Fatty acid composition of serum glycerophospholipids in children

Lipid profile variability in children at different ages measured in dried blood spots

Dried blood spot (DBS) is a minimally invasive sampling technique that has several advantages over conventional venipuncture/arterial blood sampling. More recently, DBS has also been applied for lipidomics analysis, but this is an area that requires further research. The few works found in the literature on lipidomics of DBS samples performed the analysis in adult samples, leaving pediatric ages unmapped. The objective of this study was to assess the variability of the lipid profile (identified by high-resolution C18 RP-LC-MS/MS) of DBS at pediatric age (0-10 days, 2-18 months, and 3-13 years) and to identify age-related variations. The results revealed that the lipidomic signature of the three age groups is significantly different, especially for a few species of neutral lipids and phosphatidylcholines. The main contributors to the differentiation of the groups correspond to 3 carnitine (Car), 2 cholesteryl ester (CE), 2 diacylglycerol (DG), 2 triacylglycerol (TG), 3 phosphatidylcholine (PC), 1 ether-linked PC, 1 phosphatidylethanolamine (PE), 1 ether-linked PE and 1 phosphatidylinositol (PI) species, all with statistically significant differences. Additionally, lipid species containing linoleic acid (C18:2) were shown to have significantly lower levels in the 0-10 days group with a gradual increase in the 2-18 month, reaching the highest concentrations in the 3-13 year group. The results of this study highlighted the adaptations of the lipid profile at different pediatric ages. These results may help improve understanding of the evolution of lipid metabolism throughout childhood and should be investigated further.

Maternal Plasma Glycerophospholipids LC-PUFA Levels Have a Sex-Specific Association with the Offspring's Cord Plasma Glycerophospholipids-Fatty Acid Desaturation Indices at Birth

Fatty acid desaturases, the enzymes responsible for the production of unsaturated fatty acids (FA) in fetal tissues, are known to be influenced by maternal-placental supply of nutrients and hormones for their function. We hypothesize that there could be a gender-specific regulation of unsaturated FA metabolism at birth, dependent on the maternal fatty acid levels. In this study, 153 mother-newborn pairs of uncomplicated and 'full-term' pregnancies were selected and the FA composition of plasma glycerophospholipids (GP) was quantified by gas chromatography. The FA composition of mother blood plasma (MB) was compared with the respective cord blood plasma (CB) of male newborns or female newborns. Product to substrate ratios were estimated to calculate delta 5 desaturase (D5D), delta 6 desaturase (D6D) and delta 9 stearoyl-CoA-desaturase (D9D/SCD) indices. Pearson correlations and linear regression analyses were employed to determine the associations between MB and CB pairs. In the results, the male infant's MB-CB association was positively correlated with the SCD index of carbon-16 FA, while no correlation was seen for the SCD index of carbon-18 FA. Unlike for males, the CB-D5D index of female neonates presented a strong positive association with the maternal n-6 long chain-polyunsaturated FA (LC-PUFA), arachidonic acid. In addition, the lipogenic desaturation index of SCD18 in the CB of female new-borns was negatively correlated with their MB n-3 DHA. In conclusion, sex-related differences in new-borns' CB desaturation indices are associated with maternal LC-PUFA status at the time of the birth. This examined relationship appears to predict the origin of sex-specific unsaturated FA metabolism seen in later life.

Choline, DHA, and Diarrheal Disease Associated with Growth Faltering in a Case-Control Study

Background

Children with recurrent infectious diarrhea are susceptible to growth faltering. DHA and choline may play a role in this relationship due to their involvement in lipid metabolism, gut immunity, and inflammatory pathways.

Objectives

This study aimed to characterize the contributions made by DHA and choline status and enteric damage in young children in the association between diarrheal illness and child growth.

Methods

A longitudinal case-control study was conducted among children aged 6-36 mo (N = 195) in Cap-Haitien, Haiti. Mother-child dyads were recruited from community health posts and outpatient clinics. Cases were defined as children experiencing acute diarrhea within the last 3 d and matched to healthy controls. Child anthropometry, dietary intake, and blood and stool samples were collected at baseline and follow-up. Plasma DHA, choline, and betaine were determined by LC-MS/MS methods (n = 49) and intestinal fatty acid-binding protein (I-FABP) by ELISA (n = 183). Multivariate regression models were applied with mediation analyses to examine associations and adjust for confounding factors.

