Interaction between alpha-linolenic acid-enriched oil and ACE inhibitor concerning the decrease in blood pressure in SHR

Alpha-linolenic acid (ALA) has been reported to exhibit an antihypertensive effect. Angiotensin-converting enzyme inhibitor (ACEI) is also an antihypertensive agent. We evaluated the interaction between ALA-enriched oil (test oil) and ACEI concerning the decrease in blood pressure by administering test oil, ACEI, or test oil + ACEI to 7-week-old spontaneously hypertensive rats (SHR). After administration, the systolic pressure decreased significantly in all groups compared with the level before administration, but the diastolic pressure decreased significantly only in the test oil + ACEI group. No significant difference was noted in systolic or diastolic pressure among the 3 groups. These results suggest that the interaction between ALA-enriched oil and ACEI is limited. Our study suggested the safety of consuming foods containing a large amount of ALA in combination with hypotensive agents.     

Lowering systolic blood pressure and increases in vasodilator levels in SHR with oral alpha-linolenic acid administration

The present study attempted to clarify the antihypertensive effect and its mechanism when alpha-linolenic acid (ALA) is administered orally. For this purpose, 1 mL of flaxseed oil, which is rich in ALA, and high oleic safflower oil was administered orally to spontaneously hypertensive rats (SHR) of a control and an ALA group on days 1 and 5. Systolic blood pressure was measured on day 1, and blood and liver were collected on day 5. Four hours after the oral administration on day 1, systolic blood pressure of the ALA group was lower than that of the control group. Levels of plasma vasodilators, such as prostaglandin I(2) metabolite, nitric oxide metabolites, and bradykinin, in the ALA group were significantly higher than those in the control group, but levels of vasoconstrictors, such as angiotensin II and thromboxane A(2) metabolite, did not differ significantly. It is known that bradykinin induces prostaglandin I(2) and nitric oxide. The present study shows that ALA reduced the systolic blood pressure of SHR, and its mechanism may be related to increases of prostaglandin I(2) and nitric oxide through bradykinin stimulation.     

Dietary High‐Oleic Acid Soybean Oil Dose Dependently Attenuates Egg Yolk Content of n‐3 Polyunsaturated Fatty Acids in Laying Hens Fed Supplemental Flaxseed Oil

Chickens can hepatically synthesize eicosapentaenoic acid (20:5 n‐3) and docosahexaenoic acid (22:6 n‐3) from α‐linolenic acid (ALA; 18:3 n‐3); however, the process is inefficient and competitively inhibited by dietary linoleic acid (LNA; 18:2 n‐6). In the present study, the influence of dietary high‐oleic acid (OLA; 18:1 n‐9) soybean oil (HOSO) on egg and tissue deposition of ALA and n‐3 polyunsaturated fatty acids (PUFA) synthesized from dietary ALA was investigated in laying hens fed a reduced‐LNA base diet supplemented with high‐ALA flaxseed oil (FLAX). We hypothesized that reducing the dietary level of LNA would promote greater hepatic conversion of ALA to very long‐chain (VLC; >20C) n‐3 PUFA, while supplemental dietary HOSO would simultaneously further enrich eggs with OLA without influencing egg n‐3 PUFA contents. Nine 51‐week‐old hens each were fed 0, 10, 20, or 40 g HOSO/kg diet for 12 weeks. Within each group, supplemental dietary FLAX was increased every 3 weeks from 0 to 10 to 20 to 40 g/kg diet. Compared to controls, dietary FLAX maximally enriched the total n‐3 and VLC n‐3 PUFA contents in egg yolk by 9.4‐fold and 2.2‐fold, respectively, while feeding hens 40 g HOSO/kg diet maximally attenuated the yolk deposition of ALA, VLC n‐3 PUFA, and total n‐3 PUFA by 37, 15, and 32%, respectively. These results suggest that dietary OLA is not neutral with regard to the overall process by which dietary ALA is absorbed, metabolized, and deposited into egg yolk, either intact or in the form of longer‐chain/more unsaturated n‐3 PUFA derivatives.     

