High-fat ketogenic diets are used to treat intractable seizures in children, but little is known of the mechanism by which
these diets work or whether fats rich in n−3 polyunsaturates might be beneficial. Tissue lipid and fatty acid profiles were
determined in rats consuming very high fat (80 weight%), low-carbohydrate ketogenic diets containing either medium-chain triglyceride,
flaxseed oil, butter, or an equal combination of these three fat sources. Ketogenic diets containing butter markedly raised
liver triglyceride but had no effect on plasma cholesterol. Unlike the other fats, flaxseed oil in the ketogenic diet did
not raise brain cholesterol. Brain total and free fatty acid profiles remained similar in all groups, but there was an increase
in the proportion of arachidonate in brain total lipids in the medium-chain triglyceride group, while the two groups consuming
flaxseed oil had significantly lower arachidonate in brain, liver, and plasma. The very high dietary intake of α-linolenate
in the flaxseed group did not change docosahexaenoate levels in the brain. Our previous report based on these diets showed
that although ketosis is higher in rats consuming a ketogenic diet based on medium-chain triglyceride oil, seizure resistance
in the pentylenetetrazol model is not clearly related to the degree of ketosis achieved. In combination with our present data
from the same seizure study, it appears that ketogenic diets with widely differing effects on tissue lipids and fatty acid
profiles can confer a similar amount of seizure protection. 相似文献
The first law of thermodynamics dictates that body mass remains constant when caloric intake equals caloric expenditure. It
should be noted, however, that different diets lead to different biochemical pathways that are not equivalent when correctly
compared through the laws of thermodynamics. It is inappropriate to assume that the only thing that counts in terms of food
consumption and energy balance is the intake of dietary calories and weight storage. Well-controlled studies suggest that
calorie content may not be as predictive of fat loss as is reduced carbohydrate consumption. Biologically speaking, a calorie
is certainly not a calorie. The ideal weight loss diet, if it even exists, remains to be determined, but a high-carbohydrate/low-protein
diet may be unsatisfactory for many obese individuals. 相似文献
Dietary supplementation with marine omega‐3 polyunsaturated fatty acids (n‐3 PUFA) can have beneficial effects on a number of risk factors for cardiovascular disease (CVD). We compared the effects of two n‐3 PUFA rich food supplements (freeze‐dried Odontella aurita and fish oil) on risk factors for CVD. Male rats were randomly divided into four groups of six animals each and fed with the following diets: control group (C) received a standard diet containing 7 % lipids; second group (HF high fat) was fed with a high‐fat diet containing 40 % lipids; third group (HFFO high fat+fish oil) was fed with the high‐fat diet supplemented with 0.5 % fish oil; and fourth group (HFOA high fat+O. aurita) received the high‐fat diet supplemented with 12 % of freeze‐dried O. aurita. After 8 weeks rats fed with the high‐fat diet supplemented with O. aurita displayed a significantly lower bodyweight than those in the other groups. Both the microalga and the fish oil significantly reduced insulinemia and serum lipid levels. O. aurita was more effective than the fish oil in reducing hepatic triacyglycerol levels and in preventing high‐fat diet‐induced steatosis. O. aurita and fish oil also reduced platelet aggregation and oxidative status induced by high fat intake. After an OA supplementation, the adipocytes in the HFOA group were smaller than those in the HF group. Freeze‐dried O. aurita showed similar or even greater biological effects than the fish oil. This could be explained by a potential effect of the n‐3 PUFA but also other bioactive compounds of the microalgae. 相似文献
Gut microbiota is well known as playing a critical role in inflammation and asthma development. The very low-calorie ketogenic diet (VLCKD) is suggested to affect gut microbiota; however, the effects of VLCKD during pregnancy and lactation on the infant gut microbiota are unclear. The VLCKD appears to be more effective than caloric/energy restriction diets for the treatment of several diseases, such as obesity and diabetes. However, whether adherence to VLCKD affects the infant gut microbiota and the protective effects thereof on asthma remains uncertain. The exact mechanisms underlying this process, and in particular the potential role of short chain fatty acids (SCFAs), are still to be unravelled. Thus, the aim of this review is to identify the potential role of SCFAs that underlie the effects of VLCKD during pregnancy and lactation on the infant gut microbiota, and explore whether it incurs significant implications for reducing asthma. 相似文献
