Plasma Lipid Fractions Research Articles

Erratum

Objective: The aim of this study was to examine the distribution of trans fatty acids (TFA) in plasma lipid classes and the relationship with dietary intake of TFA. Design: After a 2 week baseline (habitual) diet, all subjects consumed a moderate fat (MF) diet for 3 weeks with the fat being derived mainly from margarine and the rest from lean beef and then a very low fat (VLF) diet for 3 weeks with the TFA being derived only from the lean beef. Blood samples were collected 2 days prior to the end and also on the last day of each dietary period. Setting: Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia. Subjects: Ten free-living mildly hypercholesterolaemic subjects aged 22–66 were recruited in Geelong. Outcome measures: TFA intake was calculated from analyses of Australian margarines, butter, lean meat and animal fat. The TFA in plasma lipid fractions were separated by AgNO3 thin-layer chromatography and quantitated by capillary gas–liquid chromatography using internal standards. Results: The phospholipid (PL) fraction contained more than 60% of the trans-18:1 isomers in the plasma lipids in all subjects. On the baseline diet, the predominant positional isomer of trans-18:1 in PL was Δ11, whereas in the other lipid classes it was the Δ9 isomer. The concentration of the Δ9 isomer increased on the MF diet, particularly in the PL fraction, while the concentration of the Δ11 isomer decreased in all fractions. On the VLF diet, the total TFA level decreased by approximately 50%, mainly due to decreases in the TFA isomers in the PL and TG fractions. Changes in plasma total and PL TFA, PL Δ9, Δ10 and Δ11 were strongly correlated with dietary TFA intake (P<0.0001). There were also significant association between dietary TFA intake and PL Δ12 (P=0.003), triacylglycerol Δ9 (P=0.009), Δ11 (P=0.0005), total triacylglycerol (P=0.023) and free fatty acid TFA (P=0.042). Conclusions: The results suggest that the measurement of trans-18:1 in plasma PL and TAG and plasma total TFA could be used to estimate the intake of TFA. Sponsorship: Meat Research Corporation of Australia. European Journal of Clinical Nutrition (2001) 55, 59–64

A relation between plasma lipid fractions and gallstone contents

A relation between plasma lipid fractions and gallstone contents

A relation between plasma lipid fractions and gallstone contents

A relation between plasma lipid fractions and gallstone contents

Utilisation of fish oil in ruminants: I. Fish oil metabolism in sheep

Five sheep with rumen and abomasal cannulae were offered three diets sequentially in the order: control (C) pellets (lucerne hay-oat grain: 60/40, w/w), control plus unprotected tuna oil (UTO pellets), and control plus tuna oil protected (casein-formaldehyde matrix) against ruminal biohydrogenation (PTO pellets). In supplemented diets, tuna oil constituted 3% (w/w) of total dry matter (DM), and each supplement was fed for 12 days, with 9 days allowed between the two fish oil feeding periods to minimise carry-over effects. Daily DM intake was 785±38 g/head during the control period. It was significantly reduced by UTO feeding (6.2%, P<0.05) but not PTO feeding. The level of EPA in the abomasum during PTO feeding was double that measured during UTO feeding (1.30 versus 0.61% of FA, P<0.05). The level of DHA in the abomasum did not significantly differ between UTO and PTO feeding periods. Both tuna oil supplements significantly increased the levels of 18:1 trans and that of a fatty acid derivative identified as 10-hydroxystearic acid (10-HSA) in both the rumen and abomsum. Tuna oil supplementation also altered the fatty acid composition of plasma lipid fractions and 10-HSA was solely incorporated into plasma free fatty acids. This study indicates that substantial protection of tuna oil against ruminal hydrogenation inhibited reduced feed intake, but increased the proportion of 18:1 trans isomer and fatty acids derivatives (10-HSA), which indicate interference with metabolism in the rumen.

