Simultaneous capillary gas chromatographic profiling of medium-and long-chain fatty acid methyl esters with split injection. Correction for injection-related discrimination by the 'bracketing' method

Mothers' Breast Milk Composition and Their Respective Infant's Gut Microbiota Differ between Five Distinct Rural and Urban Regions in Vietnam

Microbiota colonization and development in early life is impacted by various host intrinsic (genetic) factors, but also diet, lifestyle, as well as environmental and residential factors upon and after birth. To characterize the impact of maternal nutrition and environmental factors on vaginally born infant gut microbiota composition, we performed an observational study in five distinct geographical areas in Vietnam. Fecal samples of infants (around 39 days old) and fecal and breast milk samples of their mothers (around 28 years) were collected. The microbiota composition of all samples was analyzed by 16S rRNA gene Illumina sequencing and a bioinformatics workflow based on QIIME. In addition, various breast milk components were determined. Strong associations between the geographically determined maternal diet and breast milk composition as well as infant fecal microbiota were revealed. Most notable was the association of urban Ha Noi with relatively high abundances of taxa considered pathobionts, such as Klebsiella and Citrobacter, at the expense of Bifidobacterium. Breast milk composition was most distinct in rural Ha Long Bay, characterized by higher concentrations of, e.g., docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), selenium, and vitamin B12, while it was characterized by, e.g., iron, zinc, and α-linolenic acid (ALA) in Ha Noi. Breast milk iron levels were positively associated with infant fecal Klebsiella and negatively with Bifidobacterium, while the EPA and DHA levels were positively associated with Bifidobacterium. In conclusion, differences between five regions in Vietnam with respect to both maternal breast milk and infant gut microbiota composition were revealed, most likely in part due to maternal nutrition. Thus, there could be opportunities to beneficially steer infant microbiota development in a more desired (rural instead of urban) direction through the mother's diet.

Temporal Changes in Breast Milk Fatty Acids Contents: A Case Study of Malay Breastfeeding Women

The composition of human breast milk changes in the first two months of life, adapting itself to the evolving needs of the growing new-born. Lipids in milk are a source of energy, essential fatty acids (FA), fat-soluble vitamins, and vital bioactive components. Information on breast milk FA of Malaysian lactating women is scarce. Based on convenience sampling, a total of 20 Malay breastfeeding women who fulfilled the inclusion criteria were recruited. Breast milk was collected three times from each subject at consecutive intervals of 2–3 weeks apart. A total of 60 breast milk samples were collected and classified into “transitional milk” (n = 8), “early milk” (n = 26) and “mature milk” (n = 26). All milk samples were air freighted to University of Groningen, Netherlands for analysis. The dominant breast milk FA were oleic acid, constituting 33% of total fatty acids, followed by palmitic acid (26%). Both these FA and the essential FA, linoleic acid (10%) and alpha-linolenic acid (0.4%), showed no significant changes from transitional to mature milk. Breast milk ratio of n-6:n-3 polyunsaturated fatty acids (PUFA) was comparatively high, exceeding 10 throughout the lactation period, suggesting a healthier balance of PUFA intake is needed in pregnancy and at postpartum.

Fish oil supplemental dose needed to reach 1g% DHA+EPA in mature milk

INTRODUCTION

Erythrocyte (RBC) DHA+EPA is considered optimal at 8g%. Mothers with lifetime high fish intakes exhibiting this status produce milk with about 1g% DHA+EPA. We established DHA+EPA supplemental dosages needed to augment RBC DHA+EPA to 8g% and milk DHA+EPA to 1g%.

MATERIALS AND METHODS

Pregnant women were randomly allocated to DHA+EPA dosages of: 225+90 (n=9), 450+180 (n=9), 675+270 (n=11) and 900+360 (n=7) mg/day. Samples were collected at 20 and 36 gestational weeks and 4 weeks postpartum.

RESULTS

Linear regression revealed needed dosages rounded at 750mg/day to reach 8g% RBC DHA+EPA and 1000mg/day for 1g% milk DHA+EPA. RBC DHA+EPA increment depended on baseline values. There was no effect on milk AA, but milk EPA/AA ratio increased.

