Coconut Oil Diet Research Articles

High fat diet induced oxidative DNA damage estimated by 8-oxo-7,8-dihydro-2′-deoxyguanosine excretion in rats

The role of dietary fats and energy in carcinogenesis has been partly related to oxidative damage to DNA. We have investigated the effect of dietary fat content and saturation on the urinary excretion of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) in male and female rats. Groups of Fischer F344 rats (n = 6–10) were fed control chow (3.4% fat) or diets containing 21.8% corn oil or 19.8% coconut oil + 2% corn oil for 12–15 weeks. At the end of the diet intervention period 24 h urine was collected for determination of 8-oxodG by HPLC.In the male groups fed control, corn oil and coconut oil diet the excretion of 8-oxodG was 403 ± 150, 932 ± 198 and 954 ± 367 pmol/kg 24 h, respectively (p < 0.05). In the female groups fed control and corn oil diet the excretion of 8-oxodG was 752 ± 80 and 2206 ± 282 pmol/kg 24 h, respectively (p < 0.05). Calculated per whole animal the excretion was 137 ± 51, 324 ± 70 and 328 ± 128 pmol/24 h in the control, corn and coconut oil male groups and 156 ± 21 and 464 ± 56 pmol/24 h in the control and corn oil female groups, respectively (p < 0.05). Thus, per animal or per consumed energy there was much less difference in 8-oxodG excretion between the corresponding male and female groups and only significant difference between the high fat groups. There was a close correlation (r = 0.7; p < 0.05) between 8-oxodG excretion and the energy intake.The present study suggests that a high fat diet increases oxidative DNA modification substantially irrespective of the saturation level of the fat. Energy intake appears to be the major determinant of the rate of modification.

Effects of dietary coconut oil on the density distribution and the chemical composition of plasma lipoproteins in the preruminant calf

Effects of dietary coconut oil on the density distribution and the chemical composition of plasma lipoproteins in the preruminant calf

Effects of dietary coconut oil on blood transport and in vivo hepatic metabolism of fatty acids in the preruminant calf

Effects of dietary coconut oil on blood transport and in vivo hepatic metabolism of fatty acids in the preruminant calf

Growth response and fatty acid composition of juvenile Penaeus vannamei fed different sources of dietary lipid

A study was conducted to evaluate the effects of feeding various sources of dietary lipid on weight gain, feed conversion, survival and fatty acid composition of juvenile Penaeus vannamei. Seven semi-purified diets (35% protein and 3400 kcal of metabolizable energy kg −1) containing defatted, freeze-dried shrimp meal, 1.0% soybean lecithin and 0.5% cholesterol were supplemented with 6.5% of either stearic acid, coconut, safflower, corn, soybean, linseed or menhaden fish oils. Each diet was fed to shrimp (1.00 ± 0.03 g average weight) in four replicate aquaria four times daily for 10 weeks. Weight gain, feed conversion and survival were best for shrimp fed the diet containing menhaden fish oil. Shrimp fed the linseed oil diet had the second highest weight gain, followed by shrimp on soybean oil, corn oil, stearic acid, coconut oil and safflower oil diets, respectively. Feed conversion values were a reflection of weight gain. Results of this study show that both n-6 and n-3 fatty acids are dietary essential for juvenile Penaeus vannamei, although n-3 fatty acids promoted faster growth than n-6. However, highly unsaturated fatty acids (HUFA) (20:5 n-3 and 22:6 n-3) had better growth-promoting effect than 18:3 n-3, due probably to the limited ability of shrimp to bioconvert fatty acids to polyenoic forms of longer chain length. The fatty acid composition of the shrimp generally reflected that of the dietary lipids, especially for the diets containing unsaturated fatty acids. Shrimp fed stearic acid and coconut oil diets low in polyunsaturated fatty acids accumulated high levels of 16:1 n-7 and 18:1 n-9.

Effect of dietary fats rich in lauric, myristic, palmitic, oleic or linoleic acid on plasma, hepatic and biliary lipids in cholesterol-fed hamsters.

