Dietary diacylglycerol suppresses accumulation of body fat compared to triacylglycerol in men in a double-blind controlled trial

We examined the effects of the long-term ingestion of dietary diacylglycerols (DG) in a double-blind controlled study of human lipid metabolism. Healthy men (n = 38; aged from 27 to 49 y, body mass index (BMI) ranging from 21.8 to 27.4 kg/m(2)) completed the study. To accustom the subjects to the test diets prior to the experiment, they were supplied with test diets of triacylglycerol (TG) oil for 4 wk (control period). The test oils (10 g/d) were included in bread, mayonnaise or shortbread and served for the breakfast. The target for total lipid intake was 50 g/d (15 g for breakfast, 15 g for lunch and 20 g for dinner) throughout the study. The subjects were then divided into two groups so that mean BMI and the hepatic fat content, determined by computed tomography, for each group were not different. One group (DG group) consumed test meals containing DG-rich oil (10 g/d) while the other group (TG group) consumed the same meal as during the control period. Ten grams of the DG-rich oil contained 5.5 g 1,3-DG, 2.5 g 1,2-DG and 2 g TG. The actual lipid intake during the study was 43 g/d. Body weight, BMI and waist circumference decreased in both groups at the end of the test period of 16 wk. However, the magnitudes of decreases in these variables were significantly greater in the DG group than in the TG group. Decreases of total fat, visceral fat area and subcutaneous fat area of the abdominal traverse images of computed tomography in the DG group were also significantly greater than those in the TG group. Hepatic fat content decreased significantly in the DG group while no change was observed in the TG group. Serum lipid concentrations (TG, total cholesterol, free fatty acid) and related metabolites (glucose, insulin, total ketone body) did not change significantly in either group. Thus, in contrast to TG, DG apparently suppressed accumulation of fat and possibly reduces the risk of diseases associated with visceral fat obesity.     

Ethanol with a mixed meal increases postprandial triacylglycerol but decreases postprandial non-esterified fatty acid concentrations

Plasma triacylglycerol concentrations increase after the acute ingestion of alcohol (specifically ethanol). However, the effect of ethanol when consumed with a mixed meal has not been well studied. The objective of the present study was to determine the perturbations of lipid metabolism that occur after ingestion of ethanol in combination with a mixed meal of specific fatty acid composition. Blood samples were taken from seven healthy male subjects before and after a mixed meal, with and without ethanol. The specific fatty acid composition of the test meal allowed the fatty acids to be traced into the plasma non-esterified fatty acid pool during the postprandial period. Statistical analysis by repeated measures ANOVA showed significant effects of ethanol. For example, postprandial lipaemia was enhanced after the ethanol test meal compared with the control (P < 0.05), mainly due to increases in triacylglycerol-rich lipoproteins in the flotation range Sf 60-400 (VLDL1) (P < 0.05); those in the range Sf 20-60 (VLDL2) and also Sf > 400 (chylomicrons) were not significantly affected. The later postprandial increase in plasma non-esterified fatty acid concentrations was reduced after the ingestion of ethanol (P < 0.001), but the proportions of palmitoleic acid (a marker of fatty acid content of the test meal) and of linoleic acid (a marker of endogenous lipolysis) were not affected. The results suggest a primary effect of ethanol on the stimulation of secretion of large VLDL particles, which then compete for clearance with chylomicrons by lipoprotein lipase. The results do not support an effect of ethanol on the release of non-esterified fatty acid into the plasma. The suppression of plasma non-esterified fatty acid concentrations during the postprandial period may contribute towards the beneficial effects of moderate ethanol consumption.     

Double-blind controlled study on the effects of dietary diacylglycerol on postprandial serum and chylomicron triacylglycerol responses in healthy humans

