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1.
To compare the effects of dietary palmitic acid (16:0) vs oleic acid (18:1) on serum lipids, lipoproteins, and plasma eicosanoids, 33 normocholesterolemic subjects (20 males, 13 females; ages 22-41 years) were challenged with a coconut oil-rich diet for 4 weeks. Subsequently they were assigned to either a palm olein-rich or olive oil-rich diet followed by a dietary crossover during two consecutive 6-week periods. Each test oil served as the sole cooking oil and contributed 23% of dietary energy or two-thirds of the total daily fat intake. Dietary myristic acid (14:0) and lauric acid (12:0) from coconut oil significantly raised all the serum lipid and lipoprotein parameters measured. Subsequent one-to-one exchange of 7% energy between 16:0 (palm olein diet) and 18:1 (olive oil diet) resulted in identical serum total cholesterol (192, 193 mg/dl), low-density lipoprotein cholesterol (LDL-C) (130, 131 mg/dl), high-density lipoprotein cholesterol (HDL-C) (41, 42 mg/dl), and triglyceride (TG) (108, 106 mg/dl) concentrations. Effects attributed to gender included higher HDL in females and higher TG in males associated with the tendency for higher LDL and LDL/HDL ratios in men. However, both sexes were equally responsive to changes in dietary fat saturation. The results indicate that in healthy, normocholesterolemic humans, dietary 16:0 can be exchanged for 18:1 within the range of these fatty acids normally present in typical diets without affecting the serum lipoprotein cholesterol concentration or distribution. In addition, replacement of 12:0 + 14:0 by 16:0 + 18:1, but especially 16:0 or some component of palm olein, appeared to have a beneficial impact on an important index of thrombogenesis, i.e., the thromboxane/prostacyclin ratio in plasma.  相似文献   

2.
The observation that dietary stearic acid does not raise plasma cholesterol concentration is well documented, although the regulating mechanisms are not completely understood. Therefore, we examined the effect of dietary stearic acid on cholesterol absorption and sterol balance using male Syrian hamsters fed modified NIH-07 cereal-based diets selectively enriched in palmitic acid (16:0), stearic acid (18:0), trans fatty acid (18:1t), cis oleic acid (18:1c) or linoleic acid (18:2). All diets contained 17 g/100 g total fat and 0.05 g/100 g cholesterol; the five fat blends were enriched 30% with the fatty acid of interest above a constant fatty acid background. Cholesterol absorption efficiency was 50-55% in all treatment groups except for the 18:0 group, in which cholesterol absorption was significantly reduced to 21%. Plasma total cholesterol concentration was significantly lower in the 18:0 group compared to the 16:0 group. Fecal neutral steroid excretion was significantly greater in hamsters fed the high 18:0 diet compared to the other treatment groups. After accounting for unabsorbed dietary cholesterol, endogenous cholesterol excretion was about 100% higher in the 18:0 group. Consequently, the calculated rate of whole body cholesterol synthesis was significantly increased by dietary 18:0. Bile acid excretion accounted for only 12-20% of total sterol output by the hamsters in this study. Thus, the data suggest that reduced plasma cholesterol concentration in hamsters fed high 18:0 diets may be influenced by reduced cholesterol absorption and increased excretion of endogenous cholesterol.  相似文献   

3.
OBJECTIVE: Both chitosan and glucomannan have demonstrated hypocholesterolemic effects. A recent study in rats indicates that the combination of the two is also a potent hypocholesterolemic agent that increases fecal fat excretion. The objective of the present study was to determine the hypocholesterolemic effect of a supplement containing equal amounts of chitosan and glucomannan on blood lipid concentrations and fecal excretion of fat, neutral sterols and bile acids. METHODS: Twenty-one overweight normocholesterolemic subjects (11 males and 10 females) were fed 2.4 g/day of a supplement containing equal amounts of chitosan and glucomannan. Prior to taking the supplement (initial period) and after 28 days (final period), blood was drawn for measurement of serum lipids and a three-day fecal sample collected for determination of fat, neutral sterol and bile acid excretion. Subjects maintained their normal dietary and activity patterns during the study. RESULTS: Caloric intake and intake of fat and dietary fiber (excluding the supplement) did not differ between the initial and final periods. Serum total, HDL and LDL cholesterol concentrations were significantly lower (p < 0.05) in the final period compared to the initial period. Serum triacylglycerol concentration did not change between periods. There was a trend towards greater fecal excretion of neutral sterols and bile acids (p = 0.13 and 0.16, respectively) in the final period. However, fecal fat excretion did not differ between periods. CONCLUSIONS: Serum cholesterol reduction by a chitosan/glucomannan supplement is likely mediated by increased fecal steroid excretion and is not linked to fat excretion.  相似文献   