Hyperlipidemia and reproductive failure in captive-reared alligators: vitamin E, vitamin A, plasma lipids, fatty acids, and steroid hormones

Blood samples were collected from 26 captive-reared alligators (25 females; one male) and 12 (seven females and five males) wild ‘nuisance’ alligators collected by wildlife personnel in south Louisiana in May 1995. The captive alligators, hatched from artificially incubated eggs in 1972–1973, had received vitamin E supplements during the 3 weeks before the blood sample was collected. Each sample was analyzed for vitamin E (α-tocopherol), vitamin A (retinol), total lipid, triacylglycerol, phospholipid, cholesterol, cholesteryl ester, free fatty acids, steroid hormones and a standard clinical blood panel. The fatty acid composition of the plasma lipid fraction was also analyzed. Results indicated that 18 of the captive females and three of the seven wild females were undergoing vitellogenesis, i.e. had elevated plasma estradiol and elevated plasma calcium. Vitellogenic females had higher vitamin E than non-vitellogenic females (77.4 μg/ml vs. 28.6 μg/ml in captive females; 24.0 μg/ml vs. 21 μg/ml in wild females). Plasma retinol was similar in all groups, ranging from 0.5 to 1.4 μg/ml and close to values reported in birds. All lipid fractions, with the exception of cholesteryl ester, were higher in captive alligators than in wild alligators. There were also significant differences in the fatty acid composition of wild and captive alligators. Plasma eicosapentaenoic and docasahexaenoic acid were higher in wild than in captive alligators, whereas linoleic was higher in captive than in wild.

The occurrence of trans-18:1 isomers in plasma lipids classes in humans.

The aim of this study was to examine the distribution of trans fatty acids (TFA) in plasma lipid classes and the relationship with dietary intake of TFA. After a 2 week baseline (habitual) diet, all subjects consumed a moderate fat (MF) diet for 3 weeks with the fat being derived mainly from margarine and the rest from lean beef, and then a very low fat (VLF) diet for 3 weeks with the TFA being derived only from the lean beef. Blood samples were collected 2 days prior to the end and also on the last day of each dietary period. Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia. Ten free-living mildly hypercholesterolaemic subjects aged 22-66 were recruited in Geelong. TFA intake was calculated from analyses of Australian margarines, butter, lean meat and animal fat. The TFA in plasma lipid fractions were separated by AgNO3 thin-layer chromatography and quantitated by capillary gas-liquid chromatography using internal standards. The phospholipid (PL) fraction contained more than 60% of the trans-18:1 isomers in the plasma lipids in all subjects. On the baseline diet, the predominant positional isomer of trans-18:1 in PL was delta11, whereas in the other lipid classes it was the delta9 isomer. The concentration of the delta9 isomer increased on the MF diet, particularly in the PL fraction, while the concentration of the delta11 isomer decreased in all fractions. On the VLF diet, the total TFA level decreased by approximately 50%, mainly due to decreases in the TFA isomers in the PL and TG fractions. Changes in plasma total and PL TFA, PL delta9, delta10 and delta11 were strongly correlated with dietary TFA intake (P < 0.0001). There were also significant association between dietary TFA intake and PL delta12 (P = 0.003), triacylglycerol delta9 (P=0.009), delta11 (P=0.0005), total triacylglycerol (P=0.023) and free fatty acid TFA (P = 0.042). The results suggest that the measurement of trans-18:1 in plasma PL and TAG, and plasma total TFA could be used to estimate the intake of TFA.

Fatty Acid Content of Plasma Lipid Fractions, Blood Lipids, and Apolipoproteins in Children Fed Milk Products Containing Different Quantity and Quality of Fat

ABSTRACTBackgroundDifferences in fatty acid content of plasma lipid fractions and serum lipid concentrations were investigated among young children fed different milk diets composed to achieve a recommended saturated fat intake.MethodsThirty‐eight healthy children were randomly assigned to one of four feeding groups at 12 months: 1) low‐fat milk (1.0 g/dL cow's milk fat); 2) standard‐fat milk (3.5 g/dL cow's milk fat); 3) partially vegetable fat milk (3.5 gtat/dL fat; 50% vegetable fat: rapeseed oil); and 4) full vegetable‐fat milk (3.5 gtat/dL fat; 100% vegetable fat: palm, coconut, and soy oil). Plasma fatty acids, blood lipids, and apolipoproteins were analyzed at 15 months, and dietary intakes at 12, 15, and 18 months.ResultsThere were significantly lower percentage contributions of saturated fatty acids in plasma triglycerides in children fed low‐fat milk or milk with 50% or 100% vegetable fat than in children fed standard‐fat milk. Plasma polyunsaturated fatty acid levels were significantly higher in children fed milks with vegetable fat than in children fed standard‐fat milk. Plasma saturated and polyunsaturated fatty acids in triglycerides most closely reflected dietary intake. Blood lipid concentrations were lower in children fed milk with 50% vegetable fat.ConclusionsChildren fed milk with 50% or 100% vegetable fat, together with high vegetable‐fat and low milk‐fat dairy products have lower percentages of plasma saturated fatty acids and higher percentages of polyunsaturated fatty acids than children fed standard‐or low‐fat milk and dairy products.