OBJECTIVE: The effects of dietary diacylglycerol (DG) on postprandial lipemia in healthy humans were investigated. METHODS: Forty normolipidemic male volunteers ingested fat emulsions containing either DG oil or triacylglycerol (TG) oil, at different doses: 10 g (n = 13), 20 g (n = 10) and 44 g (n = 17). Two test emulsions were given at seven-days intervals in random order. Fatty acid compositions of the test oils had been adjusted to be equal. Fasting and postprandial serum lipid concentrations in each group and plasma lipoprotein lipids in the 20 g-fat ingestion group were measured during the postprandial intervals. RESULTS: When DG emulsion was ingested, serum TG concentrations were significantly lower (p < 0.05) in the late postprandial phase, i.e., 4 hours, 6 hours as compared to the TG emulsion. The magnitude of postprandial lipemia (the area bounded by the curve above the fasting concentration) after ingestion of 44 g-DG emulsion was significantly less than that of 44 g-TG emulsion (6.54 +/- 5.12 and 8.45 +/- 7.54 mmol x h/L, mean +/- SD, respectively). Chylomicron TG, cholesterol, and phospholipid concentrations at 4 hours after ingestion of DG emulsion were significantly lower (p < 0.05) than those after the ingestion of TG emulsion at the same time point. No marked differences were observed for VLDL, LDL and HDL lipids between the test emulsions. CONCLUSION: In the usual range of fat intake (10-44 g), postprandial response after ingestion of DG emulsion was significantly less than that after ingestion of TG emulsion in healthy human subjects.     

Long-term ingestion of dietary diacylglycerol lowers serum triacylglycerol in type II diabetic patients with hypertriglyceridemia.

We examined the effect of daily consumption of dietary diacylglycerol (DG) oil on serum lipid concentrations in patients with diabetes whose serum triacylglycerol (TG) levels were persistently increased despite continuous nutritional counseling at the outpatient clinic. Patients (n = 16) were divided into DG and control groups (n = 8 each). DG was incorporated (target dose 10 g/d) by substituting DG oil (80 g DG/100 g oil) for the ordinary TG cooking oil used at home for 12 wk. The control group continued consuming ordinary TG cooking oil. Dietary records indicated that there were no differences between groups in total energy intake or percentage of energy from fat. In the DG group, TG intake decreased from 26.8 +/- 9.3 to 15.7 +/- 8.9 g/d, whereas DG intake increased from 0.3 +/- 0.1 to 10.6 +/- 3.9 g/d. No differences between groups were observed in body weight, total fat intake or total oil consumption throughout the study period. In the DG group, serum TG levels decreased 39.4% from 2.51 +/- 0.75 mmol/L to 1.52 +/- 0.28 mmol/L. Serum glycohemoglobin A(1c) (HbA(1c)) concentration also decreased 9.7%. In contrast, there were no changes in these variables in the control group. Serum total and HDL cholesterol were not affected in either group. These results indicate that DG oil may be useful as an adjunct to the standard diet therapy of fat restriction in the management of diabetics with hypertriglyceridemia.     

Effects of dietary fish oil on lipid peroxidation and serum triacylglycerol levels in psychologically stressed mice

OBJECTIVE: The intake of omega-3 polyunsaturated fatty acids and psychological stress can each induce tissue lipid peroxidation. In our present study, we investigated their combined effects on the oxidative status of mouse tissues. METHODS: Mice were group-housed (four mice/cage) and fed a diet containing fish oil (as a source of omega-3 polyunsaturated fatty acids), soybean oil, or olive oil for 3 wk. These animals were then 1) housed under the same conditions (four per cage, control group) or 2) individually housed to generate psychological stress conditions (isolation stress). After 2 wk of isolation stress, the levels of thiobarbituric acid-reactive substances (an index of lipid peroxidation) and antioxidants in the liver and kidney and the serum levels of triacylglycerol were measured. RESULTS: Fish oil-fed mice showed increased levels of thiobarbituric acid-reactive substances in their livers and kidneys compared with soybean oil- or olive oil-fed mice. These increases in thiobarbituric acid-reactive substance levels in the fish oil-fed mice were less profound under isolation stress conditions when compared with the group-housed animals on the same diet. In the fish oil-fed mice, isolation stress led to an increase in liver vitamin E levels when compared with their group-housed counterparts. The fish oil-fed mice exhibited lower serum triacylglycerol levels compared with the soybean oil- or olive oil-fed mice, and this decrease was more profound under conditions of isolation stress when compared with group-housing conditions. CONCLUSION: Dietary fish oil combined with isolation stress results in lower levels of lipid peroxidation in the liver and kidney compared with dietary fish oil alone.     