Cardiovascular disease (CVD) and insulin resistance are directly linked to overweight and obesity. Thus, any dietary strategy capable of causing weight reduction will lower CVD and diabetes risk. Oils rich in medium‐chain saturated fatty acids (MCFA) are among several dietary components that may have potential in the treatment of obesity. MCFA are less energy dense and highly ketogenic compared to long‐chain saturated and unsaturated fatty acids (LCFA). MCFA also differ from LCFA in their digestive and metabolic pathways, since they are easily oxidized and utilized as energy, with little tendency to deposit as body fat. The dietary intake of short (SCFA) and medium‐chain saturated fatty acids from natural food sources is approximately 2.4 g/day and accounts for about 9% of the total saturated fatty acid (SFA) intake. Although early clinical studies with high levels of MCFA resulted in increased levels of plasma triacylglycerols (TAG) and low‐density lipoprotein cholesterol (LDL‐C), and reduced levels of high‐density lipoprotein cholesterol (HDL‐C) compared to diets enriched in unsaturated LCFA, these adverse effects have not been observed in more recent studies with smaller more realistic amounts of MCFA. The lower caloric value of SCFA and MCFA and their unique metabolic features form the basis for their clinical use in enteral and parenteral nutrition and for novel reduced calorie lipids for use in conventional food products. 相似文献
The experiments reported are part of our effort to dissociate the tumor-enhancing effects of dietary fat and high caloric
intake. Rats either were fed ad libitum diets containing 4% corn oil or their calories were restricted by 40% and their diets
contained 13.1% corn oil. Incidence of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors was 80% in rats fed ad
libitum and 20% in those fed the calorie-restricted diets. Incidence of 1,2-dimethylhydrazine (DMH)-induced colon tumors was
100% in rats fed ad libitum and 53% in those whose caloric intake was restricted by 40%. The tumor yield (tumors per tumor-bearing
rat) was significantly lower in rats on caloric restriction. In another series, rats were fed diets containing 5, 15 or 20%
corn oil ad libitum or were fed calorie-restricted (by 25%) diets which provided 20 or 26.6% corn oil (therefore, the same
absolute amount of fat was consumed in each of the pair-fed groups). Tumor incidence and tumor yield in the two calorie-restricted
groups were similar to those seen in the rats fed 5% fat ad lititum; tumor burden (total g of tumor) was 45–65% lower in the
calorie-restricted rats. The data suggest that caloric intake is a more stringent determinant of tumor growth than fat intake. 相似文献
The impact of a moderate Zn deficiency on growth and plasma and liver lipids was investigated in two 4-week experiments with
male weanling rats fed fat-enriched diets. Semisynthetic, approximately isocaloric diets containing 3% soybean oil were supplemented
with either 7 or 100 mg Zn/kg diet and with 22% beef tallow (BT) or sunflower oil (SF). In Experiment 1, which compared the
dietary fat level and the fat source in a factorial design of treatments, all diets were fed ad libitum to 6 × 8 animals,
whereas intake of the high-Zn BT and SF diets was restricted in Experiment 2 (5 × 6 rats) to the level of intake of the respective
low-Zn diets. The low-Zn SF diet consistently depressed food intake and final live weights of the animals to a greater extent
than the other low-Zn diets, while intake and growth were comparable among the animals fed the high-Zn diets. The marginal
Zn deficit per se did not alter plasma triglyceride and cholesterol concentrations nor hepatic concentrations of triglyceride,
cholesterol and phospholipids. The fatty acid pattern of liver phospholipids did not indicate that chain elongation and desaturation
of fatty acids was impaired by a lack of zinc. It was concluded that dietary energy and fat intake, and fat source have a
greater effect on plasma and liver lipids than a moderate Zn deficiency. Marginally Zn-deficient diets enriched with sunflower
oil as a major energy source cause a greater growth retardation than diets rich in carbohydrates or beef tallow. 相似文献
Four diets which differed in fatty acid composition were provided for five months each to a group of 24 healthy nun volunteers.
The diets contained 54% carbohydrates, 16% proteins and 30% lipids. One-third of the lipid part remained unchanged during
the whole study, and two-thirds were modified during each period. For this latter portion, one of the following dietary fats
was used: sunflower oil, peanut oil, low erucic acid rapeseed (LEAR) oil or milk fats. This procedure allowed an evaluation
of the effects of various amounts of dietary linoleic acid (C18∶2ω6) and alpha-linolenic acid (C18∶3ω3) on the serum level
of their metabolites. A diet providing a large amount of linoleic acid (14% of the total caloric intake) resulted in low levels
of dihomo-gamma-linolenic acid (C20∶3ω6) and arachidonic acid (C20∶4ω6) in serum phospholipids and cholesteryl esters. A diet
providing a small amount of linoleic acid (0.6% to 1.3% of the total caloric intake) induced high levels of ω6 fatty acid
derivatives. Intermediate serum levels of C20∶3ω6 and C20∶4ω6 were found with a linoleic acid supply of about 6.5% of the
total caloric intake. Serum levels of ω6 metabolites were not different after two diets providing a similar supply of C18∶2ω6
(4.5% to 6.5% of the total caloric intake), although in one of them the supply of C18∶3ω3 was higher (1.5% for LEAR oil versus
0.13% for peanut oil).
