Compositional Changes and Enrichment of Mediterranean Finfish During Pan Frying With Virgin Olive Oil

Eight species of small Mediterranean finfish were prepared and pan-fried in virgin olive oil, according to traditional Greek culinary practices. The changes in their proximate composition, energy content, fatty acids, squalene, cholesterol, β-sitosterol, campesterol, and stigmasterol were investigated. Pan-fried fish contained more protein, total fat, monounsaturated fatty acids, energy, and cholesterol and were enriched in squalene and phytosterols than the raw samples. The results suggest that fish pan-fried in olive oil can be classified as highly nutritive in regard to its protein, major fatty acid classes, n-6/n-3 ratios, and total fat content. It provides an additional intake of squalene and phytosterols for Mediterranean people.     

Dietary Evaluation of Vegetables Pan-Fried in Virgin Olive Oil Following the Greek Traditional Culinary Practice

The aim of this work was the nutritional evaluation of fresh vegetables, pan-fried in virgin olive oil according to the traditional Greek culinary practices. The vegetables studied (potatoes, green peppers, zucchini, and eggplant) are traditionally consumed after pan-frying in virgin olive oil in Greece and other Mediterranean countries. The fried samples contained less moisture, more fat, and more energy when compared to the raw ones, while they were significantly enriched in squalene, β-sitosterol, campesterol, and stigmasterol. Their fatty acid composition reflected that of the olive oil they absorbed. The results obtained indicate that among other nutritional benefits of their consumption, vegetables fried in virgin olive oil appear to represent a healthy lipid profile in regard to fatty acid classes and their atherogenic and thrombogenic indices, while they furthermore provide an additional intake of monounsaturated fat, squalene, and phytosterols for Mediterranean peoples.     

Dietary Evaluation of Vegetables Pan-Fried in Virgin Olive Oil Following the Greek Traditional Culinary Practice

The aim of this work was the nutritional evaluation of fresh vegetables, pan-fried in virgin olive oil according to the traditional Greek culinary practices. The vegetables studied (potatoes, green peppers, zucchini, and eggplant) are traditionally consumed after pan-frying in virgin olive oil in Greece and other Mediterranean countries. The fried samples contained less moisture, more fat, and more energy when compared to the raw ones, while they were significantly enriched in squalene, β-sitosterol, campesterol, and stigmasterol. Their fatty acid composition reflected that of the olive oil they absorbed. The results obtained indicate that among other nutritional benefits of their consumption, vegetables fried in virgin olive oil appear to represent a healthy lipid profile in regard to fatty acid classes and their atherogenic and thrombogenic indices, while they furthermore provide an additional intake of monounsaturated fat, squalene, and phytosterols for Mediterranean peoples.     

Lipid metabolism responses in rats fed beef tallow, native or randomized fish oil and native or randomized peanut oil

In experiments with male Wistar rats, we measured the effects of nonpurified diets containing 9.1% added fat (beef tallow, native or randomized fish oil, native or randomized peanut oil) on apparent digestibility of total fat and individual fatty acids. We also investigated the effects of the diets on plasma contents of triglyceride, cholesterolesters and free and total cholesterol as well as on the fatty acid profiles of plasma and liver phospholipids. Randomization of fish oil or peanut oil had no significant effect on any of the lipid measurements. Fat digestibility was significantly lower in the rats fed beef tallow. Apparent absorption of 18:1(n-9) and polyunsaturated fatty acids was not dependent on the fatty acid profile of the dietary fat. Apparent absorption of 16:1(n-7) and saturated fatty acids was generally highest in the rats fed fish oil. Intake of fish oil or peanut oil significantly decreased plasma triglyceride content. Intake of fish oil resulted in substantially decreased contents of total cholesterol and cholesterolesters in plasma, but intake of peanut oil did not. Efficiency of conversion of 18:2(n-6) into 20:4(n-6) was inhibited by long-chain (n-3) fatty acids.     