Fatty acid composition of plasma lipids in HIV‐infected children. Comparison with seroreverters

Children infected with the type‐1 human immunodeficiency virus (HIV) are at risk of nutritional deficiencies leading to an impaired polyunsaturated fatty acid (PUFA) status. The aim of the present study was to compare the PUFA composition of plasma lipid classes (total lipids, phospholipids (PL), cholesteryl esters (CE) and triglycerides) in well‐growing HIV‐infected children with an age‐matched group of HIV‐seroreverter children born to infected mothers. Eighteen HIV children, of both sexes, mean age 4.6 y, most of whom under combined antiretroviral regimen, were compared with 18 seroreverters, mean age 5.4 y, comparable for demographic, anthropometric and dietary characteristics. All children had adequate growth parameters (weight and height&gt;3rd percentile). The plasma fatty acid content was similar in the two groups. HIV seropositive subjects showed lower linoleic acid (LA) levels in all the plasma lipid fractions, with higher 20:3n‐9 and 20:5n‐3 levels in PL and CE. The plasma PL triene/ tetraene ratio (marker of relative LA deficiency) related positively to the viral load and negatively to the blood CD4+ lymphocyte count. Compared to age‐matched seroreverter subjects, HIV‐seropositive children show a lipid fatty acid status suggestive of relative LA deficiency and increased turnover of the PUFA series.

Folate Administration Increases n-3 Polyunsaturated Fatty Acids in Rat Plasma and Tissue Lipids

It has been shown that folic acid deficiency can modify polyunsaturated fatty acid (PUFA) metabolism and thus could contribute to the development of cardiovascular diseases. We have studied the effect of folate administration on fatty acid composition of plasma, platelet, erythrocyte, intestinal and liver lipids. Two groups of rats were daily injected with either saline solution (control group) or 5-methyl-tetrahydrofolate (MTHF) solution (MTHF group) for 15 days. Changes induced by folate treatment on n-6 PUFA were not very significant. Linoleic acid only decreased in liver and intestinal phospholipids of MTHF rats whereas arachidonic acid was unaffected by folate administration. However, n-3 PUFA significantly increased in plasma lipid fractions and in platelet, erythrocyte and intestinal phospholipids. It is well known that n-3 PUFA show antithrombotic properties. Thus, the increase of n-3 PUFA observed after MTHF administration might contribute to the prevention of vascular disorders.

Erythrocyte susceptibility to lipid peroxidation in patients with coronary atherosclerosis.

In recent years it has been reported that free oxygen radicals play an important role in the pathogenesis of degenerative diseases and that antioxidant vitamins such as vitamins E or C prevent their harmful effects. In this study, we evaluated the following: Erythrocyte susceptibility to lipid peroxidation; the role of erythrocyte glutathione (GSH) as an antioxidant; plasma lipid fractions; and the relationship between plasma lipid peroxides and antioxidant vitamin levels. Thiobarbituric acid-reactive substance (TBARS) levels were measured to determine the levels of plasma lipid peroxides and the susceptibility to lipid peroxidation when erythrocytes were stressed by hydrogen peroxide for 2 h in vitro. Erythrocyte TBARS production was significantly higher in patients with coronary atherosclerosis than in the controls. On the other hand, the levels of plasma high-density lipoproteins, vitamin C, vitamin E and erythrocyte GSH were significantly lower, and the levels of plasma total cholesterol, triglycerides, low-density lipoproteins and TBARS were significantly higher in the patients with coronary atherosclerosis than in the controls. In conclusion, our results indicate that erythrocytes from patients with coronary atherosclerosis are more susceptible to oxidation than those of controls and that these patients have lowered antioxidant capacity as revealed by decreased plasma levels of vitamins C and E.