High dose flaxseed oil supplementation may affect fasting blood serum glucose management in human type 2 diabetics

Type 2 diabetes is characterized partially by elevated fasting blood serum glucose and insulin concentrations and the percentage of hemoglobin as HbA1c. It was hypothesized that each of blood glucose and its co-factors insulin and HbA1c and would show a more favorable profile as the result of flaxseed oil supplementation. Patients were recruited at random from a population pool responding to a recruitment advertisement in the local newspaper and 2 area physicians. Completing the trial were 10 flaxseed oil males, 8 flaxseed oil females, 8 safflower (placebo) oil males and 6 safflower oil females. Patients visited on two pre-treatment occasions each three months apart (visits 1 and 2). At visit 2 subjects were randomly assigned in double blind fashion and in equal gender numbers to take flaxseed oil or safflower oil for three further months until visit 3. Oil consumption in both groups was approximately 10 g/d. ALA intake in the intervention group was approximately 5.5 g/d. Power was 0.80 to see a difference of 1 mmol of glucose /L using 12 subjects per group with a p < 0.05. Flaxseed oil had no impact on fasting blood serum glucose, insulin or HbA1c levels. It is concluded that high doses of flaxseed oil have no effect on glycemic control in type 2 diabetics.     

Camelina sativa Oil,Fatty Fish,and Lean Fish Do Not Markedly Affect Urinary Prostanoids in Subjects with Impaired Glucose Metabolism

Dietary fatty acids are suggested to affect oxidative stress; however, results from interventions have been inconclusive. The aim was to examine if fatty fish, lean fish, and Camelina sativa oil (CSO) affect the urinary prostanoid levels in subjects with impaired glucose metabolism. Altogether 79 participants aged 43–72 years completed a randomized controlled study lasting 12 weeks. There were four parallel groups, fatty fish, lean fish (four fish meals/week in both), CSO providing 10 g/day alpha-linolenic acid (ALA), and control diet with limited fish and ALA containing oil consumption. Urinary prostanoids (prostaglandin F_2α, 5-F_2t-isoprostanes and 15-F_2t-isoprostane metabolites, isofuran, 8-F_3t-isoprostanes, and 4 - (RS)-4-F_4t-neuroprostane) of 72 participants (age: mean (±SD) 58.9 ± 6.5 years; body mass index: 29.3 ± 2.5 kg/m²) collected over 12-h were measured using liquid chromatography tandem-mass spectrometry. Plasma phospholipid fatty acids were determined using gas chromatography. Our study showed that the proportion of ALA in plasma phospholipids increased in the CSO group (overall difference among the groups p-value <0.001). In the fatty fish group, proportions of eicosapentaenoic and docosahexaenoic acids increased (overall p-value <0.001 for both). Prostaglandin F_2α was higher in the CSO group than in the control group (p < 0.05), however, there were no other significant changes in urinary excretion of other prostanoids among the study groups. At baseline, arachidonic acid in plasma phospholipids was positively (r = 0.247, p < 0.05) and ALA negatively (r = −0.326, p < 0.05) associated with urinary total isoprostanes. In conclusion, CSO, fatty fish, and lean fish consumption do not cause major changes in oxidative stress markers in subjects with impaired glucose tolerance.     

Rapid Absorption of Dietary 1,8-Cineole Results in Critical Blood Concentration of Cineole and Immediate Cessation of Eating in the Common Brushtail Possum (<Emphasis Type="Italic">Trichosurus vulpecula</Emphasis>)

The blood concentration of 1,8-cineole and its metabolites was measured in six male brushtail possums while they voluntarily fed on diets laced with varying concentrations of cineole for 3 d. On the third day, blood samples were collected during and after each bout of feeding for 3 hr. Blood cineole was measured by using headspace solid-phase microextraction (SPME), while cineole metabolites were measured by liquid–liquid extraction followed by gas chromatography-mass spectroscopy. Feeding patterns were measured by continual recording of residual food weight and time. Cineole absorption was rapid, resulting in a peak blood concentration at the end of each feeding bout. The blood concentration of cineole did not exceed a critical value (51.8 ± 14.1 μmol/l) regardless of the concentration in the diet. Food and, therefore, cineole intake was regulated. The amount of food ingested in the first feeding bout decreased from 236 ± 52 g on the control diet to 36 ± 20 g on the 4% cineole diet. The amount of cineole ingested in the first bout (1.18 ± 1.10 g) was the same regardless of the dietary concentration and was controlled by the size of the meal. Total food eaten during the 7-hr feeding session decreased by 64% from 368 ± 94 g (control diet) to 131 ± 52 g (4% diet). Total cineole intake increased from 2.47 ± 0.60 g (1% diet) to 5.05 ± 2.41 g (4% diet). Cineole metabolites accumulated throughout the sampling period and were generally still rising at the end of blood sampling period. Blood levels of metabolites were at least 10-fold higher than cineole levels. The immediate control of feeding seems to be regulated by blood levels of cineole, whereas metabolites are likely to be more important in regulating the chronic ingestion of cineole.     