CONCLUSION

Women with an RBC DHA+EPA status of 5.5g% need 750 and 1000mg DHA+EPA/day to reach 8g% RBC DHA+EPA at the pregnancy end and 1g% mature milk DHA+EPA, respectively.

Milk vitamin D in relation to the 'adequate intake' for 0-6-month-old infants: a study in lactating women with different cultural backgrounds, living at different latitudes

Breast-fed infants are susceptible to vitamin D deficiency rickets. The current vitamin D 'adequate intake' (AI) for 0-6-month-old infants is 10 µg/d, corresponding with a human milk antirachitic activity (ARA) of 513 IU/l. We were particularly interested to see whether milk ARA of mothers with lifetime abundant sunlight exposure reaches the AI. We measured milk ARA of lactating mothers with different cultural backgrounds, living at different latitudes. Mature milk was derived from 181 lactating women in the Netherlands, Curaçao, Vietnam, Malaysia and Tanzania. Milk ARA and plasma 25-hydroxyvitamin D (25(OH)D) were analysed by liquid-chromatography-MS/MS; milk fatty acids were analysed by GC-flame ionisation detector (FID). None of the mothers reached the milk vitamin D AI. Milk ARA (n; median; range) were as follows: Netherlands (n 9; 46 IU/l; 3-51), Curaçao (n 10; 31 IU/l; 5-113), Vietnam: Halong Bay (n 20; 58 IU/l; 23-110), Phu Tho (n 22; 28 IU/l; 1-62), Tien Giang (n 20; 63 IU/l; 26-247), Ho-Chi-Minh-City (n 18; 49 IU/l; 24-116), Hanoi (n 21; 37 IU/l; 11-118), Malaysia-Kuala Lumpur (n 20; 14 IU/l; 1-46) and Tanzania-Ukerewe (n 21; 77 IU/l; 12-232) and Maasai (n 20; 88 IU/l; 43-189). We collected blood samples of these lactating women in Curaçao, Vietnam and from Tanzania-Ukerewe, and found that 33·3 % had plasma 25(OH)D levels between 80 and 249·9 nmol/l, 47·3 % between 50 and 79·9 nmol/l and 19·4 % between 25 and 49·9 nmol/l. Milk ARA correlated positively with maternal plasma 25(OH)D (range 27-132 nmol/l, r 0·40) and milk EPA+DHA (0·1-3·1 g%, r 0·20), and negatively with latitude (2°S-53°N, r -0·21). Milk ARA of mothers with lifetime abundant sunlight exposure is not even close to the vitamin D AI for 0-6-month-old infants. Our data may point at the importance of adequate fetal vitamin D stores.

A fish is not a fish: patterns in fatty acid composition of aquatic food may have had implications for hominin evolution

From c. 2 Ma (millions of years ago) onwards, hominin brain size and cognition increased in an unprecedented fashion. The exploitation of high-quality food resources, notably from aquatic ecosystems, may have been a facilitator or driver of this phenomenon. The aim of this study is to contribute to the ongoing debate on the possible role of aquatic resources in hominin evolution by providing a more detailed nutritional context. So far, the debate has focused on the relative importance of terrestrial versus aquatic resources while no distinction has been made between different types of aquatic resources. Here we show that Indian Ocean reef fish and eastern African lake fish yield on average similarly high amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA). Hence a shift from exploiting tropical marine to freshwater ecosystems (or vice versa) would entail no material difference in dietary long-chain polyunsaturated fatty acid (LC-PUFA) availability. However, a shift to marine ecosystems would likely mean a major increase in access to brain-selective micronutrients such as iodine. Fatty fish from marine temperate/cold waters yield twice as much DHA and four times as much EPA as tropical fish, demonstrating that a latitudinal shift in exploitation of African coastal ecosystems could constitute a significant difference in LC-PUFA availability with possible implications for brain development and functioning. We conclude that exploitation of aquatic food resources could have facilitated the initial moderate hominin brain increase as observed in fossils dated to c. 2 Ma, but not the exceptional brain increase in later stages of hominin evolution. We propose that the significant expansion in hominin brain size and cognition later on may have been aided by strong directional selecting forces such as runaway sexual selection of intelligence, and nutritionally supported by exploitation of high-quality food resources in stable and productive aquatic ecosystems.