4.
5.
Epidemiologic studies and clinical trials have demonstrated that the unique fatty acid profile of nuts beneficially affects serum lipids/lipoproteins, reducing cardiovascular disease (CVD) risk. Nuts are low in SFA and high in PUFA and monounsaturated fatty acids (MUFA). Macadamia nuts are a rich source of MUFA. A randomized, crossover, controlled feeding study (5-wk diet periods) compared a Macadamia nut-rich diet [42.5 g (1.5 ounces)/8.79 MJ (2100 kcal)] [MAC; 33% total fat (7% SFA, 18% MUFA, 5% PUFA)] vs. an average American diet [AAD; 33% total fat (13% SFA, 11% MUFA, 5% PUFA)] on the lipid/lipoprotein profile of mildly hypercholesterolemic (n = 25; 15 female, 10 male) subjects. Serum concentrations of total cholesterol (TC) and LDL cholesterol (LDL-C) following the MAC (4.94 +/- 0.17 mmol/L, 3.14 +/- 0.14 mmol/L) were lower than the AAD (5.45 +/- 0.17 mmol/L, 3.44 +/- 0.14 mmol/L; P < 0.05). The serum non-HDL cholesterol (HDL-C) concentration and the ratios of TC:HDL-C and LDL-C:HDL-C were reduced following consumption of the MAC diet (3.83 +/- 0.17, 4.60 +/- 0.24, and 2.91 +/- 0.17, respectively) compared with the AAD (4.26 +/- 0.17, 4.89 +/- 0.24, and 3.09 +/- 0.18, respectively; P < 0.05). There was no change in serum triglyceride concentration. Thus, macadamia nuts can be included in a heart-healthy dietary pattern that reduces lipid/lipoprotein CVD risk factors. Nuts as an isocaloric substitute for high SFA foods increase the proportion of unsaturated fatty acids and decrease SFA, thereby lowering CVD risk.  相似文献   

6.
A group of 33 adult males was fed for 21 days a formula diet that supplied 38 per cent of their calories as fat. The fatty acid composition of the diet was 25 per cent saturates, 16 per cent polyunsaturates and 58 per cent monounsaturates. All of the unsaturated acids were in the cis configuration. The subjects were then divided into two groups. One group of 17 men continued on the same diet. In the diet of the remaining subjects, 80 per cent of the dietary fat was replaced with a hydrogenated fat. Over 60 per cent of the monounstaurated acids and approximately one-half of the polyunsaturated acids of the diet of this latter group were in the trans configuration. Except for the presence or absence of trans acids, the fatty acid intakes of the two groups were the same. Over the 4-week period that the two diets were consumed, the group receiving the hydrogenated fat showed no change in plasma cholesterol or triglyceride levels relative to the subjects consuming the unhydrogenated fat. It is concluded that the effect of a hydrogenated fat on blood lipid level is determined by its fatty acid composition and this effect is not altered by the isomeric form of the unsaturated acids.  相似文献   

7.

Objective

We tested whether diets containing partially hydrogenated fat (PHVO, rich in trans fatty acids) or palm oil (PO, rich in saturated fat—C16 palmitic fatty acid) had different effects on the propensity for venous thrombosis, a marker of haemostatic cardiovascular risk.