Consumption of alpha-linolenic acid-enriched diacylglycerol induces increase in dietary fat oxidation compared with alpha-linolenic acid-enriched triacylglycerol: A randomized,double-blind trial

Fat metabolism is an important consideration in obesity. Alpha-linolenic acid-enriched diacylglycerol (ALA-DAG), which mainly occurs as ALA esterifies to 1,3-diacyl-sn-glycerol (1,3-DAG), has beneficial effects on fat metabolism and body weight compared with triacylglycerol (TAG). Moreover, compared with ALA-TAG, ALA-DAG enhances β-oxidation activity in the small intestine and liver in rodents. We hypothesized that ALA-DAG consumption may increase dietary fat oxidation compared with ALA-TAG in humans. To examine this hypothesis, we conducted a randomized double-blind cross-over trial in 17 normal and moderately obese men and women (BMI: 25.7 ± 2.0 kg/m², mean ± SD). Each participant was assigned to a 4-week intervention period with 2.5 g/day of ALA-DAG or ALA-TAG consumption, followed by a 4-week washout period between consumption of each diet. Dietary fat oxidation, assessed based on the ¹³CO₂ recovery rate in the breath, was significantly increased by ALA-DAG consumption compared with ALA-TAG consumption (17.0 ± 4.5% and 14.1 ± 5.9%, respectively, P < .05). In addition, ALA-DAG consumption significantly decreased the visceral fat area compared with ALA-TAG (102.9 ± 51.9 cm² and 110.9 ± 51.7 cm², respectively; P < .05). These results indicate that ALA-DAG consumption may be useful for preventing obesity.     

L-arabinose feeding prevents increases due to dietary sucrose in lipogenic enzymes and triacylglycerol levels in rats

L-Arabinose is a natural, poorly absorbed pentose that selectively inhibits intestinal sucrase activity. To investigate the effects of L-arabinose feeding on lipogenesis due to its inhibition of sucrase, rats were fed 0-30 g sucrose/100 g diets containing 0-1 g L-arabinose/100 g for 10 d. Lipogenic enzyme activities and triacylglycerol concentrations in the liver were significantly increased by dietary sucrose, and arabinose significantly prevented these increases. Arabinose feeding reduced the weights of epididymal adipose tissue. Moreover, plasma insulin and triacylglycerol concentrations were significantly reduced by dietary L-arabinose. These findings suggest that L-arabinose inhibits intestinal sucrase activity, thereby reducing sucrose utilization, and consequently decreasing lipogenesis.     

三酰甘油对代谢综合征患者餐后脂代谢的影响

目的 探讨空腹TG水平对代谢综合征患者餐后脂代谢的影响.方法 将40例代谢综合征患者分为空腹TG水平升高(≥1.70 mmol/L)组(MS+HTG组,24例)和空腹TG水平正常(＜1.70 mmol/L)组(MS-HTG组,16例),同时将20例健康者作为对照组.三组受试者分别进行口服脂肪容许量测试,于餐后2、4、6、8、10 h测定TG水平,并计算其餐后TG代谢的曲线下面积(AUC).结果 MS+HTG组餐后TG的高峰水平和餐后TG代谢的AUC[(6.83±2.81)mmol/L和(26.08±16.40)mmol/(L·10 h)]均显著高于MS-HTG组[(4.12±1.14)mmol/L和(12.71±7.05)mmol/(L·10 h)]及对照组[(3.14±1.26)mmol/L和(10.28±6.09)mmol/(L·10 h)].MS+HTG组餐后TG的高峰水平较其他两组延迟2 h.MS-HTG组餐后TG的高峰水平高于对照组(P＜0.05),MS-HTG组餐后TG代谢的AUC虽高于对照组,但差异无统计学意义.相关分析结果表明,餐后TG代谢的AUC与空腹TG水平及体重指数(BMI)相关(r=0.60,P＜0.01;r=0.27,P＜0.05).多元线性回归分析结果显示,仅空腹TG水平对餐后TG代谢的AUC有预测价值(P＜0.01).结论 代谢综合征患者的空腹TG水平及BMI与餐后高TG血症独立相关.空腹TG水平对餐后高TG血症有预测价值.空腹TG水平越高,餐后TG的清除越迟缓.     