Lipid dismetabolism in Leydig and Sertoli cells isolated from streptozotocin-diabetic rats

This work evaluates how the abnormalities in fatty acid biosynthesis, already described in diabetic rats, were extended to Sertoli and Leydig cells isolated from testes of streptozotocin-treated rats. Both kinds of cells were incubated in the presence of labeled eicosa-8,11,14-trienoic acid. The uptake of the substrate and its conversion to arachidonic acid were significantly depressed in both cell types compared to the non-diabetic controls. The indirect evidence of this inhibition was observed in the total fatty acid pattern of the cells where the 20:4 n−6/18:2 n−6 ratio was significantly decreased. The addition of insulin to the incubation medium produced no changes in the uptake of the substrate by the cells. Under similar experimental conditions the synthesis of arachidonic acid was partially recovered, however, the values obtained were still below those ones of cells isolated from control animals. These results were correlated with the fatty acid profile of different lipid fractions of plasma and with the activity of enzymes involved in polyunsaturated fatty acids biosynthesis measured in the testicular microsomes of diabetic rats. We conclude that Sertoli and Leydig cells evidenced similar lipid disorders than those observed in the whole testis or in other tissues of diabetic rats, and that the biosynthesis of arachidonic acid is under insulin regulation.

Abnormalities in plasma and red blood cell fatty acid profiles of patients with colorectal cancer.

We evaluated total plasma fatty acid concentrations and percentages, and the fatty acid profiles for the different plasma lipid fractions and red blood cell lipids, in 17 patients with untreated colorectal cancer and 12 age-matched controls with no malignant diseases, from the same geographical area. Cancer patients had significantly lower total plasma concentrations of saturated, monounsaturated and essential fatty acids and their polyunsaturated derivatives than healthy controls; when the values were expressed as relative percentages, cancer patients had significantly higher proportions of oleic acid and lower levels of linoleic acid than controls. With regard to lipid fractions, cancer patients had higher proportions of oleic acid in plasma phospholipids, triglycerides and cholesterol esters, and lower percentages of linoleic acid and its derivatives. On the other hand, alpha-linolenic acid was significantly lower in triglycerides from cancer patients and tended to be lower in phospholipids. Its derivatives also tended to be lower in phospholipids and triglycerides from cancer patients. Our findings suggest that colorectal cancer patients present abnormalities in plasma and red blood cell fatty acid profiles characterized by lower amounts of most saturated, monounsaturated and essential fatty acids and their polyunsaturated derivatives, especially members of the n-6 series, than their healthy age-matched counterparts. These changes are probably due to metabolic changes caused by the illness per se but not to malnutrition.

The effect of dietary docosahexaenoic acid on plasma lipoproteins and tissue fatty acid composition in humans

