Increases in Indicators of Iron, Zinc, Folate and Vitamin B12 Status in Urban Cameroon Following Wheat Flour Fortification

Abstract

Large‐scale food fortification is being scaled up globally, but little information is available on program effectiveness. We evaluated the impact of wheat flour fortification with iron, zinc, folic acid, and vitamin B12 on micronutrient (MN) status among women and young children in urban Cameroon.We conducted representative cluster surveys (30 clusters, 10 households/cluster; n=~300/survey) in Yaoundé and Douala, Cameroon, 2 y before and 1 y after flour fortification. Fortified food intake and MN content was assessed, and blood specimens were collected to measure hemoglobin (Hb), and markers of malaria, inflammation, and MN status (ferritin, soluble transferrin receptor (sTfR), zinc, folate, and B12).In the previous week, >95% of respondents had consumed wheat flour. Mean frequency of flour consumption was 1–2 times/d; 76% of flour samples were fortified, with average iron and zinc concentrations near the target fortification levels (60 and 95 ppm, respectively). Hb concentrations and child anemia prevalence did not differ by survey, but prevalence of anemia among women was lower post‐fortification (46.7 vs 39.1%; P=0.01), after adjusting for age, pregnancy, malaria and inflammatory markers. Differences in mean plasma ferritin and sTfR concentrations and body iron stores were consistent with increased iron status among women and children post‐fortification (P<0.05), adjusting for inflammation, malaria, age, and other covariates. Mean inflammation‐adjusted plasma zinc concentrations increased from 64.5 to 79.5 μg/dL [women] and 61.0 to 72.2 μg/dL [children], and prevalence of low plasma zinc concentrations decreased (39.4 to 21.6% [women] and 46.8 to 28.4% [children]; P<0.01 for all). Mean plasma folate concentrations increased 3‐fold among women (15 vs 47 nmol/L) and children (20 vs 56 nmol/L)(P<0.001). Post‐fortification, <1% of participants had plasma folate <10 nmol/L, and median (IQR) folic acid concentrations were 0.48 (0.69, 1.01) nmol/L among 59 fasted women, 0.70 (1.02, 1.71) nmol/L among 90 nonfasting women, and 0.77 (1.51, 4.64) nmol/L among 124 mostly nonfasted children in a non‐representative subset. Prevalence of plasma B12 concentrations <221 pmol/L decreased from 12–13% to < 4%, and mean milk B12 concentrations doubled post‐fortification (P<0.001 for all). Plasma B12 was positively associated with flour intake among women and children post‐fortification, but not pre‐fortification (P=0.084 and P=0.063 for interaction), but the interaction between flour intake and survey year was not significant for other MN.Although the pre‐post design limits causal inference, results suggest that flour fortification increased the iron, zinc, folate, and B12 status of women and children. Evaluation in other regions is needed to inform adjustments to the program design.Support or Funding InformationThis study was supported by the Michael and Susan Dell Foundation and Sight and Life.