Fatty acid profile, tocopherol, squalene and phytosterol content of walnuts, almonds, peanuts, hazelnuts and the macadamia nut

Nuts are high in fat but have a fatty acid profile that may be beneficial in relation to risk of coronary heart disease. Nuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols and squalene. In the present study, the total oil content, peroxide value, composition of fatty acids, tocopherols, phytosterols and squalene content were determined in the oil extracted from freshly ground walnuts, almonds, peanuts, hazelnuts and the macadamia nut. The total oil content of the nuts ranged from 37.9 to 59.2%, while the peroxide values ranged from 0.19 to 0.43 meq O2/kg oil. The main monounsaturated fatty acid was oleic acid (C18:1) with substantial levels of palmitoleic acid (C16:1) present in the macadamia nut. The main polyunsaturated fatty acids present were linoleic acid (C18:2) and linolenic acid (C18:3). alpha-Tocopherol was the most prevalent tocopherol except in walnuts. The levels of squalene detected ranged from 9.4 to 186.4 microg/g. beta-Sitosterol was the most abundant sterol, ranging in concentration from 991.2 to 2071.7 microg/g oil. Campesterol and stigmasterol were also present in significant concentrations. Our data indicate that all five nuts are a good source of monounsaturated fatty acid, tocopherols, squalene and phytosterols.     

Fatty acid saturation of the diet and plasma lipid concentrations, lipoprotein particle concentrations, and cholesterol efflux capacity

BACKGROUND: The fatty acid content and saturation degree of the diet can modulate HDL composition and cholesterol efflux. OBJECTIVE: We studied the modifications in plasma lipoprotein particles and serum capacity to stimulate cholesterol efflux induced by different fatty acids. DESIGN: Seventeen women and 24 men followed in the same sequence 4 diets containing 35% of total energy as fat. The saturated fat diet contained 17% palm oil; the monounsaturated fat diet, 20.9% olive oil; the n-6 polyunsaturated fat diet, 12.5% sunflower oil; and the n-3 polyunsaturated fat diet, sunflower oil supplemented with 4-4.5 g fish oil/d. Each phase lasted 4-5 wk. RESULTS: In both sexes, apolipoprotein (apo) A-I concentrations were significantly lower with unsaturated fat diets than with the saturated fat diet, but concentrations of lipoproteins containing only apo A-I (Lp A-I) were lower only in the men. Concentrations of lipoproteins containing both apo A-I and apo A-II (Lp A-I:A-II) were lower with both polyunsaturated fat diets in the women but significantly higher in the men. Lp E concentrations were significantly higher with the 2 polyunsaturated fat diets. Lp E non-B particle concentrations were not modified in the men but were significantly higher in the women in both polyunsaturated fat phases. Lp C-III concentrations were higher with the saturated fat diet only in the men. The serum samples taken after the n-3 polyunsaturated fat phase were the most efficient for extracting cellular cholesterol in both sexes. CONCLUSIONS: The monounsaturated and polyunsaturated fat diets were healthier, producing a better lipid profile. The n-3 polyunsaturated fat diet increased the capacity of serum to promote the efflux of cholesterol from cells in culture.     

Fatty acid profile,tocopherol, squalene and phytosterol content of walnuts,almonds, peanuts,hazelnuts and the macadamia nut