Normal, healthy male volunteers (n = 6) were fed diets [high docosahexaenoic acid-DHA] containing 6 g/d of DHA for 90 d. The stabilization (low-DHA) diet contained less than 50 mg/d of DHA. A control group (n = 4) remained on the low-DHA diet for the duration of the study (120 d). Blood samples were drawn on study days 30 (end of the stabilization period), 75 (midpoint of the intervention period), and 120 (end of the intervention period). Adipose tissue (AT) samples were taken on days 30 and 120. The plasma cholesterol (C), low density lipoprotein (LDL)-C and apolipoproteins (apo) [Al, B, and lipoprotein (a)] were unchanged after 90 d, but the triglycerides (TAG) were reduced from a mean value of 76.67 +/- 24.32 to 63.83 +/- 16.99 mg/dL (n = 6, P < 0.007 using a paired t-test) and the high density lipoprotein (HDL)-C increased from 34.83 +/- 4.38 mg/dL to 37.83 +/- 3.32 mg/dL (n = 6, P < 0.017 using a paired t-test). The control group showed no significant reduction in plasma TAG levels. Apo-E, however, showed a marked increase in the volunteers' plasma after 90 d on the high-DHA diet, from 7.06 +/- 4.47 mg/dL on study day 30 to 12.01 +/- 4.96 mg/dL on study day 120 (P < 0.002 using a paired t-test). The control subjects showed no significant change in the apo-E in their plasma (8.46 +/- 2.90 on day 30 vs. 8.59 +/- 2.97 on day 120). The weight percentage of plasma DHA rose from 1.83 +/- 0.22 to 8.12 +/- 0.76 after 90 d on the high-DHA diet. Although these volunteers were eating a diet free of eicosapentaenoic acid (EPA), plasma EPA levels rose from 0.38 +/- 0.05 to 3.39 +/- 0.52 (wt%) after consuming the high-DHA diet. The fatty acid composition of plasma lipid fractions--cholesterol esters, TAG, and phospholipid--showed marked similarity in the enrichment of DHA, about 10%, after the subjects consumed the high-DHA diet. The DHA content of these plasma lipid fractions varied from less than 1% (TAG) to 3.5% (phospholipids) at baseline, study day 30. EPA also increased in all plasma lipid fractions after the subjects consumed the high-DHA diet. There were no changes in the plasma DHA or EPA levels in the control group. Consumption of DHA also caused an increase in AT levels of DHA, from 0.10 +/- 0.02 to 0.31 +/- 0.07 (wt%) (n = 6, P < 0.001 using a paired t-test), but the amount of EPA in their AT did not change. Thus, dietary DHA will lower plasma TAG without EPA, and DHA is retroconverted to EPA in significant amounts. Dietary DHA appears to enhance apo-E synthesis in the liver. It appears that DHA can be a safe and perhaps beneficial supplement to human diets.

Changes in plasma fatty acids indicate change in nutritional status in developing Weddell seal pups

The concentrations and the fatty acid compositions (weight percent) of three plasma lipid fractions (phospholipids, cholesteryl esters, and triacylglycerols) were examined in five Weddell seal pups through suckling, the post-weaning fast and periods of independent foraging. The principal plasma fatty acids in Weddell seal pups during suckling were the same as those previously reported for milk samples collected from lactating Weddell seals. In contrast to the stable milk fatty acid composition suggested by the previous study, significant changes in the fatty acid composition of plasma lipids occurred during suckling. These included an increase in the weight% of 20:4(n-6) and 18:0 in phospholipids, an increase of 20:4(n-6) in cholesteryl esters, and an increase of 20:1(n-9) and a decrease of 20:5(n-3) in triacylglycerols. Weaning and the subsequent fasting period were accompanied by a dramatic drop in the plasma concentration and 14:0 content of triacylglycerols and by marked decrease and increase in the weight% of 20:1(n-9) and 20:5(n-3), respectively, in this lipid fraction. Weight% of 14:0 in triacylglycerols and/or plasma concentration of triacylglycerols clearly distinguish post-weaning from suckling. However, fasting versus foraging pups could not be clearly distinguished.

Distribution of the total unsaturation in lipid components of plasma as a new differential diagnostic method in clinical analysis

Using ozonization and thin-layer chromatographic methods we determined the qualitative and quantitative correlation of unsaturation distribution (UD) in individual fractions of blood plasma lipids in children suffering from insulin-dependent diabetes mellitus (IDDM). The research was aimed at elucidation of biochemical criterion of the degree of metabolic disorders in children with IDDM and at development of methods for quantitative assessment of such disorders. Twenty children were examined during the compensation stage (group 1), and twelve during decompensation with ketoacidosis (group 2). The present investigation shows that in the case of insulin-dependent diabetes mellitus in children the total unsaturation distribution (TUD) in plasma lipid fractions were found to be decreased significantly compared to healthy controls. The pattern of TUD in plasma lipid fractions may serve as a new biochemical criterion for metabolic disorders and decompensation in IDDM.

