| Vitamin A | Vitamin D | Calcium |
---|---|---|---|
Number of SR | Five SRs (Oliveira et al. [21]; Caminha et al. [19]; Neves et al. [20]; McCauley et al. [24]; Thorne-Lyman and Fawzi [25]) | Six SRs (Chakhtoura et al. [26]; Christesen et al. [22]; Reid et al. [27]; De-Regil et al. [17]; Roth et al. [9]; Das et al. [28]) | Supplementation: six SRs (Trowman et al. [29]; Cumming [30]; Buppasiri et al. [31]; Onakpoya et al. [32]; Arthur et al. [18]) Fortification: one SR (Das et al. [28]) |
Population details | Postpartum women, breastfeeding or not, from the region where vitamin A deficiency (VAD) is a major concern, i.e. low-income settings in India, Bangladesh, Indonesia, Tanzania, Gambia, Zimbabwe, Kenya, Ghana, Peru, and Brazil (Oliveira et al. [21]) Pregnant and puerperal women (Neves et al. [20]) Lactating women (Caminha et al. [19]) Pregnant women (Thorne-Lyman and Fawzi [25]; McCauley et al. [24]) | Pregnant women (Christesen et al. [22]; De-Regil et al. [17]; Roth et al. [9]) Adult women of age > 18 years (Reid et al. [27]) Pregnant women, children, and adolescents (Chakhtoura et al. [26]) Children, adolescents, pre-pregnant women, women of reproductive age group, and post-menopausal women (Das et al. [28]) | Adult women of age > 18 years (Trowman et al. [29]; Cumming [30]) Pregnant women (Buppasiri et al. [31]). Obese/ overweight participants (Onakpoya et al. [32]) Pregnant and puerperal women (Arthur et al. [18]) Pre-pregnant women, women of reproductive age group, and post-menopausal women (Das et al. [28]) included |
Intervention | Supplementation of vitamin A alone or in combination with other micronutrients (Oliveira et al. [21]; McCauley et al. [24]; Neves et al. [20]) Supplementation of vitamin A/beta carotene (Thorne-Lyman and Fawzi [25]; Caminha et al. [19]) | Supplementation of vitamin D (Chakhtoura et al. [26]; Christesen et al. [22]; Reid et al. [27]; De-Regil et al. [17]; Roth et al. [9]) Fortified food with vitamin D along with other micronutrients (Das et al. [28]) | Calcium supplementation with or without dairy products or combined calcium supplementation (Trowman et al. [29]; Cumming [31]; Buppasiri et al. [31]; Onakpoya et al. [32]; Arthur et al. [18]) Alkaline phosphatase and serum parathyroid hormone as a fortificant (Das et al. [28]) |
Outcomes of our interest | The five included SRs provided information on the effect of vitamin A supplementation on serum retinol levels (Oliveira et al. [21]; Caminha et al. [19]) and hepatic reserves (Oliveira et al. [21]) of the women, vitamin A contents in breast milk (Oliveira et al. [21]; Caminha et al. [19]; Neves et al. [20]), proportion of women with low vitamin A contents (Oliveira et al. [21]), secretary immunoglobulin A levels in colostrum (Neves et al. [20]), subclinical vitamin A deficiency (Oliveira et al. [21]; McCauley et al. [24]), and maternal anemia and hemoglobin (Thorne-Lyman and Fawzi [25]) | Vitamin D supplementation: 25(OH)D levels at term/delivery (De-Regil et al. [17]; Roth et al. [9]; Chakhtoura et al. [26]), vitamin D symptoms (Christesen et al. [22]), bone mineral density (Reid et al. [27]), serum calcium levels (Chakhtoura et al. [26]), weight gain (Christesen et al. [22]); side effects of vitamin D (De-Regil et al. [17]), and hypercalcemia, hypocalcemia, hypercalciuria (Roth et al. [9]) Vitamin D fortification: serum vitamin D levels, serum calcium levels (Das et al. [28]) Vitamin D and calcium fortification: serum vitamin D levels, CTx and P1NP (bone resorption marker) levels (Das et al. [28]) | The SRs assessed effect of supplementation on body weight, weight gain, BMI, body fat, bone mass, and anemia |
Methodological quality (the detail scoring is provided in Additional file 4) | High quality (McCauley et al. [24]; Oliveira et al. [26]) Moderate quality (Neves et al. [20]; Thorne-Lyman and Fawzi [25]) Low quality (Caminha et al. [19]) | High quality (De-Regil et al. [17]; Roth et al. [9]) Moderate quality (Chakhtoura et al. [26]; Christesen et al. [22]; Das et al. [28]; Reid et al. [27]) | High quality (Buppasiri et al. [31]) Moderate quality (Trowman et al. [29]; Onakpoya et al. [32]; Das et al. [28]) |