Nuts are high in fat but have a fatty acid profile that may be beneficial in relation to risk of coronary heart disease. Nuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols and squalene. In the present study, the total oil content, peroxide value, composition of fatty acids, tocopherols, phytosterols and squalene content were determined in the oil extracted from freshly ground walnuts, almonds, peanuts, hazelnuts and the macadamia nut. The total oil content of the nuts ranged from 37.9 to 59.2%, while the peroxide values ranged from 0.19 to 0.43 meq O₂/kg oil. The main monounsaturated fatty acid was oleic acid (C18:1) with substantial levels of palmitoleic acid (C16:1) present in the macadamia nut. The main polyunsaturated fatty acids present were linoleic acid (C18:2) and linolenic acid (C18:3). α-Tocopherol was the most prevalent tocopherol except in walnuts. The levels of squalene detected ranged from 9.4 to 186.4 μg/g. β-Sitosterol was the most abundant sterol, ranging in concentration from 991.2 to 2071.7 μg/g oil. Campesterol and stigmasterol were also present in significant concentrations. Our data indicate that all five nuts are a good source of monounsaturated fatty acid, tocopherols, squalene and phytosterols.     

Effects of trace components of dietary fat on cholesterol metabolism: phytosterols,oxysterols, and squalene

The effect of dietary fats on serum cholesterol is widely assumed to be due solely to the fatty acids and cholesterol they contain. Phytosterols, sterol oxidation products, and sterol precursors such as squalene, however, are often present in dietary fats. Little is known of the physiology of these substances in natural foods and most published diet studies do not consider them at all. Supplementation of the diet with high-dose phytosterols is now recommended for prevention of heart disease, but both recent and old data strongly suggest that the lower levels of phytosterols naturally present in vegetable fats may also reduce cholesterol absorption and serum cholesterol substantially. Moreover, unmeasured phytosterols may confound otherwise well-controlled diet studies because there is an inverse correlation between phytosterol and saturated fatty acid content of vegetable fats. Sterol oxidation products, many of which are found in foods, are potent regulators of lipoprotein and cholesterol transport pathways in vitro. Squalene is a phytosterol precursor abundant in olive oil that is at least partly absorbed and then quantitatively converted to cholesterol. The effects of dietary triglyceride-derived fatty acids have not been experimentally separated from the effects of trace fat components in most clinical studies. A better understanding of the activity of sterol-related dietary components is needed to reduce variability in diet studies, accurately assess the effects of dietary fatty acids and to maximize the effectiveness of dietary treatment for hypercholesterolemia.     

Fat and protein from olive oil-fried sardines interact to normalize serum lipoproteins and reduce liver lipids in hypercholesterolemic rats

Fatty fish consumption has been recommended due to its high (n-3) PUFA content. However, an effect of its protein on serum lipids and lipoproteins has also been suggested. The present study was designed to determine the acceptability of diets containing sardines fried in olive oil or the fat extracted from those sardines and the normalization of serum lipids and lipoproteins, the hepatic lipid profile, and the fatty acid composition of the liver of growing Wistar rats fed these diets after dietary loading of cholesterol. Hypercholesterolemia was induced for 3 wk by feeding rats a casein/olive oil/cholesterol diet. Rats were then switched for 2 wk to cholesterol-free purified diets containing casein plus olive oil (CO), sardines fried in olive oil (S) and casein plus the fat extracted from sardines fried in olive oil (CSF). The S and CSF diets were well accepted by the rats. Withdrawal of dietary cholesterol markedly reduced (P < 0.05) serum cholesterol level in all of the groups, but the S group had the greatest decrease and the CO group the smallest decrease. The S group had a more normal lipoprotein profile, in which HDL was the major lipid carrier, whereas rats of the CO group still had beta-VLDL particles. CSF-fed rats had an intermediate profile. Liver fat and total, free and esterified cholesterol levels were lower (P < 0,05) in the S group than in the other two groups. The S and CSF diets increased (P < 0.05) the (n-3) PUFA content in hepatic triacylglyceride, cholesterol ester and phospholipid fractions. The liver fatty acid profile of the S group was more normalized than those of the other two groups. These findings suggest that the inclusion in the diet of whole sardines fried in olive oil normalizes cholesterol metabolism in hypercholesterolemic rats more quickly than consumption of their extracted fat.     

