Red Blood Cell Fatty Acid Composition Research Articles

Red Blood Cell Polyunsaturated Fatty Acid Composition and Mortality Following Breast Cancer: Results From the Women's Healthy Eating and Living (WHEL) Study

Purpose: To examine the associations between red blood cell (RBC) composition of polyunsaturated fatty acids (PUFAs) and mortality among women with breast cancer. Methods: This nested case-control study included 1,104 women from the Women's Healthy Eating and Living Study, a randomized controlled trial of a plant-based dietary change on breast cancer survival. Cases were women who died from any cause (n = 290) from 1995 to 2006. Controls were women who were alive at the end of follow-up matched to cases on age at diagnosis, years since randomization, intervention group, and stage (n = 814). RBC fatty acid composition was measured in blood samples collected at baseline using gas chromatography and included the proportions of four n-3 and seven n-6 PUFAS. We examined each PUFA individually as well as factor analysis-derived factors in association with all-cause and breast cancer-specific mortality using conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: In fully-adjusted models, all-cause mortality ORs were elevated among women with PUFAs >median (versus ≤ median) for alpha-linolenic acid (ALA, C18:3n3; OR = 1.56; 95% CI = 1.14–2.14) and for linolenic acid (LnA, C18:2n6, OR = 1.54; 95% CI = 1.15–2.07), and breast cancer-specific mortality ORs were elevated for LnA (OR = 1.72, 95% CI = 1.24–2.38) and gamma-linolenic acid (GLA, C18:3n6; OR = 1.40; 95% CI = 0.97–2.00). Factor 1 [arachidonic acid, C20:4n6; adrenic acid, C22:4n6; and docosapentaenoic acid, C22:5n6] scores >median (versus ≤median) were associated with lower odds of all-cause (OR = 0.72; 95% CI = 0.53–0.98) and breast cancer-specific (OR = 0.67; 95% CI = 0.47–0.94) mortality, and Factor 4 [ALA and GLA] scores >median (versus ≤median) were associated with increased odds of breast cancer-specific mortality (OR = 1.42; 95% CI = 1.01–2.01). Additionally, 1-SD increase in Factor 4 scores were associated with ORs of 1.22 (95% CI = 1.04–1.42) for all-cause mortality and 1.24 (95% CI = 1.05–1.47) for breast cancer-specific mortality. Conclusions: RBC PUFA composition profiles are associated with all-cause and breast cancer-specific mortality risk among women with breast cancer.

Validation of a Food Frequency Questionnaire to Assess Intake of n-3 Polyunsaturated Fatty Acids in Switzerland.

Population-based data suggest that high intake of omega-3 (n-3) polyunsaturated fatty acids (PUFA) may be beneficial in a variety of health conditions. It is likely that mainly those patients with preexisting n-3 deficiency are those that benefit most from n-3 fatty acid supplementation. Therefore, for targeted interventions, a fast and reliable screening tool for n-3 PUFA intake is necessary. Thus, the aim of this project was to adapt and validate a food frequency questionnaire (FFQ) for n-3 PUFA intake in Switzerland while using as references the following: (1) 7-day food records (FR), and (2) n-3 fatty acid composition of red blood cells (RBC). We recruited 46 healthy adults for the first part of the study and 152 for the second. We used the dietary software EBISpro for the analysis of n-3 PUFA intake. RBC fatty acid composition was determined by gas chromatography mass spectrometry (GC-MS). Using correlation analysis, we found a moderate significant association between FFQ and FR for α-linolenic acid (ALA), eicosapentanoic acid (EPA), docosahexanoic acid (DHA), and total n-3 fatty acids (all r between 0.523 and 0.586, all p < 0.001). Bland Altman analysis further showed good agreement between the two methods and no proportional bias. Correlations between FFQ and RBC fatty acid composition were also moderate for EPA and DHA (r = 0.430 and r = 0.605, p < 0.001), but weaker for ALA and total n-3 (r = 0.314 and r = 0.211, p < 0.01). The efficacy of the FFQ to classify individuals into the same or adjacent quartile of RBC PUFA content ranged between 70% and 87% for the different fatty acids. In conclusion, we showed that the Swiss n-3 PUFA FFQ is a valid tool to assess dietary n-3 PUFA intake, especially DHA and EPA, to determine population groups at risk for low intake.