Interrelationships between maternal DHA in erythrocytes, milk and adipose tissue. Is 1 wt% DHA the optimal human milk content? Data from four Tanzanian tribes differing in lifetime stable intakes of fish

Little is known about the interrelationships between maternal and infant erythrocyte-DHA, milk-DHA and maternal adipose tissue (AT)-DHA contents. We studied these relationships in four tribes in Tanzania (Maasai, Pare, Sengerema and Ukerewe) differing in their lifetime intakes of fish. Cross-sectional samples were collected at delivery and after 3 d and 3 months of exclusive breast-feeding. We found that intra-uterine biomagnification is a sign of low maternal DHA status, that genuine biomagnification occurs during lactation, that lactating mothers with low DHA status cannot augment their infants' DHA status, and that lactating mothers lose DHA independent of their DHA status. A maternal erythrocyte-DHA content of 8 wt% was found to correspond with a mature milk-DHA content of 1·0 wt% and with subcutaneous and abdominal (omentum) AT-DHA contents of about 0·39 and 0·52 wt%, respectively. Consequently, 1 wt% DHA might be a target for Western human milk and infant formula that has milk arachidonic acid, EPA and linoleic acid contents of 0·55, 0·22 and 9·32 wt%, respectively. With increasing DHA status, the erythrocyte-DHA content reaches a plateau of about 9 wt%, and it plateaus more readily than milk-DHA and AT-DHA contents. Compared with the average Tanzanian-Ukerewe woman, the average US woman has four times lower AT-DHA content (0·4 v. 0·1 wt%) and five times lower mature milk-DHA output (301 v. 60 mg/d), which contrasts with her estimated 1·8-2·6 times lower mobilisable AT-DHA content (19 v. 35-50 g).

Fatty acid compositions of preterm and term colostrum, transitional and mature milks in a sub-Saharan population with high fish intakes

BACKGROUND

There are no data on the fatty acid (FA) compositions of preterm and term milks for sub-Saharan African populations with advancing lactation. However, it is generally acknowledged that our ancestors evolved in sub-Saharan East-Africa, where they inhabited the land-water ecosystems.

METHODS

We compared the FA-compositions of preterm (28-36 weeks) and term (37-42) colostrum (2-5 day), transitional (6-15) and mature (16-56) milks in rural African women with stable dietary habits and lifelong high freshwater fish intakes.

RESULTS

From colostrum to mature milk: the median docosahexaenoic acid (DHA) content decreased from 1.11 to 0.75; and arachidonic acid (AA) from 0.93 to 0.69 g% in preterm milk. In term milk, DHA decreased from 0.81 to 0.53 and AA from 1.08 to 0.55 g%. Medium-chain saturated-FA (MCSAFA) increased from 16.9 to 33.7, and 7.92-29.0 g%, while mono-unsaturated FA (MUFA) decreased from 32.5 to 22.6, and 40.0-26.5 g%, in preterm and term milk, respectively. Consistent with the literature, preterm colostrum contained higher DHA and MCSAFA, and lower MUFA compared to term colostrum. These differences vanished rapidly with advancing lactation. MUFA and MCSAFA were inversely related.

CONCLUSIONS

The presently found DHA in preterm colostrum and mature milks and AA in premature mature milk proved the highest reported in the literature so far, as derived from analysis with capillary GC-columns. We confirmed the much higher MCSAFA and lower MUFA contents in milk of rural African, compared to Westernized women. The milk FA composition of this traditional population might show us the FA composition on which our species evolved and consequently to which our genome has become adapted to optimally support (infant) health.

Gestational age dependent content, composition and intrauterine accretion rates of fatty acids in fetal white adipose tissue

BACKGROUND

Little is known about the gestational age (GA) dependent content, composition and intrauterine accretion rates of fatty acids (FA) in fetal white adipose tissue (WAT).

OBJECTIVE & DESIGN

To acquire this information, we collected abdominal subcutaneous WAT samples from 40 preterm and term fetuses. Their GA ranged from 22 to 43 weeks. FA were expressed as mg/g wet WAT and g/100g FA (g%). Intrauterine WAT FA accretion rates were estimated for appropriate (AGA) and large (LGA) for gestational age infants.