Effects of fat emulsions with different fatty acid composition on plasma and hepatic lipids in rats receiving total parenteral nutrition

Effects of different fatty acids on the development of hepatic steatosis were studied in rats receiving total parenteral nutrition (TPN). 65 rats, with internal jugular catheters, were divided into one control group (n = 8), and four experimental groups (n = 13-15 each). The control group was fed a chow diet and all experimental groups received TPN. TPN provided 300 kcal/kg/day with 40% of the non-protein energy provided as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fatty acid composition of the fat emulsion. Four kinds of fat emulsions rich in: 1) medium chain fatty acids (C8:0,C10:0), 2) oleic acid (C18:1 n-9), 3) linoleic acid (C18:2 n-6), 4) eicosapentaenoic acid (C20:5 n-3)/docosahexaenoic acid (C22:6 n-3), were used. These fat emulsions were prepared with: 1) a mixture of medium chain triglycerides (MCT) and soybean oil (9:1), 2) olive oil, 3) safflower oil, 4) fish oil, respectively. The results of the study demonstrated a higher hepatic lipid content in the olive oil and safflower oil groups than in the control group, whereas no significant difference was seen between the MCT and control groups. Also, no difference was observed between the fish oil and control groups. With regard to the plasma lipids, the MCT group and olive oil group produced hyperlipidaemia. The plasma of the safflower oil and fish oil groups, however, had a low lipid concentration comparable to the control group. These results suggest that TPN with a fat emulsion prepared with fish oil does not cause hyperlipidaemia nor induce hepatic steatosis in normal rats.     

Absorption of the n-3 eicosapentaenoic and docosahexaenoic acids as ethyl esters and triglycerides by humans.

Five normolipemic subjects received three test meals containing 28 g n-3 (omega-3) fatty acids provided as 1) triglycerides, 2) ethyl esters, and 3) ethyl esters + 12 g olive oil. The control meal contained olive oil. When equivalent amounts of fat were given, the increase in chylomicron and plasma triglycerides was similar; n-3 fatty acid contents were also similar after n-3 fatty acid intake as ethyl esters or triglycerides. Ethyl esters alone were well absorbed and produced similar n-3 fatty acid responses in plasma triglycerides and chylomicrons. At 24 h after the n-3 fatty acid-containing meals, the fatty acid plasma concentration of these acids was similar. This study showed that n-3 fatty acids in fish oil given as ethyl esters or triglycerides were equally well absorbed. Eicosapentaenoic and docosahexaenoic acids were also equally absorbed.     

Effect of extra-virgin olive oil and fish-oil supplementation on plasma lipids and susceptibility of low-density lipoprotein to oxidative alteration in free-living spanish male patients with peripheral vascular disease.

The aim of this study was to analyse the in vivo effect of a diet rich in extra-virgin olive oil and a fish-oil supplement on plasma and lipoprotein fatty-acid composition and on LDL susceptibility to oxidative modification in free-living Spanish male patients with peripheral vascular disease. A total of 12 patients were included in the experimental group which received extra virgin olive oil and a fish oil supplement (group OF). On the other hand, 13 patients which had refined olive oil as the main visible fat were considered as Control group. Plasma triglycerides decreased significantly after three months of dietary intervention. The LDL and plasma fatty-acid pattern in the group OF was characterized by a significant increase in n-3 polyunsaturated fatty acids, mainly 20:5 n-3 and 22:6 n-3. The slopes of LDL oxidative susceptibility were similar between baseline and endpoint values in both groups. However, the uptake of oxidized LDL by macrophages was significantly reduced in OF patients in comparison with the Control group. In conclusion, the daily intake of about 40 g/d of extra-virgin olive oil in combination with a daily supplement of 16 g of fish oil for 3 months in patients with peripheral vascular disease leads to a plasma-lipid profile less atherogenic than in patients having refined olive oil as the main visible food fat. The simultaneous consumption of alpha-tocopherol and natural antioxidants provided by extra-virgin olive oil seems to have a protective effect on the LDL susceptibility to oxidative modifications in spite of a higher proportion of n-3 polyunsaturated fatty acids.     