Association of Bright Liver With the PNPLA3 I148M Gene Variant in 1-Year-Old Toddlers.

Nonalcoholic fatty liver disease (NAFLD) is being increasingly diagnosed at younger ages, pointing toward an early-life origin. To evaluate the frequency and risk factors for bright liver (BL) in 1-year-old toddlers. Secondary analysis of the 1-year follow-up of the Feeding Study. Exposures were child PNPLA3 and TM6SF2 gene variants; child anthropometry at birth and at 1 year of follow-up; child subcutaneous, visceral, and epicardial adipose tissue at 1 year of follow-up; maternal anthropometry at the start and at the end of pregnancy; and maternal red blood cell fatty-acid composition at the third trimester of pregnancy. General population. Among 505 mother-toddler pairs, 391 children (77%) underwent liver and abdominal ultrasonography at the 1-year follow-up. BL as diagnosed by ultrasonography. Seventeen (4%) of 391 toddlers had BL. Compared with the toddlers with the PNPLA 3 CC genotype, the odds (95% CI) of BL were 3.01 (1.05 to 8.64, P < 0.05) times higher in those with the PNAPLA3 CG genotype and 5.37 (1.12 to 25.77, P < 0.05) higher in those with the PNPLA3 CC genotype. We found no association between BL status and TM6SF2. Body weight, body mass index, and maternal weight gain during pregnancy were higher in BL+ than in BL- children. Visceral adipose tissue was higher but subcutaneous adipose tissue and epicardial adipose tissue were similar in BL+ and BL- children. Four percent of the Feeding Study children had BL at 1 year of age. In line with expectations, PNAPLA3 was already a predictor of BL at this early age.

Fatty acid intake and erythrocyte fatty acid profile in women with breast, ovarian and cervical cancers

Summary Aim To assess dietary fat and fatty acid (FA) intakes and to correlate it with red blood cell (RBC) FA composition in women with newly diagnosed breast, cervical and ovarian cancer. Methods 185 women who were newly diagnosed with breast, cervical or ovarian cancer were recruited for the study and dietary information was obtained using food frequency questionnaires. RBC fatty acid composition was analyzed in a subset of 96 women with cancers (35 breast cancer, 31 cervical cancer and 30 ovarian cancer) and 56 age-matched controls. Results Subjects with malignancies were seen to consume lower amounts of fat and higher amounts of carbohydrates compared with controls. While the intakes of saturated fatty acids (SFA) were similar across the groups, The intakes of PUFA, specifically linoleic acid (LA, 18:2 n-6) and long chain n-3 PUFA (LC n-3 PUFA) were significantly lower (p Conclusion The study shows a good correlation between dietary PUFA intakes and RBC PUFA composition, and suggests that elongation of fatty acids is significantly affected in cancer such that it favours the formation of pro-inflammatory n-6 PUFA while repressing the formation of anti-inflammatory n-3 PUFAs.

Erythrocyte fatty acid composition of Nepal breast-fed infants.

Essential fatty acids play a critical role in the growth and development of infants, but little is known about the fatty acid status of populations in low-income countries. The objective was to describe the fatty acid composition of red blood cells (RBC) in breastfeed Nepali infants and a subsample of their mothers and to identify the main sources of fatty acids in the mother's diet, as well as the fatty acid composition of breast milk. RBC fatty acid composition was analyzed in a random sample of 303 infants and 72 mother, along with 68 breastmilk samples. Fatty acid profiles of the most important dietary fat sources were analyzed. Information on mother's diet and intake of fat was collected by three 24-h dietary recalls. In infant RBC's, docosahexaenoic acid (DHA) was the main n-3 fatty acid, and arachidonic acid (AA) was the major n-6 fatty acid. Total n-6 PUFA was three times higher than total n-3 PUFA. Height-for-age (HAZ) was positively associated with DHA status and AA status in multivariable models. The concentration of all fatty acids was higher in children, compared to mothers, except Total n-6 PUFA and Linoleic acid (LA) where no differences were found. The mother's energy intake from fat was 13% and cooking oil (sesame, mustard, soybean or sunflower oil) contributed 52% of the fat intake. RBC-DHA levels in both infants and mother was unexpected high taking into account few dietary DHA sources and the low DHA concentrations in breastmilk.

