gamma-linolenic-acid and Weight-Gain

The purpose of this study was to determine whether gamma-linolenate (GLA) supplementation would suppress weight regain following major weight loss. Fifty formerly obese humans were randomized into a double-blind study and given either 890 mg/d of GLA (5 g/d borage oil) or 5 g/d olive oil (controls) for 1 y. Body weight and composition and adipose fatty acids of fasting subjects were assessed at 0, 3, 12, and 33 mo. After 12 subjects in each group had completed 1 y of supplementation, weight regain differed between the GLA (2.17 +/- 1.78 kg) and control (8.78 +/- 2.78 kg) groups (P < 0.03). The initial study was terminated, and all remaining subjects were assessed over a 6-wk period. Unblinding revealed weight regains of 1.8 +/- 1.6 kg in the GLA group and 7.6 +/- 2.1 kg in controls for the 13 and 17 subjects, respectively, who completed a minimum of 50 wk in the study. Weight regain did not differ in the remaining 10 GLA and 5 control subjects who completed <50 wk in the study. In a follow-up study, a subgroup from both the original GLA (GLA-GLA, n = 9) and the original control (Control-GLA, n = 14) populations either continued or crossed over to GLA supplementation for an additional 21 mo. Interim weight regains between 15 and 33 mo were 6.48 +/- 1.79 kg and 6.04 +/- 2.52 kg for the GLA-GLA and Control-GLA groups, respectively. Adipose triglyceride GLA levels increased 152% (P < 0.0001) in the GLA group at 12 mo, but did not increase further after 33 mo of GLA administration. In conclusion, GLA reduced weight regain in humans following major weight loss, suggesting a role for essential fatty acids in fuel partitioning in humans prone to obesity.

Topics: Adipose Tissue; Double-Blind Method; Female; gamma-Linolenic Acid; Humans; Male; Middle Aged; Obesity; Regression Analysis; Weight Gain; Weight Loss

To test the efficacy and safety of long-chain polyunsaturated fatty acid (LCPUFA) supplementation with gamma-linolenic acid, a precursor of arachidonic acid, and docosahexaenoic acid in preterm infants.. Preterm (<35 weeks, < or =2000 g birth weight) infants (n=238) randomly assigned to unsupplemented or LCPUFA-supplemented formula to 9 months after term. The main outcome measure was the Bayley Mental and Psychomotor Indexes (MDI, PDI) at 18 months after term. Safety outcome measures were anthropometry (9 and 18 months), feed tolerance, infection, and clinical complications.. There were no significant differences in neurodevelopment between groups overall. In preplanned subgroup analyses, LCPUFA-supplemented boys had significantly higher Bayley MDI than did control boys (difference, 5.7 points; 95% CI, 0.3 to 11.1; P=.04). LCPUFA-supplemented infants showed significantly greater weight gain (difference, 310 g; 95% CI, 30 to 590 g; P=.03) and length gain (difference, 1.0 cm; 95% CI, 0.02 to 1.9; P=.05) between birth and 9 months, with greater effect in boys (weight difference at 9 months, 510 g; 95% CI, 80 to 930 g; P=.02; length difference at 18 months, 1.8 cm; 95% CI, 0.1 to 1.8; P=.03).. This trial, using the strategy of providing gamma-linolenic acid as a source of arachidonic acid, showed efficacy for growth and for neurodevelopment in boys, with no adverse effects. These data have important implications for LCPUFA-supplementation strategy in preterm infants.

Topics: Body Height; Cognition; Docosahexaenoic Acids; Double-Blind Method; Eicosapentaenoic Acid; Female; gamma-Linolenic Acid; Humans; Infant; Infant Formula; Infant Nutritional Physiological Phenomena; Infant, Newborn; Infant, Premature; Male; Milk, Human; Psychomotor Performance; Sex Factors; Weight Gain

This study evaluated the effects of dietary supplementation of gamma-Linolenic acid (18:3n-6, GLA) on the lipid profile of serum and other tissues of rats fed erucic acid (C22:1) rich oil like mustard oil. The rats were fed diet containing 20% mustard oil as erucic acid rich oil and 20% groundnut oil as dietary fat. These groups were kept as reference groups. Another group fed diet containing 20% fat to which evening primrose oil as a source of GLA was blended with mustard oil and groundnut oil at 5% level. The feeding experiment was done for 4 weeks. In another set mustard oil fed group was kept as control while the experimental group was fed evening primrose oil as a source of GLA blended with mustard oil at 2.5% level. The feeding experiment was carried out for 12 weeks. The other dietary components remained same for all the groups. After the scheduled feeding period, it was found that there was no significant change in weight gain, food intake and food efficiency ratio. It was found that dietary GLA resulted in significant decrease in serum triglyceride (TG) and very low density lipoprotein (VLDL) cholesterol and significant increase in high density lipoprotein (HDL) cholesterol in serum in the experimental group. In liver total cholesterol (TC) is significantly higher and in heart and liver TG is significantly lower in GLA fed group.