Effects of different dietary fats on plasma, hepatic and biliary lipids were determined in male golden Syrian hamsters (Mesocricetus auratus) fed on purified diets for 7 weeks. Diets were made by blending different fats containing characteristic fatty acids: butter (14:0 + 16:0), palm stearin (16:0), coconut oil (12:0 + 14:0), rapeseed oil (18:1), olive oil (18:1) and sunflowerseed oil (18:2). In all diets except the sunflowerseed oil diet dietary 18:2 was held constant at 2% energy. Total fat supplied 12% of energy and cholesterol was added at 4 g/kg diet. Plasma cholesterol and triacyglycerol concentrations were increased by dietary cholesterol. After 7 weeks, plasma cholesterol concentrations were highest with the palm stearin, coconut oil and olive oil diets (8.9, 8.9 and 9.2 mmol/l) and lowest with the rapeseed oil and sunflowerseed oil diets (6.7 and 5.5 mmol/l) while the butter diet was intermediate (8.5 mmol/l). Hepatic cholesterol concentration was highest in hamsters fed on the olive oil diet and lowest with the palm stearin diet (228 v. 144 mumol/g liver). Biliary lipids, lithogenic index and bile acid profile of the gall-bladder bile did not differ significantly among the six diets. Although the gallstone incidence was generally low in this study, three out of 10 hamsters fed on the palm stearin diet developed cholesterol gallstones. In contrast, no cholesterol gallstones were found with the other diets. Rapeseed and sunflowerseed oils caused the lowest plasma cholesterol and triacyglycerol concentrations whereas olive oil failed to demonstrate a cholesterol-lowering effect compared with diets rich in saturated fatty acids. Since 18:2 was kept constant at 2% of energy in all diets, the different responses to rapeseed and olive oils could possibly be attributed to their different contents of 16:0 (5.6% v. 12.8% respectively). Other possible explanations are discussed.

The influence of dietary lipids on the composition and membrane fluidity of rat hepatocyte plasma membrane.

Weanling male Wistar rats were fed for five weeks on standard rat chow (23 g fat/kg diet) or one of four synthetic diets with butterfat, coconut oil, corn oil, or fish oil as the main lipid source (100 g fat/kg diet). In all diets, 10% of the fat was provided as corn oil to prevent essential fatty acid deficiency. Significant differences were observed in the saturated, monounsaturated, and polyunsaturated fatty acid composition, and in the ratio of cholesterol to phospholipid, in the hepatocyte membranes. The fluidity of hepatocyte plasma membranes was assessed using the fluorescence recovery after photobleaching technique and steady-state fluorescence anisotropy of diphenylhexatriene. No significant differences were found in the fluidity of plasma membranes between animals on the different fat diets, despite diet-induced changes in their fatty acid composition. However, the proportion of lipid free to diffuse in the plasma membrane varied with diet, being significantly greater (P < 0.05) in animals fed chow (63.7%), coconut oil (61.5%), and butterfat (57.6%) diets than in those fed the corn oil (47.3%) diet. Animals fed fish oil showed an intermediate (50.0%) proportion of lipid free to diffuse. The data support the hypothesis that dietary lipids can change both the chemical composition and lateral organization (lipid domain structure) of rat hepatocyte plasma membranes.

Varying Folate Pattern in Different Strains of Mice Fed Coconut Oil and Sesame Seed Oil Diet

Summary The effect of coconut oil feeding with and without cholesterol on folate metabolism in the two strains of mice, C57BL/6 and AKR have been studied. Liver total folate levels are higher in AKR mice. Coconut oil feeding markedly decreased the ratio of nonmethyl/methyl folates in C57BL/6 strain but not in AKR. Cholesterol supplementation to the coconut oil diet increased the percentage of monoglutamyl folates at the expense of polyglutamyl folates in both strains. Only C57BL/6 strain showed growth retardation on coconut oil feeding. The differences in hepatic folate metabolism between the two strains could possibly have an important role in determining their differences in susceptibility to diet induced atherosclerosis.