Under our experimental conditions (healthy human adults fed on a normo-caloric diet with 30% lipids), we tried to determine
PUFA (linoleic and linolenic acid) allowances which should be recommended for adults. The aim of the study was to obtain a
hypocholesterolemic or normocholesterolemic effect while keeping normal 20∶3ω6 and 20∶4ω6 serum levels which would evidence
a normal linoleic acid metabolism. The amounts recommended are: linoleic acid 5 to 6% of the total calories; alpha-linolenic
acid 0.5 to 1% of the total calories. 相似文献
This study aims at investigating whether the intake of butter blends containing diacylglycerol (DAG) oil may result in reduced fat accumulation, in similarity to DAG oil, and the potential metabolic differences between butter blends and DAG oil. Four experimental diets containing either 10 wt% DAG butter blend (BDAG), triacylglycerol (TAG) butter blend (BTAG), DAG oil (ODAG) or TAG oil (OTAG) were prepared, and each was fed to a group of 8 male Wistar rats. The design of the experiment was a combined balance and feeding experiment. The rats fed the BTAG and ODAG‐diets had a significantly higher protein content than rats fed the BDAG and OTAG‐diets, and the fat content was significantly lower in rats fed the ODAG‐diet as compared to rats fed the OTAG and BDAG‐diets. A significantly higher content of ash was observed in rats fed the two TAG diets. The ratio of abdominal fat weight/body weight was significantly higher for rats fed the BDAG‐diet than for rats fed the BTAG and ODAG‐diets. To conclude, the beneficial effects of DAG oil in reducing body fat accumulation cannot be observed in DAG oil containing butter blends, and the effect of DAG on bone health requires further investigation. 相似文献
The objective of this study was to evaluate the beneficial effect of α‐linolenic acid‐rich black raspberry seed (BRS) oil on lipid metabolism in high‐fat diet (HFD)‐induced obese and db/db mice. Five‐week‐old C57BL/6 mice were fed diets consisting of 50% calories from lard, 5% from soybean, and 5% from corn oil (HFD), or 50% calories from lard and 10% from BRS oil (HFD + BRS oil diet) for 12 weeks. Six‐week‐old C57BL/KsJ‐db/db mice were fed diets consisting of 16% calories from soybean oil (standard diet), 8% from soybean, and 8% from BRS oil, or 16% from BRS oil for 10 weeks. The BRS oil diets lowered the levels of triacylglycerol, nonesterified fatty acids, and total cholesterol in serum and liver of both of the obese and db/db mice as compared with the HFD and standard diet, respectively. mRNA levels of lipogenesis markers including cluster of differentiation 36, fatty‐acid‐binding protein 1, sterol regulatory element binding protein 1c, fatty‐acid synthase, and solute carrier family 25 member 1 in the liver of the BRS oil groups were lower than those in the liver of the HFD and standard groups in the obese and db/db mice, respectively. On the other hand, fatty‐acid oxidation markers including carnitine palmitoyltransferase 1A, acyl‐CoA dehydrogenase, hydroxylacyl‐CoA dehydrogenase α, and acyl‐CoA oxidase in the liver of the BRS oil groups were higher than those in the liver of the HFD and standard groups in the obese and db/db mice, respectively. Peroxisome proliferator‐activated receptor α mRNA and protein levels increased in the liver and epididymal adipose tissue of the obese and db/db mice fed BRS oil compared with HFD and standard diet, respectively. BRS oil might improve lipid metabolism by inhibiting lipogenesis and promoting fatty‐acid oxidation in HFD‐induced obese and db/db mice. 相似文献
Given the popularity of ketogenic diets, their potential long-term consequences deserve to be more carefully monitored. Mitochondrially derived formate has a critical role in mammalian one-carbon (1C) metabolism and development. The glycine cleavage system (GCS) accounts for another substantial source for mitochondrially derived 1C units. Objective: We investigated how the ketogenic state modulates mitochondrial formate generation and partitioning of 1C metabolic fluxes. Design: HepG2 cells treated with physiological doses (1 mM and 10 mM) of β-hydroxybutyrate (βHB) were utilized as the in vitro ketogenic model. Eight-week male C57BL/6JNarl mice received either a medium-chain fatty-acid-enriched ketogenic diet (MCT-KD) or a control diet AIN 93M for 8 weeks. Stable isotopic labeling experiments were conducted. Results and Conclusions: MCT-KD is effective in weight and fat loss. Deoxythymidine (dTMP) synthesis from the mitochondrial GCS-derived formate was significantly suppressed by βHB and consumption of MCT-KD. Consistently, plasma formate concentrations, as well as the metabolic fluxes from serine and glycine, were suppressed by MCT-KD. MCT-KD also decreased the fractional contribution of mitochondrially derived formate in methionine synthesis from serine. With the worldwide application, people and medical professionals should be more aware of the potential metabolic perturbations when practicing a long-term ketogenic diet. 相似文献