Methods

Female Wistar rats were fed normolipidic diets containing PHVO or PO during lactation, and their young male pups were fed the same diets from weaning until the 180th day of life. We evaluated platelet fatty acid composition, serum lipids, platelet aggregation, clotting time, and venous thrombus formation.

Results

A significant and cumulative incorporation of trans fatty acid was observed only in the platelet lipids from the PHVO group, associated with an increased sensitivity to adenosine diphosphate (ADP) and venous thrombus formation in vivo. Platelets from rats raised on the PO diet also exhibited platelet aggregation induced by ADP and an increase in venous thrombus weight, with a concomitant increase in serum triglycerides.

Conclusion

The prolonged replacement of dietary hydrogenated fat by PO impaired platelet aggregability and venous thrombosis, suggesting an increased risk of thromboembolic diseases.  相似文献   

8.
BACKGROUND: The apolipoprotein E (APOE) gene promoter polymorphism (-219G-->T) has been associated with increased risk of myocardial infarction, premature coronary artery disease, and decreased plasma apolipoprotein E concentrations. OBJECTIVE: We aimed to determine in healthy subjects whether this polymorphism modifies the susceptibility of LDL to oxidation and the lipid response to the content and quality of dietary fat. DESIGN: Fifty-five healthy men with the APOE3/E3 genotype (7 GG, 38 GT, and 10 TT) completed 3 dietary periods, each lasting 4 wk. The first was a saturated fatty acid (SFA)-rich diet [38% fat-20% SFA and 12% monounsaturated fatty acid (MUFA)-and 47% carbohydrates (CHO)], which was followed by a CHO-rich diet (30% fat-<10% SFA and 12% MUFA-and 55% CHO) or a MUFA-rich diet (38% fat-<10% SFA and 22% MUFA-and 47% CHO) in a randomized crossover design. At the end of each dietary period, LDL oxidation susceptibility, lipids, and lipoproteins were measured. RESULTS: Compared with carriers of the G allele, TT subjects had a significantly (P < 0.05) shorter lag time after the SFA diet. The replacement of the SFA diet by the CHO or MUFA diet induced a greater increase (P < 0.05) in lag time in the TT subjects than in the GG or GT subjects. Carriers of the T allele had higher LDL-cholesterol (P < 0.05) and apolipoprotein B (P < 0.05) plasma concentrations after the SFA diet than did GG subjects. Compared with GG subjects, carriers of the T allele had a significantly (P < 0.05) greater decrease in LDL cholesterol and apolipoprotein B when they changed from the SFA to the CHO diet. CONCLUSION: The -219G-->T polymorphism may partially explain differences in individual responses to diet.  相似文献   

9.
(-)-Hydroxycitric acid (HCA) is a competitive inhibitor of the enzyme ATPcitrate-lyase, which inhibits lipogenesis in the body. Moreover, HCA increases endurance exercise performance in trained mice and athletes. However, had not been investigated in untrained animals and humans. Therefore, we investigated the effects of short-term HCA ingestion on endurance exercise performance and fat metabolism in untrained women. In two experiments designed as a double-blind crossover test, six subjects ingested 250 mg of HCA or placebo (same amount of dextrin) via capsule for 5 d and then participated in cycle ergometer exercise. They cycled at 40% VO2max for 1 h and then the exercise intensity was increased to 60% VO2max until exhaustion on day 5 of each experiment. HCA tended to decrease the respiratory exchange ratio (RER) and carbohydrate oxidation during 1 h of exercise. In addition, exercise time to exhaustion was significantly enhanced (p<0.05). These results suggest that HCA increases fat metabolism, which may be associated with a decrease in glycogen utilization during the same intensity exercise and enhanced exercise performance.  相似文献   

