Postprandial Triacylglycerolemia Research Articles

Polyphenol extracts interfere with bacterial lipopolysaccharide in vitro and decrease postprandial endotoxemia in human volunteers

The intestinal absorption of bacterial lipopolysaccharide (LPS) and dietary fat has been implicated in the development of metabolic endotoxemia. This study first compared the ability of polyphenol extracts from grape, cranberry, avocado and apple to interfere with pancreatic lipase and LPS in vitro. The grape extract displayed a higher inhibitory activity of lipase (IC50 = 8.6 ± 1.1 mg/ml) and LPS binding (IC50 = 90 ± 1.1 µg/ml). Then, a study was carried out in 12 normal weight and 17 overweight/obese subjects to determine the effect of this extract on the postprandial changes in plasma triacylglycerols, LPS and IL-6. The presence of small intestine bacterial overgrowth (SIBO), in which higher levels of bacteria and eventually LPS are present in the upper intestine, i.e. where dietary fat absorption occurs, was also evaluated. Compared with placebo, the grape extract did not affect postprandial triacylglycerolemia but decreased plasma LPS, without affecting the IL-6-associated inflammatory response. SIBO did not affect these variables.

Physiology in Medicine: update on lifestyle determinants of postprandial triacylglycerolemia with emphasis on the Mediterranean lifestyle

This review updates the effect of lifestyle on plasma triacylglycerols (TAG) in the postprandial state, commonly reported as postprandial lipemia (PPL), an independent risk factor for cardiovascular diseases (CVD). Numerous studies have shown that Mediterranean diet may reduce PPL. However, most of these studies were focused on the type of fat (i.e., monounsaturated fat from olive oil), and the other components of the Mediterranean lifestyle were neglected. Physical activity, an integral part of this lifestyle, is widely investigated on its own and shown to reduce PPL. In addition, preliminary results of studies examining other Mediterranean "ingredients", such as legumes, fish, and herbs, showed additional benefits; however, data on the long-term effects are limited. More studies are needed to confirm short-term results and investigate the effects of the whole Mediterranean lifestyle on PPL and whether these effects mediate its protective role on CVD. Moreover, investigation of the effects in nonhealthy populations and the underlying mechanisms would be clinically helpful in individualizing the appropriate intervention.

Lifestyle Intervention Leading to Moderate Weight Loss Normalizes Postprandial Triacylglycerolemia Despite Persisting Obesity

Obesity is associated with impaired postprandial triacylglycerolemia, an independent risk factor for cardiovascular disease. Given that obesity is hard to treat, efforts should focus on treating its comorbidities. We aimed to investigate whether moderate weight loss normalizes postprandial triacylglycerol (TAG) concentrations, in the absence of the acute effects of negative energy balance. For this purpose, postprandial lipemia was investigated in eight obese but otherwise healthy, sedentary men (age: 41.3 ± 4.1 years, BMI: 36.5 ± 1.6 kg·m(-2)), once before and again after a 10% weight loss followed by ≥4 weeks of weight maintenance, and was compared with that of eight age-matched healthy lean men (BMI: 24.7 ± 0.6 kg·m(-2)). Dietary intervention consisted of reduced carbohydrate and saturated fat intake and increased monounsaturated fat intake. Obese volunteers were advised to increase physical activity using pedometers to record daily activity. Postprandial triacylglycerolemia after weight loss was reduced by 27-46% (P < 0.05), and became similar to that of lean men despite persisting obesity (BMI after weight loss: 32.9 ± 1.5 kg·m(-2)). Reduction in postprandial TAG responses was inversely correlated with the decrease in postprandial insulin sensitivity index (ISI) after weight loss (r = -0.714, P = 0.047). We conclude that moderate weight loss induced by a low-carbohydrate and saturated fat diet and a slight increase in daily physical activity normalizes postprandial triacylglycerolemia in obese men, independently of acute diet-induced negative energy balance, and possibly through enhancement of insulin action.