RESULTS

From 25 to 40 weeks gestation, saturated-FA (SAFA) increased from 83 to 298 mg/g WAT and monounsaturated-FA (MUFA) from 83 to 226 mg/g WAT, while polyunsaturated-FA (PUFA) increased insignificantly from 18.0 to 23.2 mg/g WAT. As percentages of total FA, SAFA increased from 46 to 55 g%, MUFA decreased from 44 to 41 g%, and PUFA from 10.3 to 4.26 g%. Docosahexaenoic (DHA) and arachidonic acid (AA) accretion rates in WAT during the 3rd trimester for AGA infants were 88 and 193 mg/week, respectively. Contemporaneous DHA and AA accretion rates for 4500 g LGA infants were 184 and 402 mg/week, respectively. Compared to the whole 3rd trimester, increment rates during the last 5 weeks of gestation were about 2-fold higher.

CONCLUSION

FA accretion rates, notably those of DHA and AA, may be important for designing nutritional regiments for preterm infants. The current WAT-DHA and WAT-AA accretion rates are considerably lower than previously reported in the literature.

The influence of supplemental docosahexaenoic and arachidonic acids during pregnancy and lactation on neurodevelopment at eighteen months

Docosahexaenoic acid (DHA) and arachidonic acid (AA) are important for neurodevelopment. The effects of DHA (220 mg/day, n=41), DHA+AA (220 mg/day, n=39) or placebo (n=34) during pregnancy and lactation on neurodevelopment at 18 months, and the relations between umbilical cord DHA, AA and Mead acid and neurodevelopment were studied. An age-specific, standardized neurological assessment for the evaluation of minor neurological dysfunction (MND), and the Bayley Scales of Infant Development (BSID) were used. The intervention did not influence any of the outcomes. Umbilical venous (UV) Mead acid was negatively and n-6 fatty acids were weakly positively associated to the BSID mental developmental index. Children with simple MND had lower UV DHA compared to normally classified children. We conclude that relatively short-term maternal DHA or DHA+AA supplementation does not influence neurodevelopment at toddler age, although some parameters of brain development are related to perinatal DHA and AA status.

Mildly abnormal general movement quality in infants is associated with higher Mead acid and lower arachidonic acid and shows a U-shaped relation with the DHA/AA ratio

We showed that docosahexaenoic acid (DHA) supplementation during pregnancy and lactation was associated with more mildly abnormal (MA) general movements (GMs) in the infants. Since this finding was unexpected and inter-individual DHA intakes are highly variable, we explored the relationship between GM quality and erythrocyte DHA, arachidonic acid (AA), DHA/AA and Mead acid in 57 infants of this trial. MA GMs were inversely related to AA, associated with Mead acid, and associated with DHA/AA in a U-shaped manner. These relationships may indicate dependence of newborn AA status on synthesis from linoleic acid. This becomes restricted during the intrauterine period by abundant de novo synthesis of oleic and Mead acids from glucose, consistent with reduced insulin sensitivity during the third trimester. The descending part of the U-shaped relation between MA GMs and DHA/AA probably indicates DHA shortage next to AA shortage. The ascending part may reflect a different developmental trajectory that is not necessarily unfavorable.

Maternal and fetal brain contents of docosahexaenoic acid (DHA) and arachidonic acid (AA) at various essential fatty acid (EFA), DHA and AA dietary intakes during pregnancy in mice

We investigated essential fatty acids (EFA) and long-chain polyunsaturated fatty acids (LCP) in maternal and fetal brain as a function of EFA/LCP availability to the feto-maternal unit in mice. Diets varying in parent EFA, arachidonic acid (AA), and docosahexaenoic acid (DHA) were administered from day 3 prior to conception till day 15 of pregnancy. We concentrated on DHA, AA, Mead acid, and EFA-index [(omega-3+omega-6)/(omega-7+omega-9)] in maternal erythrocytes, maternal brain, and fetal brain. It was found that erythrocyte EFA/LCP sensitively reflects declining EFA/LCP status in pregnancy, although this decline was not apparent in maternal brain. Differences in erythrocyte EFA/LCP coincided with larger differences in fetal brain EFA/LCP as compared to EFA/LCP in maternal brain. Both maternal and fetal brains were affected by short-term EFA/LCP intake, but the developing fetal brain proved most sensitive. The inverse relationship between fetal brain AA and DHA suggests the need of a maternal dietary DHA/AA balance, at least in mice.