What are the health effects of fat?

In order to answer the question which health benefits are to be expected from dietary fat, we have to differentiate between different kinds of fat with varying fatty acid composition. Saturated fatty acids are commonly judged to have a negative health impact as they lead to increased serum cholesterol levels and a higher risk of coronary heart disease. Therefore, all recommendations stress the importance to limit the intake of saturated fatty acids. Monounsaturated fatty acids, on the other hand, have a positive impact on the serum lipid profile, lead to decreased LDL-oxidation and favorably influence the metabolism of diabetics. However, it is essential that monounsaturated fatty acids be mainly supplied by plant oils like rape seed or olive oil and not by foods that are simultaneously rich in saturated fatty acids. Concerning polyunsaturated fatty acids, it is important to increase the supply of n-3 fatty acids (ratio of n-6:n-3: about 5:1) as there is substantial evidence for their protective effects. If the fatty acid composition of the diet is optimized, even a total dietary fat content of 35% of total energy intake can be adequate as long as there is enough physical activity and the diet is rich in plant-derived foods like vegetables, fruits, cereals, potatoes, beans and legumes.     

Effect of dietary olive oil, corn oil and medium-chain triglycerides on the lipid composition of rat red blood cell membranes

The effects of dietary olive oil, corn oil and medium-chain triglycerides (MCT) on factors that characterized erythrocyte membrane lipid fluidity were studied. Weanling rats were fed for 3 or 5 wk high fat diets (10%) containing olive oil, corn oil or a mixture of MCT with olive oil or corn oil. Total phospholipids and phosphatidylcholine of erythrocyte ghosts obtained from olive oil-fed animals, as compared to those fed corn oil, showed an increase in long-chain polyunsaturated fatty acids (PUFA) of the (n-6) and (n-3) series and a decrease in saturated fatty acids. The addition of MCT to the olive oil diet induced an increase in palmitic, palmitoleic and delta-5,8,11-eicosatrienoic acids and a decrease in long-chain PUFA of the (n-6) series in erythrocyte membrane phospholipids. Conversely, rats fed a mixture of MCT and corn oil, as compared to those fed exclusively corn oil, showed increase in long-chain PUFA of the (n-6) and (n-3) series, with no changes in saturated fatty acid levels. The cholesterol/phosphorus molar ratio showed only a slight increase with MCT supplementation. Olive oil feeding induced important changes in fatty acid composition of erythrocyte membrane phospholipids as compared to corn oil feeding without modifying the cholesterol/phosphorus ratio and MCT feeding slightly affected red blood cell membrane lipid composition.     

Dietary n-3 and n-6 fatty acids alter avian metabolism: metabolism and abdominal fat deposition

The effects of dietary saturated fatty acids and polyunsaturated fatty acids (PUFA) of the n-3 and n-6 series on weight gain, body composition and substrate oxidation were investigated in broiler chickens. At 3 weeks of age three groups of chickens (n 30; ten birds per group) were fed the fat-enriched experimental diets for 5 weeks. These diets were isonitrogenous, isoenergetic and contained 208 g protein/kg and 80 g edible tallow, fish oil or sunflower oil/kg; the dietary fatty acid profiles were thus dominated by saturated fatty acids, n-3 PUFA or n-6 PUFA respectively. Resting RQ was measured in five birds from each treatment group during weeks 4 and 5 of the experiment. There were no significant differences between treatments in total feed intake or final body mass. Birds fed the PUFA diets had lower RQ and significantly reduced abdominal fat pad weights (P<0.01) compared with those fed tallow. The dietary lipid profile changes resulted in significantly greater partitioning of energy into lean tissue than into fat tissue (calculated as breast lean tissue weight:abdominal fat mass) in the PUFA groups compared with the saturated fat group (P<0.01; with no difference between the n-3 and n-6 PUFA groups). In addition, the PUFA-rich diets lowered plasma concentrations of serum triacylglycerols and cholesterol. The findings indicate that dietary fatty acid profile influences nutrient partitioning in broiler chickens.     

