Showing papers on "Fish oil published in 1985"

Effect of dietary enrichment with eicosapentaenoic and docosahexaenoic acids on in vitro neutrophil and monocyte leukotriene generation and neutrophil function

Abstract: The effects of dietary fish-oil fatty acids on the function of the 5-lipoxygenase pathway of peripheral-blood polymorphonuclear leukocytes and monocytes were determined in seven normal subjects who supplemented their usual diet for six weeks with daily doses of triglycerides containing 3.2 g of eicosapentaenoic acid and 2.2 g of docosahexaenoic acid. The diet increased the eicosapentaenoic acid content in neutrophils and monocytes more than sevenfold, without changing the quantities of arachidonic acid and docosahexaenoic acid. When the neutrophils were activated, the release of [3H]arachidonic acid and its labeled metabolites was reduced by a mean of 37 per cent, and the maximum generation of three products of the 5-lipoxygenase pathway was reduced by more than 48 per cent. The ionophore-induced release of [3H]arachidonic acid and its labeled metabolites from monocytes in monolayers was reduced by a mean of 39 per cent, and the generation of leukotriene B4 by 58 per cent. The adherence of neutrophils to bovine endothelial-cell monolayers pretreated with leukotriene B4 was inhibited completely, and their average chemotactic response to leukotriene B4 was inhibited by 70 per cent, as compared with values determined before the diet was begun and six weeks after its discontinuation. We conclude that diets enriched with fish-oil-derived fatty acids may have antiinflammatory effects by inhibiting the 5-lipoxygenase pathway in neutrophils and monocytes and inhibiting the leukotriene B4-mediated functions of neutrophils.

Reduction of Plasma Lipids, Lipoproteins, and Apoproteins by Dietary Fish Oils in Patients with Hypertriglyceridemia

Abstract: Dietary fish oils, which are rich in omega-3 fatty acids, have been reported to reduce plasma lipid levels in normolipidemic subjects. We examined the effects of fish oil in 20 hypertriglyceridemic patients: 10 with Type IIb hyperlipidemia and 10 with Type V. These patients were put on three diets differing primarily in fatty acid composition and fat content. The control diet contained a fatty acid mixture typical of a low-fat therapeutic diet (ratio of polyunsaturated to saturated fat, 1.4), the fish-oil diet contained omega-3 fatty acids, and the vegetable-oil diet was rich in the omega-6 fatty acid, linoleic acid. Each diet was followed for four weeks. In the Type IIb group, the fish-oil diet led to decreases in both plasma cholesterol (-27 per cent) and triglyceride (-64 per cent), as compared with the control diet. Very-low-density lipoproteins (VLDLs) were also reduced markedly. The vegetable-oil diet had much less effect. With fish oil, the Type V group had marked decreases in total cholesterol and triglyceride levels (-45 and -79 per cent, respectively). VLDL levels were dramatically lowered, as were apoprotein E levels. The vegetable-oil diet (unlike the fish-oil diet) produced a rapid and significant rise in plasma triglyceride levels. We conclude that fish oils and fish may be useful components of diets for the treatment of hypertriglyceridemia.

Metabolism and Effects on Platelet Function of the Purified Eicosapentaenoic and Docosahexaenoic Acids in Humans

Abstract: Metabolism and effects on platelet function of 6 g/d for 6 d of either eicosapentaenoic acid (EPA, C20:5 omega-3) or docosahexaenoic acid (DCHA, C22:6 omega-3) in volunteers were compared in a randomized crossover study. Incorporation kinetics revealed that EPA appeared in plasma free fatty acids and plasma phospholipids after 4 h, but was not incorporated into platelet phosphatidylcholine and -ethanolamine until day 6. This indicates that platelet fatty acid composition does not immediately reflect that of the surrounding plasma milieu, but rather may be determined during megakaryocyte maturation. Importantly, EPA was not incorporated into platelet phosphatidylinositol or -serine in vivo, thus reflecting selective biosynthesis of platelet phospholipids. After dietary EPA, C22:5 omega-3 increased in plasma and platelet phospholipids. In contrast, DCHA-levels were unaltered. After DCHA-ingestion, C20:5 omega-3 concentrations rose in plasma phospholipids, implying that retroconversion took place. These findings indicate that dietary DCHA can serve as a source of EPA. During this short-term study, ingestion of both EPA and DCHA resulted in reduced platelet aggregation in response to collagen. The response to ADP was lowered significantly only by DCHA. After either EPA or DCHA, thromboxane formation was unchanged in serum derived from clotted whole blood as was total in vivo synthesis measured by excretion of immunoreactive 2,3-dinor thromboxane B2/3. We conclude that DCHA reduces platelet responsiveness, contributing to the antithrombotic effects of omega-3 fatty acid-rich fish oil ingestion, of which DCHA is a major component.