Exocrine Pancreatic Secretions in Growing Pigs Fed Diets Containing Fish Oil, Rapeseed Oil or Coconut Oil

Two experiments were performed to study the effect of feeding diets containing oils with different fatty acid composition on exocrine pancreatic secretions in growing pigs using two different methods to collect pancreatic juice. In the first experiment, three barrows (initial weight 37 kg) were fitted with a pancreatic pouch re-entrant cannula. An isolated pouch was prepared where the pancreatic duct enters the duodenum. In the second experiment, also using three barrows (initial weight 32 kg), a catheter was inserted into the pancreatic duct. Three wheat starch and fish meal-based diets were formulated to contain either 15 g fish oil, rapeseed oil or coconut oil/100 g. In both experiments, the diets were fed according to a 3 times 3 Latin square design. The volume of pancreatic juice secreted, pH and secretion of bicarbonate, protein, amylase, trypsin, lipase and colipase were not significantly affected by the diets in the first experiment. In the second experiment, chymotrypsin secretion was significantly greater in pigs fed the coconut oil diet, and secretion of carboxyl ester hydrolase was significantly higher in pigs fed the fish oil diet. When compared qualitatively, pigs in Experiment 2 secreted more pancreatic juice; the pancreatic juice had a higher pH, and trypsin, carboxyl ester hydrolase and colipase secretions were substantially higher whereas amylase secretion was lower than for pigs in Experiment 1. The fatty acid composition of the different oils had minor effects on exocrine pancreatic secretion in growing pigs. However, there were considerable differences between the two surgical methods used to collect pancreatic juice, and these differences may be explained by physiological changes induced by the two methods.

Intrauterine programming of hypertension in the rat: nutrient interactions.

The feeding of low protein diets to pregnant rats is known to programme hypertension in their offspring though a glucocorticoid-dependent mechanism. To establish whether diets of differing fatty acid composition could produce the same effects, or modulate the effects of a low protein diet, pregnant rats were fed 1 of 4 different diets. Control animals were fed an 18% casein:corn oil (18 + Corn) diet, while experimental groups were fed 18% casein:coconut oil (18 + Coco), 9% casein:corn oil (9 + Corn) or 9% casein:coconut oil (9 + Coco). Feeding of coconut oil diets significantly reduced weight gain of the rats, an effect attributable to a lower food intake. Despite this, reproductive performance of the rats was not compromised. While pups of the 9 + Corn group were of normal birthweight, the dams in the 18 + Coco and 9 + Coco groups gave birth to pups of significantly lower weight. At 7 weeks of age male and female pups exposed to the 9 + Corn diet in utero had significantly elevated systolic blood pressure. Males exposed to the 9 + Coco and 18 + Coco diets also had higher blood pressures than control animals, but the effect was not observed in females. Female rats exposed to the three experimental diets in utero had enlarged hearts, relative to controls and the same effect of maternal diet was observed in male rats exposed to the 9 + Coco and 18 + Coco diets. Effects of maternal diet upon liver size were also noted in males exposed to 18 + Coco and 9 + Corn diets (smaller livers). Males exposed to 9 + Corn had smaller lungs than control rats, whilst the rats from the 9 + Coco group had significantly enlarged lungs. In rats exposed to the 9 + Corn diet in utero there was evidence of increased glucocorticoid action in both liver and hypothalamus, where activities of corticosteroid inducible enzymes were elevated. There was no evidence of a role for glucocorticoids in programming the hypertension of male rats exposed to high saturated fat diets in utero. The data would suggest that high saturated fatty acid, or low linoleic acid intake in pregnancy may programme hypertension in the fetal rat. This effect of maternal diet occurs through a mechanism different to that initiated by protein restriction and is sex specific.