Topics: Animals; Cholesterol; Eating; Erucic Acids; Fatty Acids; gamma-Linolenic Acid; Lipids; Male; Mustard Plant; Plant Oils; Rats; Triglycerides; Weight Gain

Dietary supplementation of a high-gamma-linolenic acid canola oil (HGCO) containing approximately 36% (w/w) of gamma-linolenic acid (GLA, 18:3n-6) from the seeds of a genetically transformed canola strain, was assessed for its long-term biological effects. Growing Sprague-Dawley rats (n = 30) were fed a purified AIN93G diet containing 5, 10, or 15% (w/w) of HGCO as the fat source. For comparison, a separate group of rats (n = 10) was given the diet containing 15% (w/w) of borage oil (BO), which contained 22% (w/w) of GLA. After 12 weeks of feeding, the growth, relative organ weights, hematology, and serum biochemistry were found to be similar among rats fed the 5, 10, and 15% HGCO diets. The GLA levels in plasma and liver phospholipids (PL) were also similar. However, the levels of GLA in peripheral tissues (muscle PL and adipose triacylglycerols) were significantly higher in rats fed the 10 and 15% HGCO diets than those fed the 5% HGCO diet. When the above biologic parameters were compared between the 15% HGCO and 15% BO dietary groups, there were no significant differences except for lower final body weights and higher tissue levels of GLA, dihomo-gamma-linolenic acid (20:3n-6) and arachidonic acid (20:4n-6) in the 15% HGCO dietary group as compared with the 15% BO dietary group. This is due to a higher GLA content and possibly a more favorable stereospecific distribution of GLA in HGCO. Overall, long-term (12-week) feeding with diets containing up to 15% HGCO resulted in no adverse effects on growth, organ weight, hematology and serum biochemistry as compared to the diet containing 15% BO, suggesting that HGCO may be a safe alternative source of GLA.

Topics: Adipose Tissue; Animals; Dietary Fats, Unsaturated; Fatty Acids, Monounsaturated; Fatty Acids, Omega-6; gamma-Linolenic Acid; Hematocrit; Leukocyte Count; Lipids; Liver; Male; Organ Size; Plant Oils; Rapeseed Oil; Rats; Rats, Sprague-Dawley; Weight Gain

gamma-linolenic acid (GLA) has been reported to improve several inflammatory disorders through regulation of eicosanoid production. However, since GLA is a precursor of arachidonic acid, it may bring about increasing tissue arachidonic acid levels with subsequent pro-inflammatory events. To explore this possibility, we examined the effect of high-dose GLA acid on the fatty acid profile of immune cells, leukotriene B4 production by peritoneal exudate cells and immunoglobulin productivity of mesenteric lymph node lymphocytes of Sprague-Dawley rats. Male rats were fed 10% fat diets containing graded levels, 0, 20, 40 and 60% of GLA for 3 weeks. The results showed the distinction in activity of metabolizing GLA between immune cells and liver. Thus, in immune cells such as mesenteric lymph node and spleen lymphocytes and peritoneal exudate cells, more dihomo-gamma-linolenic acid was found than in the liver. Leukotriene B4 production by peritoneal exudate cells was significantly suppressed when fed the highest level of GLA suggesting a lower risk of allergic reaction. Moreover, immunoglobulin productivity in mesenteric lymph node lymphocytes was promoted by dietary GLA. The present study indicates that a high dose of GLA may exert anti-inflammatory effects through suppression of leukotriene B4 release and strengthening of gut immune system, thus ameliorating allergic reaction.