A fish oil diet rich in eicosapentaenoic acid reduces cyclooxygenase metabolites, and suppresses lupus in MRL-lpr mice.

Abstract: Dietary supplementation of fish oil as the exclusive source of lipid suppresses autoimmune lupus in MRL-lpr mice. This marine oil diet decreases the lymphoid hyperplasia regulated by the lpr gene, prevents an increase in macrophage surface Ia expression, reduces the formation of circulating retroviral gp70 immune complexes, delays the onset of renal disease, and prolongs survival. We show that a fatty acid component uniquely present in fish oil but not in vegetable oil decreases the quantity of dienoic prostaglandin E, thromboxane B, and prostacyclin normally synthesized by multiple tissues, including kidney, lung, and macrophages, and promotes the synthesis of small amounts of trienoic prostaglandin in autoimmune mice. We suggest that this change in endogenous cyclooxygenase metabolite synthesis directly suppresses immunologic and/or inflammatory mediators of murine lupus.

Triglyceride-lowering effect of marine polyunsaturates in patients with hypertriglyceridemia.

Abstract: Twenty male patients with primary hypertriglyceridemia were treated for 4 weeks with daily supplements (15 g) of oil, which provided approximately 6 g of polyunsaturated fatty acid (PUFA) either of fish or of vegetable origin. Total plasma cholesterol concentrations were unaffected, but both types of supplement increased high density lipoprotein-3 (HDL3) cholesterol concentrations. The fish, but not the vegetable, oil supplement led to a decrease in plasma triglyceride concentrations. Very low density lipoprotein (VLDL), fatty acid composition, and VLDL triglyceride kinetics were subsequently studied in five patients (four male, one female) before and after 4 weeks of therapy with 15 g of the same fish oil. The fish oil led to increases in the proportion of eicosapentaenoic acid in both the VLDL triglyceride and phospholipid fractions, but the increase was greater in the latter. In contrast, the proportion of docosahexanoic acid was increased only in the VLDL triglycerides. The decrease in plasma triglyceride concentrations that occurred with fish-oil therapy was accompanied by a reduction in the absolute catabolic rate of VLDL triglyceride, implying a concomitant change in synthetic rate; the fractional catabolic rate of VLDL triglyceride was unaltered. It is suggested that polyunsaturated fatty acids of marine origin may be therapeutically useful for hypertriglyceridemia.

Dietary fish oil modulates macrophage fatty acids and decreases arthritis susceptibility in mice.

Abstract: B10RIII and B10G mice were transferred from a diet of laboratory rodent chow to a standard diet in which all the fat (5% by weight) was supplied as either fish oil (17% eicosapentaenoic acid [EPA], 12% docosahexaenoic acid [DHA], 0% arachidonic acid [AA], and 2% linoleic acid) or corn oil (0% EPA, 0% DHA, 0% AA, and 65% linoleic acid) The fatty acid composition of the macrophage phospholipids from mice on the chow diet was similar to that of mice on a corn oil diet Mice fed the fish oil diet for only 1 wk showed substantial increases in macrophage phospholipid levels of the omega-3 fatty acids (of total fatty acid 4% was EPA, 10% docosapentaenoic acid [DPA], and 10% DHA), and decreases in omega-6 fatty acids (12% was AA, 2% docosatetraenoic acid [DTA], and 4% linoleic acid) compared to corn oil-fed mice (0% EPA, 0% DPA, 6% DHA, 20% AA, 9% DTA, and 8% linoleic acid) After 5 wk this difference between the fish oil-fed and corn oil-fed mice was even more pronounced Further small changes occurred at 5-9 wk We studied the prostaglandin (PG) and thromboxane (TX) profile of macrophages prepared from mice fed the two diets just before being immunized with collagen Irrespective of diet, macrophages prepared from female mice and incubated for 24 h had significantly more PG and TX in the medium than similarly prepared macrophages from male mice The increased percentage of EPA and decreased percentage of AA in the phospholipids of the macrophages prepared from the fish oil-fed mice was reflected in a reduction in the amount of PGE2 and PGI2 in the medium relative to identically incubated macrophages prepared from corn oil-fed mice When this same fish oil diet was fed to B10RIII mice for 26 d before immunization with type II collagen, the time of onset of arthritis was increased, and the incidence and severity of arthritis was reduced compared to arthritis induced in corn oil-fed mice The females, especially those on the fish oil diet, tended to have less arthritis than the males These alterations in the fatty acid pool available for PG and leukotriene synthesis suggest a pivotal role for the macrophage and PG in the immune and/or inflammatory response to type II collagen