Milk in the island of Chole [Tanzania] is high in lauric, myristic, arachidonic and docosahexaenoic acids, and low in linoleic acid reconstructed diet of infants born to our ancestors living in tropical coastal regions

BACKGROUND

We need information on the diet on which our genes evolved.

OBJECTIVE

We studied the milk fatty acid [FA] composition of mothers living in the island of Chole [Tanzania, Indian Ocean]. These mothers have high intakes of boiled marine fish and coconut, and consume plenty amount of fruits and vegetables.

DESIGN

The outcome was compared with three fish-eating tribes living along Tanzanian freshwater lakes [Kerewe, Nyakius, Nyiramba], four tribes living in the Tanzanian inland [Hadzabe, Maasai, Sonjo, Iraqw] and our milk FA database.

RESULTS

Milk from Chole contained high levels of 12:0 [20.17 g%], 14:0 [21.19], 12:0/14:0 ratio [0.92 g/g], arachidonic acid [AA, 0.50 g%] and docosahexaenoic acid [DHA, 0.73], but low levels of linoleic acid [LA, 4.23]. The combination of a high medium chain fatty acid [MCFA; <C16] content and 12:0/14:0 ratio derives notably from coconut consumption, as opposed to a carbohydrate rich diet, while non-existent use of vegetable oils explains low LA. Milk AA/DHA ratios of the four fish-eating groups were related to the AA/DHA ratios of the available fish. Chole MCFA and LA did not fulfill Western recommendations for formulae, while AA and DHA were well above minimum levels.

CONCLUSIONS

The Chole milk FA composition is likely to reflect the dietary FA composition of babies born to our ancient ancestors living in East-African coastal regions. The poor compliance with present recommendations raises doubts on the validity of recommendations that are based on milk from Western mothers consuming diets that confer high risk of diseases typical for affluent countries.

Erythrocyte membrane fatty acids in benign and progressive forms of multiple sclerosis

BACKGROUND

There is no good explanation why a proportion of patients with multiple sclerosis (MS) have a relatively benign form of the disease. An imbalance between saturated and unsaturated fatty acids (FA) might influence the disease course of MS.

AIM

To assess whether the erythrocyte membrane fatty acid composition, which is a biological marker of long term dietary FA consumption, is different between patients with benign and progressive MS.

METHODS

The erythrocyte membrane FA composition was measured by gas chromatography in 23 healthy controls, 27 patients with benign MS, 32 patients with secondary progressive MS and 23 patients with primary progressive MS. None of the patients was following a special diet.

RESULTS

No significant differences in levels of saturated and unsaturated FA or in omega-3- and omega-6-polyunsaturated FA were found between controls and patients with the different subtypes of MS.

CONCLUSION

Our data suggest that factors other than dietary fatty acid consumption are responsible for the different disease courses of MS.

High contents of both docosahexaenoic and arachidonic acids in milk of women consuming fish from lake Kitangiri (Tanzania): targets for infant formulae close to our ancient diet?

Current recommendations for arachidonic (AA) and docosahexaenoic (DHA) acids in infant formulae are based on milk of Western mothers. Validity may be questioned in view of the profound dietary changes in the past 100 years, as opposed to our slowly adapting genome. Hominin evolution occurred in the proximity of East-African freshwater lakes and rivers and early homo sapiens had higher intakes of AA and DHA from a predominantly lacustrine-based diet. In search of milk AA and DHA contents of our African ancestors, we investigated the milk of 29 lactating women living in Doromoni near lake Kitangiri (Tanzania). They consumed sunflower oil-fried local fish as only animal lipid sources, maize and local vegetables. AA and DHA contents of Doromoni milk may be close to that of early homo sapiens, because of the similarity of their life-long consumption of East-African lacustrine-based foods. Human milk fatty acid relationships from our historical worldwide database and the literature revealed that disparities between the Doromoni diet and the presumed ancient diet (i.e. higher carbohydrate and linoleic acid intakes) are unlikely to affect milk AA and DHA contents. Doromoni milk had high contents of AA (median 0.70 mol%), DHA (0.75) and eicosapentaenoic acid (EPA, 0.17), and low AA/DHA ratios (median 0.91; 0.55-2.61). This tracks down to consumption of fish with high AA and DHA contents, and AA/EPA ratios. We conclude that the milk AA, DHA and EPA contents of Doromoni women might provide us with clues to optimize infant formulae and perhaps the milk of Western women.

