Identification and quantitation of major carotenoids in selected components of the Mediterranean diet: green leafy vegetables, figs and olive oil

Abstract

Objective: To characterize the carotenoid content of selected components of the Mediterranean diet commonly eaten by Greek migrants to Melbourne, a population group maintaining a traditional dietary regimen, and who exhibit relatively high circulating carotenoid concentrations and low cardiovascular disease mortality. Design and specimens: Opportunistic sampling of wild (sow thistle, amaranth, purslane and dandelion, collected from roadsides and home gardens) and commercially available (chicory, endive) green leafy vegetables and figs in season. Foods were selected on the basis that they are commonly eaten by Greek migrants but not by Anglo-Celtic persons, and had not previously been well-characterized with respect to their carotenoid contents. Extra virgin, cold-pressed olive oil and 'extra light' olive oil were obtained from commercial sources. Specimens were extracted with tetrahydrofuran (or chloroform:methanol for olive oil) and carotenoid contents were quantified using HPLC with UV detection. Two to six specimens of greens and figs were analysed. Dietary intake was assessed by food frequency questionnaire. Results: Wild green vegetables contained high concentrations of lutein (sow thistle > amaranth > purslane > dandelion) and bcarotene (sow thistle > amaranth > purslane ¼ dandelion). Sow thistle and amaranth contained lutein (15 and 13 mg=100 g, respectively) and b-carotene (3.3 and 4.0 mg=100 g, respectively) at concentrations greater than that seen in the commercially available species of chicory and endive. Figs contained all major carotenoids appearing in plasma, albeit at low concentrations. Extra virgin cold-pressed olive oil contained substantial quantities of lutein and b-carotene, but the more-refined 'extra light' olive oil did not. Conclusions: These components of the traditional Mediterranean diet contribute to the higher circulating concentrations of carotenoids in Greek migrants compared to Anglo-Celtic Australians.

African leafy vegetables consumed by households in the Limpopo and KwaZulu-Natal provinces in South Africa

“…35 Wild-growing green leafy vegetables are generally richer sources of various micronutrients than exotic or commercially produced leafy vegetables. [35][36][37] This study confirms the general belief that information on African leafy vegetables is passed down over generations. There are, however, indications from the KZN sites that clinics and radio are also an important source of information on imifino, pointing to these as potentially worthwhile communication channels for nutritional promotion of these leaves.…”

Carotenoid Content and In Vitro Bioaccessibility of Lutein in Some Leafy Vegetables Popular in Sri Lanka

“…These carotenoids are of importance in human health ( 17 ). The leafy vegetable species studied were rich in ␤ -carotene and lutein as shown in Table 1.…”

Dietary Intake of Selected Common Vegetable Foods and their Total Carotenoids Determination

“…Various studies have shown a significant correlation between habitual vegetable and fruit intake in plasma carotenoid concentrations. The use of olive oil in food preparation aids absorption of lipid-soluble compounds such as carotenoids, particularly those less polar, as well as being an important source of α-tocopherol in itself [11] .…”

“…A healthful diet has long been considered essential in prevention, or reducing the risk of developing these diseases. Vegetables are a major source of carotenoids and because of their antioxidant properties, these compounds are thought to contribute to the beneficial effects of vegetable consumption [11] .…”