Reduced triglyceride formation from long-chain polyenoic fatty acids in rat hepatocytes☆

Abstract: The mechanism for the marked reduction in hepatic triglyceride secretion when rats are fed fish oils was explored in studies with isolated rat hepatocytes. Hepatocytes obtained from Sprague-Dawley rats fed either chow or fish oil or safflower oil were incubated in the presence of [3H]-glycerol to estimate triglyceride formation. In some experiments, various fatty acids, complexed to albumin, were added to the incubations. Similar experiments were carried out with hepatocytes from a genetic strain of hypertriglyceridemic, obese rats. In the absence of added fatty acid, hepatocytes from fish oil-fed rats produced and secreted substantially less triglyceride than cells from safflower oil-fed rats. However, the addition of 2 mmol/L Na oleate stimulated triglyceride formation similarly in both types of hepatocytes. When hepatocytes from chow fed rats were incubated with fatty acids of increasing chain length and unsaturation (oleate, linolenate, arachidonate, eicosapentaenoate, and docosahexaenoate), the latter two, which characterize the fish oil used, almost totally suppressed triglyceride formation. Coincubation with oleate partly reversed this effect. Hepatocytes from the hypertriglyceridemic rats synthesized significantly more triglyceride than hepatocytes from normal rats; however triglyceride formation was markedly reduced also in this strain of rat by feeding fish oil or by adding docosahexaenoate to hepatocytes in vitro. These studies confirm previous conclusions with perfused livers from fish oil-fed rats that showed diminished triglyceride production and secretion. These findings suggest that diversion of polyenoic acids from pathways of esterification is a major factor in the triglyceride lowering effect of fish oils.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary fat and mammary carcinogenesis.

Abstract: Evidence that dietary fat has an influence on carcinogenesis comes from both epidemiological data and experiments with animals. The experimental studies have indicated that dietary fat acts primarily as a promoter of carcinogenesis and that the effect depends on the type as well as the amount of fat in the diet. Vegetable oils containing polyunsaturated fatty acids of the linoleic acid family (n‐6) have been shown to enhance mammary tumorigenesis, but a fish oil containing polyunsaturated fatty acids of the linolenic acid family (n‐3) had an inhibitory effect at higher levels of intake. These and other findings suggest that the effect may be related to prostaglandins or other biologically active products of polyunsaturated fatty acids. Epidemiological data show a positive correlation between dietary fat and mortality from cancer at various sites, and this is supported by results of animal experiments in the case of colon cancer and pancreatic cancer as well as breast cancer. In the epidemiologica...

Chain-length specificities of mitochondrial and peroxisomal beta-oxidation of fatty acids in livers of rainbow trout (Salmo gairdneri).

Abstract: Peroxisomes and mitochondria were prepared from livers of rainbow trout fed diets containing either 15% crude fish oil (CFO) or 11.5% partially hydrogenated fish oil (PHFO) plus 3.5% CFO. Peroxisomal preparations from the two dietary groups showed similar rates and substrate specificity patterns for acyl-CoA oxidation. The peroxisomal oxidation rate was highest with 12:0-CoA and decreased with increasing chain length, being negligible with 22-carbon acyl-CoA's. The trans isomer of 18:1(n-9) was oxidized at a higher rate than the cis isomer only by peroxisomes from the PHFO + CFO group. Mitochondria prepared from both groups of fish exhibited a broad chain-length specificity for the oxidation of acylcarnitines. Both polyunsaturated and trans monoenoic fatty acids were readily oxidized.