Determination of red blood cell fatty acid profiles: Rapid and high-confident analysis by chemical ionization-gas chromatography-tandem mass spectrometry.

Cellular fatty acid (FA) profiles have been acknowledged as biomarkers in various human diseases. Nevertheless, common FA analysis by gas chromatography mass spectrometry (GC-MS) requires long analysis time. Hence, there is a need for feasible methods for high throughput analysis in clinical studies. FA was extracted from red blood cells (RBC) and derivatized to fatty acid methyl esters (FAME). A method using gas chromatography tandem mass spectrometry (GC-MS/MS) with ammonia-induced chemical ionization (CI) was developed for the analysis of FA profiles in human RBC. We compared this method with classical single GC-MS using electron impact ionization (EI). The FA profiles of 703 RBC samples were determined by GC-MS/MS. In contrast to EI ammonia-induced CI resulted in adequate amounts of molecular ions for further fragmentation of FAME. Specific fragments for confident quantification and fragmentation were determined for 45 FA. The GC-MS/MS method has a total run time of 9min compared to typical analysis times of up to 60min in conventional GC-MS. Intra and inter assay variations were <10% for all FA analyzed. Analysis of RBC FA composition revealed an age-dependent increase of the omega-3 eicosapentaenoic and docosahexaenoic acid, and a decline of the omega-6 linoleic acid with a corresponding rise of the omega-3 index. The combination of ammonia-induced CI and tandem mass spectrometry after GC separation allows for high-throughput, robust and confident analysis of FA profiles in the clinical laboratory.

The proportion of total C18:1 trans-fatty acids in red blood cell membranes relates to carotid plaque prevalence

Consistent evidence supports the pro-atherogenic properties of dietary trans-fatty acids (TFAs). However, there are no clinical data on TFA intake and atheroma plaque. We cross sectionally investigated whether the proportion of total C18:1 TFA in red blood cells (RBCs), which mirrors dietary TFA intake, independently relates to carotid plaque prevalence in subjects with new-onset type 2 diabetes mellitus without prior cardiovascular disease (n=101, 56% men, mean age 61 years) and age- and sex-matched controls (n=96). RBC fatty acid composition was determined by gas chromatography. Plaque (defined as carotid intima-media thickness ≥1.5 mm) was sonographically assessed at three bilateral carotid segments. In multivariate models adjusting for group (diabetes or control) and classical cardiovascular risk factors, for each 0.1% increase in RBC total C18:1 TFA isomers, plaque prevalence increased by 53% (P=.002). In contrast, for each 0.1% increase in RBC alpha-linolenic acid, the vegetable omega-3 fatty acid, plaque prevalence decreased by 43% (P<.001). We conclude that the RBC membrane proportion of total C18:1 TFA, considered a proxy of intake, directly relates to the ultrasound feature that best predicts future cardiovascular events. Our findings support current recommendations to limit TFA intake for cardiovascular health promotion.

Protective effects of dietary supplementation with natural ω-3 polyunsaturated fatty acids on the visual acuity of school-age children with lower IQ or attention-deficit hyperactivity disorder