Comparisons of glucose and lipid metabolism in rats fed diacylglycerol and triacylglycerol oils

The effects of dietary 1,3-diacylglycerol-rich oil (DG oil) on biochemical findings related to glucose and lipid metabolisms were investigated in comparison with triacylglycerol oil (TG oil) in normal rats. Young (7 wk-old) and old (8 mo-old) rats were fed a synthetic diet containing 10% (by weight) DC or TG oil for 1, 4, 8, or 12 wk. The body weights, epididymal and perirenal adipose tissue weights, and feed efficiency were not significantly different in the dietary oil groups during any feeding period. The plasma and liver triacylglycerol concentrations were not different in the dietary groups, except that the plasma triacylglycerol concentrations were rather lower only in the portal vein of rats fed DG oil. The plasma glucose and free fatty acid concentrations were significantly higher in rats fed DG oil as compared to TG oil. In the old rats fed DG oil for 8 wk, the fasted plasma glucose and insulin concentrations were elevated and glucose intolerance was observed. The insulin receptor expression was not different due to dietary oil, but was markedly reduced with aging. Thus, the anti-obesity and lipid-lowering effects of dietary DG oil were not found. Moreover, it appeared that the glucose intolerance might be induced by dietary DG oil, particularly in the old rats.     

Solubilization of phytosterols in diacylglycerol versus triacylglycerol improves the serum cholesterol-lowering effect.

OBJECTIVE: This study was performed to investigate the difference in the serum-cholesterol- and triglyceride-lowering activities between phytosterols dissolved in diacylglycerol (PS/DG) and dispersed in triacylglycerol (PS/TG). The effects of the solvent on the concentrations of serum beta-sitosterol and campesterol were examined. DESIGN: The study had a randomised crossover design. SUBJECTS: Twelve healthy normocholesterolemic or moderately hypercholesterolemic men aged 29-50 y participated in this study. INTERVENTIONS: For 2 weeks before the test period (designated as the control period), all subjects consumed control mayonnaise (PS free) daily with supper and were randomly assigned to two groups for the 2 week test period; one group was given mayonnaise containing PS (500 mg/day) dissolved in DG (10 g/day), and the other mayonnaise containing PS (500 mg/day) dispersed in TG (10 g/day). After a wash out period consuming control PS-free mayonnaise for 4 weeks, the groups were reversed for 2 weeks. RESULTS: PS/TG feeding had no effect on the serum cholesterol level. In contrast, PS/DG feeding significantly reduced the total and LDL cholesterol levels from the initial value of 5.57 to 5.31 mmol/l (4.7%; P<0.05) and from 3.69 to 3.39 mmol/l (7.6%; P<0.05), respectively. Moreover, the degree of total cholesterol reduction induced by PS/DG feeding in the test period was significantly greater than that induced by PS/TG feeding (P<0.05). In addition, the serum beta-sitosterol and campesterol concentrations did not change during the PS/TG or PS/DG feeding periods. CONCLUSIONS: Dissolution of PS in DG had a better serum cholesterol lowering effect than dissolution in TG. SPONSORSHIP: Kao Corporation.     

Dietary phosphatidylcholine affects postprandial plasma levels and digestibility of lipid in common carp (Cyprinus carpio)

This study examined the effect of purified soyabean phosphatidylcholine (SPC) on circulating plasma lipids and nutrient digestibility in juvenile common carp. The fish (100 (SD 15) g, 25 degrees C) were fed, for 4 weeks, a casein-based diet containing either 12 % soyabean oil (diet SBO) or 8 % SBO plus 4 % SPC (diet SPC). The lipid, protein and energy contents of the faeces were analysed for the determination of apparent digestibility. At the end of the trial, the fish were fasted for 48 h and fed a single meal. Plasma lipids were then analysed over the next 48 h. The growth (1.63 v. 1.26 % per d) and apparent lipid digestibility (96.3 v. 92.1 %) were higher in SPC- than in SBO-fed fish. The amplitude of the postprandial (8 h after the meal) TAG peak was identical in fish from both treatments, despite the 33 % lower amount of TAG in diet SPC. Both observations support the idea that SPC stimulates intestinal TAG uptakes. The lower TAG:phospholipid ratio of the secreted plasma lipids at the time of absorption suggests a larger number of smaller intestinal lipoproteins in SPC- than SBO-fed fish, possibly due to the recycling of absorbed lysophosphatidylcholine for chylomicron formation. In the 48 h unfed state, phospholipid levels remained approximately 20 % higher in SPC-fed than in SBO-fed fish, but we observed no hypocholesterolaemic effect of SPC. In summary, the present data support earlier histological indications of a positive role of dietary phosphatidylcholine in intestinal TAG uptakes in carp.     