Results

At baseline, mean plasma DHA concentrations (1.03 µg/mL; 95% CI: 0.91, 1.15) were not significantly different between cases and controls, nor was there a difference in mean plasma choline concentrations (4.5 µg/mL; 95% CI: 3.8, 5.1). Mean plasma I-FABP concentrations were significantly higher at follow-up in cases (3.34; 95% CI: 3.28, 3.40) than controls (3.20; 95% CI: 3.13, 3.27; P = 0.002). In adjusted multilinear regression models, higher plasma DHA concentrations at follow-up were associated with a negative change in weight-age z score (P = 0.016), and follow-up I-FABP was inversely associated with height-age z score (P = 0.035). No interaction or mediation effects were found.

Conclusions

I-FABP concentrations were significantly higher in cases as compared with controls at follow-up, suggesting ongoing enteric damage and increased risk for malnutrition. Plasma DHA and I-FABP may have a role in childhood growth outcomes.

Plasma and Red Blood Cell PUFAs in Home Parenteral Nutrition Paediatric Patients-Effects of Lipid Emulsions

Background: Mixed lipid emulsions (LE) containing fish oil present several advantages compared to the sole soybean oil LE, but little is known about the safety of essential fatty acids (EFA) profile in paediatric patients on long-term Parenteral Nutrition (PN). Aim of the study: to assess glycerophosfolipid polyunsaturated fatty acids (PUFA) levels on plasma and red blood cell (RBC) membrane of children on long term PN with composite LE containing fish oil (SMOF), and to compare it with a group receiving olive oil LE (Clinoleic^®) and to the reference range for age, previously determined on a group of healthy children. Results: A total of 38 patients were enrolled, median age 5.56 (0.9-21.86) years, 15 receiving Clinoleic^®, 23 receiving SMOF. Patients on SMOF showed significantly higher levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), lower levels of arachidonic acid (ARA) and Mead acid (MEAD)/ARA ratio in plasma and RBC compared with patients on Clinoleic^® and with healthy children. Triene:tetraene (T:T) ratio of both groups of patients did not differ from that of healthy children-median plasma (MEAD/ARA: 0.01, interquartile rage (IQR) 0.01, p = 0.61 and 0.02, IQR 0.02, p = 0.6 in SMOF and Clinoleic^® patients, respectively), and was considerably lower than Holman index (>0.21). SMOF patients showed no statistically significant differences in growth parameters compared with Clinoleic^® patients. Patients of both groups showed stiffness class F0-F1 of liver stiffness measure (LSM) 5.6 (IQR 0.85) in SMOF patients and 5.3 (IQR 0.90) in Clinoleic^® patients, p = 0.58), indicating absence of liver fibrosis. Conclusions: Fatty acids, measured as concentrations (mg/L), revealed specific PUFA profile of PN patients and could be an accurate method to evaluate nutritional status and eventually to detect essential fatty acid deficiency (EFAD). SMOF patients showed significantly higher EPA, DHA and lower ARA concentrations compared to Clinoleic^® patients. Both LEs showed similar hepatic evolution and growth.

Impact of Treatment with RUTF on Plasma Lipid Profiles of Severely Malnourished Pakistani Children

(1) Background: Little is known on impacts of ready-to-use therapeutic food (RUTF) treatment on lipid metabolism in children with severe acute malnutrition (SAM). (2) Methods: We analyzed glycerophospholipid fatty acids (FA) and polar lipids in plasma of 41 Pakistani children with SAM before and after 3 months of RUTF treatment using gas chromatography and flow-injection analysis tandem mass spectrometry, respectively. Statistical analysis was performed using univariate, multivariate tests and evaluated for the impact of age, sex, breastfeeding status, hemoglobin, and anthropometry. (3) Results: Essential fatty acid (EFA) depletion at baseline was corrected by RUTF treatment which increased EFA. In addition, long-chain polyunsaturated fatty acids (LC-PUFA) and the ratio of arachidonic acid (AA)/linoleic acid increased reflecting greater EFA conversion to LC-PUFA, whereas Mead acid/AA decreased. Among phospholipids, lysophosphatidylcholines (lyso.PC) were most impacted by treatment; in particular, saturated lyso.PC decreased. Higher child age and breastfeeding were associated with great decrease in total saturated FA (ΣSFA) and lesser decrease in monounsaturated FA and total phosphatidylcholines (ΣPC). Conclusions: RUTF treatment improves EFA deficiency in SAM, appears to enhance EFA conversion to biologically active LC-PUFA, and reduces lipolysis reflected in decreased ΣSFA and saturated lyso.PC. Child age and breastfeeding modify treatment-induced changes in ΣSFA and ΣPC.