ObjectiveLittle attention has been paid to the possible protective role of ω-3 polyunsaturated fatty acids (PUFAs) on the visual acuity of school-age children with lower IQs or attention-deficit hyperactivity disorder (ADHD). The aim of this study was to evaluate the effect of dietary ω-3 PUFAs on the visual acuity and red blood cell (RBC) fatty acid compositions of these children. MethodsWe randomly assigned 179 children with lower IQs or ADHD to receive ordinary eggs (control group, n = 90) or eggs rich in C18:3 ω-3, eicosapentaenoic acid (EPA, 20:5 ω-3) and docosahexaenoic acid (DHA, 22:6 ω-3) for 3 mo (study group, n = 89). Before and after the intervention, distance visual acuity was tested using an E chart and the RBC fatty acid composition was determined using capillary gas chromatography. ResultsThree months later, 171 children completed the follow-up with the exception of 8 children who were unavailable during follow-up. Both groups of children showed a significant improvement in visual acuity (P < 0.05), however, visual acuity in the study group was significantly better than that of the control group (P = 0.013). The C18:3 ω-3 (P = 0.009), DHA (P = 0.009) and ∑ω-3 (P = 0.022) levels of the intervention group were significantly higher than those of the control group, while the C20:4 ω-6 (P = 0.003), C22:4 ω-6 (P = 0.000), ∑ω-6 (P = 0.001), ∑ω-6/∑ω-3 (P = 0.000) and arachidonic acid/DHA (P = 0.000) of the study group were significantly lower than those of the control group. No significant differences in the levels of C18:2 ω-6 (P = 0.723), C20:2 ω-6 (P = 0.249), C20:3 ω-6 (P = 0.258), C20:5 ω-3 (P = 0.051), or C22:5 (P = 0.200) were found between the two groups. ConclusionsDietary supplementation with ω-3 PUFAs improves both visual acuity and the RBC fatty acid profile in school-age children with lower IQs or ADHD.

Unexpected similarity in RBC DHA and AA levels between bottlenose dolphins and humans

BackgroundThe Omega-3 Index [red blood cell (RBC) content of eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA)] is inversely related to risk of cardiovascular disease in humans. In the U.S., the average Omega-3 Index is about 4–6% of RBC fatty acids, whereas in Japan it is 9–10%. The range of physiologically-possible levels for the Omega-3 Index in other mammals is unknown. ObjectiveTo compare the RBC fatty acid composition of a common piscivorous mammal, the bottlenose dolphin (Tursiops truncatus), with that of (U.S.) humans, and to examine the extent to which dietary fatty acid patterns were reflected in RBCs. MethodsRBCs were isolated from routine blood samples collected from 35 healthy dolphins at two display facilities and were analyzed by gas chromatography. For humans, historic, deidentified RBC fatty acid data from our laboratory were used (n=11,329; mean age 58). ResultsThe mean Omega-3 Index of the dolphins was 19.9% compared with 6.0% for humans. EPA levels were 15.3% vs 1.2%, respectively, but DHA levels were virtually identical (4.6% vs 4.8%). Linoleic acid (LNA) levels were much lower in dolphins vs humans (0.5% vs 12.5%) whereas arachidonic acid (ARA) levels were similar (12.3% vs 14.5%). In a subgroup of humans with an Omega-3 Index in the >99.2 percentile, the mean index was similar to that of the dolphins. Based on an analysis of their food, the dolphins consumed about 60g of EPA+DHA per day as compared to about 0.1g in humans. ConclusionDolphins have an Omega-3 Index that is (only) 3–4× higher than that of U.S. adults despite their intake of EPA+DHA being about 165× higher (as a percent of kcal). RBC, EPA and LNA levels are relatively more reflective of dietary intakes than are DHA and ARA levels. The mechanisms by which certain fatty acid levels appear to be fixed and others may vary in RBC membranes are unknown.

Effect of dietary omega-3 fatty acids on red blood cell lipid composition and plasma metabolites in the cockatiel, Nymphicus hollandicus1

Although dietary n-3 fatty acids have been extensively studied in poultry, they have not yet been prospectively investigated in psittacines, despite potential benefits for preventing and treating atherosclerosis, osteoarthritis, and other chronic disease processes. The objectives of this study were to investigate the incorporation of dietary n-3 fatty acids into red blood cells (RBC) and to determine the effects of supplementation of psittacine diets with fish or flax oil on plasma lipids and lipoproteins in the cockatiel. Adult cockatiels were fed a custom-formulated diet containing either 4% (wt/wt, as-fed) beef tallow (CON), 3% fish oil + 1% tallow (FSH), or 3.5% flax oil + 0.5% tallow (FLX; n = 20 per diet group). Baseline measurements were obtained for RBC fatty acid composition, triacylglycerides (TAG), and cholesterol. After 8 to 13 wk on the study diets, plasma chemistry profiles, lipoprotein density profiles, and RBC fatty acid composition were determined. At 8 wk, total plasma cholesterol was least in FSH birds (P < 0.05) and TAG concentrations were less in FSH birds than FLX birds (P < 0.05). Total n-3 fatty acids, docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid were markedly greater in the RBC of FSH birds than FLX or CON birds (P < 0.05). Alpha linolenic acid was greatest in FLX (P < 0.05). Initial and final BW, and nonlipid plasma chemistry values did not differ among diet groups. No adverse effects of dietary supplementation of cockatiels with 3.5% flax oil or 3% fish oil were observed during the 13-wk feeding period. Although fish and flax oils provided similar total n-3 PUFA to the diets, fish oil caused greater reductions in cholesterol and TAG, and greater total RBC n-3 incorporation. Thus, dietary modification of psittacine diets with long chain n-3 PUFA from fish oil appears safe and may be beneficial to these long-lived companion birds.