Effects of diet on responses to exhaustive exercise in Nile tilapia ( Oreochromis nilotica) acclimated to three different temperatures

The effects of exhaustive exercise on O 2 consumption (Ṁ O 2 ), waste nitrogen (ammonia and urea) excretion, and on lactate, ammonia and water content of white muscle and liver, were determined in tilapia fed a diet enriched either in long chain polyunsaturated fatty acids of the ω3 series (ω3 LCPUFA) as menhaden oil (menhaden oil diet; MOD) or in saturated fatty acids (SFA) as coconut oil (coconut oil diet; COD), and acclimated to three different temperatures (16°, 23° and 33°C). At all temperatures, exhaustive exercise elicited an increase in postexercise Ṁ O 2 and ammonia excretion rates, and in white muscle lactate and ammonia levels. There were no differences between the two dietary groups in the total amount of O 2 consumed and muscle lactate accumulated, but at 23°C and 33°C exhaustive exercise stimulated a significantly greater increase in ammonia excretion in COD as compared with MOD tilapia. The magnitude of the difference in postexercise ammonia excretion between COD and MOD animals increased with increases in environmental temperature, being greater at 33°C than at 23°C. The increased ammonia excretion observed in the COD group was not a result of differences in white muscle ammonia or water content following exhaustive exercise. The data indicate that diets enriched in ω3 LCPUFA are beneficial in that tilapia fed these diets exhibited reduced ammonia excretion following exhaustive exercise, compared with tilapia fed diets enriched in SFA.

Attenuation of experimental hypertension by dietary linoleic acid is model dependent.

The purpose of this study was to evaluate the interaction of a linoleic acid enriched diet with NaCl on the development of hypertension in Dahl salt sensitive (Dahl-S) rats and in two-kidney, one-clip Sprague Dawley rats. In both experimental models, separate groups of animals were fed either linoleic acid enriched (provided as safflower oil) or control (containing coconut oil) diets for 5 weeks. Diets were further subdivided on the basis of either a low NaCl (0.3%) or a high NaCl (3.0%) content. Tail systolic blood pressure, direct mean intra-arterial pressure, and cardiac output were measured in chronically instrumented, conscious rats. In Dahl-S, on both NaCl intakes, and in two-kidney, one-clip rats on a high NaCl diet, safflower oil had no effect on arterial pressure. In contrast, in two-kidney, one-clip rats fed the low NaCl diet, both indirect tail systolic blood pressures and direct mean arterial pressure were lower (p<0.01) in animals on the linoleic acid enriched diet; total peripheral resistance was also decreased (p<0.01). Safflower oil has a hypotensive effect only in the two-kidney, one-clip rat on a low NaCl, but not on a high NaCl intake, and not in Dahl-S rats. Additional studies are required to identify the mechanism(s) for the hypotensive effect of safflower oil and to define the relationship of this animal study to human hypertension.

Effects of dietary fats and curcumin on IgE-mediated degranulation of intestinal mast cells in brown Norway rats.

Brown Norway rats were primed intraperitoneally with beta-lactoglobulin for 3 wk to induce reaginic antibody, during which time they were fed diets containing 10% each of coconut oil (CO), high oleic safflower oil, safflower oil (SO), or fish oil, then they were challenged for 3 h orally with the antigen. The dietary SO, compared to other dietary fats, resulted in lower circulatory release of rat chymaseII (RChyII), an indicator of degranulation of mucosal mast cells in the intestine, in response to the antigen. Addition of 0.5% curcumin to the CO or SO diet lowered the release. The SO diet, compared to CO diet, tended to increase the concentration of reaginic antibody, but the influence of curcumin addition was not prominent. These results indicate that dietary ingredients differently influence the synthesis of immunoglobulin E and degranulation of mast cells.

