Milk Phospholipids Research Articles

Effect of docosahexaenoic acid supplementation of lactating women on the fatty acid composition of breast milk lipids and maternal and infant plasma phospholipids

To determine whether docosahexaenoic acid (DHA) supplementation of breast-feeding mothers increases the DHA contents of breast milk and infant plasma phospholipids (PPs), breast-feeding women were randomly assigned to 3 DHA-supplementation groups (170-260 mg/d) or a control group. Group 1 (n = 6) consumed an algae-produced high-DHA triacylglycerol; group 2 (n = 6) consumed high-DHA eggs; group 3 (n = 6) consumed a high-DHA, low-eicosapentaenoic acid marine oil; and group 4 (n = 6) received no supplementation. From before to after supplementation (2 and 8 wk postpartum), mean (+/-SD) maternal PP DHA increased in groups 1, 2, and 3 by 1.20 +/- 0.53, 0.63 +/- 0.82, and 0.76 +/- 0.35 mol% of fatty acids, respectively (23-41%), but decreased in group 4 by 0.44 +/- 0.34 mol% (15%). Breast-milk DHA of groups 1, 2, and 3 increased by 0.21 +/- 0.16, 0.07 +/- 0.11, and 0. 12 +/- 0.07 mol%, respectively (32-91%) but decreased in group 4 by 0.03 +/- 0.04 mol% (17%). Mean infant PP DHA in groups 1, 2, and 3 increased by 1.63 +/- 0.79, 0.40 +/- 1.0, and 0.98 +/- 0.61 mol%, respectively (11-42%), but only by 0.18 +/- 0.74 mol% (5%) in group 4. Correlations between the DHA contents of maternal plasma and breast milk and of milk and infant PPs were significant. Breast-milk and maternal and infant PP 22:5n-6 concentrations were lowest in group 2. DHA supplementation increases the plasma and breast-milk DHA concentrations of lactating women, resulting in higher PP DHA concentrations in infants.

Trans Fatty acids in human milk are inversely associated with concentrations of essential all-cis n−6 and n−3 fatty acids and determine trans, but not n−6 and n−3, fatty acids in plasma lipids of breast-fed infants

Human milk fatty acids vary with maternal dietary fat composition. Hydrogenated dietary oils with trans fatty acids may displace cis n-6 and n-3 unsaturated fatty acids or have adverse effects on their metabolism. The effects of milk trans, n-6, and n-3 fatty acids in breast-fed infants are unclear, although n-6 and n-3 fatty acids are important in infant growth and development. We sought to determine the relations between trans and cis unsaturated fatty acids in milk and plasma phospholipids and triacylglycerols of breast-fed infants, and to identify the major maternal dietary sources of trans fatty acids. We collected milk from 103 mothers with exclusively breast-fed 2-mo-old infants, blood from 62 infants, and 3-d dietary records from 21 mothers. Mean (+/-SEM) percentages of trans fatty acids were as follows: milk, 7.1 +/- 0.32%; infants' triacylglycerols, 6.5 +/- 0. 33%; and infants' phospholipids, 3.7 +/- 0.16%. Milk trans fatty acids, alpha-linolenic acid (18:3n-3), arachidonic acid (20:4n-6), docosahexaenoic acid (22:6n-3) (P < 0.001), and linoleic acid (18:2n-6) (P = 0.007) were each related to the same fatty acid in infant plasma phospholipids. Milk trans fatty acids were inversely related to milk 18:2n-6 and 18:3n-3, but not to milk or infant plasma 20:4n-6 or 22:6n-3. trans Fatty acids represented 7.7% of maternal total fat intake (2.5% of total energy); the major dietary sources were bakery products and breads (32%), snacks (14%), fast foods (11%), and margarines and shortenings (11%). There were comparable concentrations of trans fatty acids in the maternal diet, breast milk, and plasma triacylglycerols of breast-fed infants. Prepared foods were the major dietary source of trans fatty acids.