Topics: Animals; Cells, Cultured; Dietary Supplements; Dose-Response Relationship, Drug; Fatty Acids; gamma-Linolenic Acid; Immunoglobulins; Leukotriene B4; Lymph Nodes; Lymphocytes; Male; Organ Size; Peritoneum; Phospholipids; Rats; Rats, Sprague-Dawley; Spleen; Weight Gain

Ligation of the coronary artery in rats produces severe ventricular fibrillation (VF) and malignant cardiac arrhythmia. Mortality increases with the age of the animal. Diets rich in saturated fatty acids (SF) but low in linoleic acid (LA) increase, but diets high in LA and low in SF decrease the severity of VF and mortality in older animals. The effects of an LA enriched diet can be blocked by inhibition of cyclooxygenase suggesting that conversion of LA to eicosanoids is central to the development of VF. Conversion of LA to gamma-linolenic acid (GLA) via delta-6 desaturase is the first step in the process. The activity of delta-6 desaturase declines with age. Thus inclusion of GLA in the diet of older animals may provide an additional benefit over LA alone. Dietary supplements of evening primrose oil (EPO) to one year old rats reduced ischaemic VF more than a supplement of sunflower seed oil (SSO) without GLA. Substitution of borage oil (more GLA than EPO but less LA than either EPO or SSO) was without additional benefit.

Topics: Aging; alpha-Linolenic Acid; Animals; Coronary Vessels; Cyclooxygenase Inhibitors; Dietary Fats; Dietary Fats, Unsaturated; Fatty Acid Desaturases; Fatty Acids, Essential; gamma-Linolenic Acid; Ligation; Linoleic Acid; Linoleic Acids; Linoleoyl-CoA Desaturase; Male; Oenothera biennis; Oleic Acid; Plant Oils; Rats; Rats, Wistar; Ventricular Fibrillation; Vitamin E; Weight Gain

We have utilized transgenic technology to develop a new source of gamma-linolenic acid (GLA) using the canola plant as a host. The aim of the present study was to compare the growth and fatty acid metabolism in rats fed equal amounts of GLA obtained from the transgenic canola plant relative to GLA from the borage plant. Young male Sprague-Dawley rats (n = 10/group) were randomized and fed a purified AIN93G diet (10% lipid by weight) containing either a mixture of high GLA canola oil (HGCO) and corn oil or a control diet containing borage oil (BO) for 6 wk. GLA accounted for 23%, of the triglyceride fatty acids in both diets. Growth and diet consumption were monitored every 2-3 d throughout the study. At study termination, the fatty acid composition of the liver and plasma phospholipids was analyzed by gas chromatography. The growth and diet consumption of the HGCO group were similar to the BO group. There were no adverse effects of either diet on the general health or appearance of the rats, or on the morphology of the major organs. There was no significant difference between the diet groups for total percentage of n-6 polyunsaturated fatty acids present in either the total or individual phospholipid fractions of liver or plasma. The relative percentage of GLA and its main metabolite, arachidonic acid, in each phospholipid fraction of liver or plasma were also similar between groups. The percentage of 18:2n-6 in liver phosphatidylethanolamine and phosphatidylinositol/serine was higher (P < 0.05) and 22:5n-6 was lower in the HGCO group than the BO group. This finding could be attributed to the higher 18:3n-3 content in the HGCO diet than the BO diet. Results from this long-term feeding study of rats show for the first time that a diet containing transgenically modified canola oil was well-tolerated, and had similar biological effects, i.e., growth characteristics and hepatic metabolism of n-6 fatty acids, as a diet containing borage oil.

Topics: Adipose Tissue; alpha-Linolenic Acid; Animals; Dietary Fats; Fatty Acids; Fatty Acids, Monounsaturated; gamma-Linolenic Acid; Genetic Engineering; Liver; Male; Phospholipids; Plant Oils; Plants, Genetically Modified; Random Allocation; Rapeseed Oil; Rats; Rats, Sprague-Dawley; Time Factors; Triglycerides; Weight Gain

The effect on Oenothera paradoxa oil on blood serum and liver lipids metabolism in rats fed a semisynthetic high-fat cholesterol enriched diets was investigated. The source of fats was sunflower oil or lard in 15% quantities and the source of protein was soybean protein isolate in 27% quantity. The diets were enriched with 0.5% cholesterol. This dietary experiment was carried on for 8 weeks. For the first 4 weeks rats were fed standard diet and for the next 4 weeks Oe. paradoxa oil (300 mg/day/rat) was additionally given by stomach-tube. At the end of experiment the contents of total cholesterol, HDL-cholesterol, triglycerides and free fatty acids in blood serum as well as cholesterol and triglycerides level in liver were determined. It was found that the addition of cholesterol to the diet decreased the hypocholesterolemic and hypotriglyceridemic effects of Oe. paradoxa oil both in blood serum and liver. It have not had any significant effect on the free fatty acid concentration in blood serum decrease by Oe. paradoxa oil intake.

