Objectives: Oxidative stress contributes to the development of chronic diseases. Fruits and vegetables contain several phytonutrients (carotenoids, polyphenols) that exert antioxidant effects. The aim of this study was to investigate sex differences in fruit and vegetable intake, and the relationship to plasma levels of carotenoids as well as to total antioxidant capacity (pTAC). We studied also sex differences in the relationship between fruit and vegetables intake and plasma levels of lipid hydroperoxides, as well as of oxidized low-density lipoprotein (ox-LDL).
Methods: This study included 83 healthy adults (35 men and 48 women, mean age 40 ± 10 y). Dietary intake of carotenoids and total antioxidant capacity (dTAC) were evaluated on the basis of a 15-d food frequency questionnaire. Plasma levels of β-carotene, lutein, and pTAC were studied. Moreover, levels of plasma lipid hydroperoxides and ox-LDL were evaluated using the ferrous oxidation-xylenol orange 2 (FOX2) assay and a monoclonal antibody-based enzyme-linked immunosorbent assay procedure, respectively.
Results: Dietary habits were sex-related with a higher intake of fruits and vegetables (P < 0.05) and β-carotene (P < 0.001) in women than in men. Mean values of plasma lutein and β-carotene were higher in women than in men. Mean values of ox-LDL and lipid hydroperoxides were higher in men than in women (P < 0.05). Significant negative correlations were established between the individual values of ox-LDL and the levels of lutein versus β-carotene and versus pTAC values in plasma in both groups. Individuals belonging to the tertile with the highest daily intake of fruits and vegetables or the highest daily dTAC showed the lowest levels of plasma ox-LDL. In each category, sex-related differences were observed with men showing higher levels of ox-LDL than women. Moreover, lower levels of plasma β-carotene were observed in men in each tertile of daily intake of fruits and vegetables compared with females.
Conclusions: Based on the data obtained, we confirm that high fruit and vegetable consumption exerts a positive effect on antioxidant defenses and decreases oxidative damage of plasma lipoproteins for both sexes. The results suggest that the protective effect can be found to a higher extent in women than in men. Sex-based differences are apparent in many chronic diseases. Thus, a higher consumption of antioxidant-rich fruits and vegetables should be recommended in efforts to prevent diseases in which sex-related differences in oxidative stress play a considerable role.
Keywords: Carotenoids; dietary habits; fruit and vegetable intake; gender; oxidative stress.
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