Einfluß von Lebertrangaben auf die Funktion der Lebermitochondrien in Langzeitfütterungsstudien an Ratten

Influence of n-3 Fatty Acids on Mitochondrial Function and Stability of Erythrocyte Membrane of Rats in Long Term Experiments with Cod Liver Oil The influence of different amounts of polyunsaturated fatty acids (PUFA) (1.3, 2.6 and 6.3% of total energy intake) on mitochondrial respiration and the stability of erythrocyte membrane was tested in experiments with rats lasting 12 and 32 weeks. The fat component of the semisynthetic diets (6g/100 g diet) was made up of coconut fat and cod liver oil (Gr. I, II, III) and cod liver oil and linoleic methylester (G1. IV). The n-3 fatty acids amounted to 1.18 cal% (I), 2.35 cal% (II,III) and 2.1cal% (IV). The diets of the groups I, III and IV wre supplemented with 6 mg D-α-tocopherylequivalents per 100g; the tocopherol/PUFA-ratios (mg/g) in the diets I, II, III, IV were 10.7, 0.1, 5.4 and 2.3 respectively. After 12 weeks cod liver oil had no significant influence on total lipids of the liver, hemolysis rate of red blood cells as well as the respiration of liver mitochondria. Highest weight gained was reported for the animals of group I receiving 1.3 cal% of PUFA derived from cod liver oil. All groups had similar relative liver weights. After 32 weeks the consequences of the insufficient supply tocopherol in group II were a significantly increased hemolysis rate of the erythrocytes and a decreased respiratory control index as well as the ADP/O-ratios of liver mitochondria using succinate and malate/glutamate as substrates. The highest PUFA amount fed (6.3 cal%; derived from cod liver oil and linoleic methylester) with the adequate vit. E supplementation did not cause any major alterations. The results show that fatty acids of the α-linolenic acid group can replace in part the n-6 fatty acid in their essential role for integrity of the membranes of mitochondria and erythrocytes. This is possible only if the increased antioxidant requirement of the body caused by ingestion of fish oil PUFA's is adequately compensated through additional supplements with antioxidants like α-tocopherol.     

Effects of acidic polysaccharides from gastrodia rhizome on systolic blood pressure and serum lipid concentrations in spontaneously hypertensive rats fed a high-fat diet

The effects of acidic polysaccharides purified from Gastrodia rhizome on blood pressure and serum lipid levels in spontaneously hypertensive rats (SHR) fed a high-fat diet were investigated. Acidic polysaccharides were purified from crude polysaccharides by DEAE-Sepharose CL-6B. Thirty-six male SHR were randomly divided into three groups: Gastrodia rhizome crude polysaccharide (A), acidic polysaccharide (B) groups, and a control group (C). A 5-week oral administration of all treatment groups was performed daily in 3- to 8-week-old SHRs with a dose of 6 mg/kg of body weight/day. After 5 weeks of treatment, total cholesterol in the acidic polysaccharide group, at 69.7 ± 10.6 mg/dL, was lower than in the crude polysaccharide group (75.0 ± 6.0 mg/dL) and the control group (89.2 ± 7.4 mg/dL). In addition, triglyceride and low-density lipoprotein cholesterol levels in the acidic polysaccharide group were lower than in the crude polysaccharide and control groups. The atherogenic index of the acidic polysaccharide group was 46.3% lower than in the control group. Initial blood pressure after the initial three weeks on the high-fat diet averaged 195.9 ± 3.3 mmHg among all rats. Compared with the initial blood pressure, the final blood pressure in the control group was increased by 22.8 mmHg, whereas it decreased in the acidic polysaccharide group by 14.9 mmHg. These results indicate that acidic polysaccharides from Gastrodia rhizome reduce hypertension and improve serum lipid levels.     