Determinants of Plasma Docosahexaenoic Acid Levels and Their Relationship to Neurological and Cognitive Functions in PKU Patients: A Double Blind Randomized Supplementation Study

Children with phenylketonuria (PKU) follow a protein restricted diet with negligible amounts of docosahexaenoic acid (DHA). Low DHA intakes might explain subtle neurological deficits in PKU. We studied whether a DHA supply modified plasma DHA and neurological and intellectual functioning in PKU. In a double-blind multicentric trial, 109 PKU patients were randomized to DHA doses from 0 to 7 mg/kg&day for six months. Before and after supplementation, we determined plasma fatty acid concentrations, latencies of visually evoked potentials, fine and gross motor behavior, and IQ. Fatty acid desaturase genotypes were also determined. DHA supplementation increased plasma glycerophospholipid DHA proportional to dose by 0.4% DHA per 1 mg intake/kg bodyweight. Functional outcomes were not associated with DHA status before and after intervention and remained unchanged by supplementation. Genotypes were associated with plasma arachidonic acid levels and, if considered together with the levels of the precursor alpha-linolenic acid, also with DHA. Functional outcomes and supplementation effects were not significantly associated with genotype. DHA intakes up to 7 mg/kg did not improve neurological functions in PKU children. Nervous tissues may be less prone to low DHA levels after infancy, or higher doses might be required to impact neurological functions. In situations of minimal dietary DHA, endogenous synthesis of DHA from alpha-linolenic acid could relevantly contribute to DHA status.

Determinants of Serum Glycerophospholipid Fatty Acids in Cystic Fibrosis

The etiology of altered blood fatty acid (FA) composition in cystic fibrosis (CF) is understood only partially. We aimed to investigate the determinants of serum glycerophospholipids’ FAs in CF with regard to the highest number of FAs and in the largest cohort to date. The study comprised 172 CF patients and 30 healthy subjects (HS). We assessed Fas’ profile (gas chromatography/mass spectrometry), CF transmembrane conductance regulator (CFTR) genotype, spirometry, fecal elastase-1, body height and weight Z-scores, liver disease, diabetes and colonization by Pseudomonas aeruginosa. The amounts of saturated FAs (C14:0, C16:0) and monounsaturated FAs (C16:1n-7, C18:1n-9, C20:1n-9, C20:3n-9) were significantly higher in CF patients than in HS. C18:3n-6, C20:3n-6 and C22:4n-6 levels were also higher in CF, but C18:2n-6, C20:2n-6 and C20:4n-6, as well as C22:6n-3, were lower. In a multiple regression analysis, levels of seven FAs were predicted by various sets of factors that included age, genotype, forced expiratory volume in one second, pancreatic status and diabetes. FA composition abnormalities are highly prevalent in CF patients. They seem to be caused by both metabolic disturbances and independent clinical risk factors. Further research into the influence of CFTR mutations on fat metabolism and desaturases’ activity is warranted.

Serum lipid profile and fatty acid composition of erythrocyte phospholipids in children and adolescents with primary hyperlipidemia

This study aimed at characterizing the fatty acid (FA) composition of red blood cell (RBC) phospholipids in children and adolescents with primary hyperlipidemia, and to ascertain potential association with serum lipid profile and dietary factors. At this purpose, 54 probands aged 6-17 years were recruited. Subjects showed a low omega-3 index (eicosapentaenoic acid, EPA + docosahexaenoic acid, DHA <4%). Compared to males, females had a trend toward lower levels of total monounsaturated fatty acids (MUFA) and MUFA/saturated fatty acids (SFAs) ratio in RBCs. An inverse relationship between MUFA concentration in RBCs and serum cholesterol or HDL-C/triglycerides ratio was found. Omega-6 polyunsaturated fatty acids (n-6 PUFA) were positively associated to serum HDL-C levels, and inversely to dietary cholesterol. Fiber intake was positively associated with MUFA/SFA ratio. In conclusion, we provide the first experimental data on phospholipid FA composition of RBCs in hyperlipidemic children, showing sex differences and an overall low omega 3-index.