Topics: Animals; Body Composition; Cholesterol; Cholesterol, Dietary; Diet; Dietary Fats; Eating; Fatty Acids, Essential; Female; gamma-Linolenic Acid; Hematocrit; Hemoglobins; Hypolipidemic Agents; Linoleic Acids; Lipid Metabolism; Lipids; Liver; Male; Oenothera biennis; Organ Size; Plant Oils; Rats; Rats, Inbred BUF; Weight Gain

The hypocholesterolemic efficacies of various polyunsaturated fatty acids were compared in rats given cholesterol-enriched diets. Oenothera biennis Linn oil (OBLO, linoleic + gamma-linolenic), sunflower oil (linoleic), palm oil (PLO, oleic + linoleic), soybean oil (linoleic + alpha-linolenic), high-oleic safflower oil (oleic + linoleic), or mixed oil (linoleic + alpha-linolenic) was added to the diet at 200 g/kg (20% groups). OBLO was also added at 100 g/kg diet (10% group). The serum total and very low density lipoprotein + intermediate lipoprotein + low density lipoprotein cholesterol concentrations of the 10 and 20% OBLO groups were consistently lower than those in the other groups. The liver cholesterol concentration in the PLO group was lower in all groups. The liver cholesterol concentrations in the 10 and 20% OBLO groups were also lower than in the other groups. There were no significant differences in the fecal neutral sterol and bile acid extraction among groups.

Topics: alpha-Linolenic Acid; Animals; Anticholesteremic Agents; Cholesterol; Cholesterol, Dietary; Cholesterol, HDL; Cholesterol, LDL; Cholesterol, VLDL; Fatty Acids; Fatty Acids, Unsaturated; Feces; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Lipoproteins; Liver; Male; Organ Size; Palm Oil; Phosphatidylcholines; Plant Oils; Rats; Rats, Inbred F344; Soybean Oil; Steroids; Sunflower Oil; Time Factors; Triglycerides; Weight Gain

Cachexia is common in patients with pancreatic cancer and has been associated with persistent activation of the hepatic acute phase response and increased energy expenditure. Fatty acids have been shown to have anticachectic effects in animal models and to reduce inflammatory mediators in healthy subjects and patients with chronic inflammatory disease. Eighteen patients with unresectable pancreatic cancer received dietary supplementation orally with fish oil capsules (1 g each) containing eicosapentaenoic acid 18% and docosahexaenoic acid 12%. Anthropometric measurement, body composition analysis, and measurement of resting energy expenditure and serum C-reactive protein were performed before and after supplementation with a median of 12 g/day of fish oil. Patients had a median weight loss of 2.9 kg/month (IQR 2-4.6) prior to supplementation. At a median of 3 months after commencement of fish oil supplementation, patients had a median weight gain of 0.3 kg/month (IQR 0-0.5) (p < 0.002). Changes in weight were accompanied by a temporary but significant reduction in acute phase protein production (p < 0.002) and by stabilisation of resting energy expenditure. This study suggests a component fish oil, perhaps EPA, merits further investigation in the treatment of cancer cachexia.

Topics: Acute-Phase Proteins; Cachexia; Dietary Fats, Unsaturated; Eicosapentaenoic Acid; Energy Metabolism; Fish Oils; gamma-Linolenic Acid; Humans; Pancreatic Neoplasms; Weight Gain

1. The importance of linoleic acid (18:2n-6) itself and of dietary gamma-linolenic acid (18:3n-6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g gamma-linolenic acid/kg, or 20 g linoleic acid/kg to an n-6 EFA-free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets. 2. Liver weight and lipid content in birds fed the 2 and 4 g gamma-linolenic acid/kg diet were significantly lower than those in birds fed the gamma-linolenic acid-free diet. However, no significant difference was observed between the gamma-linolenic acid- and linoleic acid-supplemented diets. 3. In birds fed the 4 g gamma-linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to gamma-linolenic acid of approximately 20% of whole body content. 4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of gamma-linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.