Stearidonic Acid-Enriched Soybean Oil Increased the Omega-3 Index, an Emerging Cardiovascular Risk Marker

A plant source of omega-3 fatty acid (FA) that can raise tissue eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) is needed. A soybean oil (SBO) containing approximately 20% stearidonic acid [SDA; the delta-6 desaturase product of alpha-linolenic acid (ALA)] derived from genetically modified soybeans is under development. This study compared the effects of EPA to SDA-SBO on erythrocyte EPA+DHA levels (the omega-3 index). Overweight healthy volunteers (n=45) were randomized to SDA-SBO (24 ml/day providing approximately 3.7 g SDA) or to regular SBO (control group) without or with EPA ethyl esters (approximately 1 g/day) for 16 weeks. Serum lipids, blood pressure, heart rate, platelet function and safety laboratory tests were measured along with the omega-3 index. A per-protocol analysis was conducted on 33 subjects (11 per group). Compared to baseline, average omega-3 index levels increased 19.5% in the SDA group and 25.4% in the EPA group (p<0.05 for both, vs. control). DHA did not change in any group. Relative to EPA, SDA increased RBC EPA with about 17% efficiency. No other clinical endpoints were affected by SDA or EPA treatment (vs. control). In conclusion, SDA-enriched SBO significantly raised the omega-3 index. Since EPA supplementation has been shown to raise the omega-3 index and to lower risk for cardiac events, SDA-SBO may be a viable plant-based alternative for providing meaningful intakes of cardioprotective omega-3 FAs.     

Fat Utilization in Healthy Subjects Consuming Diacylglycerol Oil Diet: Dietary and Whole Body Fat Oxidation

Several studies in animals and humans have reported beneficial effects of diacylglycerol (DAG) on lipid and energy metabolism. We assessed the effect of DAG versus triacylglycerol (TAG) treatment on total energy expenditure (TEE), total fat oxidation (Fox) and respiratory quotient (RQ), and measured the oxidation rate of each oil using a respiratory chamber and the 13C-stable isotope. Eleven healthy subjects participated in a double-blind, randomized crossover study. Subjects consumed an energy maintenance diet consisting of 55% of total calories from carbohydrate, 15% from protein and 30% from fat during both the 3-day pre-chamber and 36-h chamber period. Fifty percent of the fat was test oil, containing either DAG oil or TAG oil. The oxidation rate of ingested test oils was determined by monitoring 13CO2 excretion in the breath from 13C-labeled diolein or 13C-labeled triolein. There were no significant differences in TEE, RQ and total Fox between the DAG and TAG treatment in the overall analysis. In the subgroup analysis, DAG treatment decreased RQ significantly in subjects with a high fat ratio (HFR) compared to TAG treatment. In addition, ingested diolein oxidation in DAG treatment was significantly faster than triolein oxidation in TAG treatment in the HFR group. Enhanced fat utilization with DAG treatment and rapid oxidation of ingested DAG may, at least in part, explain the greater loss of body weight and body fat related to DAG consumption found in the weight-loss studies.     

Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Camelina oil (CO) replaced 50 and 100 % of fish oil (FO) in diets for farmed rainbow trout (initial weight 44 ± 3 g fish^?1). The oilseed is particularly unique due to its high lipid content (40 %) and high amount of 18:3n‐3 (α‐linolenic acid, ALA) (30 %). Replacing 100 % of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12‐week feeding trial (FO = 168 ± 32 g fish^?1; CO = 184 ± 35 g fish^?1). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12 weeks of feeding. However, final 22:6n‐3 [docosahexaenoic acid (DHA)] and 20:5n‐3 [eicosapentaenoic acid (EPA)] amounts (563 mg) in a 75 g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250 mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound‐specific stable isotope analysis (CSIA) confirmed that the δ¹³C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ¹³C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil‐fed tissue. These results suggest that ~27 % of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.     

Effect of diacylglycerol on the development of impaired glucose tolerance in sucrose-fed rats

The effects of DAG oil and TAG oil on impaired glucose tolerance in rats that were fed a diet containing high levels of sucrose were compared. Male Wistar rats (8 wk old and 32 wk old) were fed either high-sucrose (57.5% sucrose w/w) or control diets containing either 10% (w/w) DAG or TAG oil with a similar FA composition for 48 wk in 8-wk-old rats and for 24 wk in 32-wk-old rats. Plasma lipids, the size of the islets of Langerhans, and insulin, glucose, and adipocytokine levels were measured. An oral glucose tolerance test (OGTT) was carried out during the study period. For rats in both age groups that were fed a high-sucrose diet, the DAG oil group had lower plasma glucose and insulin response in an OGTT, and lower homeostasis model assessment-R levels, than the TAG oil group. Furthermore, in 8-wk-old rats that were fed a high-sucrose diet, the DAG oil group accumulated less visceral fat and showed decreases of plasma adiponectin and suppressed increases of plasma insulin, leptin, and the size of islet of Langerhans compared with the TAG oil group. No difference in the OGTT was found between the DAG and TAG oil groups in either age group of rats fed a control diet. In conclusion, these results suggest that DAG oil ingestion prevents the high-sucrose-diet-induced development of impaired glucose tolerance compared with TAG oil ingestion.     