Influence of Dietary Fats Upon Systolic Blood Pressure in the Rat

Studies were performed to determine whether feeding diets with differing fatty acid content and composition had an influence on systolic blood pressure in the rat. Weanling male rats were fed standard laboratory chow (2.9% fat in total), or synthetic diets (10% fat in total) containing fish oil, butter, coconut oil or corn oil, for 5 weeks. Coconut oil and butter diets were rich in saturated fatty acids, whilst fish oil and corn oil were rich in the n-3 and n-6 unsaturated fatty acids respectively. Systolic blood pressure was measured using an indirect tail-cuff method at the end of the feeding period, and compared to a group of weanling rats. Feeding the different diets did not alter the growth of the rats, so all animals were of similar weights at the time of blood pressure determination. Control (chow fed) animals, at nine weeks of age, had higher systolic blood pressures than the weanling, baseline control group. Fish oil fed rats had similar pressures to the chow fed rats. Corn oil fed rats had significantly lower systolic pressures than the controls. The rats led the diets rich in saturated fatty acids (butter and coconut oil) had significantly higher blood pressures than all other groups. Systolic blood pressure was found to be significantly related to the dietary intakes of saturated and unsaturated fatty acids. The dietary intake of linoleic acid was significantly higher in corn oil fed rats than in other groups. Systolic blood pressure was inversely related to linoleic acid intake. Feeding a diet rich in saturated fatty acids significantly increases blood pressure in the rat. A high intake of n-6 fatty acids, and in particular linoleic acid, appears to have a hypotensive effect. Prenatal exposure of the rats to a maternal low protein diet, abolished the hypertensive effects of the coconut oil diet and the hypotensive effect of the corn oil diet upon young adult females. The intrauterine environment may, therefore, be an important determinant of the effects of these fatty acids on blood pressure in later life.

Dissociation of protein kinase C activities and diacylglycerol levels in liver plasma membranes of rats on coconut oil and safflower oil diets

The activation of protein kinase C (PKC) is affected differently in vitro by different fatty acids. Whether this event occurs in response to fatty acid has not heretofore been determined in animal tissues. We addressed this question using the liver of rats on diets containing saturated or polyunsaturated fats. Rats on coconut oil, which is rich in saturated fatty acids, had a markedly lower PKC activity in liver plasma membranes with a slight but significant reduction of the activity in the cytosol than did rats fed safflower oil rich in linoleic acid. Ingestion of coconut oil resulted in a higher content of diacylglycerols (DG) in these membranes than did ingestion of safflower oil, whereas the proportions of saturated fatty acids and phospholipids and membrane fluidity were similar between rats ingesting different fats. These results are the first evidence that ingestion of coconut oil disproportionately affects PKC activation and the DG level in mammalian membranes. It seems likely that saturated fats exert various physiological effects on lipid and lipoprotein metabolism, in part through PKC pathways.

Effects of coconut oil, butter, and safflower oil on lipids and lipoproteins in persons with moderately elevated cholesterol levels.

The physiological effects of coconut oil, butter, and safflower oil on lipids and lipoproteins have been compared in moderately hypercholesterolemic individuals. Twenty eight participants (13 men, 15 women) followed three 6-week experimental diets of similar macronutrient distribution with the different test fats providing 50% total dietary fat. Total cholesterol and low density lipoprotein cholesterol were significantly higher (P < 0.001) on the diet containing butter [6.8 +/- 0.9, 4.5 +/- 0.8 mmol/l] (mean +/- SD), respectively than on the coconut oil diet (6.4 +/- 0.8; 4.2 +/- 0.7 mmol/l) when levels were significantly higher (P < 0.01) than on the safflower diet (6.1 +/- 0.8; 3.9 +/- 0.7 mmol/l). Findings with regard to the other measures of lipids and lipoproteins were less consistent. Apolipoprotein A-I was significantly higher on coconut oil (157 +/- 17 mg/dl) and on butter (141 +/- 23 mg/dl) than on safflower oil (132 +/- 22 mg/dl). Apolipoprotein B was also higher on butter (86 +/- 20 mg/dl) and coconut oil (91 +/- 32 mg/dl) than on safflower oil (77 +/- 19 mg/dl). However gender differences were apparent. In the group as a whole, high density lipoprotein did not differ significantly on the three diets whereas levels in women on the butter and coconut oil diet were significantly higher than on the safflower oil diet. Triacylglycerol was higher on the butter diet than on the safflower and coconut oil diets but the difference only reached statistical significance in women. Cholesteryl ester transfer activity was significantly higher on butter than safflower oil in the group as a whole and in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary Cholesterol and Fat Saturation Effects on Plasma Esterified and Unesterified Cholesterol in Selected Lines of Japanese Quail Females

