Acid Composition Of Serum Lipids Research Articles

Effects of an Ala54Thr polymorphism in the intestinal fatty acid-binding protein on responses to dietary fat in humans

A polymorphism in FABP2 that results in an alanine-to-threonine substitution at amino acid 54 of the intestinal fatty acid-binding protein (IFABP) is associated with insulin resistance in Pima Indians. In vitro, the threonine form (Thr54) has a higher binding affinity for long-chain fatty acids than does the alanine form (Ala54). We tested whether this polymorphism affected metabolic responses to dietary fat, in vivo. Eighteen healthy Pima Indians, half homozygous for the Thr54 form of IFABP and half homozygous for the Ala54 form, were studied. The groups were matched for sex, age, and body mass index. Plasma triglyceride, nonesterified fatty acid (NEFA), glucose, and insulin responses were measured after a mixed meal (35% of daily energy requirements, 50 g of fat) and after a high fat challenge (1362 kcal, 129 g of fat). NEFA concentrations were approximately 15% higher after the mixed meal and peaked earlier and were approximately 20% higher at 7 h in response to the high fat test meal in Thr54 homozygotes compared with Ala54 homozygotes. Insulin responses to the test meals tended to be higher in Thr54 homozygotes, but glucose and triglyceride responses were not different.The results of this study suggest that the Thr54 form of IFABP is associated with higher and prolonged NEFA responses to dietary fat in vivo. Higher NEFA concentrations may contribute to insulin resistance and hyperinsulinemia in individuals with this allele.

Blood compartmental metabolism of docosahexaenoic acid (DHA) in humans after ingestion of a single dose of [13C]DHA in phosphatidylcholine

Blood compartmental metabolism of docosahexaenoic acid (DHA) in humans after ingestion of a single dose of [13C]DHA in phosphatidylcholine

Pentadecanoic acid in serum as a marker for intake of milk fat: relations between intake of milk fat and metabolic risk factors

The fatty acid composition of the diet is known to be partially reflected by the fatty acid composition of serum lipids. We examined whether pentadecanoic acid (15:0) in serum lipids can be used as a marker for intake of milk fat, the major dietary source of 15:0. We also investigated the relations between intake of milk fat and cardiovascular disease risk factors. Sixty-two 70-y-old men completed 7-d dietary records. The intake of milk products was studied in relation to the proportions of 15:0 in serum cholesterol esters and phospholipids, as well as to the clinical characteristics of these men, by using Spearman's rank correlation. The proportions of 15:0 in serum cholesterol esters were positively related to butter intake (r = 0.36. P = 0.004) and to the total amount of fat from milk products (r = 0.46, P < 0.0001): 15:0 in phospholipids was related to the amount of fat from milk and cream (r = 0.34, P = 0.008) and to the total amount of fat from milk products (r = 0.34, P = 0.008). Inverse associations were found between intake of milk products and body mass index, waist circumference, LDL-HDL ratio, HDL triacylglycerols, and fasting plasma glucose, whereas relations to HDL cholesterol and apolipoprotein A-I tended to be positive. The results suggest that 15:0 in serum can be used as a marker for intake of milk fat. The explanation for the inverse associations between the intake of milk products and certain cardiovascular risk factors is not known.

Concordance of diet with the recommended cholesterol lowering diet in patients with coronary heart disease.

The aim was to examine the concordance of diet with the recommended cholesterol lowering diet in Coronary Heart Disease (CHD) patients receiving usual care. CHD patients were selected for a survey from hospital records at least six months after hospitalization. Four patient groups divided according to the severity of disease were examined in cross-sectional setting. Food records and fatty acid composition of serum lipids were used to assess dietary intake. The study population consisted of 109 patients with coronary bypass grafting, 106 patients with balloon angioplasty, 101 patients with acute myocardial infarction and 99 patients with acute myocardial ischemia. Concordance of the diet with the cholesterol lowering diet was similar in the patient groups. One third of the patients achieved the recommended fat intake and only one fourth achieved the recommended saturated fat intake. Concordance was better in the patients who also used lipid lowering drugs, but previous myocardial infarction did not affect dietary intake of fat and saturated fat. Diabetic or obese patients tended to have a higher intake of saturated fat. Myristic acid in cholesterol esters, triglycerides and phospholipids and also palmitic and linoleic acids in triglycerides were markers of dietary saturated fat intake. Concordance of the diet with the recommended cholesterol lowering diet in CHD patients was moderate. Concordance was not affected by disease severity or previous myocardial infarction and was slightly worse in CHD patients who had diabetes or were obese or did not use lipid lowering drugs.

