Adipose tissue essential fatty acid composition in patients with atopic eczema.

We have measured adipose tissue total lipid and plasma phospholipid essential fatty acid composition by capillary column gas chromatography in patients with atopic eczema. In both adipose tissue and plasma phospholipids there was a significant elevation of linoleic acid in patients compared to a control group (adipose tissue P less than 0.05; plasma P less than 0.001), and a substantially higher ratio of linoleic acid to the sum of its longer chain highly unsaturated derived fatty acids, dihomogamma linolenic acid and arachidonic acid. These findings add support to the proposition that patients with atopic eczema have a defect in the conversion of linoleic acid.     

Serum cholesteryl fatty acid composition and plasma glucose concentrations in Amerindian women

BACKGROUND: Diabetes mellitus has reached epidemic proportions in women of Amerindian origin. The risk of developing diabetes has been found to be related to the serum fatty acid composition in whites. OBJECTIVE: We prospectively investigated the relation between the serum cholesteryl fatty acid composition and changes in fasting plasma glucose concentrations in Peruvian Indian women who are characterized by hyperinsulinemia in comparison to white women. DESIGN: A 5-y follow-up study of 73 women with normal fasting plasma glucose values was undertaken by performing a survey in 1999 and a follow-up survey in 2004. The studied variables included anthropometric measurements, plasma insulin and leptin, dietary food consumption from 24-h recall, blood pressure, and serum fatty acid composition. RESULTS: The participants developed significantly higher fasting plasma glucose concentrations in 2004 compared with 1999 (P < 0.0001) with unaltered plasma insulin values. Palmitoleic acid (16:1n-7) in 1999 was the only fatty acid that was significantly correlated to glucose concentration at follow-up. In a multiple regression analysis that included waist circumference, percentage of body fat, systolic blood pressure, and circulating triacylglycerol, insulin, leptin, and 16:1n-7 as independent determinants, 16:1n-7 and systolic blood pressure were the only significant determinants of plasma glucose concentration 5 y later. CONCLUSIONS: A high proportion of 16:1n-7 in serum is an independent predictor of high plasma glucose concentrations in Amerindian women. The reason for this association remains to be elucidated.     

Adipose tissue biomarkers of fatty acid intake

BACKGROUND: Biomarkers can provide a more accurate measure of long-term intake than can dietary questionnaires. OBJECTIVE: The objective was to identify which adipose tissue fatty acids are suitable biomarkers of intake as assessed with a validated food-frequency questionnaire. DESIGN: Costa Rican men with a mean (+/- SD) age of 56 +/- 11 y (n = 367) and women aged 60 +/- 10 y (n = 136) completed a 135-item food-frequency questionnaire and provided an adipose tissue sample. Fifty fatty acids were identified by capillary gas chromatography. Correlation coefficients were calculated after adjustment for age, sex, body mass index, and smoking status. RESULTS: The best adipose tissue marker for total intake of saturated fatty acids was 15:0 + 17:0 (r = 0.18). Both 15:0 and 17:0 were also the best correlates of dairy product intake (r = 0.31 for each). The diet-adipose tissue correlations for n-3 fatty acids were r = 0.34 for 18:3, r = 0.15 for 20:5, and r = 0.18 for 22:6. Fish intake correlated significantly with these adipose tissue n-3 fatty acids. Dietary and adipose tissue n-6 fatty acids were highly correlated: 18:2 (r = 0.58) and 18:3 (r = 0.24). The best indicators of total trans fatty acid intake were ct18:2n-6 and tc18:2n-6 (r = 0.58 for each); total 18:1 trans fatty acid (r = 0.45) and 16:1 trans fatty acid (r = 0.16) were the next best indicators. CONCLUSIONS: Adipose tissue is a suitable biomarker of dietary fatty acid intake, particularly for n-3 and n-6 cis polyunsaturated fatty acids and trans fatty acids. Ideally, adipose tissue and dietary questionnaires should complement, rather than substitute for, each other in epidemiologic studies.     