Dietary fiber suppresses elevations of uric acid and allantoin in serum and urine induced by dietary RNA and increases its excretion to feces in rats

This study was performed to examine the effects of several kinds of dietary fibers (DF) with different physical properties on dietary RNA metabolism. Male Wistar strain rats, 4 wk old, were fed diets with or without a 3% yeast RNA and a 5% DF (cellulose, chitin, chitosan, inulin, and xanthan gum) for 20 d (Experiment 1) or 5 d (Experiment 2). Feeding DF tested lowered the serum uric acid and allantoin concentrations and the urinary excretions of their compounds and increased the amount of RNA excreted into the feces compared with fiber-free. The water-holding capacity and nucleotide adsorption of chitin and chitosan in acidic solutions were higher than those of cellulose. The digestion rate of RNA by RNase A in vitro was found to be lower in the DF tested than in fiber-free. The decrease was remarkable in chitosan and xanthan gum. The uptakes of 14C-labeled adenosine and adenosine 5'-monophosphate (5'-AMP) in the rat jejunum were markedly decreased in regard to chitosan and xanthan gum in comparison with the fiber-free. These phenomena suggest that DF with high viscosity is more strongly associated with the suppression of RNA digestion by RNase A and the depression of the uptake of purine compounds to jejunum. The present results reveal that the elevation of serum uric acid concentration induced by dietary RNA can be suppressed by DF in rats.     

膳食脂肪对高血压人群血脂水平的影响

目的 探讨改善膳食脂肪摄入情况对血脂的影响。方法 对营养健康教育前后高血压患者的膳食脂肪摄入情况及血脂水平进行测定分析。结果 基线调查表明人群膳食脂肪及胆固醇摄入量过高,脂肪供能比占总热能的30％以上;血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL－L）水平偏高。相关分析表明,体质指数（BMI）和饱和脂肪酸（SFA）与血清TC、TG、LDL－C呈正相关;高密度脂蛋白（HDL－C）／TC与BMI、SFA呈负相关,而与单不饱和脂肪酸（MUFA）呈正相关。进行社区营养干预后,干预组脂肪供能比小于总热能的30％,与对照组相比及自身干预前后比较差异均有显著性,胆固醇摄入量有下降趋势;干预组人群血脂TC、LDL－C水平显著降低。结论 研究结果提示减少膳食脂肪和胆固醇摄入量,适当增加单不饱和脂肪酸摄入对高血压人群降低血脂水平,控制血压是有效的。     

Effect of dietary antioxidants on postprandial endothelial dysfunction induced by a high-fat meal in healthy subjects

BACKGROUND: Persons following current dietary guidelines have a lower risk of mortality from coronary heart disease. OBJECTIVE: The objective was to compare the short-term effect of a high-fat meal and a high-carbohydrate meal, with and without dietary antioxidants, on vasomotor, antiplatelet, and hemostatic functions of the endothelium in healthy subjects. DESIGN: In an observer-blinded, randomized crossover study, 25 (13 men and 12 women) healthy subjects were given each of 3 meals in random order at 1-wk intervals: a high-fat meal (760 kcal), an isoenergetic high-carbohydrate meal, and a high-fat meal with dietary antioxidants from vegetables (865 kcal). Endothelial functions, as assessed by hemodynamic and rheologic responses to L-arginine--the natural precursor of nitric oxide--were evaluated before and 4 h after each meal. RESULTS: Unlike the high-carbohydrate meal, the high-fat meal increased the plasma concentrations of triacylglycerol (P < 0.01); both meals activated hemostasis. The high-carbohydrate meal did not modify blood pressure, and platelet aggregation decreased in response to the L-arginine load (-7.1 +/- 2.3 mm Hg and -8.5 +/- 4.5%, respectively). After the high-fat meal, the decrease in blood pressure in response to L-arginine was reduced (-1 +/- 0.8 mm Hg), and platelet aggregation showed a paradoxical increase (4.1 +/- 2.1%; P < 0.01 compared with the high-carbohydrate meal). The high-fat meal with antioxidants partially restored the vascular response to L-arginine. CONCLUSION: Compared with a high-carbohydrate meal, a high-fat meal can modify endothelial functions toward a more atherogenetic profile, which is partially prevented by dietary antioxidants.     