Threonine allele in codon 54 of the fatty acid binding protein 2 gene does not modify the fatty acid composition of serum lipids in obese subjects.

Intestinal fatty acid binding protein (I-FABP) participates in the metabolism of fatty acids in the intestinal enterocytes. Threonine encoding allele in codon 54 of the I-FABP gene has been suggested as regulating the absorption of long-chain fatty acids. We examined the fatty acid composition of serum lipid fractions and the concentration of serum free fatty acids after an overnight fast in obese subjects, aged 24-56 years, on their habitual diet. The body mass index of the subjects ranged from 29.7 to 43.3 kg m-2. Six subjects were homozygous for the Thr-54 allele of the I-FABP gene, 37 subjects were heterozygous for the Thr-54/Ala-54 allele and 24 subjects were homozygous for the Ala-54 allele. We did not find any consistent differences in the proportions of long-chain fatty acids in serum triglycerides, cholesterol esters or phospholipids, but the concentration of serum free fatty acids tended to be higher in subjects who were homozygous for the Thr-54 allele (P = 0.13, for trend). In conclusion, our findings suggest that a polymorphism at codon 54 of the I-FABP2 gene does not substantially modify the fatty acid composition of serum lipids in obese Finns.

Long-term effects on lipid metabolism in miniature swine (Sus scrofa) of diets enriched in saturated, monounsaturated and polyunsaturated (N-6 and N-3) fatty acids.

In this paper we study the effect of long-term adaptation (twelve months) of lipidic parameters of miniature swine to diets enriched in saturated (lard; L-group), monounsaturated (olive-oil; O-group) and polyunsaturated (sunflower and fish-oil; S- and F-groups respectively). The experimental group with the highest level of total cholesterol, free cholesterol and phospholipids was the S-group. This group had as well levels of HDL-C and LDL-C significantly higher when compared with the remaining groups. The L-group had the lowest value of HDL-C. In spite of that, the index of artherogenicity (HDL/LDL+VLDL) was significantly higher in the L-group, followed by the O-, F- and S-group respectively. On the other hand, after 12 months adaptation we observed that the fatty acid composition of serum lipids clearly reflects the quality of the dietary fats. The O-group had significantly higher serum oleic acid levels than all the other groups, and its content in saturated fatty acids was the lowest. The same happens with red blood cell (Rbcs) membranes fatty acids but the effect is less marked. Membranes of the L-group were found to have the highest saturation index (SI) in Rbcs membranes, while the F-group had the highest unsaturation index (UI), followed by the O-group. Taken together, our findings show that the diet enriched in olive oil produces a lipid pattern intermediate between that obtained with the fish-oil-diet and the sunflower-oil-diet but with the advantage of Rbcs membranes with a lower amount of PUFAS. As it is known, membranes with high percentages of PUFAS are more accessible for peroxidation, and the degree of peroxidation of lipids is directly related with changes in the membranes functionality.

Insulin sensitivity is related to the fatty acid composition of serum lipids and skeletal muscle phospholipids in 70-year-old men.

Recent data indicate that peripheral insulin sensitivity may be influenced by dietary fat quality and skeletal muscle phospholipid fatty acid composition. During a health survey of 70-year-old men insulin sensitivity was measured by the euglycaemic hyperinsulinaemic clamp technique and the fatty acid composition of the serum cholesterol esters was determined (n = 215) by gas liquid chromatography. In a subsample the fatty acids of the skeletal muscle phospholipids and triglycerides were determined after fine needle biopsy from m. vastus lateralis (n = 39). The peripheral insulin sensitivity was significantly and negatively correlated to the proportion of palmitic (r = -0.31, p < 0.001), palmitoleic (r = -0.25, p < 0.001) and di-homo-gamma-linolenic (r = -0.33, p < 0.001) acids and positively to the content of linoleic (r = 0.28, p < 0.001) acid in the serum cholesterol esters. There was an even stronger negative relationship to the proportion of palmitic acid in the skeletal muscle phospholipds (r = -0.45, p < 0.004). The fatty acid composition was also significantly related to insulin sensitivity in a stepwise multiple regression analysis in the presence of other clinical variables, which were associated with insulin action in univariate analysis. Thus, more than 51% of the variation of the insulin sensitivity was explained by an equation containing body mass index, serum triglyceride concentration and the content of palmitic acid in the skeletal muscle phospholipids. It is concluded that the fatty acid composition in serum and of the phospholipids of skeletal muscle may influence insulin action in elderly men.