The effects of smoking on antioxidant defence system and membrane free fatty acid content of erythrocytes and plasma lipid parameters: Protective role of antioxidant vitamins

Activities of antioxidant enzymes were measured in the erythrocytes from 15 smokers and 15 non-smokers. Superoxide dismutase (SOD) and catalase (CAT) activities were found lower but, glutathione peroxidase (GSH-Px) activity unchanged in the erythrocytes from smokers compared with non-smokers. Levels of thiobarbituric acid-reactive substances (TBARS) were however higher both in erythrocytes and plasma from smokers. Antioxidant vitamin (vitamins E and C) supplementation for the period of 15 days caused significant increases in the activities of all antioxidant enzymes and decreases in the TBARS levels of erythrocytes and of blood plasma in smoker group. It has been observed that smoking caused significant changes in the concentrations of plasma lipid fractions as well. In this regard, total cholesterol level (TC) was found unchanged, LDL cholesterol and triglyceride (TG) levels increased and HDL cholesterol decreased in the plasma from smokers compared with non-smokers. Vitamin supplementation caused a significant increase in HDL cholesterol and a decrease in LDL cholesterol in plasma from smokers. The vitamins normalised the HDL HDL ratio in smokers. Fatty acid composition of erythrocyte membranes from smokers also presented significant changes. In particular, oleic acid (18:1) was almost in the erythrocyte membranes of smokers. In contrast, the relative amount of stearic acid (18:0) was found to be significantly increased but, those of some fatty acids (12:0, 14:0, 14:1 and 16:0) decreased in the erythrocyte membranes of smokers. Results suggested that enzymatic antioxidant defence system of erythrocytes was depressed and the erythrocytes were exposed to oxidant stress due to smoking. Increased plasma TBARS levels indicated that not only erythrocytes but also some other tissues and cells might be exposed to the radical stress by cigarette smoke. Smoking also caused significant changes in the levels of plasma lipid parameters and antioxidant vitamins partly protected erythrocytes against such harmful effects of smoking by scavenging free radical species and by activating and/or inducing antioxidant enzymes.

No evidence for direct incorporation of esterified palmitic acid from plasma into brain lipids of awake adult rat

Awake adult rats were given a solution of [9,10-3H]palmitate ([3H]PAM) by gavage. The appearance of radiolabel in plasma lipid fractions was monitored by thin-layer chromatography at fixed intervals thereafter. At 2 h, the rats were killed by microwave irradiation and radioactivity in whole brain and individual brain phospholipids was determined. In plasma, esterified [3H]PAM was mainly associated with triglyceride, phospholipid, and cholesterol ester. Radioactivity appeared to a larger extent in triglyceride than in unesterified fatty acid, suggesting that unesterified [3H]PAM in plasma was largely due to release from esterified [3H]PAM by lipoprotein lipase hydrolysis. Brain radioactivity could be accounted for entirely by incorporation of unesterified plasma [3H]PAM. Esterified [3H]PAM in chylomicrons or lipoproteins was calculated to make no measurable contribution using a published value for the incorporation coefficient of [3H]PAM into brain in the evaluation. These results suggest that ingested palmitic acid (PAM) in adult rats enters blood as esterified triglyceride within chylomicrons and lipoproteins and, in part, eventually is converted to circulating unesterified PAM. It is the circulating unesterified PAM that is incorporated into brain from blood, whereas esterified PAM within plasma chlomicrons and lipoproteins makes no measurable direct contribution.

Effect of dietary n-9 eicosatrienoic acid on the fatty acid composition of plasma lipid fractions and tissue phospholipids.

n-9 Eicosatrienoic acid (ETrA), also known as Mead acid, is a minor fatty acid in essential fatty acid (EFA)-sufficient healthy subjects but is found at increased levels in EFA deficiency. This study examined the influence of dietary ETrA from a biological source on plasma and tissue ETrA. A synthetic fat-free diet was prepared to which was added Mut 48 oil which contains 19% ETrA (wt%) as well as other n-9 fatty acids. Blends of vegetable oils were used to achieve overall diets with 5% fat (wt%) and varying amounts of ETrA at two different dietary levels of linoleic acid (LA), approximately 4.4 and 19% of total fatty acids. These diets were fed to 5-week-old Dark Agouti rats for four weeks. Plasma lipid fractions and liver, spleen, and peritoneal exudate (PE) cells were analyzed for fatty acid composition. ETrA was present at up to 20% total fatty acids in plasma triglyceride, cholesterol ester, and phospholipid fractions. ETrA also accumulated to substantial levels in phospholipids of liver and spleen (up to 15% of total fatty acids) and PE cells (up to 11%). ETrA was found in plasma and tissue phospholipids in proportion to the amount of ETrA present in the diet. The incorporation was reduced in diets with higher LA content compared to diets containing similar amounts of ETrA but lower LA. All rats remained apparently healthy, and histological survey of major organs revealed no abnormality. While the long-term implications for health of ingestion of diets rich in ETrA remain to be established, rats appear to tolerate high levels of dietary ETrA without adverse effects. Dietary enrichment with ETrA warrants further investigation for possible beneficial effects in models of inflammation and autoimmunity, as well as in other conditions in which mediators derived from n-6 fatty acids can affect homeostasis adversely.