Effects of dietary polyunsaturated fatty acid deficiencies on mortality, growth and gill structure in the turbot, Scophthalmus maximus

Abstract: The preparation of fish oil concentrates containing only (n-3) polyunsaturated fatty acids (PUFA) with different ratios of 20:5 (n-3)/22:6 (n-3) is described. Three groups of turbot were maintained on different diets containing: 1, 10% of the dry weight of the diet as natural fish oil, equivalent to 2.5% (n-3) PUFA and 0–23% (n-6) PUFA; 2, 10% of the dry weight of the diet as palmitic acid, i.e. no PUFA; 3, 8–7% palmitic acid and 1–3% of the dry weight as (n-3 PUFA and negligible (n-6) PUFA. Only the fish on the diet containing natural fish oil showed significant growth over a 15-week period. In addition there were high mortalities on the two experimental diets (2 and 3). Changing the ratio of 20:5 (n-3)/22:6 (n-3) from 13–8 to 2–2 in the diet containing 1 3% (n-3) PUFA and negligible (n-6) PUFA markedly decreased the mortalities. Fish fed the two experimental diets (2 and 3) developed gross changes in gill structure involving the disappearance of chloride cells, a ‘sloughing off’ of the epithelium along the primary and secondary filaments and an accumulation of cellular material in the inter-lamellar spaces. The tissue ultimately disintegrated to leave a skeleton of connective tissue and a mass of cellular material in the inter-lamellar spaces. It is concluded that 22:6 (n-3) is an essential fatty acid for turbot and that the gill epithelium is a sensitive indicator of this deficiency in this species.

Effects of dietary fish oil supplementation on the fatty acid composition of the human platelet membrane: demonstration of selectivity in the incorporation of eicosapentaenoic acid into membrane phospholipid pools.

Abstract: The fatty acid composition of membrane phospholipids of stimulated and unstimulated platelets was studied in six normal volunteers given a daily dietary supplement of a fish oil rich in eicosapentaenoic acid (EPA) for 4 weeks. The supplement was equivalent to 1.8 g of EPA daily. Thromboxane synthesis and platelet aggregation responses to sodium arachidonate, thrombin and the ionophore A23187 were also investigated. A marked increase in the relative EPA content of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was noted after 2 and 4 weeks fish oil supplementation. However, there was no incorporation into phosphatidylinositol (PI) or phosphatidylserine (PS). The relative arachidonic acid (AA) content of PC and PE was significantly reduced at 2 and 4 weeks but that of PI and PS remained unchanged. Significant reductions in the relative linoleic acid content of total phospholipids, PC and PE were also noted. Stimulation of platelets obtained after 4 weeks fish oil supplementation by thrombin and A23187 was associated with a marked reduction in the AA content of PI and a minor reduction in that of PE. There was no change in the relative proportions of EPA in PI, PS, PC or PE after stimulation. Throughout the study there were no significant changes in platelet aggregation responses or in platelet thromboxane production. Our results indicate that the incorporation of EPA into the platelet membrane phospholipids is selective and that if PI is the major source of AA for platelet prostaglandin biosynthesis then the reported beneficial effects of EPA on haemostasis cannot be explained on the basis of its incorporation into and mobilization from the platelet membrane phospholipid pool.

Effect of Dietary Intake of Fish Oil and Fish Protein on the Development of l-Azaserine-Induced Preneoplastic Lesions in the Rat Pancreas

Abstract: The effect of dietary intake of fish (menhaden) oil and fish (cod) protein on the development of pancreatic preneoplastic lesions was examined in male Wistar rats. Fourteen-day-old animals were given a single ip injection of 30 mg L-azaserine/kg body weight [CAS: 115-02-6; diazoacetate serine (ester)]. At 21 days of age they were weaned and maintained on dietary treatment for 4 months. Fish protein did not appear to produce a significantly different preneoplastic response when compared to casein as a protein source. However, a 20% menhaden oil diet, rich in omega 3 fatty acids, produced a significant decrease in the development of both the size and number of preneoplastic lesions when compared to a 20% corn oil diet rich in omega 6 fatty acids. This study provides evidence that fish oils, rich in omega 3 fatty acids, may have potential as inhibitory agents in cancer development.

The isolation of omega-3 polyunsaturated fatty acids and methyl esters of fish oils by silver resin chromatography

Abstract: Multigram quantities of the highly unsaturated ω3 component from samples of fish oil fatty acids and esters were isolated by silver resin chromatography. An XN1010 resin column saturated with silver ions was utilized. Polyunsaturated fatty acid (PUFA) esters from fish oil concentrate (FOC) were fractionated based on the number of double bonds by using solvent programming (acetonitrile in methanol). Larger samples (4–9 g) of FOC acids and esters and menhaden acids and esters were enriched in ω3 polyunsaturates to 82–99% (95–99% total PUFA) by use of a large 100% silver resin column and isocratic elution with 30, 35 or 45% acetonitrile in acetone.