Relationship of diet to the fatty acid composition of human adipose tissue structural and stored lipids

The habitual intake of 20 healthy free-living subjects was determined by two 7-day food records. Documented fatty acid intakes were utilized to examine the influence of fatty acid intake on fatty acid composition of stored and structural lipids in subcutaneous adipose tissue. Subjects with higher intakes of saturated fatty acids exhibited increased levels of total saturated fatty acids and decreased polyunsaturated fatty acids in adipose tissue triglycerides (p less than 0.01). The dietary P/S ratio was significantly related to the saturated and polyunsaturated content of stored lipids. In the phospholipid fraction, relationships were found between dietary C18:2(6) and the P/S ratio of phosphatidylcholine (p less than 0.05). The essential fatty acid content of the two phospholipids studied was related to the dietary fats consumed. Relationships were identified between major fatty acids in the triglyceride and phospholipid fraction. Although diet was found to relate to fatty acid composition, the structural lipids in human adipose tissue appear more resistant to compositional change than stored triglycerides.     

Iron intake influences essential fatty acid and lipid composition of rat plasma and erythrocytes

In view of the clinical importance of iron deficiency as well as the known role of iron in stearic acid desaturation, the effects of higher or lower iron intake on fatty acid composition of blood and liver in the rat were studied. Male Sprague-Dawley rats were fed purified diets that contained iron at 12, 27 or 237 mg/kg. After 12 wk the lipid and fatty acid composition of plasma, erythrocytes and liver was analyzed. Linoleic acid in plasma phospholipids and triacylglycerols was higher, but arachidonic acid was lower in the group fed 12 mg/kg iron than in the groups fed 27 or 237 mg/kg iron. Liver fatty acid and lipid composition was not different between groups. In the group fed 237 mg/kg iron, plasma cholesterol and triacylglycerols were 150%, erythrocyte cholesterol was 137% and erythrocyte phospholipids were 148% of levels in the rats fed 27 mg/kg iron. The fatty acid data suggest a mild impairment in essential fatty acid metabolism in moderately iron-deficient rats. The lipid data suggest a significant alteration in the total lipid content of plasma and erythrocytes of iron-supplemented rats.     

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.     

Changes in dietary lipid saturation modify fatty acid composition and high-density-lipoprotein binding of adipocyte plasma membrane

Binding of rat high-density lipoprotein (HDL) to adipocyte plasma membranes appears to be mediated by specific protein-recognition sites, but membrane lipids may also affect these interactions. To study the effect of dietary fatty acid composition on adipocyte-membrane phospholipid composition and HDL binding, male Wistar rats (250 +/- 10 g) were fed diets high in polyunsaturated (20% wt:wt sunflowerseed oil) or saturated and monounsaturated fatty acids (20% lard, by weight). Sunflower-oil vs lard feeding significantly increased the polyunsaturated fatty acid content of membrane diacylglycerophospholipids and the (22:0 and 24:0) content of long-chain fatty acids of sphingomyelin (p less than 0.05) from epididymal and perirenal adipocyte plasma membranes. Concomitant with these changes in membrane phospholipid composition, sunflower-oil vs lard treatment significantly increased the maximum binding capacity (Bmax) of 125I-labeled HDL2 (p less than 0.05). These results show that feeding polyunsaturated fatty acids enhanced HDL2 Bmax of adipocyte plasma membranes, possibly as a consequence of altering the fatty acid composition of membrane phospholipids.     

Effect of fish oil and safflower oil in common Japanese diet on human plasma fatty acid composition

The influence of fish oil and safflower oil contained in the common Japanese diet as the main dietary polyunsaturated fatty acid source on plasma fatty acids in ten female student volunteers (21-22 years old) was investigated. The subjects were divided into two groups and fed the experimental diets for five days. The total daily fat intake in the fish diet and safflower oil diet was 54.4 g and 56.2 g, respectively, and the fat derived from fish and safflower oil was 16 g and 23 g, respectively. The proportion of linoleic acid was reduced in the plasma of subjects fed the fish diet and increased in the plasma of subjects fed the safflower oil diet. The plasma levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were significantly elevated in the fish diet group. The ratio of EPA/arachidonic acid (AA) was higher, and those of n-6/n-3 and n-9/n-3 were lower in the plasma of subjects fed the fish diet when compared to the results obtained from plasma of subjects fed the safflower oil diet. From these results, it seems likely that fish oil in the common Japanese diet is a favorable source of plasma EPA and DHA even in such short term supplementation and with such a small amount of daily consumption.     