Three lines of Japanese quail females, randombred controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant-source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. In all three lines, plasma cholesterol increased when cholesterol was fed; however, responses were greater in the HL than in the LL line, with CL intermediate. In a second experiment, females of the three lines were fed, from 6 to 14 wk of age, four isocaloric, isonitrogenous plant-source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. Baseline data obtained before feeding experimental diets indicated that the HL had significantly higher plasma total, esterified (EC) and unesterified (UEC) cholesterol than LL and that nonovulating females had higher concentrations of esterified cholesterol than ovulating females. Diets used did not affect cholesterol fractions in the ovulating females, although there were significant differences among lines. Dietary cholesterol significantly increased the ratio of EC to UEC. Sclerotic lesion scores were higher in the HL than the LL birds and in birds fed the coconut oil diet.

Activities of liver microsomal fatty acid desaturases in zinc-deficient rats force-fed diets with a coconut oil/safflower oil mixture of linseed oil.

The present study was conducted to investigate the effect of zinc deficiency on fatty acid desaturation in rats fed two different types of dietary fat, a mixture of coconut oil and safflower oil (7:1, w/w, "coconut oil diet") or linseed oil ("linseed oil diet"). In order to ensure an adequate food intake, all rats were force-fed by gastric tube. Zinc deficiency caused statistical significant reduction of delta 9-desaturase activity in liver microsomes of rats fed coconut oil diet and tendencial reduction (p < 0.15) in rats fed linseed oil diet compared with control rats fed diets with the same type of fat. In agreement with this effect, zinc deficiency in the rats fed both types of dietary fat increased the ratio between total saturated and total monounsaturated fatty in liver phospholipids and liver microsomes. Zinc deficient rats on the coconut oil diet had unchanged delta 6-desaturase activity with linoleic acid as substrate and lowered activity with alpha-linolenic acid as substrate. In contrast, zinc deficient rats on the linseed oil diet had increased delta 6-desaturase activity with linoleic acid as substrate and unchanged activity with alpha-linolenic acid. Because linoleic acid is the main substrate for delta 6-desaturase in the rats fed coconut oil diet, and alpha-linolenic acid is the main substrate in the rats fed linseed oil diet, it is concluded that in vivo delta 6-desaturation was not changed by zinc deficiency in the rats fed both types of dietary fat. Activity of delta 5-desaturase was also not changed by zinc deficiency in the rats fed both dietary fats. Levels of fatty acids in liver phospholipids and microsomes derived by delta 4-, delta 5-, and delta 6-desaturation were not consistently changed by zinc deficiency in the rats fed both types of dietary fat. Thus, the enzyme studies and also fatty acid composition data of liver phospholipids and microsomes indicate that zinc deficiency does not considerably disturb desaturation of linoleic and alpha-linolenic acid. Therefore, it is suggested that similarities between deficiencies of zinc and essential fatty acids described in literature are not due to disturbed desaturation of linoleic acid in zinc deficiency. The present study also indicates that zinc deficiency enhances incorporation of eicosapentaenoic acid into phosphatidylcholine of rats fed diets with large amounts of n-3 polyunsaturated fatty acids.