One day of moderate energy deficit reduces fasting and postprandial triacylglycerolemia in women: The role of calorie restriction and exercise

Fasting and postprandial hypertriacylglycerolemia are important cardiovascular risk factors in women. We sought to examine the effects of acute (1 day), moderate ( approximately 2 MJ) energy deficit induced by calorie restriction, exercise, or combination of both on fasting and postprandial triacylglycerol (TAG) metabolism in women. Six healthy premenopausal women performed four oral fat tolerance tests in the morning after a day of a) rest (control), b) calorie restriction ( approximately 2 MJ), c) exercise (net deficit of approximately 2 MJ) and d) calorie restriction-plus-exercise (total energy deficit of approximately 2 MJ). All energy deficit trials significantly reduced fasting and postprandial total plasma TAG concentrations by 15-23% and 12-23%, respectively, and triacylglycerol-rich lipoprotein TAG concentrations by 37-43% and 25-39%, respectively, compared with the control condition (P<0.05). Postprandial, but not fasting, total TAG concentrations were approximately 12% lower after exercise compared with diet-induced energy deficit (P=0.05). Acute, moderate energy deficit independently of its origin (i.e. diet or exercise or combination of both) reduces fasting and postprandial triacylglycerolemia in women. Exercise elicits a somewhat greater effect than calorie restriction in the postprandial state. The acute effect of diet and exercise should be taken into account when studying the long-term effects of weight loss and exercise training on TAG metabolism.

Isolation of Pancreatic Lipase Activity-inhibitory Component of Spirulina Platensis and It Reduce Postprandial Triacylglycerolemia

In the process of investigating the hypolipidemic effects of Spirulina platensis, we found that the aqueous extract of S. platensis may inhibit the intestinal absorption of dietary fat by inhibiting pancreatic lipase activity. The aqueous extract of S. platensis (500 m/kg) reduced the elevation of rat plasma triacylglycerol levels after oral administration of the lipid emulsion 2 h after administration. To clarify the hypolipidemic effects of S. platensis, the active component was isolated and designated 1'-O-(palmitonyl)-2'-O-(caprylonyl) glyceryl-beta-alpha-D-galactopyranoside (glycolipid H-b2). Glycolipid H-b2 was found to inhibit pancreatic lipase activity in a dose-dependent manner. The fractions containing glycolipid H-b2 (250 mg/kg) reduced the elevation of rat plasma triacylglycerol levels after oral administration of the lipid emulsion 2 h after administration. Furthermore, we examined the effects of phycocyanin isolated from S. platensis on pancreatic lipase activity. Phycocyanin inhibited the pancreatic lipase activity in a dose-dependent manner. These results suggest that the inhibitory effects of S. platensis on postprandial triacylglycerolemia may be due in part to the inhibition of pancreatic lipase activity by glycolipid H-b2 and phycocyanin.

Addition of glucose to an oral fat load reduces postprandial free fatty acids and prevents the postprandial increase in complement component 3

Elevated fasting plasma concentrations of complement component 3 (C3) are associated with elevated fasting and postprandial triacylglycerol concentrations, insulin resistance, obesity, and coronary artery disease. C3 is the central component of the complement system and the precursor of acylation-stimulating protein (ASP). Insulin and ASP are principal determinants of free fatty acid (FFA) trapping by adipose tissue. Because controversy exists concerning postprandial changes in C3 and because meal composition may influence complement activation, we studied postprandial lipemia in relation to changes in plasma C3. After an overnight fast, 6 healthy men ( +/- SD age: 23 +/- 2 y) underwent 4 oral liquid challenges: fat (50 g/m(2) body surface), glucose (37.5 g/m(2)), fat and glucose (mixed test), and water (as a control test) in a random, crossover design. Plasma ASP concentrations did not change postprandially in any test. Changes in C3 concentration were observed only after the fat challenge: elevated concentrations occurred between 1 and 3 h, and a maximum increase of 11% occurred at 2 h (P = 0.05). Postprandial triacylglycerolemia did not differ significantly between the fat and mixed tests. The FFA response after the fat challenge was the highest of all the tests (P < 0.05 for all comparisons) and was accompanied by an increase in ketone bodies (maximum at 6 h); this increase did not occur after the mixed test, which suggests less hepatic FFA delivery. When glucose is added to an oral fat load, the postprandial FFA response is reduced, and the fat-specific increase in C3 is prevented. After ingestion of fat without glucose, the lack of insulin response may lead to C3-mediated peripheral FFA trapping, which probably serves as a backup system in case of insufficient or inefficient insulin-dependent FFA trapping.

