RESUMO
BACKGROUND: There is a metabolic pathway by which mammals can convert the omega-3 (n-3) essential fatty acid α-linolenic acid (ALA) into longer-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). As far as we know there are currently no studies that have specifically examined sex differences in the LC n-3 PUFA response to increased dietary ALA intake in humans, although acute studies with isotope-labelled ALA identified that women have a significantly greater capacity to synthesise EPA and DHA from ALA compared to men. FINDINGS: Available data from a placebo-controlled, randomised study were re-examined to identify whether there are sex differences in the LC n-3 PUFA response to increased dietary ALA intake in humans. There was a significant difference between sexes in the response to increased dietary ALA, with women having a significantly greater increase in the EPA content of plasma phospholipids (mean +2.0% of total fatty acids) after six months of an ALA-rich diet compared to men (mean +0.7%, P = 0.039). Age and BMI were identified as predictors of response to dietary ALA among women. CONCLUSIONS: Women show a greater increase in circulating EPA than men during increased dietary ALA consumption. Further understanding of individual variation in the response to dietary ALA could inform nutrition advice, with recommendations being specifically tailored according to habitual diet, sex, age and BMI.
Assuntos
Dieta , Ácido Eicosapentaenoico/sangue , Caracteres Sexuais , Ácido alfa-Linolênico/administração & dosagem , Adulto , Idoso , Índice de Massa Corporal , Peso Corporal , Suplementos Nutricionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fosfolipídeos/sangue , PlacebosRESUMO
Familiarity, through conditioned responses and expectations, may play a significant role in the expression of liking for, and mood and performance effects of, food and drink constituents. The role of familiarity and the effects of caffeine and glucose in Lucozade Energy were investigated by testing this familiar soft drink, and its non-caffeine/non-CHO placebo match, against novel coloured/flavoured full and placebo drinks. Both the familiar drink and its placebo improved alertness, mental energy and mental performance compared to baseline and compared to the novel placebo drink. After repeated exposure, that is, after having gained familiarity with the novel drinks in addition to the already existing familiarity with Lucozade Energy, only the full (caffeine and CHO containing) drinks showed sustained beneficial effects compared to placebo drinks and baseline measures, as well as an increase in liking compared to placebo drinks. Therefore, participants appeared to have learned that beneficial effects were mainly linked to the full products. The results illustrate the restorative combination of caffeine and CHO in the drink, and emphasises the need to implement the appropriate placebo(s) in any study design employing familiar foods or drinks.
Assuntos
Bebidas , Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Glucose/farmacologia , Adolescente , Adulto , Afeto/efeitos dos fármacos , Atenção/efeitos dos fármacos , Cognição/efeitos dos fármacos , Interpretação Estatística de Dados , Feminino , Humanos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Pessoa de Meia-Idade , Análise de Componente Principal , Desempenho Psicomotor/efeitos dos fármacos , Tempo de Reação/efeitos dos fármacos , Paladar/efeitos dos fármacosRESUMO
The APOC3 -2854T>G polymorphism lies in the APOC3-A4 intergenic region. In a group of healthy adults, this polymorphism was associated with circulating triglycerides, with 55% lower fasting levels in the homozygous wild-type (TT) compared to the homozygous rare allele (GG) genotype. Age and gender had a significant impact on genotype-triglyceride interactions.
Assuntos
Apolipoproteínas C/genética , Lipídeos/sangue , Adulto , Fatores Etários , Idoso , Apolipoproteína C-III , Peso Corporal/genética , DNA Intergênico , Jejum , Feminino , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Fatores Sexuais , Triglicerídeos/sangueRESUMO
BACKGROUND: There is little information about the relation between the fatty acid composition of human immune cells and the function of those cells over the habitual range of fatty acid intakes. OBJECTIVE: The objective of the study was to determine the relation between the fatty acid composition of human peripheral blood mononuclear cell (PBMC) phospholipids and the functions of human immune cells. DESIGN: One hundred fifty healthy adult subjects provided a fasting blood sample. The phagocytic and oxidative burst activities of monocytes and neutrophils were measured in whole blood. PBMCs were isolated and used to measure lymphocyte proliferation in response to the T cell mitogen concanavalin A and the production of cytokines in response to concanavalin A or bacterial lipopolysaccharide. The fatty acid composition of plasma and PBMC phospholipids was determined. RESULTS: Wide variations in fatty acid composition of PBMC phospholipids and immune cell functions were identified among the subjects. The proportions of total polyunsaturated fatty acids (PUFAs), of total n-6 and n-3 PUFAs, and of several individual PUFAs in PBMC phospholipids were positively correlated with phagocytosis by neutrophils and monocytes, neutrophil oxidative burst, lymphocyte proliferation, and interferon gamma production. The ratios of saturated fatty acids to PUFAs and of n-6 to n-3 PUFAs were negatively correlated with these same immune functions. The relation of PBMC fatty acid composition to monocyte oxidative burst was the reverse of its relation to monocyte phagocytosis and neutrophil oxidative burst. CONCLUSION: Variations in the fatty acid composition of PBMC phospholipids account for some of the variability in immune cell functions among healthy adults.