Zinc deficiency and activities of lipogenic and glycolytic enzymes in liver of rats fed coconut oil or linseed oil

In previous studies, zinc-deficient rats force-fed a diet with coconut oil as the major dietary fat developed a fatty liver, whereas zinc-deficient rats force-fed a diet with linseed oil did not. The present study was conducted to elucidate the reason for this phenomenon. In a bifactorial experiment, rats were fed zinc-adequate or zinc-deficient diets containing either a mixture of coconut oil (70 g/kg) and safflower oil (10 g/kg) ("coconut oil diet") or linseed oil (80 g/kg) ("linseed oil diet") as a source of dietary fat, and activities of lipogenic and glycolytic enzymes in liver were determined. In order to ensure adequate food intake, all the rats were force-fed. Zinc-deficient rats on the coconut oil diet developed a fatty liver, characterized by elevated levels of triglycerides with saturated and monounsaturated fatty acids. These rats also had markedly elevated activities of the lipogenic enzymes acetyl-CoA carboxylase, fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and citrate cleavage enzyme, whereas activities of malic enzyme and glycolytic enzymes were not different compared with zinc-adequate rats on the coconut oil diet. In contrast, rats receiving the linseed oil diet had similar triglyceride concentrations regardless of zinc status, and activities of lipogenic enzymes and glycolytic enzymes were not different between the two groups. Zinc-deficient rats fed either type of dietary fat exhibited statistically significant correlations between activities of FAS, G6PDH, 6PGDH and concentrations of saturated and monounsaturated fatty acids in liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dietary soybean phospholipid and fats differing in the degree of unsaturation on fatty acid synthesis and oxidation in rat liver.

The activities of enzymes in fatty acid oxidation and synthesis in the liver of rats fed soybean phospholipids and soybean oil corresponding to the dietary levels of 3% fatty acid added to the diets containing a saturated fat (coconut oil) and a polyunsaturated fat (safflower oil) at the amounts corresponding to 12% fatty acid levels were compared. Soybean phospholipid compared with soybean oil added to both coconut and safflower oil diets significantly reduced the activities of enzymes in fatty acid synthesis (fatty and synthetase, glucose-6-phosphate dehydrogenase and malic enzyme). However, there were no significant differences in the activities of enzymes in fatty acid oxidation (carnitine palmitoyltransferase, acyl-CoA dehydrogenase and acyl-CoA oxidase) between the groups of rats fed soybean phospholipid and soybean oil added to coconut and safflower oil diets except for one occasion. Soybean phospholipid compared with soybean oil added to coconut oil diet significantly decreased the concentrations of triacylglycerol, cholesterol and phospholipid in the serum and of triacylglycerol and cholesterol in the liver. However, the dietary phospholipid added to safflower oil diet failed to alter these values. These results suggested that the alteration in the rate of fatty acid synthesis, but not oxidation, in the liver is responsible for the lipid-lowering effect of dietary soybean phospholipid added to a saturated fat diet.

Myocardial protection by ischemic preconditioning: the influence of the composition of myocardial phospholipids.

It was the aim of this study to investigate (1) whether preconditioning modifies the fatty acid (FA) composition of myocardial phospholipids (PL), (2) whether a previous modification of membrane PL composition by the administration of coconut oil or fish oil influences the preconditioning, and (3) to compare the protective effects of preconditioning to those of dietary fish oil. To this end, three groups of rats were given during 10 weeks either a standard diet, or a standard diet + 10% coconut oil, or a standard diet + 10% fish oil. The preconditioning was performed in situ in the anesthetized open-chest rats by 2 cycles of 3 min left anterior descending coronary artery occlusion and 10 min reperfusion. It was followed by a 40 min ischemia and a 60 min reperfusion. ECG was recorded and used for the continuous count of the salves of extrasystoles, ventricular flutter and fibrillation. These rhythm disturbances were subsequently added and evaluated as total arrhythmias. The FA of tissue PL were analyzed in a sample of the ischemic zone the size of which was determined by means of malachite green. Coconut oil diet (rich in saturated FA) modified slightly the myocardial PL by increasing oleic acid and decreasing linoleic acid and resulted in the highest incidence of arrhythmias. Fish oil diet had the opposite effect in modifying drastically the PLFA (replacement of the n-6 FA by the n-3 FA) and minimizing significantly the arrhythmias in comparison with the standard diet group.(ABSTRACT TRUNCATED AT 250 WORDS)