Long‐chain polyunsaturated fatty acids in human milk

Arachidonic acid and docosahexaenoic acid are the most representative long-chain polyunsaturated fatty acids (LCPUFA) since they may affect infants' growth and development. LCPUFA are present in the milk of all lactating women throughout lactation. The mothers' dietary habits may affect the levels of these fatty acids in maternal blood lipids and then in milk. LCPUFA show marked differences in levels as wt%, particularly from colostrum to mature human milk, but only mild differences in absolute content. Both the major presence of LCPUFA in human milk phospholipids and some regulatory mechanisms in the mammary gland cells could contribute to the LCPUFA levels in milk beyond those in maternal plasma.

Ethanol and Lactation: Effects on Milk Lipids and Serum Constituents

To determine how chronic alcohol administration during lactation affects milk composition and the nutritional status of the dam, EtOH (3 g/kg) as a 20% solution was administered by intubation to Sprague–Dawley rats from days 2 through 15 of lactation. Control dams were pair fed to account for the reduction in food intake observed in the alcohol group, while another control group maintained ad lib food intake. Dams and their litters were weighed daily throughout the study. On day 16, dams were sacrificed and samples taken for further analysis. Blood alcohol levels as well as serum levels of calcium, cholesterol, glucose, iron, lipids, phosphorous, and triglycerides were measured. Liver lipid levels and the total composition and fatty acid profile of the phospholipids in milk were also measured. Results indicate that EtOH administration and pair feeding reduced dam body weight, but not litter growth. Serum iron levels was increased in both EtOH-exposed and pair-fed controls, whereas serum cholesterol was elevated only in EtOH-exposed dams. Finally, of the phospholipids in milk, only one, phosphatidylserine, was slightly but significantly increased by EtOH. If and how these changes impact the development of the offspring remain to be studied.

Whey proteins modify the phase transition of milk fat globule phospholipids

The phospholipids extracted from milk fat globule membranes were composed of three major classes, phosphatidylethanolamines (37.2 %), phosphatidylcholines (30.0 %), sphingomyelin (28.2 %), and two minor classes, phosphatidylinositols (2.0 %) and phosphatidylserines (2.6 %). The thermogram showed that the extracted phospholipids presented a single wide-phase transition cen- tered at 18.3 oc.The effects of temperature on the phase behaviour of milk phospholipids in the presence of ~-Iactoglobulin and a-Iactalbumin have been studied at pH 4.0 and 7.0 (with or without calcium) using Fourier transform infrared spectroscopy. Principal component analysis carried out on the spectra in the 3 000-2 800 cm-i region showed that the binding of the whey proteins to the phos- pholipids modified the Iipid phase transition in different ways, depending on the in-solution pro- tein. © Inra/Elsevier, Paris

Importance of milk and diet on the ontogeny and adaptation of the intestine.

Importance of milk and diet on the ontogeny and adaptation of the intestine.

Changes in the breast milk fatty acids and plasma lipids of nursing mothers following consumption of n-3 polyunsaturated fatty acid enriched eggs

The effect of chicken eggs enriched with n-3 fatty acids on breast milk and plasma fatty acids was determined in eight nursing women. The n-3 polyunsaturated fatty acid (PUFA) enriched eggs (n-3 eggs) contained 690 mg of n-3 fatty acid with 165 mg composed of longer chain n-3 fatty acid (C20:5 n-3, C22:5 n-3, and C22:6 n-3). Consuming two n-3 eggs as a part of their normal daily meal for 6 wk resulted in a significant ( p < 0.05) deposition of total n-3 fatty acids at 3.6% compared with 1.9% for the pretest milk and a reduction in n-6:n-3 ratio (6.7 vs. 3.0). The C20 and C22 n-3 PUFA comprised 1.2% compared with 0.4% in the pretest milk ( p < 0.05). Consuming n-3 eggs did not ( p > 0.05) alter the C20:4 n-6 or the total n-6 fatty acid content of breast milk. Mean plasma total cholesterol and triglycerides were unchanged at the end of the 6-wk trial. Analysis of the breast milk lipids revealed increased ( p < 0.05) predominance of n-6 and n-3 PUFA in the milk phospholipids over triglycerides. Positional distribution of phospholipid fatty acids indicated 20:4 n-6 and 20:5 n-3 in the sn-2 position, whereas the sn-1 position had increased levels of C16:0 and C18:0 ( p < 0.05). The present study demonstrates that breast milk n-3 PUFA content can be increased without altering the plasma cholesterol or triglycerides when the n-3 PUFA eggs were consumed by nursing women.