Effect of long-chain n−3 polyunsaturated fatty acids on fasting and postprandial triacylglycerol metabolism

Elevated plasma triacylglycerol concentrations have been associated with increased risk of coronary heart disease (CHD). In the past, the epidemiologic evidence about the causal role of triacylglycerols in CHD has not been well regarded, but recent prospective evidence shows that nonfasting plasma triacylglycerol concentration is a strong and independent predictor of future myocardial infarction. Elevated plasma triacylglycerol concentrations are associated with other CHD risk factors, namely reduced HDL-cholesterol concentrations and a preponderance of highly atherogenic, small, dense LDL particles. Plasma triacylglycerol concentrations increase after the ingestion of a fat-containing meal, and elevated postprandial triacylglycerolemia leads to a series of metabolic reactions that reduce HDL-cholesterol concentrations and promote the formation of small, dense LDL particles. The magnitude of the postprandial response is largely determined by fasting plasma triacylglycerol concentrations. Metabolism of plasma triacylglycerols also influences postprandial factor VII activation and the postprandial lipemic responsiveness to dietary cholesterol. Therefore, dietary factors that improve fasting plasma triacylglycerol concentrations must have a role in a healthy diet. Eicosapentaenoic and docosahexaenoic acids are n-3 polyunsaturated fatty acids (PUFAs) in fish oil that effectively reduce plasma triacylglycerol concentrations. Because n-3 PUFAs are effective at low doses (1 g n-3 PUFA/d), they provide a realistic option for the optimization of plasma triacylglycerol metabolism.

Alpha-1 Adrenergic Blockade Interacts with Dietary Carbohydrates on Triacylglycerol Metabolism in Rats

The purpose of this study was to evaluate the effects of prazosin, an alpha-1 adrenergic antagonist, on determinants of triacylglycerol metabolism in rats fed chronically diets high in starch or sucrose. Hepatic triacylglycerol secretion rate (HTGSR), lipoprotein lipase in white and brown adipose tissues, red vastus lateralis muscle and heart, as well as serum triacylglycerol concentration, were assessed in the post-prandial state, after injection of prazosin or saline. Post-prandial triacylglycerolemia was higher in the sucrose-fed than in the starch-fed rats. After the injection of prazosin, triacylglycerol concentrations were decreased in both dietary groups. This effect was more marked in sucrose-fed than in starch-fed rats (diet x blocker interaction: P < 0.0003). HTGSR was higher in rats fed sucrose than in starch-fed rats (+49%, P < 0.01). Prazosin decreased HTGSR (-45%) in the sucrose-fed rats but not in animals fed starch. Lipoprotein lipase activities in brown adipose tissue, vastus lateralis muscle and heart in rats injected with prazosin were enhanced compared with those of the saline-treated rats, but no change was found in enzyme activity in white adipose tissue. This effect of prazosin was independent of the type of diet. These results suggest that prazosin reduced serum triacylglycerol concentrations after food ingestion at least partly by enhancing lipoprotein lipase activity in several tissues. In addition, the prazosin-induced decrease in HTGSR in sucrose-fed rats, which was absent in starch-fed animals, probably accounted for the greater magnitude of the hypotriacylglycerolemic effect of the blocker in animals given sucrose.