Essential fatty acid and lipid profiles in plasma and erythrocytes in patients with multiple sclerosis

This study was conducted to investigate the possible differences in erythrocyte lipid composition, which might account for the previously reported increase in erythrocyte membrane zinc levels in patients with multiple sclerosis (MS). Compared with healthy control subjects, plasma lipids in patients with MS contained less sphingomyelin but more phosphatidylserine and the cholesterol-phospholipid ratio was 42% higher in the plasma from MS patients (p less than 0.01). In erythrocytes from MS patients, phosphatidylinositol was lower and erythrocyte cholesterol per milligram protein was significantly lower than concentrations in healthy control subjects (p less than 0.01). Among the long-chain fatty acids, the omega-3 fatty acids were lower in plasma from MS patients and linoleic acid was lower in erythrocyte ghosts from MS patients (p less than 0.01). We conclude that altered levels of cholesterol in plasma and erythrocytes from MS patients may contribute to increased erythrocyte-membrane Zn in MS patients. It cannot be stated with certainty whether the altered fatty acid profiles in MS patients were a function of the disease or of altered fatty acid intake.     

Essential fatty acid composition of human colostrum triglycerides: its relationship with adipose tissue composition

The relationships between essential fatty acid (EFA) composition of colostrum and white adipose tissue (WAT) were examined on day 5 after delivery in 69 healthy women. Fatty acid composition was assessed by capillary gas chromatography, and 33 fatty acids were detected in colostrum and in WAT. Total polyunsaturated fatty acid (PUFA) content was similar in colostrum and in WAT (15.7 +/- 3.1% and 16.1 +/- 3.8%, respectively), but long-chain PUFA content was higher in colostrum than in WAT (2.9 +/- 0.6% and 1 +/- 0.2%, respectively; P less than 0.001). The concentrations of linoleic acid were significantly correlated between colostrum and WAT (r = 0.77, P less than 0.0001). No correlation was found for alpha-linolenic acid. The relationships between long-chain PUFA composition of colostrum and WAT suggested that individual factors along with tissue specificity of the mammary gland are involved in either the capacity of desaturating and chain-elongating pathways and/or incorporation of long-chain PUFAs into colostrum.     

Effect of linseed oil ingestion on plasma lipid fatty acid composition and platelet aggregability in healthy volunteers

Eight healthy volunteers ingested 60 ml linseed oil over a period of six weeks. Icosapentaenoic acid increased in plasma triglycerides (TG), phospholipids (PL) and cholesteryl esters (CE) but did not exceed mean values of 2%. α-Linolenic acid rose markedly in TG, linoleic acid decreased in TG and CE, and arachidonic acid decreased in PL and CE. Two additional subjects on a similar regimen underwent blood platelet aggregability tests by the collagen threshold procedure. In both cases a striking decrease in platelet sensitivity to collagen was observed. The results show that linseed oil affects the polyunsaturated fatty acid profile of plasma lipids and suggest a possible alteration of platelet aggregability.     

Baseline plasma C-reactive protein concentrations influence lipid and lipoprotein responses to low-fat and high monounsaturated fatty acid diets in healthy men

To date, no studies have compared the effects of consuming a low-fat diet and a high monounsaturated fatty acid (MUFA) diet, under unrestricted energy intake conditions, on plasma C-reactive protein (CRP) concentrations. Men [n = 61; 37.5 +/- 11.5 y old (mean +/- SD), mean BMI 29.0 +/- 5.0 kg/m2] were randomly assigned to consume ad libitum a moderately low-fat diet (25.8% of energy intake from fat) or a high-fat diet rich in MUFA (40.1% of energy intake from fat, 22.5% from MUFA) for 6-7 wk. Plasma CRP concentrations were measured using a highly sensitive assay. Neither diet affected the plasma CRP concentration. However, baseline CRP concentrations predicted lipoprotein/lipid responsiveness to the experimental diets. After intake of the low-fat diet, plasma total and VLDL-triglyceride (TG) concentrations were increased in the subgroup with high CRP concentrations (P < 0.05 and P < 0.01, respectively) whereas they were reduced in the subgroup with low CRP concentrations at baseline (P < 0.01 for both). The high-MUFA diet reduced plasma TG, VLDL-TG, and VLDL cholesterol only in the subgroup with low CRP at baseline (P < 0.0001). In conclusion, the low-fat diet and the high-MUFA diet did not affect plasma CRP concentrations. However, baseline plasma CRP concentrations may modulate the diet-induced changes in plasma lipid and lipoprotein concentrations.     