Bee Bread Ameliorates Vascular Inflammation and Impaired Vasorelaxation in Obesity-Induced Vascular Damage Rat Model: The Role of eNOS/NO/cGMP-Signaling Pathway

Obesity and hyperlipidemia are major risk factors for developing vascular diseases. Bee bread (BB) has been reported to exhibit some biological actions, including anti-obesity and anti-hyperlipidemic. This study aims to investigate whether bee bread can ameliorate vascular inflammation and impaired vasorelaxation activity through eNOS/NO/cGMP pathway in obese rats. Forty male Sprague-Dawley rats were randomly divided into four groups (n = 10/group), namely: control (normal group), obese rats (OB group), obese rats treated with bee bread (0.5 g/kg/day, OB/BB group) and obese rats treated with orlistat (10 mg/kg/day, OB/OR group). The latter three groups were given a high-fat diet (HFD) for 6 weeks to induced obesity before being administered with their respective treatments for another 6 weeks. After 12 weeks of the total experimental period, rats in the OB group demonstrated significantly higher Lee obesity index, lipid profile (total cholesterol, triglyceride, low-density lipoprotein), aortic proinflammatory markers (tumor necrosis factor-α, nuclear factor-κβ), aortic structural damage and impairment in vasorelaxation response to acetylcholine (ACh). Bee bread significantly ameliorated the obesity-induced vascular damage manifested by improvements in the lipid profile, aortic inflammatory markers, and the impaired vasorelaxation activity by significantly enhancing nitric oxide release, promoting endothelial nitric oxide synthase (eNOS) and cyclic guanosine monophosphate (cGMP) immunoexpression. These findings suggest that the administration of bee bread ameliorates the impaired vasorelaxation response to ACh by improving eNOS/NO/cGMP-signaling pathway in obese rats, suggesting its vascular therapeutic role.     

Lower Efficacy in the Utilization of Dietary ALA as Compared to Preformed EPA + DHA on Long Chain n-3 PUFA Levels in Rats

We made a comparative analysis of the uptake, tissue deposition and conversion of dietary α-linolenic acid (ALA) to its long chain metabolites eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with preformed EPA + DHA. Diets containing linseed oil [with ALA at ~2.5 (4 g/kg diet), 5 (8 g/kg diet), 10 (16 g/kg diet), 25% (40 g/kg diet)] or fish oil [with EPA + DHA at ~1 (1.65 g/kg diet), 2.5 (4.12 g/kg diet), 5% (8.25 g/kg diet)] or groundnut oil without n-3 polyunsaturated fatty acids (n-3 PUFA) were fed to rats for 60 days. ALA and EPA + DHA in serum, liver, heart and brain increased with increments in the dietary ALA level. When preformed EPA + DHA were fed, the tissue EPA + DHA increased significantly compared to those given ALA. Normalized values from dietary n-3 PUFA to tissue EPA + DHA indicated that 100 mg of dietary ALA lead to accumulation of EPA + DHA at 2.04, 0.70, 1.91 and 1.64% of total fatty acids respectively in liver, heart, brain and serum. Similarly 100 mg of preformed dietary EPA + DHA resulted in 25.4, 23.8, 15.9 and 14.9% of total fatty acids in liver, heart, brain and serum respectively. To maintain a given level of EPA + DHA, the dietary ALA required is 12.5, 33.5, 8.3 and 9.1 times higher than the dietary EPA + DHA for liver, heart, brain and serum respectively. Hence the efficacy of precursor ALA is lower compared to preformed EPA + DHA in elevating serum and tissue long chain n-3 PUFA levels.     