Recently, the pro‐inflammatory effects of linoleic acid (LNA) have been re‐examined. It is now becoming clear that relatively few studies have adequately assessed the effects of LNA, independent of obesity. The purpose of this work was to compare the effects of several fat‐enriched but non‐obesigenic diets on inflammation to provide a more accurate assessment of LNA's ability to induce inflammation. Specifically, 8‐week‐old male C57Bl/6 mice were fed either saturated (SFA), monounsaturated (MUFA), LNA, or alpha‐linolenic acid enriched diets (50 % Kcal from fat, 22 % wt/wt) for 4 weeks. Chow and high‐fat, hyper‐caloric diets were used as negative and positive controls, respectively. Expression of pro‐inflammatory and pro‐coagulant markers from epididymal fat, liver, and plasma were measured along with food intake and body weights. Mice fed the high SFA, MUFA, and high‐fat diets exhibited increased pro‐inflammatory markers in liver and adipose tissue; however, mice fed LNA for four weeks did not display significant changes in pro‐inflammatory or pro‐coagulant markers in epididymal fat, liver, or plasma. The present study demonstrates that LNA alone is insufficient to induce inflammation. Instead, it is more likely that hyper‐caloric diets are responsible for diet‐induced inflammation possibly due to adipose tissue remodeling. 相似文献
Several biochemical parameters of male Wistar rats fed during 15 weeks with standard laboratory chow, supplemented with 0.1 g of brominated vegetable oil (olive, sunflower) per 100 g of diet, were compared to those of a control group fed a normal diet during the same period of time. The former group showed a significant increase of triglyceride content in both heart and soleus muscle, as well as of total and sterified cholesterol in heart muscle. This increase was accompanied by decreased plasma levels of total and HDL-cholesterol. Some of these abnormalities were similar to those observed in rats fed the same standard laboratory chow, supplemented with 0.5 g of brominated oil per 100 g of diet. The hepatic levels of triglycerides, total proteins and glycogen, as well as the weight gain and caloric intake of the animals which were fed 0.1 g of brominated oil per 100 g diet, were similar to those of the control group. In summary, the toxicologic effects observed during the chronic intake of diets supplemented with relatively low doses of brominated oils, suggest the need to undertake wider and deeper biochemical studies. The authors consider that these are necessary in order to ascertain the maximum tolerance levels for the use of these compounds, to minimize the risk of inducing important biological alterations. 相似文献
Summary: UV curable acrylate formulations with a high content of fumed, nano‐sized silica were prepared to improve their application for abrasion and scratch resistant top coats. Grafting of trialkoxysilanes onto the surface of nanoparticles facilitated their embedding in the formulation and alleviated the effect of undesired increase in viscosity and dilatancy. Modified nanoparticles were obtained from several organosilanes and characterized by a multitechnique approach. To avoid problems during redispersion, in situ modification of nano‐sized silica was performed using the liquid acrylate formulation as a diluting and deagglomerating agent. These nanocomposite materials exhibit markedly improved properties as compared to neat acrylate coatings, e.g. heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nanoparticles and corundum microparticles. By using various grades of corundum, a synergetic effect of nano/micro hybrid composite materials has been studied for parquet and flooring applications.
Pictures of neat polyacrylate coating (on the left) and nano/micro hybrid composite material (18 wt.‐% silica +15 wt.‐% corundum) on parquet substrate after Taber Abraser Test. 相似文献
Plate-out is the undesired deposition of materials from a compound onto the surface of processing equipment. Plate-out causes problems with quality control and down-time. Changes in processing conditions can help alleviate plate-out, but adjustments in the formulation are usually needed for significant improvements in plate-out, the deposition. The addition of precipitated silica to a PVC formulation is a simple and effective method to reduce plate-out. This study explores the relationship between plate-out reduction and the physical properties of precipitated silica. Silica properties such as surface area, average particle size, and oil absorption can all be controlled by a patented process developed by the Chemicals Division of J. M. Huber Corporation. Plate-out reduction is related to the properties of precipitated silica, the loading of the silica, the order of addition, and type of PVC formulation. The effect of precipitated silica on the physical properties of the PVC compound, such as, tensile strength, tear strength, elongation and stiffness, are explored. Finally, the effectiveness of plate-out reduction by precipitated silica as compared to fumed silica will be discussed. 相似文献