10.
ObjectiveOur previous study indicated that partially hydrogenated fat (PHF) diets, rich in trans-isomers, alter plasma lipids and increase the lipogenesis rate on adipose tissue in rats at a young age. In the present study we investigated the effects of dietary PHF on the expression of genes associated with glucose and lipid metabolism in rat adipose tissue.MethodsFemale Wistar rats were fed normolipidic diets containing PHF (rich in trans-fatty acids and poor in polyunsaturated fatty acids [PUFAs]), soy oil (rich in ω-6 PUFAs), and fish oil (rich in ω-3 PUFAs) during gestation and lactation; young male pups were fed the same diets from weaning until 120 d of life. The mRNA expression of peroxisome proliferator-activated receptor-γ, tumor necrosis factor-α, resistin, adiponectin, and leptin were analyzed in retroperitoneal adipose tissue (RET) using real time polymerase chain reaction.ResultsThe PHF group showed the highest triacylglycerol, glucose, and insulin levels and the lowest plasma adiponectin level. The RET of PHF incorporated trans-fatty acids, whereas fish oil and soy oil groups had increased ω-3 and ω-6 PUFAs, respectively. In the RET the PHF group had the highest resistin and tumor necrosis factor-α levels and the lowest adiponectin and peroxisome proliferator-activated receptor-γ gene expressions, whereas the fish oil group had the highest peroxisome proliferator-activated receptor-γ and the lowest leptin gene expression.ConclusionProlonged intake of PHF has a negative effect on the expression of genes in RET when compared with diets with ω-6 and ω-3 PUFAs. These changes may be an effect of the smaller proportions of PUFAs in this fat, instead of being only caused by trans-fatty acids.  相似文献   

11.
The hypocholesterolemic effects of phytosterols have not been evaluated in bakery products, and the addition of liposoluble antioxidants to the carrier has never been tested. We investigated the effects of consuming croissants and magdalenas (Spanish muffins) enriched with sterol esters, alpha-tocopherol and beta-carotene on plasma lipid and fat-soluble antioxidant concentrations in normocholesterolemic, habitual consumers of bakery products following their usual diet and lifestyle. Using a randomized, double-blind, placebo-controlled design, the control (C) group (n = 29) received two pieces daily (standard croissant and muffin) and the sterol ester (SE) group (n = 28), the same products with sterol esters added (3.2 g/d) for 8 wk. Total and LDL cholesterol (LDL-C) decreased in the SE group by 0.24 mmol/L (P < 0.01) and 0.26 mmol/L (P < 0.005), respectively, whereas these variables did not change in the control group. The total difference in total and LDL-C changes between groups was 0.38 mmol/L (8.9%) and 0.36 mmol/L (14.7%), respectively (P < 0.001). Within-group changes in HDL cholesterol, triacylglycerol or lipoprotein(a) concentrations did not differ. Similarly, within-group changes over time in plasma tocopherol and carotenoid concentrations did not differ between groups. Our findings suggest that bakery products are excellent carriers for phytosterols, and their consumption is associated with a decrease in total and LDL-C concentrations, with no changes in alpha-tocopherol and beta-carotene. The ability of bakery products to include sufficient quantities of beta-carotene to compensate for a potential deficiency, and the fact that their efficacy was not associated with the time of day at which they were consumed, are interesting findings.  相似文献   

12.
Diet intervention trials are currently testing whether reduced fat intake can reduce the risk and progression of breast cancer. Energy from dietary fat is generally replaced by energy from carbohydrate in these studies, and altering the proportion of energy from dietary carbohydrate and fat has been shown to affect plasma lipid concentrations in controlled feeding studies. The purpose of this study was to examine the effect of increased carbohydrate and reduced fat intakes on plasma lipids in a randomized, controlled trial that is testing the effect of diet modification on risk for recurrence and survival in women previously treated for breast cancer. Plasma concentrations of lipids and related factors were measured at enrollment and 1-y follow-up in 393 women enrolled in the trial. Dietary goals for the intervention group focused on an increase in vegetable, fruit and fiber intakes, and reduced fat intake. Women assigned to the intervention group significantly reduced fat intake (from 28.1 to 21.0% of energy), and significantly increased intakes of carbohydrate (from 56.9 to 65.3% of energy) and fiber (from 21.0 to 29.6 g/d) (P < 0.05). Body weight did not change significantly in either study group. A small but significant increase in fasting plasma triacylglycerol concentration, and decreases in HDL cholesterol and apoprotein-A1 concentrations, were observed in the intervention group (P < 0.05) but not in the comparison group. Changes in total cholesterol, LDL cholesterol, apoprotein-B, lipoprotein (a), and insulin concentrations, and in the LDL cholesterol/HDL cholesterol ratio, were not observed in either group. The lipid responses that were observed in this study provide biological evidence that validates the self-reported change in dietary intakes of fat and carbohydrate in response to the intervention efforts. The degree of change in these lipid concentrations was small and does not suggest increased cardiovascular disease risk.  相似文献   