Dietary manipulation of postprandial colonic lactose fermentation: I. Effect of solid foods in a meal

The effect of adding solid foods--cornflakes, banana and hard-boiled egg--to a meal with 360 ml of intact milk containing 18 g of lactose was investigated in 13 lactose-malabsorbers and 10 lactose-absorbers chosen from 36 Guatemalan adults screened for their capacity to digest and absorb completely the lactose in this volume of milk. A six-hour hydrogen breath test was used as the index of carbohydrate absorption. Minimal breath H2 was excreted by lactose-absorbers with either the intact milk alone, the intact milk with solid foods, or lactose-prehydrolyzed milk with solids. In lactose-malabsorbers, however, the 6-h excretion of H2 with intact milk plus solid food was intermediary between milk alone and prehydrolyzed milk with solids. A relative net reduction of 47% in lactose malabsorption was produced by adding food, and the peak-rise in breath H2 was delayed by 2 hours. A physiological consequence of taking solid foods along with milk is a slower rate of colonic fermentation, and this may be the basis for reducing gastro-intestinal symptoms in lactose-intolerant malabsorbers.     

Dietary medium-chain triacylglycerol prevents the postprandial rise of plasma triacylglycerols but induces hypercholesterolemia in primary hypertriglyceridemic subjects

BACKGROUND: Previous studies showed divergent results concerning the influence of medium-chain triacylglycerol (MCT) on lipoprotein metabolism. OBJECTIVE: The objective of this study was to compare the effects of MCT and corn oil on plasma lipids in primary hypertriglyceridemic patients. DESIGN: Ten subjects ate different proportions of corn oil and MCT for 12 wk. The subjects first ate a low-fat diet for 2 wk and during the next 4 wk, corn oil was added as the sole source of fat. Thereafter, for 2-wk periods, the subjects were sequentially fed corn oil and MCT mixed in the following proportions: 3:1, 1:1, and 0:1. Fasting plasma total cholesterol, triacylglycerol, and HDL-cholesterol concentrations were measured at the end of each period. At the end of the 100%-corn oil and of the 100%-MCT periods, subjects were fed a test meal containing the respective oil (40 g fat/m(2) body surface area) and total cholesterol and triacylglycerols were measured at 2-h intervals over 8 h; fasting lipoprotein composition was also measured. RESULTS: Compared with corn oil, MCT was associated with a higher mean (+/-SD) fasting total cholesterol concentration (6.39 +/- 1.14 compared with 5.51 +/- 0.98 mmol/L, respectively; P < 0. 05); non-HDL-cholesterol concentrations were also higher with MCT (5. 36 +/- 1.11 mmol/L) than with corn oil (4.51 +/- 0.92 mmol/L; P < 0. 005). In response to the liquid test meal, plasma total cholesterol did not change with either diet but triacylglycerols increased with the 100%-corn oil diet. CONCLUSIONS: MCT prevents the risk of pancreatitis due to postprandial hypertriglyceridemia but has the inconvenience of raising total cholesterol concentrations in primary hypertriglyceridemic subjects.     

Impact of menstrual periodicity on serum lipid levels and estimates of dietary intakes

Nine eumenorrheic women were studied at five separate times each month for a minimum of 2 months. Fasting bloods and 1-day food records were obtained from all women at these times to describe the pattern and magnitude of within-person variation in selected nutrient and lipid indicators attributable to menstrual cyclicity. Serum cholesterol, beta-carotene, 17 beta-estradiol (E2), and dietary selenium intakes exhibited significant periodic regressions against time. For the group as a whole, however, only serum cholesterol and E2 measures exhibited significantly strong consistent periodicities. Future studies with a larger sample of women are warranted to confirm these findings. Unless strict blood sampling protocols are followed, variation attributable to menstrual cyclicity may mitigate the reliability of the serum cholesterol screenings advocated in the past few years.     