Insulin sensitivity is related to the fatty acid composition of serum lipids and skeletal muscle phospholipids in 70-year-old men

Insulin sensitivity is related to the fatty acid composition of serum lipids and skeletal muscle phospholipids in 70-year-old men

Physical Activity and Fibrinogen Concentration in Newly Diagnosed NIDDM

To evaluate whether plasma fibrinogen concentration is correlated with the level of physical activity and aerobic power in patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM). We studied 78 middle-aged (54 +/- 6 years, mean +/- SD), obese (body mass index [BMI] 32+/- 5 kg/m2) patients (45 men and 33 women) before and after a 12-month treatment period consisting of either conventional treatment given by community health centers or intensified dietary and exercise education given by a university outpatient clinic. Plasma fibrinogen concentration was measured by using a coagulometer. Physical activity was assessed by a questionnaire, and the patients were classified into a sedentary group or moderately or intensively exercising groups. Aerobic power (maximum oxygen uptake [VO2max], anaerobic threshold [VO2at]) was measured by direct breath-by-breath technique. At baseline, the sedentary patients had higher fibrinogen concentration than those with moderate or high physical activities (3.8 +/- 0.8 vs. 3.3 +/- 0.7 g/l, P < 0.01). Both VO2max and VO2at (ml.min-1.kg-1) showed an inverse linear correlation with fibrinogen (r = -0.38, P < or = 0.001, and r = -0.29, P < 0.01, respectively). In the stepwise multiple regression analysis, BMI, VO2 (ml/min), and smoking were the only significant independent factors explaining 23% of the variance in fibrinogen concentration. In sedentary patients, poor glycemic control was related with high fibrinogen concentration. During the follow-up period, patients maintained, on the average, good to moderate glycemic control. The originally sedentary group showed a decrease in fibrinogen concentration (to 3.3 +/- 0.7 g/l, P < or = 0.001) that reached the same level that the physically more active groups had at baseline. This change was associated with improved glycemic control, but not with any of the other assessed factors, including fatty acid composition of serum lipids reflecting dietary intake of fats. In addition to BMI and smoking, low reported physical activity and low aerobic power are independently associated with high plasma fibrinogen concentration in newly diagnosed NIDDM.

Effects of adaptation to diets enriched with saturated, monounsaturated and polyunsaturated fats on lipid and serum fatty acid levels in miniature swine (Sus scrofa)

A total of 37 miniature swine (Sus scrofa) was fed with three diets of 9% fat content, differing only in the quality of the fat source (sunflower oil, olive oil and lard fat). Three groups of animals were fed for a 3 month period, and three other groups were fed for a 12 month period. After the two experimental periods, the influence of the diet on serum lipids and serum fatty acids was studied. In the short term, the serum cholesterol level was higher in the lard group, but with time, it undergoes a significant increase in the sunflower group, due to increases both in HDL-C and in LDL-C. In the olive oil group, LDL-C hardly varies with time, while HDL-C tends to decrease. In the lard group, LDL-C increases and HDL-C decreases. The atherogenic index is, in the long term, lower in the lard group and higher in the polyunsturated fat group. The fatty acid composition of serum lipids in the long term shows a greater saturation index (SI) for the sunflower group and lard group, an increase in monounsaturated fatty acids in the olive oil group, and a higher percentage of linoleic acid in the sunflower group.

Enrichment of selected serum fatty acids after a small oral dosage of (1-13C)- and (8-13C)triolein in human volunteers analysed by gas chromatography/combustion isotope ratio mass spectrometry

In this study the fate of 100 mg orally administered (1-13C)- and (8-13C)triolein was traced in the serum lipids of four healthy human subjects. After an overnight fast the subjects consumed hourly meals of a liquid formula diet over 12 h. Ninety minutes after the first meal in the first study (1-13C)triolein was given and in the repeat study the same subject received (8-13C)triolein. Triacylglycerol (TG), phospholipid (PL) and cholesterol ester (CE) were isolated from serum sampled prior to and in intervals after isotope administration. Fatty acid composition of serum lipids was measured using gas chromatography/mass spectrometry. 13C enrichment in palmitic, stearic, oleic and linoleic acids of these fractions was determined by gas chromatography/isotope ratio mass spectrometry. With (8-13C)triolein a significantly higher enrichment (peak +17.1 +/- 14.3/1000 delta 13C) was found in the oleic acid of TG fraction than with (1-13C)triolein (peak -7.1 +/- 4.2/1000), which may be due to a faster elimination of (1-13C)oleic acid from serum TG. 13C enrichments in the other fatty acids of the TG fraction as well as of PL and CE fractions were in the range of natural 13C abundance (-25 to -32/1000).