Topics: Analysis of Variance; Animals; Body Weight; Chromatography, Gas; Coturnix; Dietary Fats, Unsaturated; Fatty Acids; Fatty Acids, Essential; Female; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Lipids; Liver; Organ Size; Safflower Oil; Weight Gain

The present study was carried out to investigate the effect of different dietary oils representing special fatty acids which varied in chain length, position and number of double bonds on fatty acid composition of erythrocyte membranes and on the osmotic fragility of rat erythrocytes after incubation in NaCl solutions of different concentrations. For this purpose all animals were initially fed a control diet (CO) containing 10% coconut oil and 0.4% safflower oil for 28 days. After that 10 groups of 10 animals each were switched to test diets for another 20 days in which 50% or 100% of the coconut oil was exchanged for one of the following oils: olive oil (OO 5, OO 10), safflower oil (SFO 5, SFO 10), evening primrose oil (EPO 5, EPO 10), linseed oil (LO 5, LO 10) or salmon oil (SLO 5, SLO 10). The results show that the fatty acid composition of rat erythrocyte membranes was affected by the fatty acid composition of the dietary fats. Rats fed OO 10, EPO 10, LO 5 and LO 10 had a slightly lower concentration of saturated fatty acids (SFA) in erythrocyte membranes than control rats. Groups fed olive oil showed the highest level of monounsaturated fatty acids (MUFA) in the erythrocyte membrane. This increase in MUFA at the expense of SFA and (n-6) polyunsaturated fatty acids (PUFA) was most pronounced with respect to 18:1 and occurred in a dose-dependent fashion. Rats fed SFO, EPO or LO had higher linoleic acid levels in the erythrocyte membrane than control rats. This increase in 18:2 (n-6) was mainly at the expense of 18:1 and occurred in a dose-dependent fashion. The proportion of 20:4 (n-6) did not remarkably change feeding diets with (n-6) PUFA-rich oils. The (n-3) PUFA concentration in the erythrocyte membranes considerably increased, whereas (n-6) PUFA decreased feeding linseed oil or salmon oil rich in (n-3) PUFA. Linseed oil and salmon oil caused similar changes in the membrane, which were more pronounced in rats fed salmon oil than in rats fed linseed oil. The osmotic fragility of erythrocytes was also influenced by dietary oil, respectively fatty acid pattern of the erythrocytes. In almost all NaCl solutions erythrocytes from rats fed the dietary oils were less resistant to hemolysis than those from control rats. These changes became statistically apparent feeding EPO 5, LO 5, LO 10 and SLO 5.

Topics: Animals; Dietary Fats; Dose-Response Relationship, Drug; Eating; Erythrocyte Membrane; Fatty Acids; Fatty Acids, Essential; Fish Oils; gamma-Linolenic Acid; Hypolipidemic Agents; Linoleic Acids; Linseed Oil; Male; Oenothera biennis; Olive Oil; Osmotic Fragility; Plant Oils; Rats; Rats, Sprague-Dawley; Safflower Oil; Salmon; Weight Gain

The objectives of this study were to examine the effects of dietary gamma-linolenic acid-enriched oil extracted from fungi on rat body composition and on the various enzyme activities relating to fat metabolism in the liver. The oil contained 25.3 g gamma-linolenic acid/100 g fatty acids. The levels of gamma-linolenic acid-enriched oil in the diets were 0, 1.5 and 4%, to give 0, 2.88 and 7.68 g gamma-linolenic acid/kg diet. The control diet contained 8% soybean oil. The rats were given free access to these diets for 4 wk. Body weight gain was less in the gamma-linolenic acid oil-fed groups than in the control group, although food intake was similar among the three groups. Absolute and relative carcass fat weights were significantly lower in the gamma-linolenic acid oil-fed groups than in the control group. Carcass protein and water contents were not different among the three groups, although values were slightly greater than controls in gamma-linolenic acid-fed groups when expressed relative to body weight. Plasma total cholesterol and free fatty acid concentrations generally were lower in the gamma-linolenic acid oil-fed groups than in the control group. In the liver, there were no significant differences in activities of malic enzyme and citrate cleavage enzyme among the three groups. However, the activities of carnitine palmitoyl-transferase and peroxisomal beta-oxidation were significantly higher in the gamma-linolenic acid oil-fed groups than in the control group. These results clearly demonstrate that dietary gamma-linolenic acid oil reduces body fat content and facilitates fatty acid beta-oxidation in the liver.