Dietary fiber suppresses elevation of uric acid and urea nitrogen concentrations in serum of rats with renal dysfunction induced by dietary adenine

This study was conducted to examine the effects of several kinds of dietary fiber (DF) with different physical properties on the elevation of uric acid and urea nitrogen concentrations in serum of rats induced by dietary adenine. DF decreased an uptake of 14C-labeled adenine in the rat jejunum in vitro, but the reduction varied with the physical property of DF. Male Wistar rats (3 weeks old) were fed a diet with or without a 0.4% adenine and a 5% DF (cellulose, chitin, chitosan, or xanthan gum) for 20 days. Feeding of adenine in the fiber-free group elevated the concentrations of uric acid, creatinine, and urea nitrogen in serum, but decreased the excretions of these compounds into urine and increased the amounts of 2,8-dihydroxyadenine (2,8-DHA) in kidney and urine. The test DF was found to suppress the elevation of uric acid, creatinine, and urea nitrogen concentrations in serum induced by dietary adenine, and to mitigate the decreased excretions of these compounds into urine and the increased retention of 2,8-DHA in kidney and urine. This phenomenon was remarkable in the xanthan gum group. These results suggest that DF suppresses the elevation of uric acid and urea nitrogen concentrations in serum by attenuating the absorption of dietary adenine.     

Regular meal frequency creates more appropriate insulin sensitivity and lipid profiles compared with irregular meal frequency in healthy lean women

OBJECTIVE: To investigate the impact of irregular meal frequency on circulating lipids, insulin, glucose and uric acid concentrations which are known cardiovascular risk factors. DESIGN: A randomised crossover dietary intervention study. SETTING: Nottingham, UK--Healthy free-living women. SUBJECTS: A total of nine lean healthy women aged 18-42 y recruited via advertisement. INTERVENTION: A randomised crossover trial with two phases of 14 days each. In Phase 1, subjects consumed their normal diet on either 6 occasions per day (regular) or by following a variable meal frequency (3-9 meals/day, irregular). In Phase 2, subjects followed the alternative meal pattern to that followed in Phase 1, after a 2-week (wash-out) period. Subjects were asked to come to the laboratory after an overnight fast at the start and end of each phase. Blood samples were taken for measurement of circulating glucose, lipids, insulin and uric acid concentrations before and for 3 h after consumption of a high-carbohydrate test meal. RESULTS: Fasting glucose and insulin values were not affected by meal frequency, but peak insulin and AUC of insulin responses to the test meal were higher after the irregular compared to the regular eating patterns (P < 0.01). The irregular meal frequency was associated with higher fasting total (P < 0.01) and LDL (P < 0.05) cholesterol. CONCLUSION: The irregular meal frequency appears to produce a degree of insulin resistance and higher fasting lipid profiles, which may indicate a deleterious effect on these cardiovascular risk factors. SPONSORSHIP:: The Ministry of Health and Medical Education, IR Iran.     

Chronic dietary fat intake modifies the postprandial response of hemostatic markers to a single fatty test meal

BACKGROUND: Hemostasis is the result of a complex equilibrium between coagulation and fibrinolysis, and the influence of different dietary models on this equilibrium is not entirely known. OBJECTIVE: The objective was to compare the effects of the chronic intake of different dietary models on postprandial hemostasis. DESIGN: In a randomized crossover design, 20 healthy men consumed for 28 d each diets rich in monounsaturated fatty acids (MUFAs), saturated fatty acids (SFAs), and carbohydrates plus n-3 fatty acids (CHO/N3). Fasting and postprandial hemostatic factors (factor VII coagulant activity, plasminogen activator inhibitor-1, tissue-type plasminogen activator, d-dimer, and thromboxane B(2)) were measured; meal tests for the postprandial measures were based on butter, virgin olive oil, and walnuts for the SFA, MUFA, and CHO/N3 diets, respectively. RESULTS: There were no differences in the fasting variables after the dietary periods. After the 3 fatty meals were consumed, we observed an increase in thromboxane B(2) and d-dimer and a reduction in tissue plasminogen activator, irrespective of the dietary model. The MUFA or CHO/N3 meals lowered postprandial concentrations of factor VII coagulant activity, although the reduction was greater after the MUFA-enriched meal. The concentration of plasminogen activator inhibitor-1 was greater after the SFA meal than after the other 2 meals. CONCLUSIONS: The administration of a fatty meal induces a postprandial procoagulant tendency, irrespective of the type of fat consumed. However, the use of a dietary model rich in SFA creates a more procoagulant environment than does a model that includes MUFA or CHO/N3 as the source of fatty acids.