The associations of plasma carotenoids and α-tocopherol concentrations with fasting glucose in Cameroon

Abstract

Previous estimations of the associations between fruits and vegetables intake with diabetes markers showed mixed results, possibly partly because of the subjective assessment of dietary intake. We aimed to examine the relationship between the biomarkers (plasma carotenoids and α-tocopherol) as objective markers of fruit and vegetables (F/V) intake and fasting glucose in adults. This was a population-based cross-sectional study in 592 adults in Cameroon. Self-reported F/V intake was assessed using the WHO STEPS questionnaire and the biomarkers were analysed by high-performance liquid chromatography coupled with a photodiode array detector. The mean age of participants was 38.5±8.6 years (63.7% women). The median (IQR) number of times participants self-reported consuming fruits in a typical week was 2(1-5) times/week and vegetables was 4(2-7) times/week. Plasma total carotenoids was positively correlated with self-reported intake of fruits (<i>r</i>=0.13) and vegetables (<i>r</i> = 0.29), both p-value < 0.01. In unadjusted analysis, the difference in fasting glucose comparing the highest against the lowest tertile of the biomarkers concentrations was -0.28(95% CI -0.56 to -0.001) mmol/L for total carotenoids and -0.31(-0.59 to -0.03) mmol/L for plasma α-carotene. The inverse associations became stronger after adjusting for socio-demographics, smoking status, alcohol intake, season, physical activity, BMI and total cholesterol (-0.36(-0.73 to -0.002) mmol/L for total carotenoids and -0.41(-0.79 to -0.03) mmol/L for α-carotene). There was no evidence of an association between α-tocopherol and fasting glucose. We showed an inverse association of total carotenoids and α-carotene, objective indicators of F/V intake with fasting glucose. This suggests that a higher intake of F/V could be beneficial for diabetes prevention in African populations in whom the intake of F/V is low.