Topics: Adipose Tissue; Animals; Body Composition; Carnitine O-Palmitoyltransferase; Cholesterol; Dietary Fats, Unsaturated; Enzyme Induction; Fatty Acids; Fatty Acids, Nonesterified; gamma-Linolenic Acid; Insulin; Liver; Male; Oxidation-Reduction; Rats; Rats, Wistar; Triglycerides; Weight Gain

Obese Zucker rats (fa/fa) have low levels of arachidonic acid (AA) in liver phospholipids (PL). We have previously shown that a 70% gamma-linolenate concentrate (GLA; an AA intermediate) fed at a fixed dose (0.07 g/day) normalized hepatic PL AA and reduced weight gain selectively in the obese animals. In a follow-up study, 16 obese (fa/fa) and 16 lean (Fa/Fa) 4-week-old male rats were randomized into 4 groups of 8 each and gavaged daily with soybean oil (SOY) containing 55% 18:2omega6 (an AA precursor) or GLA, using a progressive dose (< or = 5% of total calories) based on body weight. A defined diet with 11% of energy as SOY was fed ad libitum for 60 days. GLA obese had lower body weight (p<0.0001) and 60-day cumulative food intake (p<0.05) compared to SOY obese, but neither parameter differed between the lean groups. For the last twenty days cumulative food intake was identical for GLA obese and SOY lean, whereas SOY obese consumed 18% more (p<0.05). Thus the progressive dose of GLA selectively suppressed hyperphagia in obese Zucker rats. Erythrocytes collected at 15-day intervals showed parallel increases in AA in both genotypes over time, suggesting normal AA availability during rapid growth. Thus, the reduced PL AA in the livers from the obese rats probably reflects impaired distribution in selected tissues rather than reduced hepatic production. Due to the potential health risks of enriching tissue lipids with AA, great caution is advised in considering GLA as therapy for human obesity.

Topics: Adipose Tissue; Animals; Anti-Obesity Agents; Body Composition; Body Weight; Dietary Supplements; Disease Models, Animal; Eating; Energy Metabolism; Erythrocytes; Fatty Acids; gamma-Linolenic Acid; Genotype; Glycine max; Growth; Hyperphagia; Linoleic Acid; Lipid Metabolism; Lipids; Liver; Male; Obesity; Phospholipids; Rats; Rats, Zucker; Time Factors; Weight Gain

Below-normal proportions of phospholipid (PL) arachidonic acid (20:4 omega 6) have been reported in serum from obese humans and in liver from obese Zucker rats. This implies an abnormality of 20:4 omega 6 formation from linoleic acid (18:2 omega 6), possibly in the delta 6 desaturase step, or alternatively an abnormality in the catabolism or distribution of arachidonate. We previously speculated that a reduced proportion of 20:4 omega 6 in hepatic PL could contribute to the etiology of genetic obesity. Providing 18:3 omega 6 would bypass delta 6 desaturase and possibly normalize hepatic PL 20:4 omega 6. Therefore weanling Zucker rats were given free access to a defined diet (11% of energy as soy oil) and gavaged daily with 100 microL of either black currant oil concentrate ([BCO] 8% 18:2 omega 6 and 70% 18:3 omega 6) or soy oil ([Soy] 55% 18:2 omega 6 and < 0.1% 18:3 omega 6). Groups of eight lean and eight obese animals were randomized to receive Soy or BCO in a 2 x 2 design; 10 obese and 10 lean rats were fed a stock diet (nongavaged reference). All groups of lean rats had identical weight gain; food intake for Soy lean and BCO lean did not differ. The obese reference animals and Soy obese animals did not differ in weight gain. However, BCO obese animals ate less food (P < .06), gained less weight (P < .0001), and had lower percent body fat (P < .05) compared with the Soy obese animals. The fatty acid constituents from serum, liver, and adipose tissue showed marked differences between lean and obese animals. Hepatic PL 20:4 omega 6 was lower in Soy obese than in lean (P < .002), but was normalized by BCO gavage (diet effect, P < .007). The paucity of hepatic PL 20:4 omega 6 was not due to reduced desaturase activity, as the proportions of other desaturase products (20:3 omega 6, 20:3 omega 9, 20:5 omega 3) were significantly elevated in Soy obese rat liver and serum. Serum and hepatic cholesteryl ester 20:4 omega 6 levels were elevated in obese versus lean rats (P < .02 and P < .0001), indicating abnormal arachidonate distribution in the obese Zucker rat. Because BCO selectively reduced weight gain and percent body fat in obese Zucker rats, our results imply a role for abnormal omega 6 fatty acid metabolism in the etiology of Zucker obesity.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Adipose Tissue; Animals; Dietary Fats, Unsaturated; Fatty Acids, Essential; gamma-Linolenic Acid; Genotype; Lipid Metabolism; Liver; Male; Obesity; Rats; Rats, Zucker; Reference Values; Triglycerides; Weight Gain