Hypoglycemic effect and protein nutritive quality of soy and methionine-supplemented whole durum pasta products.

New low cost, high-protein and high-fiber pasta products processed from whole durum meal (WD) solely, WD supplemented with 7% or 12% defatted soy flour (SF), or 12% SF plus 0.3% methionine were evaluated in comparison with the regular pasta made of pure durum semolina (DS). Their protein nutritive quality was biologically evaluated by rat growth studies using diets containing 9% protein, through the parameters: food efficiency ratio (FER), protein efficiency ratio (PER), net protein utilization (NPU), digestibility coefficient (DC) and biological value (BV). The original products were administered to diabetic hypercholesterolemic albino rats, (injected with alloxane) to study their effects on the levels of blood glucose and plasma lipid fractions. The results indicate that diets based on pasta made of WD supplemented with SE or SF plus methionine had superior protein quality and succeeded in supporting normal growth of rats in contrast to the diets based on pasta made of unsupplemented WD or DS. These assays demonstrated that the values of FER, PER, NPU and BV of WD-pasta increased with increasing SF supplementation. However, high-fiber pasta made of unrefined WD solely or with SF had lower DC values compared to that of the regular DS-pasta. DC values decreased as the added SF increased. Adding methionine evidently affected FER, PER, BV and NPU values. Administration of high-protein and high-fiber pasta samples made of WD solely, supplemented with SF or SF plus methionine significantly reduced the elevated blood glucose as well as plasma cholesterol and plasma lipid fractions in hypercholesterolemic diabetic rats. Overall, considering nutritional evaluation, protein cost as well as hypoglycemic and hypocholesterolemic effects the pasta composed of 12% SF-WD and supplemented with 0.3% methionine represented the best high-fiber; high-protein and high-quality product.

Determination of DNA adducts of malonaldehyde in humans: effects of dietary fatty acid composition.

The effects of dietary fatty acid composition on the endogenous formation of DNA adducts of malonaldehyde (MA), the major product of lipid peroxidation, were investigated in humans. A group of 59 healthy individuals of both sexes and different ages was initially fed a milk fat-based diet rich in saturated fatty acids for 14 days. Following this initial period, after which the group was considered homogeneous with respect to diet, 30 randomly chosen subjects were given a sunflower oil-based (rich in polyunsaturated fatty acids) (SO) diet and the remaining 29 individuals a low erucic acid rapeseed oil-based (rich in monounsaturated fatty acids) (RO) diet for 25 days. The fatty acid composition of plasma lipid fractions and the level of DNA adducts of MA in total white blood cells were then determined at the end of the SO and RO dietary periods. DNA adduct levels were measured by 32p-postlabelling using reversed-phase HPLC with on-line detection of radioactivity. Higher concentrations of polyunsaturated fatty acids in plasma triglycerides and higher levels of DNA adducts of MA were found in the subjects on the SO diet when compared with those in the RO dietary group. A large inter-individual variation in adduct levels was observed. The average adduct level in the SO diet group was 7.4 +/- 8.7 adducts/10(7) nucleotides (n = 23). This level was 3.6-fold higher than that found in individuals in the RO diet group (P < 0.001). Our results, in conjunction with the mutagenic and carcinogenic properties of MA, thus suggest the interaction of lipid peroxidation products such as MA with DNA as one plausible mechanism explaining the involvement of dietary fat in carcinogenesis.