Assuntos
Ácidos Graxos Insaturados/sangue , Leucócitos Mononucleares/imunologia , Neutrófilos/imunologia , Fosfolipídeos/sangue , Adulto , Idoso , Citocinas/biossíntese , Ácidos Graxos Insaturados/administração & dosagem , Feminino , Humanos , Interferon gama/biossíntese , Leucócitos Mononucleares/química , Leucócitos Mononucleares/citologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Neutrófilos/química , Neutrófilos/citologia , Fagocitose , Valores de Referência , Explosão RespiratóriaRESUMO
BACKGROUND: Dietary alpha-linolenic acid (ALA) can be converted to long-chain n-3 polyunsaturated fatty acids (PUFAs) in humans and may reproduce some of the beneficial effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular disease risk factors. OBJECTIVE: This study aimed to compare the effects of increased dietary intakes of ALA and EPA+DHA on a range of atherogenic risk factors. DESIGN: This was a placebo-controlled, parallel study involving 150 moderately hyperlipidemic subjects randomly assigned to 1 of 5 interventions: 0.8 or 1.7 g EPA+DHA/d, 4.5 or 9.5 g ALA/d, or an n-6 PUFA control for 6 mo. Fatty acids were incorporated into 25 g of fat spread and 3 capsules to be consumed daily. RESULTS: The change in fasting or postprandial lipid, glucose, or insulin concentrations or in blood pressure was not significantly different after any of the n-3 PUFA interventions compared with the n-6 PUFA control. The mean (+/- SEM) change in fasting triacylglycerols after the 1.7-g/d EPA+DHA intervention (-7.7 +/- 4.99%) was significantly (P < 0.05) different from the change after the 9.5-g/d ALA intervention (10.9 +/- 4.5%). The ex vivo susceptibility of LDL to oxidation was higher after the 1.7-g/d EPA+DHA intervention than after the control and ALA interventions (P < 0.05). There was no significant change in plasma alpha-tocopherol concentrations or in whole plasma antioxidant status in any of the groups. CONCLUSION: At estimated biologically equivalent intakes, dietary ALA and EPA+DHA have different physiologic effects.
Assuntos
Ácidos Graxos Ômega-3/administração & dosagem , Óleos de Peixe/administração & dosagem , Hiperlipidemias/sangue , Peroxidação de Lipídeos , Lipídeos/sangue , Óleos de Plantas/administração & dosagem , Antioxidantes/análise , Glicemia/análise , Gorduras Insaturadas na Dieta/administração & dosagem , Ácidos Docosa-Hexaenoicos/administração & dosagem , Método Duplo-Cego , Ácido Eicosapentaenoico/administração & dosagem , Jejum , Ácidos Graxos/sangue , Alimentos , Humanos , Insulina/sangue , Fosfolipídeos/sangue , Placebos , Ácido alfa-Linolênico/administração & dosagemRESUMO
BACKGROUND: Greatly increasing dietary flaxseed oil [rich in the n-3 polyunsaturated fatty acid (PUFA) alpha-linolenic acid (ALA)] or fish oil [rich in the long-chain n-3 PUFAs eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids] can reduce markers of immune cell function. The effects of more modest doses are unclear, and it is not known whether ALA has the same effects as its long-chain derivatives. OBJECTIVE: The objective was to determine the effects of enriching the diet with ALA or EPA+DHA on immune outcomes representing key functions of human neutrophils, monocytes, and lymphocytes. DESIGN: In a placebo-controlled, double-blind, parallel study, 150 healthy men and women aged 25-72 y were randomly assigned to 1 of 5 interventions: placebo (no additional n-3 PUFAs), 4.5 or 9.5 g ALA/d, and 0.77 or 1.7 g EPA+DHA/d for 6 mo. The n-3 PUFAs were provided in 25 g fat spread plus 3 oil capsules. Blood samples were taken at 0, 3, and 6 mo. RESULTS: The fatty acid composition of peripheral blood mononuclear cell phospholipids was significantly different in the groups with higher intakes of ALA or EPA+DHA. The interventions did not alter the percentages of neutrophils or monocytes engaged in phagocytosis of Escherichia coli or in phagocytic activity, the percentages of neutrophils or monocytes undergoing oxidative burst in response to E. coli or phorbol ester, the proliferation of lymphocytes in response to a T cell mitogen, the production of numerous cytokines by monocytes and lymphocytes, or the in vivo delayed-type hypersensitivity response. CONCLUSION: An intake of Assuntos
Ácidos Docosa-Hexaenoicos/administração & dosagem
, Ácido Eicosapentaenoico/administração & dosagem
, Leucócitos Mononucleares/imunologia
, Neutrófilos/imunologia
, Fosfolipídeos/sangue
, Ácido alfa-Linolênico/administração & dosagem
, Adulto
, Idoso
, Citocinas/biossíntese
, Método Duplo-Cego
, Feminino
, Óleos de Peixe/química
, Humanos
, Hipersensibilidade Tardia/imunologia
, Leucócitos Mononucleares/química
, Leucócitos Mononucleares/efeitos dos fármacos
, Óleo de Semente do Linho/química
, Ativação Linfocitária
, Masculino
, Pessoa de Meia-Idade
, Neutrófilos/química
, Fagocitose
, Fosfolipídeos/química
, Explosão Respiratória
RESUMO