Dried blood spot omega-3 and omega-6 long chain polyunsaturated fatty acid levels in 7-9 year old Zimbabwean children: a cross sectional study

BACKGROUND

Omega-3 long chain-polyunsaturated fatty acids (LC-PUFAs)-docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and eicosapentaenoic acid (EPA)- and omega-6 LC-PUFA arachidonic acid (ARA), are essential for optimum physical and mental development in children. Prior to this study, the blood omega-3 LC-PUFA levels were unknown in Zimbabwean children, particularly in those aged 7-9 years, despite the documented benefits of LC-PUFAs. Documentation of the LC-PUFA levels in this age group would help determine whether interventions, such as fortification, are necessary. This study aimed to determine dried whole blood spot omega-3 and omega-6 LC-PUFA levels and LC-PUFA reference intervals among a selected group of Zimbabwean children aged 7-9 years old.

METHODS

We conducted a cross sectional study from September 2011 to August 2012 on a cohort of peri-urban, Zimbabwean children aged 7-9 years. The children were born to mothers enrolled at late pregnancy into an HIV prevention program between 2002 and 2004. Dried whole blood spots were sampled on butylated hydroxytoluene antioxidant impregnated filter papers and dried. LC-PUFAs were quantified using gas liquid chromatography. Differences in LC-PUFAs between groups were compared using the Kruskal Wallis test and reference intervals determined using non-parametric statistical methods.

RESULTS

LC-PUFAs levels were determined in 297 Zimbabwean children of whom 170 (57.2 %) were girls. The study determined that LC-PUFAs (wt/wt) ranges were EPA 0.06-0.55 %, DPA 0.38-1.98 %, DHA 1.13-3.52 %, ARA 5.58-14.64 % and ARA: EPA ratio 15.47-1633.33. Sixteen participants had omega-3 LC-PUFAs levels below the determined reference intervals, while 18 had higher omega-6 LC-PUFAs. The study did not show gender differences in omega-3 and omega-6 LC-PUFAs levels (all p > 0.05). EPA was significantly higher in the 8 year age group compared to those aged 7 and 9 years (median; 0.20 vs 0.17 vs 0.18, respectively, p = 0.049). ARA: EPA ratio was significantly higher in the 7 year age group compared to those aged 8 and 9 years (median; 64.38 vs 56.43 vs 55.87 respectively, p = 0.014).

CONCLUSIONS

In this cohort of children, lower EPA levels and higher ARA: EPA ratios were observed compared to those reported in apparently healthy children elsewhere. The high ARA: EPA ratios might increase the vulnerability of these children to inflammatory pathologies. Identification and incorporation into diet of locally produced foodstuffs rich in omega-3 LC-PUFAs is recommended as well as advocating for dietary supplementation with omega-3 fish oils and algae based oils.

Reference values of whole-blood fatty acids by age and sex from European children aged 3-8 years

OBJECTIVES

To establish reference values for fatty acids (FA) especially for n-3 and n-6 long-chain polyunsaturated FAs (LC PUFA) in whole-blood samples from apparently healthy 3-8-year-old European children. The whole-blood FA composition was analysed and the age- and sex-specific distribution of FA was determined.

DESIGN AND SUBJECTS

Blood samples for FA analysis were taken from 2661 children of the IDEFICS (identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study cohort. Children with obesity (n=454) and other diseases that are known to alter the FA composition (n=450) were excluded leaving 1653 participants in the reference population.

MEASUREMENTS

The FA composition of whole blood was analysed from blood drops by a rapid, validated gas chromatographic method.

RESULTS

Pearson correlation coefficients showed an age-dependent increase of C18:2n-6 and a decrease of C18:1n-9 in a subsample of normal weight boys and girls. Other significant correlations with age were weak and only seen either in boys or in girls, whereas most of the FA did not show any age dependence. For age-dependent n-3 and n-6 PUFA as well as for other FA that are correlated with age (16:0, C18:0 and C18:1n-9) percentiles analysed with the general additive model for location scale and shape are presented. A higher median in boys than in girls was observed for C20:3n-6, C20:4n-6 and C22:4n-6.

CONCLUSIONS

Given the reported associations between FA status and health-related outcome, the provision of FA reference ranges may be useful for the interpretation of the FA status of children in epidemiological and clinical studies.

Infant formula composition affects energetic efficiency for growth: the BeMIM study, a randomized controlled trial

BACKGROUND & AIMS

Protein source, macronutrient composition and content of long chain-polyunsaturated fatty acids (LC-PUFA) of infant formulae may influence infant growth. We aimed to assess the effect of a modified infant formula on growth.