Red blood cell fatty acids are associated with depression in a case-control study of adolescents

IntroductionEpidemiological studies suggest that reduced intakes and/or blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with increased risk for depression in adults, but data on adolescents are scarce. The objective of this study was to determine whether red blood cell (RBC) levels of EPA+DHA (the omega-3 index) and/or the overall RBC fatty acid profile differ between depressed adolescents (cases) and non-depressed adolescents (controls). Patients and MethodsWe measured the RBC fatty acid composition of cases admitted to the hospital for depression (n=150) and compared it to that of controls (n=161). ResultsCases and controls had similar ages, gender proportions, and body mass index (BMI) distributions, but there was a significant difference in racial/ethnic composition due to differences in recruitment sites. The unadjusted odds ratio for case status was 0.72 (95% CI; 0.55–0.95) for a 1% absolute increase in the omega-3 index. A multivariable logistic regression model was used to determine which fatty acids were useful in classifying cases and controls; BMI, age, gender, and race/ethnicity were forced into the model. Seven fatty acids were selected (DHA, myristic, stearic, oleic, trans linoleic, trans palmitoleic, and alpha-linolenic acids) to optimize the model fit to the data. In the adjusted model, the odds ratio was 0.67 (95% CI; 0.49–0.93) for a 1 SD increase in DHA. Adding the seven fatty acid profile to the basic model increased the area under the ROC curve by 12.6% (7.5%–17.6%). Discussion and ConclusionThese findings support the hypothesis that adolescent depression is associated with a perturbed RBC fatty acid pattern which includes a reduced omega-3 index. Intervention studies with EPA and DHA should be conducted in this vulnerable population for which few, safe therapeutic options currently exist.

Increased erythrocytes n-3 and n-6 polyunsaturated fatty acids is significantly associated with a lower prevalence of steatosis in patients with type 2 diabetes

Non-alcoholic fatty liver disease (NAFLD) is commonly associated with obesity, metabolic syndrome and type 2 diabetes. Although dietary fat contributes substantially to the accumulation of liver fat, the role of individual fatty acids in this accumulation is unclear. In this study, we set out to determine whether liver fat content (LFC), was associated with red blood cell fatty acid (RBC-FA) composition in people with type 2 diabetes. One hundred and sixty-two type 2 diabetic patients were included in this study. LFC was measured using (1)H-MR Spectroscopy. RBC-FA composition was measured by gas chromatography. One hundred and nine (67.2%) patients had steatosis. Patients with steatosis had a higher BMI (p = 0.0005), and higher plasma triglyceride levels (p = 0.009) than did patients without steatosis. We report a significant association between palmitic acid (16:0), palmitoleic acid (16:1n-7) concentrations and ratio of monounsaturated to saturated fatty acid (palmitoleic acid to palmitic acid) and higher liver fat content. Total polyunsaturated fatty acid (PUFA), homo-gamma-linolenic acid (20:3n-6), docosahexaenoic acid (22:6n-3), and arachidonic acid (20:4 n-6) were associated with lower LFC. Our data showed that an increased erythrocytes long-chain n-3 and n-6 fatty acids was associated with a lower prevalence of steatosis in patients with type 2 diabetes. These results suggest that n-3 and n-6 fatty acids supplementation could be a promising treatment for NAFLD in patients with type 2 diabetes.