Milk and egg phospholipids act as protective surfactants against luminal acid in Necturus gastric mucosa.

Our previous studies indicate that milk phospholipids have anti-ulcer properties in rats and humans, possibly by forming a hydrophobic surfactant layer at the epithelial surface. In the present study we measured intracellular pH and parameters of membrane resistances in gastric epithelium exposed to luminal acid using a microelectrode technique. Chambered isolated Necturus maculosus antral mucosa was exposed to pH 2.3, with or without 20-25 min pre-treatment with milk or egg phospholipids. The pH in surface epithelial cells was measured with double-barrelled liquid sensor pH/PD-microelectrodes. Pre-treatment with phospholipids (2500-5000 micrograms P/mL) significantly (P < 0.01, n = 14) opposed intracellular acidification. Phospholipids significantly (P < 0.05, n = 14) increased the ratio of apical and basal membrane resistances, suggesting that they primarily affect the apical cell membrane. In contrast, there was no significant change in transmucosal resistance suggesting lack of effect on paracellular shunts in the 'leaky' epithelium. Exogenous phospholipids of dietary origin may be used to form a protective layer in the gastric mucosa against irritants.

A film balance study of the monolayer-forming properties of dietary phospholipids and the interaction with NSAIDs on the monolayers

The monolayer-forming properties of milk and egg phospholipids and a synthetic model of human gastric mucosal phospholipids were studied by using a Langmuir film balance. Compression isotherms were constructed at pH 5.6 — the pH of unbuffered water — and at room temperature. Furthermore the pH was reduced to 2 and the temperature raised to 37°C in order to mimic the normal stomach environment. Milk egg and synthetic human gastric phospholipids formed liquid-expanded monolayers at the air-water interface. The increase in temperature to 37°C and the reduction of the pH to 2 caused only minor changes in monolaycr formation. In addition we investigated the interaction between a number of anti-inflammatory drugs (NSAIDs) and a monolayer at the air/water interface. Milk phospholipids were chosen as a representative example of monolayer-forming phospholipids. NSAIDs adsorbed from the subphase to the monolayer of milk phospholipids and increased the surface area of the monolaycr.

The effect of milk and skim milk intake on serum lipids and apoproteins in young females.

The effect of milk and skim milk intake on serum lipid and apoprotein levels was investigated in young females with consideration of each subject's menstrual period. When milk and dairy products were not allowed, the serum cholesterol concentration tended to decrease in high density lipoprotein (HDL) and very low density lipoprotein (VLDL), the triglyceride concentration tended to increase in HDL and low density lipoprotein (LDL), the phospholipid concentration showed no change, and the apoB, apoC-III and apoE significantly decreased. In the milk group, VLDL cholesterol and phospholipid concentrations were increased with a significant increase in the apoB concentration after intake of 200 ml/day of milk for one menstrual period, and these levels did not change when the milk intake was doubled. VLDL phospholipid increased and apoE decreased after the intake of 20 g/day of skim milk, and LDL cholesterol and HDL phospholipid concentrations tended to decrease when the skim milk intake was doubled.

A carbohydrate-rich diet not only leads to incorporation of medium-chain fatty acids (6:0-14:0) in milk triglycerides but also in each milk-phospholipid subclass

We isolated phospholipid (PL) subclasses from milk of women in Dominica and Belize. Fatty acid (FA) compositions of PLs and total lipids were determined. In the total-lipid fraction Dominican milk showed higher relative amounts of medium-chain saturated fatty acids (MC-SAFAs; 6:0-14:0) and 22:6n-3 and lower amounts of long-chain saturated fatty acids (LC-SAFAs) and monounsaturated fatty acids (MUFAs). There was a positive relationship between the MC-SAFA content in total lipids and total PLs. Incorporation of MC-SAFAs in PLs occurred at the expense of LC-SAFAs, MUFAs, polyunsaturated fatty acids (PUFAs), and long-chain PUFAs with greater than or equal to 20 carbon atoms (LC-PUFAs greater than or equal to C20). Previous studies from Western countries revealed low amounts of MCSAFAs and high amounts of PUFAs and LC-PUFAs greater than or equal to C20 in milk PLs. Our data show that carbohydrate-rich diets give rise to incorporation of MC-SAFAs in PLs at the expense of PUFAs and LC-PUFAs greater than or equal to C20. The data are discussed in relation to the presumed origin of fat-globule membrane phospholipids.