METHODS

In a randomized, double-blind trial, 213 healthy term infants consumed isoenergetic study formulae (intervention formula - IF, control formula - CF) from the first month of life until the age of 120 days. IF (1.89 g protein/100 kcal) contained α-lactalbumin (ALAB) and LC-PUFA, while CF (2.30 g protein/100 kcal) provided standard whey and no LC-PUFA. Anthropometry and dietary intake were regularly assessed. A venous blood sample was obtained on day 120.

RESULTS

Both formulae were well-accepted without significant differences in health related observations. Weight gain was not statistically different between formula groups (IF: 30.2 ± 6.3 vs. CF: 28.3 ± 6.5 g/day, mean ± SD, P = 0.06). Length gain was higher in IF (0.11 ± 0.02 vs. 0.10 ± 0.02 cm/day, P = 0.02). Energy intake from formula was higher in CF at 90 and 120 days (IF: 509 ± 117 and 528 ± 123 vs. CF: 569 ± 152 and 617 ± 169 kcal/day, P < 0.01). Protein intake in CF was significantly higher at each assessment. Growth per energy intake was higher in IF compared to CF for weight (6.45 ± 2.01 vs. 5.67 ± 2.21 g/100 kcal, P = 0.02) and length (0.23 ± 0.08 vs. 0.20 ± 0.08 mm/100 kcal, P = 0.04).

CONCLUSIONS

The modified infant formula with reduced protein content with added ALAB and LC-PUFA, meets infant requirements of protein for adequate growth. The increased energetic efficiency of the new infant formula might result from improved protein composition by added ALAB. Apparently minor differences in composition can markedly affect energetic efficiency for growth. The study was registered at ClinicalTrials.gov (NCT01094080).

Low blood long chain omega-3 fatty acids in UK children are associated with poor cognitive performance and behavior: a cross-sectional analysis from the DOLAB study

Background

Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), especially DHA (docosahexaenonic acid) are essential for brain development and physical health. Low blood Omega-3 LC-PUFA have been reported in children with ADHD and related behavior/learning difficulties, as have benefits from dietary supplementation. Little is known, however, about blood fatty acid status in the general child population. We therefore investigated this in relation to age-standardized measures of behavior and cognition in a representative sample of children from mainstream schools.

Participants

493 schoolchildren aged 7–9 years from mainstream Oxfordshire schools, selected for below average reading performance in national assessments at age seven.

Method

Whole blood fatty acids were obtained via fingerstick samples. Reading and working memory were assessed using the British Ability Scales (II). Behaviour (ADHD-type symptoms) was rated using the revised Conners’ rating scales (long parent and teacher versions). Associations were examined and adjusted for relevant demographic variables.

Results

DHA and eicosapentaenoic acid (EPA), accounted for only 1.9% and 0.55% respectively of total blood fatty acids, with DHA showing more individual variation. Controlling for sex and socio-economic status, lower DHA concentrations were associated with poorer reading ability (std. OLS coeff. = 0.09, p = <.042) and working memory performance (0.14, p = <.001). Lower DHA was also associated with higher levels of parent rated oppositional behavior and emotional lability (−0.175, p = <.0001 and −0.178, p = <.0001).

Conclusions

In these healthy UK children with below average reading ability, concentrations of DHA and other Omega-3 LC-PUFA were low relative to adult cardiovascular health recommendations, and directly related to measures of cognition and behavior. These findings require confirmation, but suggest that the benefits from dietary supplementation with Omega-3 LC-PUFA found for ADHD, Dyspraxia, Dyslexia, and related conditions might extend to the general school population.

Metabolomics of dietary fatty acid restriction in patients with phenylketonuria

Background

Patients with phenylketonuria (PKU) have to follow a lifelong phenylalanine restricted diet. This type of diet markedly reduces the intake of saturated and unsaturated fatty acids especially long chain polyunsaturated fatty acids (LC-PUFA). Long-chain saturated fatty acids are substrates of mitochondrial fatty acid oxidation for acetyl-CoA production. LC-PUFA are discussed to affect inflammatory and haemostaseological processes in health and disease. The influence of the long term PKU diet on fatty acid metabolism with a special focus on platelet eicosanoid metabolism has been investigated in the study presented here.