Assessment of essential fatty acid and omega3-fatty acid status by measurement of erythrocyte 20:3omega9 (Mead acid), 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3

BACKGROUND

Early suspicion of essential fatty acid deficiency (EFAD) or omega3-deficiency may rather focus on polyunsaturated fatty acid (PUFA) or long-chain PUFA (LCP) analyses than clinical symptoms. We determined cut-off values for biochemical EFAD, omega3-and omega3/22:6omega3 [docosahexaenoic acid (DHA)]-deficiency by measurement of erythrocyte 20:3omega9 (Mead acid), 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3, respectively.

METHODS

Cut-off values, based on 97.5 percentiles, derived from an apparently healthy omnivorous group (six Dominica breast-fed newborns, 32 breast-fed and 27 formula+LCP-fed Dutch low-birth-weight infants, 31 Jerusalem infants, 33 Dutch 3.5-year-old infants, 69 omnivorous Dutch adults and seven Dominica mothers) and an apparently healthy group with low dietary LCP intake (81 formula-fed Dutch low-birth-weight infants, 12 Dutch vegans). Cut-off values were evaluated by their application in an EFAD suspected group of 108, mostly malnourished, Pakistani children, three pediatric patients with chronic fat-malabsorption (abetal-ipoproteinemia, congenital jejunal and biliary atresia) and one patient with a peroxisomal beta-oxidation disorder.

RESULTS

Erythrocyte 20:3omega9, 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3 proved age-dependent up to 0.2 years. Cut-off values for ages above 0.2 years were: 0.46mol% 20:3omega9 for EFAD, 0.068mol/mol 22:5omega6/20:4omega6 for omega3-deficiency, 0.22mol/mol 22:5omega6/22:6omega3 for omega3/DHA-marginality and 0.48mol/mol 22:5omega6/22:6omega3 for omega3/DHA-deficiency. Use of RBC 20:3omega9 and 22:5omega6/20:4omega6 cut-off values identified 20.4% of the Pakistani subjects as EFAD+omega3-deficient, 12.9% as EFAD+omega3-sufficient, 38.9% as EFA-sufficient+omega3-deficient and 27.8% as EFA-sufficient+omega3-sufficient. The patient with the peroxisomal disorder was classified as EFA-sufficient, omega3-sufficient (based on RBC 22:5omega6/20:4omega6) and omega3/DHA-deficient (based on RBC 22:5omega6/22:6omega3). The three other pediatric patients were classified as EFAD, omega3-deficient and omega3/DHA-deficient.

CONCLUSION

Use of the combination of the present cut-off values for EFA, omega3 and omega3/DHA status assessment, as based on 97.5 percentiles, may serve for PUFA supplement intervention until better concepts have emerged.

Estimated biological variation of the mature human milk fatty acid composition

We estimated the biological variation (CV(biol)) of 28 fatty acids (FA) in 465 mature human milk samples from The Netherlands, Caribbean, Jerusalem, Tanzania and Pakistan, by using data from the observed variation (CV(obs)) and analytical variation (CV(anal)). CV(biol) of the various regions was remarkably similar. The average CV(biol) of 455 samples, Pakistan excluded, ranged from 12.7% for 16:0 and 18.9% for 18:1 omega 9 to 68% for 22:6 omega 3 and about 100% for 20:5 omega 3. Those of 20:4 omega 6, 18:2 omega 6 and 18:3 omega 3 were 28.0, 33.0 and 37.3%, respectively. Because of the large CV(biol) and the many dietary changes in recent history, it seems impossible to consider the present human milk FA composition as the 'gold standard' for infant formula. Optimal human milk FA composition should rather derive from populations that consume traditional diets or from the scientific data that show the function of the individual FAs in neonatal development.