Gastroprotective effects of milk phospholipids, butter serum lipids and butter serum on aspirin-induced ulcers in the rat

Gastroprotective effects of milk phospholipids, butter serum lipids and butter serum on aspirin-induced ulcers in the rat

Changes in Milk Fat Phospholipids During Lactation

Changes in lipid composition were studied in milk obtained on postpartum d 3 (colostrum), 7, 42, and 180 from 12 Holstein cows. Triglycerides, 96 to 97% of total lipids, were relatively constant during lactation. Phospholipids and cholesterol declined with advancing lactation. Concentrations of the fatty acids synthesized within the mammary gland, C10:0 to C16:0, increased about 50% from 7 to 42 d of lactation. During this period, compensatory decreases were observed in C18:1. The phospholipids were separated into five major classes: sphingomyelin, phosphatidyl choline, serine, inositol, and ethanolamine for fatty acid analysis. The changes that occurred in milk total fatty acids were reflected in phosphatidyl phospholipid fatty acid composition: an increase in medium-chain fatty acids and a decrease in polyunsaturated fatty acids of 18, 20, and 22 carbon atom chain length as lactation progressed. These changes are consistent with the theory that milk phospholipids are synthesized de novo entirely in the mammary gland.

Incorporation of deuterium-labeled fatty acids into human milk, plasma, and lipoprotein phospholipids and cholesteryl esters.

Fatty acid metabolism and the contribution of dietary fatty acids to milk cholesteryl ester (CE) and phospholipid (PL) were investigated in normal lactating mothers. The approach used was to feed mixtures of triglycerides containing deuterium-labeled palmitic acid (16:0-2H2), oleic acid (18:1-2H6), and linoleic acid (18:2-2H4). Milk and plasma samples were collected for 72 hr. Triglyceride (TG), CE, and PL fractions from milk, plasma, and lipoprotein were isolated and analyzed by gas-liquid chromatography and mass spectrometry. Data for the milk CE and PL fractions showed a definite selectivity for incorporation of 16:0-2H2 and 18:1-2H6 relative to 18:2-2H4. Based on the ratios of the deuterated fatty acids incorporated into the milk CE and PL samples, their incorporation times and isotopic enrichment data, it appears that these fatty acids are supplied mainly by the TG derived from chylomicrons and very low density lipoproteins. Plasma and lipoprotein CE data showed a progressive increase in 18:2-2H4 content, with 16:0-2H2 and 18:1-2H4 remaining relatively constant over the collection period. Plasma and lipoprotein PL data showed a higher rate for incorporation of 18:2-2H4 than 16:0-2H2 and 18:1-2H6 over the course of the sampling period. Comparison to previous data from adult males indicates lactation does not have a major effect on the general metabolism of these fatty acids. An increase with time in the isotopic enrichment of 18:2-2H4 in the plasma and lipoprotein CE and PL samples was observed which is consistent with in vitro selectivities reported for lecithin:cholesterol acyltransferase and phosphatidylcholine acyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)

Simplified quantitative determination of phospholipids in amniotic fluid, alveolar lavages and milk using high performance liquid chromatography (HPLC).

A one step HPLC method for the determination of the main phospholipids, phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylcholine (PC), sphingomyelin (SP) and lysolecithin (LL) in amniotic fluid, milk, tracheal secretion, lung lavages, gastric aspirates, infant formulas and some other human and animal media has been developed. Quantitation occurs automatically using computer calculation and lysolecithin as an internal standard. Detection limits are at about 0.2 micrograms/100 ml but may rise to about 0.3 micrograms/100 ml in cases of high fat levels or other interfering compounds. Recovery rates measured in amniotic fluid fluctuate around the 100% level. Time required for a single analysing including a blank run and a calibration standard solution measurement amounts to about two hours. In series analysis 12 samples per day can be examined, while the required time per sample is reduced to 40 minutes. As phospholipids carry an important function in many spheres of medicine, the improvement in specific quantitative determination of these compounds is of great importance.