Methodology/Principal Findings

12 children with PKU under good metabolic control and 8 healthy controls were included. Activated fatty acids (acylcarnitines C6–C18) in dried blood and the cholesterol metabolism in serum were analyzed by liquid chromatographic tandem mass spectrometry (LC-MS/MS). Fatty acid composition of plasma glycerophospholipids was determined by gas chromatography. LC-PUFA metabolites were analyzed in supernatants by LC-MS/MS before and after platelet activation and aggregation using a standardized protocol. Patients with PKU had significantly lower free carnitine and lower activated fatty acids in dried blood compared to controls. Phytosterols as marker of cholesterol (re-) absorption were not influenced by the dietary fatty acid restriction. Fatty acid composition in glycerophospholipids was comparable to that of healthy controls. However, patients with PKU showed significantly increased concentrations of y-linolenic acid (C18:3n-6) a precursor of arachidonic acid. In the PKU patients significantly higher platelet counts were observed. After activation with collagen platelet aggregation and thromboxane B₂ and thromboxane B₃ release did not differ from that of healthy controls.

Conclusion/Significance

Long-term dietary fatty acid restriction influenced the intermediates of mitochondrial beta-oxidation. No functional influence on unsaturated fatty acid metabolism and platelet aggregation in patients with PKU was detected.

Novel methodologies for assessing omega-3 fatty acid status - a systematic review

Over the last few decades n-3 long chain polyunsaturated fatty acid status became of special interest for scientists. Biochemical measures on the n-3 fatty acid status vary depending on body compartment assessed and measures chosen. Plasma phospholipids and red blood cell membrane phospholipids are mainly used as n-3 fatty acid status marker. The conventional analysis of phospholipid fatty acids involves lipid extraction and consecutive chromatographic separation of phospholipids from other lipid fractions, which is time-consuming and costly. In recent years, different investigators have tried to overcome these limitations by using other biological markers or by modifying the analytical procedures used to assess n-3 fatty acid status. The aim of this systematic review was to provide an overview on these novel analytical methods developed for the fatty acid quantification by gas chromatography, highlights the methodological limitations, and discusses advantages or disadvantages of the biological markers used. Seventeen papers were identified that fulfilled the inclusion criteria. New opportunities arise from sensitive and precise high-throughput methodologies for assessment of plasma total lipid and plasma glycerophospholipid fatty acids, as well as cheek cell fatty acid composition.

Comparison of the incorporation of orally administered DHA into plasma, erythrocyte and cheek cell glycerophospholipids

Adequate intake of n-3 fatty acids plays an important role in human health. The analysis of various blood lipids is used as a measure of fatty acid status in humans. Cheek cell phospholipids (PL) have also been proposed as biological markers, but are rarely used in clinical studies due to limitations in sample quality and quantity. An improved method for the analysis of cheek cell glycerophospholipid fatty acids is applied in a 29 d supplementation trial with 510 mg DHA daily. The DHA increases in cheek cell, plasma and erythrocyte glycerophospholipids are compared. High correlations are shown for glycerophospholipid DHA between cheek cells and plasma (r 0·88) and erythrocytes (r 0·76) before study commencement. After the daily supplementation of DHA, the half-maximal glycerophospholipid DHA level is reached after about 4 d in plasma, 6 d in erythrocytes and 10 d in cheek cells. The mean DHA increase (mol%) relative to baseline was most prominent in plasma (186 %), followed by cheek cells (180 %) and erythrocytes (130 %). Considering a lag phase of about 5 d, cheek cells reflect short-term changes in dietary fat uptake. Based on the data of the present study, they can be used alternatively to plasma and erythrocyte PL as non-invasive n-3 fatty acid status markers.

Fatty acid status determination by cheek cell sampling combined with methanol-based ultrasound extraction of glycerophospholipids

Tissue and blood fatty acid compositions are used as biological markers of fatty acid intakes to improve dietary assessments. These approaches are invasive and not well accepted, particularly in infants and young children. We developed a sensitive method for the analysis of fatty acids in cheek cell glycerophospholipids, which includes significant improvements of cell sampling, non-chromatographic isolation of glycerophospholipids and base-catalyzed synthesis of fatty acid methyl esters. Sphingophospholipids are not detected by this method. This enables a highly accurate determination of cheek cell glycerophospholipid fatty acids, even if cell numbers are limited. Coefficients of variation for fatty acids contributing more than 0.3% to total glycerophospholipid fatty acids are below 10% in samples with more than 10(5) cells. Good correlations were shown between docosahexaenoic and eicosapentaenoic acid percentages in cheek cell and plasma glycerophospholipids (r = 0.83 and 0.64, respectively; P < 0.001) with a linear relationship over the whole concentration range observed in adult study participants (n = 29). Cheek cell sampling is non-invasive and can easily be applied in infants. The accuracy and reliability of this new method is comparable to conventional invasive methods for the determination of the n-3 fatty acid status in humans, and it is well applicable in interventional or epidemiological studies.