Docosahexaenoic Acid and 17β-Estradiol Co-Treatment Is More Effective Than 17β-Estradiol Alone in Maintaining Bone Post-Ovariectomy

Bone-protective effects of combined treatment with long chain polyunsaturated fatty acids (LCPUFAs) and estrogenic compounds following ovariectomy have previously been reported. Recent evidence suggests the n-3 LCPUFA docosahexaenoic acid (DHA, 22:6n-3) is particularly bone-protective. The aim of this study was to determine whether combined treatment with DHA and estrogenic compounds has a beneficial effect on bone mass in ovariectomized (OVX) rats. Rats were randomized into 9 groups and either ovariectomized (8 groups) or sham-operated (1 group). Using a 2 x 4 factorial design approach, OVX animals received either no estrogenic compound, genistein (20 mg/kg body weight/day), daidzein, (20 mg/kg body weight/day) or 17 beta-estradiol (1 microg/day) with or without DHA (0.5 g/kg body weight/day) for 18 weeks. Bone mineral content (BMC), area (BA), and density (BMD), plasma osteocalcin and IL-6 concentrations, and red blood cell (RBC) fatty acid composition were measured. Femur BMC was significantly greater in animals treated with DHA or 17 beta-estradiol than in ovariectomized controls. Plasma carboxylated osteocalcin was significantly higher in DHA-treated animals and total osteocalcin significantly lower in 17 beta-estradiol-treated animals compared with ovariectomized controls. There were significant interactions between treatment with estrogenic compounds and DHA for femur BMC, plasma IL-6 concentration, and RBC fatty acid composition. Combined treatment with 17beta-estradiol+DHA was more effective than either treatment alone at preserving femur BMC and lowering circulating concentrations of pro-inflammatory IL-6. The percentage of n-3 LCPUFAs in RBCs was significantly greater in animals receiving 17 beta-estradiol+DHA compared with either treatment alone. There was no beneficial effect of combined DHA and phytoestrogen treatment on bone. Results from this study raise the possibility that co-treatment with 17 beta-estradiol and DHA may allow a lower dose of 17 beta-estradiol to be used to provide the same bone-protective effects as when 17 beta-estradiol is administered alone.

N‐3 Polyunsaturated Fatty Acids and Atopy in Korean Preschoolers

Atopy is a growing problem for Korean children. Since eicosapentaenoic acid is a precursor of less active inflammatory eicosanoids, n-3 polyunsaturated fatty acids (PUFA) may have a protective effect on atopy. This study was undertaken to determine whether n-3 PUFA in red blood cells (RBC) is lower in atopic than in non-atopic preschoolers. Three hundred and eight Korean children aged 4-6 years were enrolled. Total RBC fatty acid composition was measured by gas chromatography. The prevalence of atopic dermatitis, allergic rhinitis, or asthma was 29%. Total RBC n-3 PUFA were lower in preschoolers with atopy than controls (9.8 +/- 1.2 vs. 11.4 +/- 1.6%; P<0.05), while n-6 PUFA (33.0 +/- 1.4 vs. 32.2 +/- 1.0%; P<0.05) and n-6/n-3 PUFA ratio (3.4 +/- 0.6 vs. 2.8 +/- 0.5; P<0.05) were greater. The following factors were also associated with an increase in atopy: higher saturated fatty acids (39.6 +/- 1.4 vs. 40.6 +/- 1.9; P<0.05) and arachidonic acid (15.3 +/- 1.6 vs. 16.0 +/- 2.9; P<0.05), and lower total PUFA (43.8 +/- 0.7 vs. 42.8 +/- 1.4; P<0.05) and omega-3 index (EPA + DHA; 9.1 +/- 0.8 vs. 7.8 +/- 0.5; P<0.05) in RBC. Maternal history of atopy was a significant (P<0.05) risk factor, while lactation was not. The results suggest that a reduced content of n-3 PUFA in the RBC membrane could play a role in early children atopy.

