[Abstract unavailable

Previous evidence supports the concept that increased oxidative stress may play an important role in MetS (metabolic syndrome)-related manifestations. Dietary fat quality has been proposed to be critical in oxidative stress and the pathogenesis of the MetS. In the present study, we investigated whether oxidative stress parameters are affected by diets with different fat quantity and quality during the postprandial state in subjects with the MetS. Patients were randomly assigned to one of four isoenergetic diets distinct in fat quantity and quality for 12 weeks: a high-saturated-fatty-acid (HSFA) diet, a high-mono-unsaturated-fatty-acid (HMUFA) diet and two low-fat/high-complex carbohydrate diets [supplemented with 1.24 g/day of long-chain n-3 polyunsaturated fatty acid (LFHCC n-3) or with 1 g/day of sunflower oil high in oleic acid (LFHCC) as placebo]. The HMUFA diet enhanced postprandial GSH (reduced glutathione) levels and the GSH/GSSH (oxidized glutathione) ratio, compared with the other three diets. In addition, after the HMUFA-rich diet postprandial lipid peroxide levels, protein carbonyl concentrations, SOD (superoxide dismutase) activity and plasma H2O2 levels were lower compared with subjects adhering to the HSFA-rich diet. Both LFHCC diets had an intermediate effect relative to the HMUFA and HSFA diets. In conclusion, our data support the notion that the HMUFA diet improves postprandial oxidative stress in patients with the MetS. These findings suggest that the postprandial state is important for understanding the possible cardioprotective effects associated with mono-unsaturated dietary fat, particularly in subjects with the MetS.

Borage (Borago officinalis L.) seed oil has been used as a treatment for various degenerative diseases. Many useful properties of this oil are attributed to its high gamma linolenic acid content (GLA, 18:3 ω-6). The purpose of this study was to demonstrate the safety and suitability of the use of borage seed oil, along with one of its active components, GLA, with respect to DNA integrity, and to establish possible in vivo toxic and in vitro cytotoxic effects. In order to measure these properties, five types of assays were carried out: toxicity, genotoxicity, antigenotoxicity, cytotoxicity (using the promyelocytic leukaemia HL60 cell line), and life span (in vivo analysis using the Drosophila model). Results showed that i) Borage seed oil is not toxic to D. melanogaster at physiological concentrations below 125 µl/ml and the studies on GLA indicated non-toxicity at the lowest concentration analyzed ii) Borage seed oil and GLA are DNA safe (non-genotoxic) and antimutagenic compared to hydrogen peroxide, thereby confirming its antioxidant capacity; iii) Borage seed oil and GLA exhibited cytotoxic activity in low doses (IC50 of 1 µl/ml and 0.087 mM, respectively) iv) Low doses of borage seed oil (0.19%) increased the health span of D. melanogaster; and v) GLA significantly decreased the life span of D. melanogaster.Based on the antimutagenic and cytotoxic effects along with the ability to increase the health span, we propose supplementation with borage seed oil rather than GLA, because it protects DNA by modulating oxidative genetic damage in D. melanogaster, increases the health span and exerts cytotoxic activity towards promyelocytic HL60 cells.