Maternal plasma fatty acid composition and pregnancy outcome in adolescents

Adolescents are at a greater risk of adverse pregnancy outcome, including spontaneous preterm delivery and fetal growth restriction, and typically have a poorer-quality diet than adults have. In the present study, we addressed the hypothesis that low maternal dietary intake of n-3 long-chain PUFA (LCP) status adversely influences pregnancy outcome. A total of 500 adolescents (14-18 years) were recruited at ≤ 20 weeks' gestation. The frequency of consumption of oily fish was determined by questionnaire (at recruitment and during the third trimester). The fatty acid composition of plasma lipids during the third trimester was determined in 283 subjects. Principal components analysis (PCA) was used to derive components, which were divided into tertiles. The pregnancy outcomes were then compared by tertile, adjusting for potentially confounding variables. Of the participants, 69% reported never eating oily fish during pregnancy, although consumption was not associated with a shorter duration of gestation (P=0·33), lower customised birth weight (P=0·82) or higher incidence of small-for-gestational age (SGA) birth (P=0·55). PCA of the fatty acid composition of maternal plasma lipids identified a 'low PUFA:SFA (P:S) ratio' component and a 'high n-3 LCP' component. There were no differences between tertiles of the 'high n-3 LCP' component and gestational age at delivery (P=0·62), customised birth weight (P=0·38) or incidence of SGA birth (P=0·25), nor were there any associations between the 'low P:S' ratio component and pregnancy outcome. Lower proportions of n-3 LCP in plasma lipids are not associated with greater risk of adverse pregnancy outcomes in UK adolescents.     

Effect of intravenous omega-3 fatty acid infusion and hemodialysis on fatty acid composition of free fatty acids and phospholipids in patients with end-stage renal disease

Background: Patients treated with hemodialysis (HD) have been reported to have decreased levels of ω‐3 polyunsaturated fatty acids (PUFAs) in plasma and cells. The aim of this study was to investigate the effect of ω‐3 PUFAs administered intravenously during HD, as well as the effect of HD treatment, on the fatty acid composition of plasma free fatty acids (FFAs), plasma phospholipids, and platelet phospholipids. Methods: Forty‐four HD patients were randomized to groups receiving either a single dose of a lipid emulsion containing 4.1 g of ω‐3 PUFAs or placebo (saline) administered intravenously during HD. Blood was drawn immediately before (baseline) and after (4 hours) HD and before the next HD session (48 hours). Fatty acid composition was measured using gas chromatography. Results: The increase in ω‐3 FFAs was greater in the ω‐3 PUFA group compared with the placebo group, whereas the increase in total FFAs was similar between the 2 groups. In the ω‐3 PUFA group, ω‐3 PUFAs in plasma phospholipids were higher after 48 hours than at baseline, and in platelet phospholipids, ω‐3 PUFAs increased after 4 hours. In the placebo group, no changes were observed in ω‐3 PUFAs in plasma and platelet phospholipids. Conclusions: Intravenous ω‐3 PUFAs administered during HD caused a transient selective increase in ω‐3 FFA concentration. Furthermore, ω‐3 PUFAs were rapidly incorporated into platelets, and the content of ω‐3 PUFAs in plasma phospholipids increased after 48 hours.     

Phytanic acid: measurement of plasma concentrations by gas-liquid chromatography-mass spectrometry analysis and associations with diet and other plasma fatty acids

Epidemiological data suggest that a diet rich in animal foods may be associated with an increased risk of several cancers, including cancers of the prostate, colorectum and breast, but the possible mechanism is unclear. It is hypothesised that phytanic acid, a C20 branched-chain fatty acid found predominantly in foods from ruminant animals, may be involved in early cancer development because it has been shown to up regulate activity of alpha-methylacyl-coenzyme A racemase, an enzyme commonly found to be over-expressed in tumour cells compared with normal tissue. However, little is known about the distribution of plasma phytanic acid concentrations or its dietary determinants in the general population. The primary aim of the present cross-sectional study was to determine circulating phytanic acid concentrations among ninety-six meat-eating, lacto-ovo-vegetarian and vegan women, aged 20-69 years, recruited into the Oxford component of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). Meat-eaters had, on average, a 6.7-fold higher geometric mean plasma phytanic acid concentration than the vegans (5.77 v. 0.86 micromol/l; P < 0.0001) and a 47 % higher mean concentration than the vegetarians (5.77 v. 3.93 micromol/l; P = 0.016). The strongest determinant of plasma phytanic acid concentration appeared to be dairy fat intake (r 0.68; P < 0.0001); phytanic acid levels were not associated with age or other lifestyle factors. These data show that a diet high in fat from dairy products is associated with increased plasma phytanic acid concentration, which may play a role in cancer development.