Plasma Carotenoid and Vitamin E Concentrations in Women Living in a Rural West African (Gambian) Community

Abstract

Vitamin E and carotenoid pigments are important nutrients for the maintenance of health and protection of tissues against free radical damage. They also play a potential role in disease-risk-prediction and -protection, but little is known about their physiological and sociodemographic correlates and determinants, especially in a West African context. As part of a study of reproductive health in rural Gambian women, blood samples were obtained from 1286 women aged 15 to 54 years, living in the Farafenni area of The Gambia. Measurement of two forms of vitamin E and six carotenoids in plasma was performed by high performance liquid chromatography. All eight components, but especially the carotenoids: lycopene, alpha- and beta-carotene, exhibited a major seasonal variation, with maximum levels between May and July, corresponding to the end of the "mango" season and the beginning of the "rainy" season. Only the tocopherols varied significantly (increasing) with age. Several unexpected ethnic group differences were observed, and canthaxanthin was present at lower concentrations in women with manual occupations, compared to those with non-manual occupations. There were also significant differences associated with pregnancy and the postpartum period, especially for the tocopherols, but fewer differences associated with marital status. The observed patterns confirm that there are important seasonal, physiological, possibly genetic, and sociodemographic determinants of these nutrients in blood plasma, which may have significance for health and longevity.

Prevalence of vitamin E inadequacy, dietary intake and sources of alpha-tocopherol, and predictors of alpha- and gamma-tocopherol status in adolescent girls in Central Mozambique

“…(41) Finally, being pregnant was associated with a lower gamma-tocopherol:alphatocopherol ratio because pregnant girls had lower gammatocopherol concentrations than their non-pregnant peers, a finding that is in accord with the study in Gambia. (20) The plasma concentration of alpha-tocopherol found in this study (mean 13⋅52 μmol/l, median 13⋅05 μmol/l) was lower than that typical for high-income settings (11) but was roughly similar to reports from neighbouring countries. In previous studies, 10-to 19-year-old girls in Malawi had a mean serum concentration of alpha-tocopherol of 10⋅2 μmol/l, (14) 5-to 10-year-old children in Tanzania had a median of 15⋅4 μmol/l, (16) and pregnant women in Tanzania had a mean of 15⋅4 μmol/l.…”

“…(10,11) Studies in Sub-Saharan African countries have reported mean/median plasma/ serum concentrations from 9⋅4 to 16⋅1 μmol/l for infants, children, and adolescents, (12)(13)(14)(15)(16)(17) from 4⋅8 to 19⋅1 μmol/l for non-pregnant adults and elderly, (15,(18)(19)(20)(21)(22)(23) and from 11⋅0 to 25⋅5 μmol/l for women who were pregnant or up to 2 weeks post-partum. (17,20,(24)(25)(26)(27) Alpha-tocopherol is transported in the blood in lipoproteins and since blood cholesterol levels vary in different populations and age groups, the alpha-tocopherol:total cholesterol ratio is also of interest as an indicator of alpha-tocopherol status. On the other hand, lipoproteins may be low in cases of proteinenergy undernutrition; therefore, undernutrition may mask vitamin E deficiency.…”

“…( 10 , 11 ) Studies in Sub-Saharan African countries have reported mean/median plasma/serum concentrations from 9⋅4 to 16⋅1 μmol/l for infants, children, and adolescents, ( 12 – 17 ) from 4⋅8 to 19⋅1 μmol/l for non-pregnant adults and elderly, ( 15 , 18 – 23 ) and from 11⋅0 to 25⋅5 μmol/l for women who were pregnant or up to 2 weeks post-partum. ( 17 , 20 , 24 – 27 )…”

“…Seasonal fluctuations in plasma alpha-tocopherol concentrations have been observed in a study in Gambia, ( 20 ) but overall, little is known about how season or socio-demographic factors, such as rural–urban residence, are related to alpha-tocopherol intake and plasma concentrations of different tocopherols in Sub-Saharan African countries. To our knowledge, there are no previous reports based on dietary assessment on how different food groups contribute to the total dietary intake of alpha-tocopherol or how dietary sources vary by season in Sub-Saharan African populations.…”

Bioequivalence of β‐carotene and retinol

“…These workers also showed that the enzyme was down-regulated by retinoic acid and that regulation was restricted to β-carotene15, 15 dioxygenase activity in the duodenum. There is also some indirect evidence from studies in The Gambia 9 that the enzyme targets β-carotene in preference to α-carotene and enzyme studies also confirm this. 10 Interpreting plasma concentrations of carotenoids There are no generally accepted criteria of adequacy with which to assess 'carotenoid status'.…”