13.
Epidemiological studies have repeatedly found that whole-grain (WG) cereal foods reduce the risk of several lifestyle-related diseases, though consistent clinical outcomes and mechanisms are elusive. To compare the effects of a WG-rich diet with a matched refined-grain (RG) diet on plasma biomarkers and bowel health parameters, seventeen healthy subjects (eleven females and six males) completed an exploratory cross-over study with a 2-week intervention diet based on either WG- or RG-based foods, separated by a washout of at least 5 weeks. Both diets were the same except for the use of WG (150 g/d) or RG foods. Subjects undertook a 4 h postprandial challenge on day 8 of each intervention diet. After 2 weeks, the WG diet tended to decrease plasma total and LDL-cholesterol (both P = 0·09), but did not change plasma HDL-cholesterol, fasting glucose, C-reactive protein or homocysteine compared with the RG diet. Plasma betaine and alkylresorcinol concentrations were elevated after 1 week of the WG diet (P = 0·01 and P < 0·0001, respectively). Clostridium leptum populations in faeces were increased after the WG diet, along with a trend for decreased faecal water pH (P = 0·096) and increased stool frequency (P < 0·0001) compared with the RG diet. A short controlled intervention trial with a variety of commercially available WG-based products tended to improve biomarkers of CVD compared with a RG diet. Changes in faecal microbiota related to increased fibre fermentation and increased plasma betaine concentrations point to both fibre and phytochemical components of WG being important in mediating any potential health effects.  相似文献   

14.
Very low carbohydrate diets are popular, yet little is known about their effects on blood lipids and other cardiovascular disease risk factors. We reported previously that a very low carbohydrate diet favorably affected fasting and postprandial triacylglycerols, LDL subclasses and HDL cholesterol (HDL-C) in men but the effects in women are unclear. We compared the effects of a very low carbohydrate and a low fat diet on fasting lipids, postprandial lipemia and markers of inflammation in women. We conducted a balanced, randomized, two-period, crossover study in 10 healthy normolipidemic women who consumed both a low fat (<30% fat) and a very low carbohydrate (<10% carbohydrate) diet for 4 wk each. Two blood draws were performed on separate days at 0, 2 and 4 wk and an oral fat tolerance test was performed at baseline and after each diet period. Compared with the low fat diet, the very low carbohydrate diet increased (P 相似文献   

15.
A 6-month crossover diet plan was employed to study the effects on human serum lipids of adding margarine or butter to otherwise self-selected diets that included two eggs daily. Two groups of subjects were studied: 51 free-living normocholesterolemic and 20 hypercholesterolemic (greater than 240 mg dl). Four-day diet records in each interval showed that subjects ate about 16% of total dietary fat as either butter or margarine. Blood samples taken every 6 weeks showed variable mean serum total cholesterol (SCHOL), high-density-lipoprotein cholesterol (HDL-C), and serum triglycerides (STG). The normocholesterolemic subjects who ate butter first had by 24 weeks mean SCHOL values equal to their entry values; those who ate margarine first had increased SCHOL values throughout the study. By the end of the study, the hypercholesterolemic subjects showed either no change or a slight decrease in both SCHOL and HDL-C values. Specific fatty acids were distributed differently in the serum fractions of triacylglycerol (TGFA), cholesteryl esters (CEFA), and phospholipids (PLFA). These distributions remained constant in both normocholesterolemic and hypercholesterolemic subjects regardless of the type and amount of fat consumed.  相似文献   

