Effect of meal sequence on postprandial lipid, glucose and insulin responses in young men

Abstract

Objective: To investigate whether the postprandial changes in plasma triacylglycerol (TAG), nonesterified fatty acids (NEFA), glucose and insulin concentrations in young men were the same if an identical meal was fed at breakfast and lunch, and if the response to lunch was modified by consumption of breakfast. Methods: In two trials (1 and 2) healthy subjects (age 2271 y, body mass index 2272 kg/m 2 ) were fed the same mixed macronutrient meal at breakfast at 08:00 h and lunch at 14:00 h. In the third trial, no breakfast was fed and the overnight fast extended until lunch at 14:00 h. Addition of [1,1,1-13 C]tripalmitin to one meal in each trial was used to distinguish between endogenous and meal-derived lipids. Results: The postprandial changes in TAG, NEFA and glucose concentrations were similar in trials 1 and 2. The change in plasma total TAG concentration was about two fold less (Po0.05) after lunch compared to breakfast. Postprandial NEFA suppression was the same after breakfast and lunch. Glucose and insulin responses were significantly greater following lunch suggesting decreasing insulin sensitivity during the day. Consumption of breakfast did not alter the postprandial total TAG or NEFA responses after lunch. Measurement of [13 C]palmitic acid concentration showed that handling of TAG and NEFA from the meal was the same after breakfast and lunch, and was not altered by consumption of breakfast. Conclusions: Overall, these data suggest that in young, healthy men regulation of plasma TAG from endogenous sources, principally VLDL, but not chylomicrons during the postprandial period leads to differences in the magnitude of lipaemic response when the same meal was consumed at breakfast or at lunch 6 h later.

Methodology for studying postprandial lipid metabolism

“…Despite considerable demand on subjects and investigators, this type of approach can provide a sound reflection of day life dietary patterns and metabolic responses and can reveal underlying defects in postprandial efficacy not revealed by single-meal challenges. A marked difference (i.e., less suppression in circulating levels) in the postprandial non-esterified fatty acid (NEFA) response can be observed following a second meal but this was not found in all studies (Fielding et al, 1996;Burdge et al, 2003). In addition, the second insulin response can be more elevated or not compared with the insulin response to the same nutrient intake consumed after an overnight fast.…”

“…It is known that a previous meal can affect the metabolic response after a second meal, the so-called second meal effect (Fielding et al, 1996;Evans et al, 1998;Burdge et al, 2003;Silva et al, 2005). This is particularly the case when postprandial lipaemia does not come back to baseline level after a first meal.…”

“…The effect of time-of-day administration of the postprandial test has been investigated (Romon et al, 1997;Hadjadj et al, 1999;Burdge et al, 2003). Compared with breakfast time, the same meal consumed at lunch elicited a twofold less rise in triglycerides.…”

Hepatic miR-378 targets p110α and controls glucose and lipid homeostasis by modulating hepatic insulin signalling

“…FFA levels are normally at their highest in the fasting state and go down in the postprandial state due to the suppressive action of insulin on lipolysis [31][32][33] . Here we found hepatic miR-378 expression is regulated by FFA, while insulin treatment in fasted mice could reduce the expression of miR-378.…”

Análise de ácidos graxos não-esterificados de plasma humano por cromatografia gasosa capilar com injeção sem divisão de fluxo

“…O método clássico usado para a separação das diferentes classes de lipídios é a cromatografia em camada delgada que, entretanto, apresenta algumas desvantagens, como elevado tempo de análise e potencial risco de oxidação dos ácidos graxos poli-insaturados 2 . Outros métodos de separação ou isolamento dos AGNE incluem a cromatografia em coluna 3 e a separação em cartuchos de extração em fase sólida 4 . Entretanto, o preparo das colunas é trabalhoso e a reprodutibilidade dos resultados é dependente da habilidade no seu preparo.…”