Impact of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids in patients with recently diagnosed non-insulin-dependent diabetes mellitus

Compliance with dietary recommendations and the effect of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids were studied in 86 obese subjects (aged 40 to 64 years) with recently diagnosed non-insulin-dependent diabetes mellitus (NIDDM). After three months of basic education, the subjects were randomly separated into an intervention group (n = 40) and a conventional treatment group (n = 46). Members of the intervention group participated in 12 months of intensified education; those in the conventional group visited local health centers. Compliance with dietary instructions was monitored through food records. Intensified dietary therapy resulted in greater weight loss, better metabolic control, and a less atherogenic lipid profile than conventional treatment. Intake of energy and saturated fatty acids tended to decline in the intervention group. A higher percentage of patients in the intervention group had a total fat intake of 30% of energy or less after 15 months (32.5% [12 of 38] vs 17.4% [8 of 46]). Similarly, more patients in the intervention group had a saturated fatty acid intake of 10% or less of total energy intake at the end of the study (35.0% [13 of 38] vs 8.7% [4 of 46]). The mean dietary cholesterol intake was within recommendations in both groups at the end of the study. The relative percentage of linoleic acid of serum lipids increased significantly and the relative percentage of palmitic acid of serum triglycerides, phospholipids, and cholesterol esters decreased in the intervention group. These changes indicate that intensified dietary therapy improved the quality of fat in the diet of patients with NIDDM.

Effects of weight loss on the fatty acid composition of serum lipids in obese women.

The effect of a weight reduction regimen, consisting of a protein-sparing modified fast and an exercise program, on the fatty acid composition of serum phospholipids and cholesterol esters of obese women, is described. In phospholipids, this treatment did not induce any significant change of the different fatty acid families (total saturated, monounsaturated, omega 9, omega 7, omega 6 and trans-fatty acids), except for total omega 3 fatty acids which increased. Within families, individual fatty acids change however. The changes are compatible with increased delta 5 and delta 6 desaturase activity. In cholesteryl esters, significant changes occurred which are suggestive of an increase in serum of the fraction of cholesteryl esters of intracellular origin. The changes in fatty acid compositions may not be beneficial with respect to atherosclerosis.

Fatty acid composition of serum lipids of mothers and their babies after normal and hypertensive pregnancies

The biochemical essential fatty acid (EFA) status of neonates born after normal and hypertensive pregnancies (PIH) and that of their mothers was assessed by measuring the fatty acid composition of phospholipids (PL), triglycerides (TG) and cholesterol esters (CE) of umbilical cord serum and maternal serum, respectively. Relative contents of linoleic acid of serum PL and CE were significantly lower in mothers with PIH compared to normal pregnancies. Most other (n-6) polyenes in PL tended to be higher under hypertensive conditions. Total maternal (n-3) polyenes of serum PL were significantly higher in PIH, mainly due to clupanodonic acid, 22:5 (n-3), and cervonic acid, 22:6 (n-3). Total maternal (n-7) and (n-9) fatty acids were also significantly higher in PIH (PL and CE). The results indicate that PIH is associated with a relative increased unsaturation of maternal serum PL, which might facilitate the placental transfer of long-chain, polyunsaturated fatty acids. As a result, the neonatal EFA status after PIH only slightly differs from normal.

Effect of acute hyperinsulinemia on fatty acid composition of serum lipids in non-insulin-dependent diabetics and healthy men

The fatty acid pattern of serum phospholipids, cholesteryl esters, triglycerides and free fatty acids was measured before and after a 5-h two-step euglycemic hyperinsulinemic clamp (75 and 1400 μU/ml) in 21 non-insulin-dependent diabetics and 14 age-, weight-, and sex-matched healthy controls. Acute hyperinsulinemia was associated with a statistically significant increase in essential fatty acid and a decrease in non-essential fatty acid contents in triglycerides while the levels of serum triglycerides and free fatty acids dropped in both groups. The fatty acid composition of phospholipids and cholesteryl esters remained unchanged as did the levels of serum phospholipids, total cholesterol and HDL cholesterol.