The mediating role of the parathyroid gland in the effect of low calcium intake on blood pressure in the rat

Recent reports suggest an inverse relationship between calcium intake and blood pressure. This effect could be mediated by parathormone (PTH), since a low calcium intake leads to an increase in PTH and this hormone produces an increase in intracellular calcium, raising the excitability of the muscle arteriolar cells. Wistar female rats, 56 days old, were submitted to a parathyroidectomy or to a sham operation. After that, they were placed on a normal or on a calcium-free diet during 10 weeks. Four groups of nine rats were studied: parathyroidectomized animals on a normal calcium diet, parathyroidectomized ones on a calcium-free diet, controls (sham operation) on a normal calcium diet, and controls (sham operation) on a calcium-free diet. The control calcium-free diet showed a significant increase in blood pressure values over the treatment period. The parathyroidectomized calcium-free diet group did not show any increase. The difference between these two groups regarding change in blood pressure was statistically significant. The parathyroidectomized-calcium-free group showed no weight increase during the study, while rats in the other three groups significantly increased their weight. PTH could be the mediator of the blood pressure rise observed in the calcium-deprived rats in spite of the possible confounding effect of the poor weight increase detected in the parathyroidectomized-calcium deprived animals. These results warrant future studies since the role of PTH in the regulation of blood pressure needs to be confirmed. This possibility, therefore, opens a new area of research in the study of the pathophysiology of hypertension.     

Short Chain Saturated Fatty Acids Decrease Circulating Cholesterol and Increase Tissue PUFA Content in the Rat

This study investigates the effect of various dietary saturated fatty acid (SFA) profiles on plasma lipid parameters and tissue fatty acid composition in rats. The experiment was designed to monitor polyunsaturated fatty acids (PUFA) levels, while examining different amounts and types of SFA. Four isocaloric diets were prepared, containing 10–11 mol% of fatty acids (FA) as linoleic acid (LNA) and 2.5 mol% as α-linolenic acid (ALA), leading to an identical and well-balanced LNA/ALA ratio. The initial rapeseed oil/corn oil mixture providing ALA and LNA was enriched with olive oil to prepare the olive oil diet. The butterfat diet was supplemented with butterfat, containing short-chain SFA (C4:0–C10:0, 17 mol% of FA), lauric acid (C12:0, 3.2 mol%), myristic acid (C14:0, 10.5 mol%) and palmitic acid (C16:0, 14.5 mol%). The saturates diet was supplemented with trilaurin, trimyristin and tripalmitin to obtain the same level of lauric, myristic and palmitic acids as the butterfat diet, without the short-chain SFA. The trimyristin diet was enriched with trimyristin only. The results showed that the butterfat diet contributed to specific effects, compared to the olive oil diet and the saturates and trimyristin diets: a decrease in plasma total, LDL- and HDL-cholesterol, higher tissue storage of ALA and LNA, and a higher level of (n-3) highly unsaturated fatty acids in some tissues. This study supports the hypothesis that in diets with identical well-balanced LNA/ALA ratios, short chain SFA may decrease circulating cholesterol and increase tissue polyunsaturated fatty acid content in the rat.     

Metabolities of dietary triacylglycerol and diacylglycerol during the digestion process in rats

The present study investigated the metabolic fate of dietary TAG and DAG and also their digestion products in the stomach and small intestine. A diet containing 10% TAG or DAG oil, enriched in 1,3-DAG, was fed to Wistar rats ad libitum for 9 d. After 18 h of fasting, each diet was re-fed ad libitum for 1 h. The weights of the contents of the stomach and small intestine were measured, and the acylglycerol and FFA levels were analyzed by GC at 0, 1, and 4 h after the 1-h re-feeding. The amounts of re-fed diet ingested and the gastric and small intestinal content were not different between the two diet groups. In the TAG diet group, the main products were TAG and DAG, especially 1(3),2-DAG. In addition, 1,3-DAG and 1(3)-MAG were present in the stomach, and the 1,3-DAG levels increased over time after the re-feeding period. In the DAG diet group, the main products in the stomach were DAG, MAG, FFA, and TAG. There were significantly greater amounts of 1,3-DAG, 1(3)-MAG, and FFA in the DAG diet group in the stomach compared with the TAG diet group. The amount of FFA in the stomach relative to the amount of ingested TAG plus DAG in the DAG diet group was higher than that in the TAG diet group. Acylglycerol and FFA levels were considerably lower in the small intestine than in the stomach. These results indicate that, in the stomach, where acyl migration might occur, the digestion products were already different between TAG and DAG oil ingestion, and that DAG might be more readily digested by lingual lipase compared with TAG. Furthermore, almost all of the dietary lipid was absorbed, irrespective of the structure of the acylglycerol present in the small intestine.     