A Method for Separation and Quantification of Phospholipid Classes in Human Milk

A simple, isocratic method for separating the major phospholipid classes of human milk by HPLC is described. Resolution of phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylcholine, and spingomyelin from human milk phospholipids was achieved in 30min on a silica column. Total phospholipids were injected in 50 μl of chloroform:diethyl ether (1:2, vol/vol) and eluted with a solvent mixture of acetonitrile:methanol:sulfuric acid (100:3:.05, vol/vol/vol) at a flow rate of 2.5 ml/min. Fractions were collected and each phospholipid class quantified by analysis of inorganic phosphorus after sulfuric acid digestion. A repeatability study with 19 samples had a coefficient of variation of 5.3%. The analytical recoveries of phospholipid standards averaged 98%. Recoveries varied with phospholipid class; variation was greatest with spingomyelin.

Phospholipids in milk and dairy products

A rapid HPLC method has been developed for the analysis of the phospholipids in milk and dairy products. A concentrate of the phospholipids was obtained by chromatography on a cartridge of silica gel. The relative proportions of the different phospholipids were then determined by HPLC, and by means of the addition of an internal standard, dipalmitoyl phosphatidyldimethylethanolamine, the absolute amounts present were also measured. After the reproducibility of the method was demonstrated with fresh whole milk, it was applied to skimmed milk, buttermilk and various products of ultra‐high temperature processing. Small differences only were seen in the relative compositions of phospholipids in different milk products, but the absolute amounts varied appreciably. In some samples, it was tentatively concluded that the phospholipids had undergone extensive autoxidation.

A role for milk phospholipids in protection against gastric acid: Studies in adult and suckling rats

Animal milk was tested directly for antiulcer activity in a rat model system. The severe mucosal necrosis and intragastric bleeding induced by the luminal administration of supraphysiologic 0.6 N HCl was significantly reduced (50%–70%) if both suckling rats and adults were pretreated per os with raw rat or bovine milk. Pasteurized/homogenized bovine milk also gave protection, although to a lesser extent (30%–50% reduction in bleeding). Treatment of milk with cholestyramine removed 50%–80% of the surface-active phospholipids from milk and also eliminated milk's protective property, an effect that was reversed upon addition of phospholipids to the extracted milk. The antiulcer action of milk in rats could be related to its concentration of dipalmitoyl lecithin. These findings suggest that milk has a potent antiulcer activity that may be attributable to its phospholipid constituents.

Analysis of phospholipids in cow's milk by high-temperature injection gas chromatography and high-performance liquid chromatography

An investigation of the high-temperature injection (350°C) gas chromatographic behaviour of standards of various classes of phospholipids has elucidated certain characteristic fragments (“tracers”) in the pyrogram of each class. Under these conditions of pyrolysis of the phospholipids, a natural mixture of such substances (extracted and purified from cows' milk) has provided evidence for the same “tracers” as for the standards. Analogous results were obtained with a more representative specimen of cows' milk of various breeds grown in areas of different altitudes. The content of fatty acids in phospholipids, tested on each class (separated by means of radial compression high-performance liquid chromatography from polar lipids of milk) appeared to be relatively similar for all the phospholipid classes, and over half the content consisted of unsaturated fatty acids. The major component was Δ 9-octadecenoid (oleic) acid.

Effects of the diet on the composition of human milk.

In a crossover study with 3 nursing mothers it was shown that the concentration and composition of human milk lipids and the concentration of lactose, but not that of protein, quickly respond to changes in the mother's diet. Triglycerides were high with low-fat/high-carbohydrate diets as compared to high-fat/low-carbohydrate diets. Lactose was affected reversibly. The intake of linoleic-acid-rich fats resulted in milk lipids with a respective high linoleic acid content. Milk cholesterol and phospholipid concentrations correlated positively with the respective triglyceride concentrations.