Siobhán Higgins

University College Cork, Corcaigh, Munster, Ireland

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Publications (5)14.45 Total impact

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    ABSTRACT: Background: The successful incorporation of fish oil into foods may provide a means of increasing intakes of n-3 polyunsaturated fatty acids (n-3 PUFA). The aim of the present study was to evaluate the bioavailability of n-3 PUFA in microencapsulatd fish oil compared with a fish oil capsule.Methods: Twenty-eight healthy volunteers were recruited to take part in this randomized controlled trial. Volunteers were supplemented with 0.9 g n-3 PUFA daily for 4 weeks, delivered either as microencapsulated fish oil in a milkshake or as a fish oil capsule. Plasma fatty acid composition and plasma total cholesterol levels were measured at baseline and after supplementation. In addition, volunteers completed a questionnaire on fish consumption, use of supplements and exercise.Results: Responses to the questionnaire indicated that the males who took part in this study took more physical exercise, consumed less fish and were less likely than the females to take supplements. Plasma n-3 PUFA concentrations were raised significantly and by a similar level by both fish oil supplements. Furthermore, no significant difference was observed in plasma n-3 PUFA concentrations following supplementation with either form of fish oil. Plasma total cholesterol levels were not significantly altered by n-3 PUFA supplementation in either group. The results of this study indicated that there was no difference in the bioavailability of n-3 PUFA given as microencapsulated fish oil compared with n-3 PUFA delivered as a fish oil capsule. Fortification of foodstuffs with microencapsulated fish oil therefore offers the potential to increase intakes of n-3 PUFA in line with current recommendations.
    Journal of Human Nutrition and Dietetics 12/2001; 12(4):265 - 271. DOI:10.1046/j.1365-277x.1999.00175.x · 2.07 Impact Factor
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    ABSTRACT: The objective of the present study was to evaluate the oxidative susceptibility of LDL in human volunteers following supplementation with various low doses (<1 g/d) of n-3 polyunsaturated fatty acids (PUFA). Sixty-two healthy volunteers (thirty-seven males and twenty-five females, aged 19-63 years) were recruited to take part in a randomised placebo-controlled trial. Volunteers were required to take 0.9, 0.6 or 0.3 g n-3 PUFA as fish oil or placebo capsules daily for 16 weeks. Susceptibility of LDL to oxidative modification was assessed by measuring the production of conjugated dienes and thiobarbituric acid-reactive substances in LDL oxidised by Cu2+ (15 microM) or 2,2'-azobis(2-amidinopropane) dihydrochloride (1 mM) for 5 h. Plasma fatty acid and LDL-fatty acid composition, cholesterol levels and antioxidant concentrations were also measured. While post-treatment n-3 PUFA compositions of plasma and LDL reflected the capsule contents, no meaningful differences in antioxidant concentrations or cholesterol levels were observed between the groups. Supplementation with low doses of n-3 PUFA as fish oil did not influence the oxidative susceptibility of LDL. The results of the present study suggest that moderate dietary intakes of n-3 PUFA do not significantly influence the susceptibility of LDL to oxidative modification in vitro.
    British Journal Of Nutrition 02/2001; 85(1):23-31. DOI:10.1079/BJN2000220 · 3.34 Impact Factor
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    ABSTRACT: To examine the effect of low-dose fish oil supplementation on specific growth factors, purported to play a central role in lesion formation, and also on the total growth factor activity of serum, as assessed by the induction of DNA synthesis in cultured human arterial smooth muscle cells. Randomized placebo-controlled double-blind intervention study. Free-living population. Sixty-three healthy volunteers, 37 males and 26 females. Interventions: Four treatment regimes with subjects receiving 0, 0.3,0.6 or 0.9 g/day of n-3 PUFA for an 8 week period. Blood samples were taken at baseline and following the 8 week intervention. All samples were analysed in batch following completion of the study. Consumption of fish oil had no effect on serum platelet-derived growth factor (PDGF), or transforming growth factor beta (TGFbeta) concentration. Furthermore, fish oil supplementation did not alter the total growth factor activity of serum. Results indicate that low-dose fish oil supplementation, equivalent to about two portions of fatty fish per week and providing less than 1 g n-3 PUFA/day, does not alter the levels of the major serum growth factors and does not modify total serum growth factor activity in healthy human volunteers. European Union shared cost project (FAIR-CT-95-0085).
