Provision of Small-Quantity Lipid-Based Nutrient Supplements Increases Plasma Selenium Concentration in Pregnant Women in Malawi: A Secondary Outcome of a Randomized Controlled Trial

Abstract

Background: Pregnant women in Malawi are at risk of selenium deficiency, which can have adverse effects on pregnancy outcomes. Interventions for improving selenium status are needed.

Objectives: To assess the effect of provision of small-quantity lipid-based nutrient supplements (SQ-LNSs) to Malawian women during pregnancy on their plasma selenium concentrations at 36 wk of gestation.

Methods: Pregnant women (≤20 wk of gestation) were randomly assigned to receive daily either: 1) iron and folic acid (IFA); 2) multiple micronutrients (MMN; 130 µg selenium per capsule); or 3) SQ-LNS (130 µg selenium/20 g). Plasma selenium concentrations were measured by inductively coupled plasma mass spectrometry at baseline and after ≥16 wk of intervention (at 36 wk of gestation) and compared by intervention group.

Results: At 36 wk of gestation, median (quartile 1, quartile 3) plasma selenium concentrations (micromoles per liter) were 0.96 (0.73, 1.23), 0.94 (0.78, 1.18), and 1.01 (0.85, 1.28) in the IFA, MMN, and SQ-LNS groups, respectively. Geometric mean (GM) plasma selenium concentration was 5.4% (95% CI: 1.8%, 9.0%) higher in the SQ-LNS group than in the MMN group and tended to be higher than in the IFA group (+4.2%; 95% CI: 1.0%, 7.8%). The prevalence of adjusted plasma selenium concentrations <1 µmol/L was 55.1%, 57.8%, and 47.3% in the IFA, MMN, and SQ-LNS groups, respectively; it was lower in the SQ-LNS group than in the MMN group, OR = 0.44 (95% CI: 0.24, 0.83), and tended to be lower than in the IFA group, OR = 0.54 (95% CI: 0.29, 1.03). There was a significant interaction between baseline plasma selenium concentration and intervention group (P = 0.003). In the lowest tertile of baseline selenium concentrations, GM plasma selenium concentration was higher, and the prevalence of low values was lower in the SQ-LNS group compared with the MMN and IFA groups at 36 wk of gestation (P ≤ 0.007).

Conclusions: Provision of SQ-LNS containing selenium to pregnant women can be an effective strategy for improving their selenium status.This trial was registered at clinicaltrials.gov (identifier: NCT01239693).

Keywords: Malawi; lipid-based nutrient supplements; plasma; pregnancy; selenium status.

FIGURE 1

Geometric mean inflammation-corrected selenium concentration at 36 wk of gestation stratified by tertile of baseline plasma selenium concentration. Results are corrected for inflammation and adjusted for baseline plasma selenium concentration; P-interaction = 0.005. GM plasma selenium concentration was higher in the SQ-LNS group compared with the MMN and IFA groups in women in the lowest tertile (GMR = 1.14; 95% CI: 1.07, 1.23; and GMR = 1.15; 95% CI: 1.07, 1.24). In the middle tertile, it was higher in the SQ-LNS group than in the MMN group (GMR = 1.09; 95% CI: 1.01, 1.17) and tended to be higher than in the IFA group (GMR = 1.07; 95% CI: 0.99, 1.15). The GM values did not differ by group in the upper tertile. GM, geometric mean; GMR, geometric mean ratio; IFA, iron folic acid; MMN, multiple micronutrients; SQ-LNS, small-quantity lipid-based nutrient supplement.

FIGURE 2

Prevalence of plasma selenium concentrations <1 µmol/L stratified by tertile of baseline plasma selenium concentration. Results are corrected for inflammation and adjusted for baseline plasma selenium concentration; P-interaction = 0.003. Prevalence of low plasma selenium concentration was lower in the SQ-LNS group than in the MMN and IFA groups in the lowest tertile (OR = 0.39; 95% CI: 0.15, 1.00; and OR = 0.28; 95% CI: 0.10, 0.81). In the middle tertile, it was lower in the SQ-LNS group than in the MMN group (OR = 0.38; 95% CI: 0.20, 0.71), but did not differ from that of the IFA group. There were no differences by group in the upper tertile. IFA, iron folic acid; MMN, multiple micronutrients; SQ-LNS, small-quantity lipid-based nutrient supplement.