Stabilisation of protein and oil in fish silage for use as a ruminant feed supplement

Abstract: Fish silage was prepared from 96.5% offal obtained from Atlantic cod fillet processing and 3.5% (by wt) formic acid. The fish silage became an homogeneous liquid of low viscosity in 36–58 h at 20°C; however, the oil and protein components continued to be hydrolysed for several months. Addition of formaldehyde to fish silage (0.25 or 0.39% by wt) after liquefaction was complete, served to prevent continued protein hydrolysis and oxidative rancidity of the oil. It also decreased the development of ‘off-odours’, and the formation of total volatile bases. Fish silage was readily absorbed by hay at a ratio of 1.5 parts silage to 1.0 parts hay by weight; the product is referred to as ‘haylage’. Voluntary intake by wethers of ‘haylage’ prepared from de-oiled, formaldehyde-treated fish silage was better than for ‘haylage’ prepared from untreated fish silage. The crude protein content of ‘haylage’ rations was more than satisfactory for fattening lambs, although the energy content of ‘haylage’ rations may be a limiting factor. Retention of fish oil in the silage to increase the energy content of rations was unsuccessful because voluntary feed intake was depressed. The addition of formaldehyde to fish silage is advantageous when the product is to be fed to ruminant livestock since protein and lipid degradation in the feed, and also possibly in the rumen, are minimised and voluntary intake of ‘haylage’ by sheep is increased.

Value of Menhaden Oil in Diets of Florida Pompano

Abstract: Florida pompano (Trachinotus carolinus) juveniles were fed to satiation twice daily on one of four experimental diets containing 12, 8, 4, or 0% menhaden fish oil for 48 days in flowing-water tanks at 28 C (82 F). Basalingredients of the diets were lipid-extracted menhaden fish meal (50%), lipid-extracted, dehulled soybean meal (20%), dextrin (8.9%), cellulose (variable with fish oil) and vitamin and mineral supplements. Fish fed the 8% oil diet gained more weight than those fed the 0 to 12% fish oil diet. Fish fed the diet containing no fish oil gained less weight than those fed any of the diets containing fish oil and had deformed gill opercula and filaments. The gill anomalies are presumed to have been caused by essential lipid deficiencies in the diet. Energy deficiency could also have been responsible for poor growth by the fish fed the diet without fish oil. Energy excess could have caused the fish fed the highest level of fish oil to consume less diet and, therefore, been responsible for t...

Influence of fish-oil supplements on man.

Abstract: Cod-liver oil has been used as a household remedy for centuries and over the course of time scientific explanations for its properties have become available. The first extensive clinical tests of cod-liver oil seem to have been made by Samuel Kay, a physician at the Manchester Infirmary from 1752 to 1784. He gave doses of cod-liver oil to patients suffering from bone diseases and rheumatism and wrote ‘the good effects of it are so well known among the poorer sort that it is particularly requested by them for almost every lameness’. Cod-liver oil played a central role in the isolation and discovery of vitamins A and D because it was known to cure night blindness, corneal xerosis and rickets. The nutritional value of cod-liver oil was officially acknowledged during World War I1 by the Ministry of Food who established a scheme for the free distribution of the oil to all infants up to 5 years old and to pregnant and nursing women. The issue of cod-liver oil by the Ministry of Food had a remarkable effect on the sales of the oil after the war. Indeed, the administration of cod-liver oil to children was widespread until the late 1950s. Cod-liver and halibut-liver oils still remain a popular supplementary source of vitamins A and D. There has been renewed interest in fish-oil supplements since Dyerberg et al. (1978) postulated that dietary eicosapentaenoic acid (20:503; EPA) may offer protection against acute myocardial infarction by way of its influence on blood lipids, prostaglandins and haemostatic function. Fish oil is a readily available source of EPA, consequently fish-oil supplements have been used to evaluate the effect of EPA on blood lipids, haemostasis and eicosanoid production. Different fish oils of varying composition and dose have been used so there are difficulties in extrapolating the results from one study to another. It should be emphasized that fish oils do contain other pharmacologically active ingredients apart from EPA. Most fish oils contain significant amounts of other 0 3 polyunsaturated fatty acids such as docosahexaenoic acid (22:603; DHA), which shares several of the pharmacological effects of EPA (Corey et al. 1983), and so there is no justification in attributing all the effects observed with fish-oil supplements to EPA. The fatty acid composition of fish oil varies considerably from species to species and seasonally (Ackman, 1982) and is dependent on the food chain. As a rule fish oils from cold-water fish contain high proportions of 0 3 fatty acids, mainly EPA and DHA with smaller amounts of 18:403 and 22:503. The oils from certain tropical fish contain a relatively high proportion of arachidonic acid (20:406; AA) (O’Dea & Sinclair, 1982). Generally, fish-liver oils contain high levels of vitamins A and D, the highest concentrations being found in sharkand halibut-liver oil. Oils extracted from the crushed whole fish such as anchovy, sardine and menhaden oil contain far lower

Dietary fish oil prevents dexamethasone induced hypertension in the rat.