Thromboxane production and platelet aggregation in type 2 diabetes mellitus without vascular complications

Diabetic individuals frequently have platelet hyperaggregability and increased thromboxane (TXB2) production. To evaluate whether improvement of metabolic control or changes in fatty acid composition of serum lipids might alter thromboxane (TXB2) formation and platelet function, we followed up 25 newly diagnosed type 2 diabetics without angiopathy for about 6 months. Improvement of metabolic control (HbA1, fell from 12.0 +/- 0.3 to 9.0 +/- 0.3%; p less than 0.01) was associated with significant decrease in total cholesterol, triglycerides, and ratios of total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol. Palmitic acid of phospholipids decreased significantly, whereas eicosapentaenoic acid increased. Regardless of this, the ADP-induced platelet aggregability and sensitivity were not altered. There was no effect whatever on the TXB2 synthesis capacity of clotting whole blood (204.9 +/- 25.0 vs 222.8 +/- 32.0 ng/ml) over 6 months of treatment. Platelet aggregability and TXB2 formation were not correlated to the degree of metabolic control, nor were there any correlations to serum lipids and their fatty acid composition. Thus, we are tempted to speculate that glucose metabolism in diabetes itself does not affect platelet aggregation or TXB2 formation in type 2 diabetes mellitus.

Fatty acid composition of serum lipids and erythrocyte membranes in type 2 (non-insulin-dependent) diabetic men

The fatty acid (FA) composition of serum lipids and erythrocytes was studied in 21 men with non-insulin-dependent diabetes mellitus (NIDDM) and in 14 normal subjects matched for age, sex, body weight, and dietary intake. Lower levels of linoleic acid and higher levels of highly unsaturated FA (daughter) of n-3 and n-6 family FA, reflected in a higher unsaturation index, were found in serum phospholipids (S-PL), in phospholipids of erythrocyte membranes (ery-PL), and in serum cholesterolesters (S-CHE). The unsaturation index of serum phospholipids significantly correlated with glycosylated hemoglobin A 1c ( P < .05) and blood glucose levels after glucose load ( P < .001). The results suggest that elongation and desaturation of essential FA (linoleic acid in particular) are increased. The above changes may be associated with accelerated atherosclerosis in type 2 diabetics.

Fatty acid composition of serum lipids in patients with a coronary bypass operation.

The fatty acid composition of serum phospholipids and cholesteryl esters was analysed in 71 male patients with angiographically defined three-vessel coronary artery disease (CAD) selected for a coronary bypass operation. Their 71 control subjects were matched according to age, sex, smoking, relative weight, and absence of CAD. The concentrations of fatty acids, 14:0, 16:0 and 16:1 of the serum phospholipids, were significantly (P less than 0.01, P less than 0.05 and P less than 0.01, respectively) higher in CAD patients than in the controls. On the other hand, linoleic (18:2 omega 6), linolenic (18:3 omega 3) and arachidonic (20:4 omega 6) acids were at a significantly lower level in the patients when compared to the controls. The polyunsaturated/saturated fatty acids (P/S) ratio in serum phospholipids was significantly (P less than 0.01) lower in the patients than in the controls. In the cholesteryl ester fraction the results paralleled those of the phospholipids. Significant correlations were obtained between the polyunsaturated fatty acids and the high density lipoprotein cholesterol or apolipoprotein A-I in the control subjects but most of these correlations were absent in the patients. Our present results further support the importance of linoleic acid in the protection against atherosclerosis. However, no unequivocal evidence on the possible beneficial effect of long-chain omega 3-fatty acids in comparison with omega 6-acids was obtained.

Serum lipids in the sex-linked dwarf chicken.

The concentration and fatty acid composition of serum lipids from thesex-linked dwarf chickens were compared with those from the nondwarf chickensbetween 7 and 28 weeks of age. Concentrations of free fatty acids, triglycerides, phospholipids and free or total cholesterol were higher in the dwarfs than in thenondwarfs. This trend was more evident in mature birds. Differences in fattyacid composition between genotypes or sexes were not great in growing birds.

Fatty acid composition of serum lipids and its relation to diet in an elderly institutionalized population

This study was conducted to determine the nutritional status with respect to fatty acids of 53 institutionalized elderly subjects (group A). Seven-day food records and biochemical determinations were used. The same protocol was applied to 25 healthy young adults (group B). The 1981 French Recommended Dietary Allowances were used to assess adequacy of intake. Total fat intake was found to be too high in both groups. Higher intakes of animal fats and saturated fatty acids and lower intakes of polyunsaturated fatty acids and linoleic acid were documented in group A than in group B. Elderly subjects exhibited decreased 18:2 omega 6 and 20:4 omega 6 in serum phospholipids and triglycerides. Other indicators of essential fatty acid status in group A differed from group B in the direction of deficiency (double-bond index [DBI], 0.93 +/- 0.01 vs 1.13 +/- 0.04, p less than 0.001; total omega 6, 25.07 +/- 0.46% vs 32.49 +/- 0.89%, p less than 0.001). These findings indicate that institutionalized elderly people are deficient in circulating essential fatty acids, which appears to be caused by both diet and metabolism.