    European Journal of Clinical Nutrition 10/2000; 54(9):690-4. DOI:10.1038/sj.ejcn.1601076 · 2.95 Impact Factor
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    ABSTRACT: A study was designed to evaluate the effect of supplementation with a low dose (0.9 g/d) of n-3 polyunsaturated fatty acids (n-3 PUFA) in fish oil on the oxidative modification of low-density lipoprotein (LDL) in a group of healthy volunteers. Eight volunteers were randomly selected from a larger fish oil supplementation study, and were required to take either 0.9g n-3 PUFA as fish oil (FO group) or 0.9g olive oil [control oil (CO group)] for 16 weeks. Oxidative modification of LDL was assessed by measuring concentrations of free cholesterol (FC), cholesteryl esters (CE) and cholesteryl linoleate hydroperoxide (Ch18:2-OOH) in LDL following copper-induced lipid peroxidation for 0, 2, 3 and 4 h. The composition of LDL fatty acids over 4 h of copper-induced oxidation was also investigated. LDL eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) compositions were significantly (P < 0.05) higher in the FO compared with the CO group, following supplementation. Linoleic acid (C18:2n-6), arachidonic acid (C20:4n-6), C20:5n-3 and C22:6n-3 were significantly (P < 0.05) oxidised in LDL following 4 h copper-oxidation. The proportions of palmitic acid (C16:0) (P < 0.05), palmitoleic acid (C16:1) (P < 0.05), stearic acid (C18:0), and oleic acid (C18:1) increased in the FO and CO groups, after 4 h of copper-oxidation. Concentrations of cholesteryl oleate (Ch18:1), cholesteryl linoleate (Ch18:2n-6), cholesteryl arachidonate (Ch20:4n-6) and cholesteryl docosahexanoate (Ch22:6n-3) were significantly (P < 0.05) reduced following copper-stimulated oxidation, in both groups. Ch18:2-OOH concentrations were significantly increased (P < 0.05) following 3 h oxidation in both groups compared with 0 h copper-oxidation, but decreased after 4 h. There was no significant difference in concentrations of Ch18:2-OOH between the groups over the time-course of copper-mediated oxidation. The results of this study suggest that moderate dietary intakes of n-3 PUFA do not significantly influence the susceptibility of LDL to copper-induced oxidation in vitro.
    Nutrition Research 08/2000; 20(8). DOI:10.1016/S0271-5317(00)00195-0 · 2.59 Impact Factor
  • S Higgins · M H Vasconcelos · N M O'Brien
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    ABSTRACT: Muntjac cells were cultured at 5 X 10(5) cells/10 cm Petri dish for 24 h prior to addition of fatty acids (50 microM) which were delivered to the cells complexed with 2% bovine serum albumin (fatty acid-free) and incubated for a further 24 h. Parallel dishes were processed for lipid extraction and GC analysis. This analysis showed highly significant (P < 0.01) uptake by the cells of each fatty acid. Genotoxins (75 microM hydrogen peroxide, 20 microM t-butylhydroperoxide and 2.4 microM mitomycin C) were added to the cells for 1 h prior to the end of the 24 h fatty acid incubation period. Control (no genotoxin or fatty acid) treatments were included. No difference was observed in background frequencies of SCEs between controls and fatty acid treatments, thus indicating that these fatty acids per se do not cause DNA damage. The cells incubated with the genotoxins showed increased (P < 0.05) frequencies of SCEs when compared with control frequencies. Cells incubated with genotoxins in the presence of fatty acids also showed significantly higher (P < 0.05) levels of SCEs when compared with control frequencies. When cells supplemented with genotoxins in the presence of fatty acids were compared with cells treated with genotoxins alone, higher levels of SCEs were observed in the former, suggesting that the fatty acids exacerbate DNA damage caused by these genotoxins.
    Mutagenesis 05/1999; 14(3):335-8. · 3.50 Impact Factor