Abstract: 1. This study was designed to examine the effect of dexamethasone treatment on tissue and urinary prostanoids, and to determine whether inhibition of prostaglandin biosynthesis by manipulation of dietary fatty acids accelerates the development of glucocorticoid hypertension. 2. Forty-eight rats were placed on either a 2-series prostaglandin ‘inhibitory’ diet (cod liver oil/linseed oil) or a control diet of saturated fat for an initial period of 4 weeks. The groups were then divided into two so that half of each received dexamethasone in their drinking water (2.5 mg/1) for 1 week whilst continuing their respective dietary regimens. 3. Rats on the cod liver oil diet incorporated eicosapentaenoic acid into tissue stores with a corresponding decrease in arachidonic acid, and significantly impaired ability to generate serum thromboxane B 2 (33%), aortic 6-oxo-prostaglandin F 1α (44%), renal homogenate prostaglandin E 2 (45%) and 6-oxo-prostaglandin F 1α (74%) and urinary prostaglandin E 2 (84%) and 6-oxo-prostaglandin F 1α (79%). 4. Despite the diminished levels of vasodilator 2-series prostaglandins, the cod liver oil diet prevented the development of glucocorticoid induced hypertension. 5. Relative to their respective dietary controls, dexamethasone treatment resulted in decreased serum thromboxane B 2 (20%) but increased aortic 6-oxo-prostaglandin F 1α (186%), renal homogenate prostaglandins (127–230%) and urinary excretion of prostaglandin E 2 (640–860%) and 6-oxo-prostaglandin F 1α (230–365%) in both dietary groups. 6. It therefore seems unlikely that glucocorticoid induced hypertension is a consequence of inhibition of vasodilator prostaglandin synthesis.

Long‐term effects of high‐fat diets on peroxisomal β‐oxidation in male and female rats

Abstract: In weanling male rats a 4-fold increase of heart triacylglycerols was observed after three days on a high-fat diet containing partially hydrogenated fish oil (PHFO). In female rats this increase was only about 50%. No significant differences were observed between female and male rats in the fatty acid composition of the accumulated lipids. The initial level of peroxisomal β-oxidation activity was similar in male and female rats in both liver and heart. After three weeks of receiving high-fat diets, the rats showed a marked increase in peroxisomal β-oxidation activity with PHFO in the diet and less with soybean oil (SO), confirming previous studies with male rats. Catalase activity was similarly affected in hearts of both sexes. In male rats the levels of peroxisomal β-oxidation observed after three weeks of feeding on the high-fat diets were found to be maintained, both in liver and heart, during a feeding period of three months. The response to high-fat diets in females, however, seems to be further accentuated after three months of feeding, resulting in a capacity of peroxisomal β-oxidation in liver of about three times that of the male rats when calculated on a total body-weight basis.

Effect of dietary fats on experimental hypertension.

Abstract: In an experiment on 95 Wistar rats weighing 330 g the effect was studied of partially hydrogenated marine oil and cod-liver oil as well as sunflowerseed oil and animal fat on arterial hypertension induced with administration of 1.5% NaCl in drinking water. During 5 weeks the animals received diets containing 37.8 kcal% derived from the studied fats. After the first week of 1.5% NaCl solution administration a significant rise of the systolic blood pressure and heart rate was observed in all animals without regard to the fat received by them with the diet. The rise of the blood pressure was greatest in the group of rats kept on the diet with animal fat, while in the groups of rats receiving diets with sunflowerseed oil or marine oils this rise was significantly smaller, especially with cod-liver oil. The hypotensive effect of marine oils, particularly cod-liver oil, was more pronounced than that of sunflowerseed oil. The hypotensive effect of partially hydrogenated fish oil was less pronounced than that of cod-liver oil. Our experiments demonstrated a significant effect of the amount of dietary fat on the development of experimental hypertension. Greater intake of salt and animal fats in human diet may be one of the causes of essential hypertension.