富含EPA浓缩鱼油抑制血小板聚集的机理探讨

流行病学和实验室资料均提示富含EPA鱼油(简称鱼油)具有抑制血小板聚集和抗血栓形成的作用。本文主要探讨鱼油抑制血小板聚集的机理。实验分别将大鼠和家兔随机分成4组:正常组、高脂组、鱼油组、橄榄油组。按各自不同饲料喂养3个月以后,4组大鼠血浆TXB_2/6-酮-PGF_(1a)比值分别为1.4,2.2,1.0,1.7。鱼油组血小板内cAMP含量明显高于高脂组(P<0.05)。鱼油组血清总胆固醇值、血浆TXB_2、5-羟色胺(5-HT)、钙离子浓度、纤维蛋白原含量及血液粘度(低切)均明显低于高脂组(P<0.05)。鱼油组血浆、血小板、心肌及肝脏中EPA、DHA含量明显高于其它3组(P<0.001)。以上结果提示,鱼油抑制血小板聚集和血栓形成的机理可能是,鱼油中的EPA和DHA等高不饱和脂肪酸纳入细胞膜后竞争抑制花生四烯酸(AA)代谢,减少血小板TXA_2生成和释放,降低血中TXA_2/PGI_2比值,同时增加血小板内cAMP含量,稳定血小板功能,减少5-HT,钙离子等具有促聚活性物质释放。另外,鱼油降低血脂、血浆纤维蛋白原含量及血液粘度,从而改善血液流变性,使血小板本身及其周围环境得以改善,防止血小板聚集和血栓形成。     

Comparing palmolein with different predominantly monounsaturated oils: effect on plasma lipids

Our group has compared plasma lipids in randomised crossover trials in which approximately half the fat intake of subjects was changed from palmolein to each of three predominantly monounsaturated oils in a series of experiments in free living volunteers. With canola oil total cholesterols were lower than on palmolein; part of this reduction was due to lower HDL-cholesterol (HDL-c) so that total cholesterol/ HDL-c was only 2% lower. With olive oil mean total cholesterols were the same as on palmolein but HDL-cholesterols were a little lower and LDL-cholesterols a little higher. Plasma lipid fatty acid patterns confirmed the diet change, showing 5% higher 16 : 0 on palmolein and 11% higher 18 : 1 on olive oil. To test the possibility that lack of effect of the extra palmitic acid in the palmolein–olive oil comparison was because subjects were young, thin and active, comparison of a third oil, high oleic sunflower oil (HOSO) with palmolein was made in both young and middleaged subjects. Plasma total and LDL-cholesterols were 7% lower in the whole group on HOSO but HDL-c was also 5% lower so total cholesterol/HDL-c was only 3% lower than on palmolein. There was no difference in lowering of LDL-c on HOSO between young and older subjects. In comparisons of all three predominantly monounsaturated oils with palmolein a higher HDL-c on palmolein reduced the presumed health benefit of lower total cholesterols on canola and high oleic sunflower oil. The reason for no reduction of total cholesterol on olive oil compared with palmolein was presumably due to the higher linoleic and higher phytosterols in palmolein and higher squalene in the olive oil.     