Safety of dietary conjugated linoleic acid (CLA) in a 12-weeks trial in healthy overweight Japanese male volunteers

A study was conducted to investigate the short-term safety of dietary conjugated linoleic acid (CLA) in overweight Japanese male volunteers. The study design was a randomized, double-blind placebo-controlled trial including 60 healthy overweight volunteers (body mass index (BMI), 25 approximately 35 kg/m(2)). The subjects were randomly assigned to three groups: 5.4 g CLA-triacylglycerol (3.4 g as CLA), 10.8 g CLA-triacylglycerol (6.8 g as CLA) and placebo (10.8 g safflower oil) daily for 12 weeks. The CLA-triaclyglycerol contained 9c,11t- and 10t,12c-isomers at an equal proportion. The safety was evaluated by analyses of blood parameters and by clinical examinations at the baseline, and at 6 and 12 weeks, including vital signs and adverse effects. All subjects completed the study. The occurrence of adverse events tended to be higher in the CLA groups than in the placebo group, but all of the adverse events were mild to moderate, within normal ranges, and temporary. Serum aspartate aminotransferase (AST) activity did not differ significantly between the groups at 12 weeks, but in the high CLA group it was slightly increased from the baseline. Serum alanine aminotransferase (ALT) activity was higher in the high CLA group than in the placebo group after 12 weeks and was higher than at the baseline in both CLA groups. However, statistical analysis of the population of apparently healthy volunteers who had normal blood parameters at the baseline revealed that AST and ALT levels did not differ significantly among the 3 groups at 12 weeks. Moreover, no clinically significant changes in vital signs were observed in any of the groups. These results indicate that CLA at a dose of 3.4 g/day is a safe dietary level in healthy Japanese populations in terms of the parameters examined.     

Effect of cooper supplementation on blood pressure values in patients with stable moderate hypertension

Copper (Cu) deficiency is associated with changes in arterial pressure. The effect depends of the age of initiation of the copper-deficient diet. Copper deficiency started at a young age causes hypotension. When initiated in older or adult animals, copper deficiency can cause hypertension. A case-control study was carried out to investigate the effect of administrating 5 mg Cu/d in 60 subjects, both genders, with mild stable hypertension, pharmacologically untreated (treated group) and compared with 60 hypertensives (control group) who were matched by gender, age, body weight, smoking habits, calories, fat and salt intake (NaCl), and physical activity. Hypertension was diagnosed when the blood pressure was > 150/95 mm Hg. Mean age, mean corporal weight and risk factors were similar in both groups. The results suggested the existence of a marginal deficiency of the trace element in 62% of subjects and demonstrated that Cu decreases systolic (r = -0.963) and diastolic (r = -0.981) blood pressures in treated group (p < 0.05). Control patients did not show significant changes in their arterial pressures. These findings indicate a functional alteration in human blood pressure regulation during mild copper depletion and suggest that Cu could be used in the treatment of stable moderate arterial hypertension. Further investigation is needed to determine the extent of this influence.     

Effects of dietary palm oil on arterial thrombosis,platelet responses and platelet membrane fluidity in rats

Wistar rats were fed a control diet containing 5 energy % (en %) sunflowerseed oil or diets containing 50 en % of either palm oil, rich in saturated fatty acids, or sunflowerseed oil, high in linoleic acid, for at least eight weeks. Arterial thrombosis tendency, measured by the aorta loop technique, tended to be lowered by the palm oil diet and was lowered significantly by the sunflowerseed oil diet, compared with the control. Aggregation of platelets in whole blood activated with collagen was not altered by palm oil feeding, but was enhanced in the sunflowerseed oil group, compared with the control. The concomitant formation of thromboxane A₂ was decreased by palm oil feeding, although formation of prostacyclin did not change; the ratio of thromboxane/prostacyclin formed was decreased significantly in the palm oil group. Compared with the control diet, platelet membrane fluidity, measured by fluorescence polarization, was not altered in the palm oil group and was significantly increased only by sunflowerseed-oil feeding. Thus, although palm oil contains about 50% saturated fatty acids, it did not increase arterial thrombosis tendency and tended to decrease platelet aggregation, as compared with highly polyunsaturated sunflowerseed oil.