The effect of increased dietary intakes of alpha-linolenic acid (ALNA) or eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for 2 months upon plasma lipid composition and capacity for conversion of ALNA to longer-chain metabolites was investigated in healthy men (52 (SD 12) years). After a 4-week baseline period when the subjects substituted a control spread, a test meal containing [U-(13)C]ALNA (700 mg) was consumed to measure conversion to EPA, docosapentaenoic acid (DPA) and DHA over 48 h. Subjects were then randomised to one of three groups for 8 weeks before repeating the tracer study: (1) continued on same intake (control, n 5); (2) increased ALNA intake (10 g/d, n 4); (3) increased EPA+DHA intake (1.5 g/d, n 5). At baseline, apparent fractional conversion of labelled ALNA was: EPA 2.80, DPA 1.20 and DHA 0.04 %. After 8 weeks on the control diet, plasma lipid composition and [(13)C]ALNA conversion remained unchanged compared with baseline. The high-ALNA diet resulted in raised plasma triacylglycerol-EPA and -DPA concentrations and phosphatidylcholine-EPA concentration, whilst [(13)C]ALNA conversion was similar to baseline. The high-(EPA+DHA) diet raised plasma phosphatidylcholine-EPA and -DHA concentrations, decreased [(13)C]ALNA conversion to EPA (2-fold) and DPA (4-fold), whilst [(13)C]ALNA conversion to DHA was unchanged. The dietary interventions did not alter partitioning of ALNA towards beta-oxidation. The present results indicate ALNA conversion was down-regulated by increased product (EPA+DHA) availability, but was not up-regulated by increased substrate (ALNA) consumption. This suggests regulation of ALNA conversion may limit the influence of variations in dietary n-3 fatty acid intake on plasma lipid compositions.
Assuntos
Ácido alfa-Linolênico/administração & dosagem , Ácido alfa-Linolênico/metabolismo , Dióxido de Carbono/metabolismo , Gorduras Insaturadas na Dieta/administração & dosagem , Gorduras Insaturadas na Dieta/metabolismo , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/metabolismo , Ácidos Graxos/sangue , Ácidos Graxos Insaturados/administração & dosagem , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , OxirreduçãoRESUMO
Dietary alpha-linolenic acid (ALA) can be converted to long-chain (n-3) PUFA in humans and may potentially reproduce the beneficial effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on risk factors for coronary heart disease (CHD). This study compared the effects of increased intakes of ALA with those of dietary EPA and DHA on blood coagulation and fibrinolytic factors in fasting subjects. A placebo-controlled, parallel study was conducted in 150 moderately hyperlipidemic subjects, age 25-72 y. Subjects were randomly assigned to one of five interventions and consumed a total intake of 0.8 or 1.7g/d EPA+DHA, 4.5 or 9.5g/d ALA or control (linoleic acid; LA) for 6 mo. Fatty acids were incorporated into 25 g of fat spread, which replaced the subject's normal spread and three capsules. Long-term supplementation with either dietary EPA+DHA or estimated biologically equivalent amounts of ALA did not affect factors VIIa, VIIc, VIIag, XIIa, XIIag, fibrinogen concentrations, plasminogen activator inhibitor-1 or tissue plasminogen activator activity compared with the control. (n-3) PUFA of plant or marine origin do not differ from one another or from LA in their effect on a range of blood coagulation and fibrinolytic factors.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Fibrinólise/efeitos dos fármacos , Hiperlipidemias/sangue , Biologia Marinha , Adulto , Idoso , Método Duplo-Cego , Ácidos Graxos Ômega-3 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PlacebosRESUMO
The UK Food Standards Agency convened a group of expert scientists to review current research investigating whether n-3 polyunsaturated fatty acids (PUFA) from plant oils (alpha-linolenic acid; ALA) were as beneficial to cardiovascular health as the n-3 PUFA from the marine oils, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The workshop also aimed to establish priorities for future research. Dietary intake of ALA has been associated with a beneficial effect on CHD; however, the results from studies investigating the effects of ALA supplementation on CHD risk factors have proved equivocal. The studies presented as part of the present workshop suggested little, if any, benefit of ALA, relative to linoleic acid, on risk factors for cardiovascular disease; the effects observed with fish-oil supplementation were not replicated by ALA supplementation. There is a need, therefore, to first prove the efficacy of ALA supplementation on cardiovascular disease, before further investigating effects on cardiovascular risk factors. The workshop considered that a beneficial effect of ALA on the secondary prevention of CHD still needed to be established, and there was no reason to look further at existing CHD risk factors in relation to ALA supplementation. The workshop also highlighted the possibility of feeding livestock ALA-rich oils to provide a means of increasing the dietary intake in human consumers of EPA and DHA.