Fatty acid profile, tocopherol, squalene and phytosterol content of brazil, pecan, pine, pistachio and cashew nuts

Nuts contain bioactive constituents that elicit cardio-protective effects including phytosterols, tocopherols and squalene. The objective of the present study was to determine the total oil content, peroxide value, fatty acid composition and levels of tocopherols, squalene and phytosterols in oil extracted from freshly ground brazil, pecan, pine, pistachio and cashew nuts. The total oil content of the nuts ranged from 40.4 to 60.8% (w/w) while the peroxide values ranged from 0.14 to 0.22 mEq O2/kg oil. The most abundant monounsaturated fatty acid was oleic acid (C18:1), while linoleic acid (C18:2) was the most prevalent polyunsaturated fatty acid. The levels of total tocopherols ranged from 60.8 to 291.0 mg/g. Squalene ranged from 39.5 mg/g oil in the pine nut to 1377.8 mg/g oil in the brazil nut. beta-Sitosterol was the most prevalent phytosterol, ranging in concentration from 1325.4 to 4685.9 mg/g oil. In conclusion, the present data indicate that nuts are a good dietary source of unsaturated fatty acids, tocopherols, squalene and phytosterols.     

Effect of dietary fatty acid composition on inositol-, choline- and ethanolamine-phospholipids of mammary tissue and erythrocytes in the rat.

The present study investigated the effect of feeding maize-oil, olive-oil and fish-oil diets, from weaning to adulthood, on rat mammary tissue and erythrocyte phospholipid fatty acid compositions. Effects of diet on the relative proportions of membrane phospholipids in the two tissues were also investigated. Mammary tissue phosphatidylinositol (PI) fatty acids were unaltered by diet, but differences in phosphatidylethanolamine (PE) and, to a lesser extent, phosphatidylcholine (PC) fractions were found between animals fed on different diets from weaning. Differences observed were those expected from the dietary fatty acids fed; n-6 fatty acids were found in greatest amounts in maize-oil-fed rats, n-9 in olive-oil-fed rats, and n-3 in fish-oil-fed rats. In erythrocytes the relative susceptibilities of the individual phospholipids to dietary modification were: PE > PC > PI, but enrichment with n-9 and n-3 fatty acids was not observed in olive-oil- and fish-oil-fed animals and in PC and PE significantly greater amounts of saturated fatty acids were found when animals fed on olive oil or fish oil were compared with maize-oil-fed animals. The polyunsaturated:saturated fatty acid ratios of PE and PC fractions were significantly lower in olive-oil- and fish-oil-fed animals. No differences in the relative proportions of phospholipid classes were found between the three dietary groups. It is suggested that differences in erythrocyte fatty acid composition may reflect dietary-induced changes in membrane cholesterol content and may form part of a homoeostatic response the aim of which is to maintain normal erythrocyte membrane fluidity. The resistance of mammary tissue PI fatty acids to dietary modification suggests that alteration of PI fatty acids is unlikely to underlie effects of dietary fat on mammary tumour incidence rates.     

Olive oil, corn oil, and n-3 fatty acids differently affect lipids, lipoproteins, platelets, and superoxide formation in type II hypercholesterolemia.

To evaluate which dietary fat may provide the best response in terms of plasma lipids and lipoproteins and also of platelet aggregability and superoxide formation by white blood cells, 12 type II patients were randomly allocated to three different diets, which provided polyunsaturated fatty acids (corn oil), monounsaturated fatty acids (olive oil), and a supplementation of ethyl esters of n-3 fatty acids to a prudent diet. Olive oil and, more significantly, n-3 ethyl esters lowered total cholesterol best (-2.2% and -5.8%, respectively); the latter diet, as expected, also significantly lowered triglyceridemia (-21.4%). The corn-oil diet exerted a small, statistically significant reduction of high-density-lipoprotein cholesterol (HDL) (-4.3%), and it also lowered plasma total apo B concentrations (-3.8%). n-3 ethyl esters significantly raised both total (+3.1%) and particularly HDL2 cholesterol (+24%). Platelet reactivity was insignificantly reduced by the three regimens, but all three significantly reduced thrombin-stimulated formation of thromboxane B2. Finally, only the n-3 fatty acid supplementation significantly reduced O2- generation by adherent monocytes. Dietary unsaturated fatty acids are generally effective on the plasma lipid and lipoproteins in type II patients, but significant differences may be found between the three tested regimens.