16.
17.
ObjectiveThe aim of this study was to evaluate glucose uptake and the contribution of glucose to fatty acid (FA) synthesis and the glycerol-3-phosphate (G3P) of triacylglycerol synthesis by interscapular brown adipose tissue (IBAT) of low-protein, high-carbohydrate (LPHC) diet-fed rats.MethodsLPHC (6% protein; 74% carbohydrate) or control (17% protein; 63% carbohydrate) diets were administered to rats (∼100 g) for 15 d. Total FA and G3P synthesis and the synthesis of FA and G3P from glucose were evaluated in vivo by 3H2O and 14C-glucose. Sympathetic neural contribution for FA synthesis was evaluated by comparing the synthesis in denervated (7 d before) IBAT with that of the contralateral innervated side. The insulin signaling and β3 adrenergic receptor (β3-AR) contents, as well as others, were determined by Western blot (Student's t test or analysis of variance; P ≤ 0.05).ResultsTotal FA synthesis in IBAT was 133% higher in the LPHC group and was reduced 85% and 70% by denervation for the LPHC and control groups, respectively. Glucose uptake was 3.5-fold higher in the IBAT of LPHC rats than in that of the control rats, and the contribution of glucose to the total FA synthesis increased by 12% in control rats compared with 18% in LPHC rats. The LPHC diet increased the G3P generation from glucose by 270% and the insulin receptor content and the p-AKT insulin stimulation in IBAT by 120% and reduced the β3-AR content by 50%.ConclusionsThe LPHC diet stimulated glucose uptake, both the total rates and the rates derived from glucose-dependent FA and G3P synthesis, by increasing the insulin sensitivity and the sympathetic flux, despite a reduction in the β3-AR content.  相似文献   

18.
The effects of dietary sulfur-containing amino acids and glycine on plasma cholesterol level were studied in rats fed amino acid mixture diets containing cholesterol. The relationship between the amino acid composition of dietary proteins and plasma cholesterol levels was also investigated in rats fed diets containing various kinds of protein such as casein, egg albumin, pork protein, fish protein, corn gluten, wheat gluten and soy protein. Feeding the amino acid mixture corresponding to casein led to an approximately two-fold level of plasma total cholesterol as compared with feeding the amino acid mixture corresponding to wheat gluten. It was possible to reduce the plasma cholesterol of rats fed the amino acid mixture of the casein type by increasing the proportion of cystine in the total sulfur amino acids. Inversely, the deprivation of cystine resulted in an enhancement of the plasma cholesterol of rats fed the gluten type amino acid mixture. Glycine had a tendency to resist increases in the plasma cholesterol level. A significant negative correlation was noted between plasma cholesterol levels and the content of cystine in intact dietary proteins. The results suggest that the differential effect of dietary proteins on plasma cholesterol level is mainly associated with sulfur-containing amino acids included in the protein, regardless of whether it is of animal or plant origin.  相似文献   

19.
20.
Our purpose was to determine the effects of a pulse-based diet in individuals 50 years or older for reducing CVD risk factors. A total of 108 participants were randomised to receive pulse-based foods (two servings daily of beans, chickpeas, peas or lentils; about 150?g/d dry weight) or their regular diet for 2 months, followed by a washout of 1 month and a cross-over to the other diet for 2 months. Anthropometric measures, body composition and biochemical markers (i.e. serum LDL-cholesterol (LDL-C), as the primary outcome, and other lipids, glucose, insulin and C-reactive protein) were assessed before and after each diet phase. A total of eighty-seven participants (thirty males and fifty-seven females; 59·7 (sd 6·3) years, body mass 76 (sd 16) kg) completed the study. Compared with the regular diet, the pulse-based diet decreased total cholesterol by 8·3?% (pulse, 4·57 (sd 0·93) to 4·11 (sd 0·91) mmol/l; regular, 4·47 (sd 0·94) to 4·39 (sd 0·97) mmol/l; P?相似文献   

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