Serum Retinol of Chadian Nomadic Pastoralist Women in Relation to their Livestocks’ Milk Retinol and beta-Carotene Content

Abstract

Human serum retinol and livestock milk retinol levels were assessed as part of a study on the health status of Chadian nomadic pastoralists and their livestock in close partnership between Chadian public health and livestock institutions. Of the examined women (n = 99), 43% were moderately retinol-deficient (0.35 mol/L < x < 0.7 mol/L 95% CI; 33-54%), and 17% severely retinol-deficient (< 0.35 mol/L 95% CI; 10-26%). None of the interviewed women (n = 87) reported the consumption of fruit, and only two of fresh vegetables were reported consumed in the past 24 hours. Milk is the almost exclusive source of vitamin A for these populations. Goats (n = 6) had the highest average milk retinol level (329 +/- 84 micrograms/kg [mean +/- SEM]), followed by cattle (n = 25; 247 +/- 32 micrograms/kg), and camels (n = 12; 120 +/- 18 micrograms/kg). Milk retinol levels did not differ between the rainy and dry seasons. Human serum retinol depends significantly on livestock milk retinol levels (partial slope 0.23; 95% CI: 0.008-0.47). Our study supports the use of goat and cow milk as an important source of vitamin A in pastoral nomadic settings. However, the levels still require to be complemented further by promoting green leafy vegetables, fruits, and supplements.

Retinol Assessment Among Women and Children in Sahelian Mobile Pastoralists

“…Livestock milk was very rich in retinol at the end of the rainy season, and of all ruminant milk evaluated (cow, camel, sheep and goat), sheep milk was richest, which is consistent with findings by the Food and Agriculture Organization of the United Nations (1998), but higher than that recorded by Zinsstag et al (2002) in the same study area. The relationship between serum retinol level and milk consumption has been previously documented (Murphy et al 2008), and seasonal variation in nomadic communities likely depends on fluctuation in self-consumption resulting from seasonal variation in marketing practices.…”

“…High levels of vitamin A were also observed among children of cattle breeders in Mauritania (Borel and Etard 1988). Conversely, higher overall levels (40%) of retinol deficiency were found among nomadic women in Chad (Zinsstag et al 2002). This could be due to sampling time, which was at the end of the rainy season and during the dry season.…”

“…The sample size was based on a prevalence of retinol deficiency of 40% among nomadic children (Zinsstag et al 2002) and 22% among sedentary children, assuming a confidence level of 95%, a power of 90% and a minimum odds ratio of 2.2. Based on these assumptions 150 nomadic/semi-nomadic and 150 sedentary children and their mothers were selected.…”

“…In grassland areas, seasonal rainfall influences the annual growth of vegetation, including the level of β-carotene in fodder, which then determines retinol levels in livestock, milk and, ultimately, human vitamin A status. Earlier study demonstrated that human serum retinol depends significantly on livestock milk retinol in nomadic pastoralists and supported consumption of goat and cow’s milk as an important source of vitamin A (Zinsstag et al 2002). …”

“…One of the few studies done in a Chadian mobile pastoralist population found that the primary source of dietary retinol was milk and 40% of women were deficient (Zinsstag et al 2002). In the study, blood samples were transported from Chad to Switzerland for high-performance liquid chromatography analysis.…”