Diet including mold oil from a lipid accumulative fungus, containing gamma-linolenic acid, showed an inhibitory effect on thrombus formation in the microvessels of rats by the light/dye method of the authors. Male Wistar rats were fed for 3 to 4 weeks with two series of experimental diets and were examined for thrombus formation. The thrombus formation times to totally occlude, ts, were 347 sec for (mold + soybean)-oil and 236 sec for (palm + soybean)-oil in the first series of diets and 1288 sec for mold oil, 538 sec for olive oil and 575 sec for safflower oil in the second series of diets. Fatty acid composition of plasma, erythrocyte and liver lipids showed an increase in arachidonate content with the diet including the mold oil. Higher arachidonate content seem favorable in inhibiting thrombus formation with increasing PGI2 formation. In terms of the level of lipid hydroperoxides, indicated as a desaturation index of constituent fatty acids, the higher desaturation index with safflower oil gave shorter ts, which suggested some oxygen derived free radicals from polyunsaturated fatty acids were involved in the mechanism of thrombogenesis study by this method.

Topics: Animals; Blood Pressure; Dietary Fats; Fluorescein; Fluoresceins; Free Radicals; Fungi; gamma-Linolenic Acid; Light; Linolenic Acids; Lipid Peroxidation; Male; Mesenteric Vascular Occlusion; Plant Oils; Rats; Rats, Inbred Strains; Thrombosis; Weight Gain

Topics: Animals; Caseins; Cholesterol; Cholesterol Esters; Cholesterol, Dietary; Dietary Fats, Unsaturated; Dietary Proteins; Fatty Acids; gamma-Linolenic Acid; Linolenic Acids; Liver; Male; Mice; Phospholipids; Plant Proteins, Dietary; Rats; Rats, Inbred Strains; Soybean Proteins; Weight Gain

The effects of dietary cholesterol (CH) and isolation stress on fatty acid compositions of plasma and liver cholesteryl ester and phospholipids were compared in growing rats fed an 18:2n-6 or an 18:3n-6 enriched semisynthetic diet for 2 weeks. Stress, CH-feeding, and dietary fats had no significant effects on plasma CH level, but CH-feeding alone elevated the liver CH concentrations. CH-feeding also modulated the liver polyunsaturated fatty acid compositions, i.e., increasing 18:2n-6 levels, and reducing 20:4n-6 levels, indicating an inhibition of the enzymes, delta-6 and delta-5-desaturases. The extent of these changes was less in rats fed 18:3n-6 than in those fed 18:2n-6. Stress, which alone had no significant effects on plasma and liver fatty acid compositions, attenuated the CH-induced changes of fatty acid levels.

Topics: Animals; Blood Pressure; Cholesterol, Dietary; Diet, Atherogenic; Dietary Fats, Unsaturated; Fatty Acids, Essential; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Hypolipidemic Agents; Linoleic Acids; Liver; Male; Oenothera biennis; Plant Oils; Rats; Rats, Inbred WKY; Safflower Oil; Stress, Physiological; Weight Gain

Excess dietary fat has been identified as a risk factor in the development of human breast carcinoma. However, the quality of fat may be more important than the overall quantity. We have studied the growth of human MCF7 breast carcinoma xenografts in athymic mice treated with dietary supplements of N-6 and N-3 series essential fatty acids given as natural preparations of evening primrose oil and fish oil. Olive oil and normal laboratory diet lacking the essential fatty acids served as controls. Animals treated with essential fatty acids developed tumours which were significantly smaller than both control groups (Mann-Whitney U test, P less than 0.001). Median tumour weights according to diet were: evening primrose oil, 133 mg; fish oil, 70 mg; olive oil, 212 mg; and control, 270 mg. Nutritional intervention to increase the proportion of essential fatty acids in the diet may have a role in the management of breast carcinoma.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Division; Cell Line; Eicosapentaenoic Acid; gamma-Linolenic Acid; Linolenic Acids; Mice; Tumor Cells, Cultured; Weight Gain