Correlation between plasma levels of carotenoid and oxidized low density lipoproteins: A short human intervention study

The development of vegetable functional food products that provide benefits beyond their traditional nutritional value raised increasing interest. In fact several studies have shown that diet plays a role in the development of human diseases associated with oxidative damage (diabetes, cardiovascular disease and metabolic syndrome). Aim of the study was to evaluate the effects of daily intake of 300g of a frozen vegetable product containing red and green spinach, red and green chicory, red and green leaf chard (Italsur srl Notaresco, Italy) on plasma lipids and oxidized low density lipoproteins (ox-LDL). Furthermore, the bioavailability of lutein and β-carotene was investigated. The study included n=49 healthy volunteers (age ranged from 23 to 73 year), who consumed a portion of the vegetable product (300 g) every day for 2 weeks. The significant increase of plasma lutein and β-carotene after vegetable mix consumption for 2 weeks demonstrated that these phytonutrients are highly bioavailable. A significant reduction of plasma levels of total cholesterol (TC) and LDL-cholesterol (LDL-C) was observed after dietary intervention. The results demonstrated a significant decrease in plasma concentration of ox-LDL after treatment. Evaluation of ox-LDL represents a useful biochemical marker of lipid peroxidation; therefore the results demonstrated a decrease of lipid peroxidation of lipoproteins associated with the consumption of vegetable product. A significant negative correlation has been established between levels of plasma lutein and levels of ox-LDL before and after daily intake of the vegetable product. These results suggest that lutein may play a role in the protective effect against oxidation of LDL. In conclusion the increase of plasma carotenoids after dietary treatment for two weeks is associated with a protective effect against lipid peroxidation of lipoproteins.