Assessment of erythrocyte phospholipid fatty acid composition as a biomarker for dietary MUFA, PUFA or saturated fatty acid intake in a controlled cross-over intervention trial

BackgroundDietary intervention trials rely on self-reported measures of intake for assessment of energy and macronutrient composition. Dietary fat intake is of particular interest due to strong associations with pathophysiology. In epidemiological trials phospholipid fatty acid composition may reflect composition of habitual diet, although strong correlations have been identified only for essential polyunsaturated fatty acids (PUFAs). Preliminary evidence shows that saturated fatty acids (SFA) C15:0 and C17:0 may be acceptable biomarkers. This study measured changes in erythrocyte membrane fatty acids during a period of strictly controlled fat feeding to investigate their use as a short-term marker of compliance, particularly for intake of SFAs.ResultsThis was a randomised cross-over trial in which diet was provided and strictly controlled. 20 healthy, male subjects were given a 40 energy % (en%) fat diet, high in saturated (high-SFA, 20 en%) or unsaturated (high-USFA, 24 en%) fatty acids for 2 periods of 3 weeks. Subjects were residential during intervention with all food and beverages provided. Dietary composition was verified by direct chemical analysis. Blood samples were collected on days 1,7,14, 21 and analysed for red blood cell (RBC) membrane fatty acid composition. Pearson correlation showed RBC fatty acid composition to mimic dietary composition by 3 weeks, but the relationships were weak. Of the SFAs only RBC C16:0 decreased in response to decreased dietary content on high-USFA treatment (ANOVA, diet, P < 0.05). Of the USFAs, higher levels of C18:1 MUFA, C20:4 and C22:6 long chain PUFA on high-USFA diet lead to higher C18:1, C20:4 and C22:6 within RBCs (ANOVA, time*diet, P < 0.05). Pearson's correlation was significant between dietary and RBC fatty acids during the 21d dietary manipulation for C18:1, and C20:5, C22:6 only (P < 0.05).ConclusionRBC membrane fatty acids cannot reliably be used as an independent measure of compliance for dietary SFA intake in short-term studies. The MUFA oleic acid and PUFAs EPA and DHA may be more useful as markers of compliance during short term intervention trials.

Plasma and red blood cell fatty acid composition in smallfor gestational age term infants fed human milk or formula

The purpose of the present study was to evaluate the effects of feeding human milk or milkformula on the fatty acid composition of plasma and red blood cell (RBC) lipids in at term small for gestational age infants (SGA) for the first 3 months of life. One group of infants received a formula with a linoleic:α-linolenic acid ratio of 10:1 (MF group). Another group served as control and received their own mother's milk (HM group). Blood samples were taken at birth and at 1 week, 4 weeks, and 3 months of life. Plasma and RBC fatty acid composition were analyzed by gas liquid chromatography and results of total plasma lipids were expressed as concentrations by adding an internal standard. Concentrations of saturated and monounsaturated fatty acids increased in total plasma lipids with age in all infants. In contrast, those fatty acids decreased when results were expressed as percentages of total fatty acids. Long-chain polyunsaturated fatty acids (LCP) decreased regardless of how results were expressed, but the absolute concentrations of these fatty acids in plasma available for tissue accretion were greater than suggested by the percentage results. Plasma and RBC docosahexaenoic acid (22:6n-3) decreased in the MF group in comparison to the HM group. Arachidonic acid (20:4n-6) was lower in plasma of MF-fed infant but not in RBC phospholipids. We conclude that term SGA infants fed an adapted milk formula with a linoleic:α-linolenic acid ratio of 10:1 but devoid of LCP may lead to a low n-3 LCP status.

Morphology and fatty acid composition of erythrocytes from monkeys exposed to ozone for one year

Monkeys ( Macaca radiata) were exposed to a low dose (0.64 ppm) of ozone (O 3) for 8 hr each day over a 1-year period. Control monkeys were exposed to filtered air. The morphology of the red blood cell (RBC) from these monkeys was analyzed by scanning electron microscopy. Red cells from control monkeys had normal morphology with 69% having biconcave shape (discocytes). In O 3-exposed animals, blood contained only 35% discocytes. Knizocytes, stomatocytes, and spherocytes each have defined shape which are different from discocytes. The number of knizocytes and stomatocytes in O 3-exposed monkeys was twice that of controls. In addition, significant levels of spherocytes were observed while they were absent in the blood of controls. The fatty acid composition of RBC from control and O 3-exposed monkeys was the same. These were similar to that of human RBC. However, earlier reports of monkey RBC fatty acid composition differ from our results. These differences are discussed. We conclude that low-dose O 3 exposure changes the morphology, but not the fatty acid composition, of erthrocytes in vivo.