The n-3 and n-6 polyunsaturated fatty acid composition of plasma phospholipids in pregnant women and their infants. relationship with maternal linoleic acid intake

The availability of long-chain polyunsaturated fatty acids during infancy has been related to neonatal growth and development. Fatty acid concentration at birth is an important predictor of postnatal level. The primary aim of this study was to provide a description of the distribution of n-3 and n-6 polyunsaturated fatty acids in the plasma phospholipid fraction of pregnant women remaining on a Western-style diet and their neonates. The plasma phospholipid polyunsaturated fatty acid composition was determined by gas-liquid chromatography in 889 mother-infant pairs. Blood samples were taken during the first, second and third trimester of pregnancy, at delivery, and from the umbilical vein at birth. Mean (+/- SD) fatty acid concentrations are reported in mg/l and as percentage of total fatty acids (% wt/wt). In addition, the 10th, 25th, 50th, 75th and 90th percentiles are given. The distribution of docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) concentrations in umbilical plasma phospholipids is also reported as a function of gestational age and maternal linoleic acid intake during pregnancy. This data can be be used as a reference for future studies and may aid in identifying term infants with a relatively low long-chain polyene status at birth.

Does supplementation of formula with evening primrose and fish oils augment long chain polyunsaturated fatty acid status of low birthweight infants to that of breast-fed counterparts?

We investigated whether formulae with evening primrose and fish oils raise long chain polyunsaturated fatty acids (LCPUFA) in plasma cholesterol esters (CE), erythrocytes (RBC) and platelets (PLT) to levels encountered in breast-fed infants. Low birthweight infants (< or =2500 g) received LCP1 formula (n = 16; 0.31% 18:3 omega6, 0.17% 20:5 omega3 and 0.20% 22:6 omega3) or LCP2 formula (n = 13; 0.32% 18:3 omega6, 0.34% 20:5 omega3 and 0.43% 22:6 omega3). Fatty acids were measured days 10+/-2, 20+/-3 and 42+/-3. The formulae raised CE, RBC and PLT 20:5 omega3 and 22:6 omega3 dose-dependently (P<0.01), to exceed levels of breast-fed babies (n = 18) day 42 (P<0.05). CE, RBC and PLT 20:3 omega6 was comparable with, and CE, RBC, PLT 20:4 omega6 were below, that of breast-fed infants (P<0.05). Dietary 20:5 omega3 and 22:6 omega3 related with CE, RBC and PLT 20:5 omega3 and 22:6 omega3 (n = 47; P< or =0.01). Dietary 20:5 omega3 and LCPUFA omega3 related inversely with CE, RBC and PLT 20:4 omega6 and LCPUFA omega6 (P< or =0.002). LCP1 and LCP2 fed infants had similar LCPUFA omega6 status day 42. Added 18:3 omega6 does not correct 20:4 omega6 to that of breast-fed infants, but improves 20:3 omega6 status. Fish oil dose-dependently raises 20:5 omega3 and 22:6 omega3, but decreases 20:4 omega6 and other LCPUFA omega6.

The lipids in human milk

The summary will be limited to the areas that should be intensively investigated. The first is: determination of fatty acid profiles using modern methods on a world wide basis. We have no more than five or six papers in which my criterion was applied, one from Canada and the remainder from Europe with some data from Africa. Obviously, milk cannot be used as the gold standard on this meager data base. The second area is analysis of TG structure. These analyses are difficult, but structure is one of the factors controlling digestion. Data on the effects of maternal diet on structure would be useful. The third area is the role of primary or derived milk lipids as microbicidal agents. The fourth area is examination of globule parameters, i.e. number, size, volume, surface, and how they are affected by diet. There are many others which may interest the reader.

