retinyl palmitate in corn oil), or 5) low–vitamin A vegetables and a Subjects ␤-carotene capsule (375 ␮g RE/meal as 2.25 mg ␤-carotene in The study was conducted at the outpatient facility of the In- corn oil). Thus, a total of 750 ␮g RE/d was provided in the ternational Centre for Diarrhoeal Disease Research in Dhaka, vitamin A–supplemented groups. The subjects who were as- Bangladesh. Subjects attended the facility daily from Ȃ0730 to signed to the low–vitamin A control group, hereafter referred to 1930 and consumed all of their meals and snacks under super- as the control group, received a capsule containing 60 mg vitamin vision.