Gas chromatographic analysis of fatty acid methyl esters

The full process of fatty acid methyl ester (FAME) analysis consists of esterification of lipids, and of injection, separation, identification and quantitation of the FAMEs. In order for the required accuracy and precision to be attained, each of these steps has to be optimized. Esterification of lipids can be carried out with several reagents based on acid-catalysed or base-catalysed reactions. The advantages and disadvantages of these reagents are discussed. The most critical step in the gas chromatographic analysis of FAMEs is sample introduction. The classical split injection technique, which is the most widely used technique in the analysis of FAMEs, has the potential disadvantage of boiling-point-dependent sample discrimination. Cold injection of the sample, either on-column or by programmed-temperature vaporization, does not present this problem and should therefore be preferred. Modern, commercially available fused-silica capillary columns offer excellent separation of FAMEs from biological samples. Very polar stationary phases give excellent separation of all FAMEs but have relatively low thermal stability, resulting in long retention times. Non-polar phases have a much greater thermal stability but inferior selectivity. For many analyses, phases of intermediate polarity, which combine the advantages of a relatively high resolution capability with relatively high thermal stability, are the most suitable. FAMEs can be identified by comparison of their retention times with those of individual purified standards or secondary standards based on lipids that have been well characterized in literature. Relative retention times and equivalent chain-length values also provide useful information. FAMEs can be quantitated by peak areas via calibration factors, and absolute concentrations can be determined by adding an internal standard. Among numerous applications in biomedical research, the analysis of fatty acids from body tissues may contribute to the understanding of the link between the dietary intake of fatty acids and the diseases with which these acids are associated.

Indicators of long chain polyunsaturated fatty acid status of exclusively breastfed infants at delivery and after 20-22 days

The fatty acid composition of plasma cholesterol esters (CE), erythrocytes (RBC) and mature milk from seven lactating/women and their exclusively breastfed newborns, living on Dominica, were studied. Blood samples were taken from umbilical cord and mother at birth. A sample of breastmilk was collected on day 20-22 postpartum, together with a blood sample from the baby. At birth, cord blood plasma CE and RBC total long chain polyunsaturated fatty acid (LC-PUFA) contents were higher, and linoleic (18:2c, omega 6) and alpha-linolenic (18:3c, omega 3) acid contents lower, than in corresponding maternal compartments. Cord blood RBC LC-PUFA omega 3 content was lower and LC-PUFA omega 6 content higher than in maternal RBC. After birth, feeding with human milk led to a drop in LC-PUFA content in the plasma CE fraction, whereas RBC LC-PUFA content remained virtually constant. Current understanding of the origin and relative affinity of fatty acids incorporated in plasma CE and RBC suggests that RBC LC-PUFA content is a more reliable parameter for LC-PUFA status than plasma CE LC-PUFA content. The RBC LC-PUFA data suggest therefore that at birth the newborn has a lower LC-PUFA omega 3 status than the mother, and that this does not change during three weeks of exclusive breastfeeding.

The fatty acid composition of human milk in Europe and Africa

The fatty acid composition of human milk is often used as a model for artificial feeding, but it may vary with maternal diet. We reviewed 14 studies from 9 European countries and 10 studies from 7 African countries on fatty acids in mature human milk. Considering the marked differences in methods and dietary composition in different parts of Europe and Africa, average milk fatty acid composition data are surprisingly consistent. The diet of lactating women apparently influences, to a certain extent, the milk content of saturated and monounsaturated fatty acids and linoleic acid (18:2n-6). However, different self-selected diets in different geographic locations seem to have little effect on the milk content of 20 and 22 carbon long-chain polyunsaturated fatty acids (LCP), with the exception of relatively high n-3 fatty acids in the milk of African women consuming a large proportion of dietary fat from sea fish. Even then, docosahexaenoic acid (22:6n-3), and not eicosapentaenoic acid (20:5n-3), remains the predominant n-3 LCP in milk. Rural African women consuming little animal fat tend to have high milk contents of n-6 LCP. Thus the milk secretion of n-6 LCP does not appear to depend on maternal dietary intake of preformed LCP. Metabolic processes appear to be important in regulating human milk LCP.

Profiling of plasma cholesterol ester and triglyceride fatty acids as their methyl esters by capillary gas chromatography, preceded by a rapid aminopropyl-silica column chromatographic separation of lipid classes

A rapid procedure for the isolation of plasma cholesterol ester and triglyceride fractions with aminopropyl-silica columns, followed by analysis of their fatty acid compositions by capillary gas chromatography with flame ionization detection, is described. Within-series and long-term (six months) series-to-series precision were investigated. The isolation procedure caused minimal cross-over between the two lipid classes. Reference values for 57 apparently healthy Dutch adults were established and compared with data reported from other countries. Feeding of rats with four diets differing in their fatty acid compositions showed the relationship between the composition of the fatty acids in the diet and those esterified to cholesterol in plasma. The method is of potential usefulness to the establishment of the compliance of dietary interventions and basic dietary experiments.