Total Milk Lipids Research Articles

Effects of gestational diabetes mellitus, parity and mode of delivery on polar lipids compositions of mature human milk

Polar lipids in human milk such as glycerophospholipids, sphingomyelin and plasmalogen play important role in growth and development of healthy infants. This work aims to investigate the effects of gestational diabetic mellitus (GDM), parity, delivery mode on the polar lipids’ compositions of human milk. A total of 56 mature human milk samples (1–6 months postpartum) were collected from breastfeeding mothers using electric breast pump from Ningbo, Zhejiang Province of China. Our results showed GDM and parity have limited effect on polar lipid content and composition. Delivery mode was found to significantly affect the polar lipids compositions in human milk with significantly higher total polar lipids in human milk of mothers who had cesarean delivery (938 nmol/mL) as compared to that of mothers who had vaginal delivery (740 nmol/mL). Discriminatory analysis shows human milk of mothers who have cesarean delivery demonstrated up-regulation of glycerophospholipids (GPL) and plasmalogen (PLG) esterified with unsaturated fatty acids (USFAs) [such as plasmenyl-ethanolamine 40:5 and 36:4].

Fatty acid compositions of colostrum and mature breast milk in Turkey (Mardin)

AbstractIn this study, 25–25 milk samples (25 colostral and 25 mature) collected at different lactational stages were used to analyse the fatty acid composition of breast milk. A gas-chromatographic method was used to perform and analyse the transmethylation of total milk lipid extracts. The milk samples contained 20 different fatty acids. Palmitic acid (C16:0), stearic acid (C18:0), myristic acid (C14:0), oleic acid (C18:1n-9), and linoleic acid (LA, C18:2n-6) were the major components of total lipid, phospholipid (PL), and triacylglycerol (TAG) fractions. Colostrum had a lower percentage of polyunsaturated fatty acids (PUFAs), a higher percentage of saturated fatty acids (SFAs), and a lower level of eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3) in total lipid than mature milk. Triacylglycerol and PL fractions between colostrum and mature milk samples did not differ statistically.

Milk Polar Lipids: Underappreciated Lipids with Emerging Health Benefits.

Milk fat is encased in a polar lipid-containing tri-layer milk fat globule membrane (MFGM), composed of phospholipids (PLs) and sphingolipids (SLs). Milk PLs and SLs comprise about 1% of total milk lipids. The surfactant properties of PLs are important for dairy products; however, dairy products vary considerably in their polar lipid to total lipid content due to the existence of dairy foods with different fat content. Recent basic science and clinical research examining food sources and health effects of milk polar lipids suggest they may beneficially influence dysfunctional lipid metabolism, gut dysbiosis, inflammation, cardiovascular disease, gut health, and neurodevelopment. However, more research is warranted in clinical studies to confirm these effects in humans. Overall, there are a number of potential effects of consuming milk polar lipids, and they should be considered as food matrix factors that may directly confer health benefits and/or impact effects of other dietary lipids, with implications for full-fat vs. reduced-fat dairy.

Quantification of breast milk trans fatty acids and trans fat intake by Hong Kong lactating women.

Diet westernization in Hong Kong may increase trans fat intake, whereas it may decrease intake of polyunsaturated fatty acids. The present study was to determine the current breast milk fatty acid composition and trans fat intake by Hong Kong lactating mothers. Sixty lactating women were recruited for the study. Each participant donated 15 ml of milk at week 4 and 6 after delivery. Dietary data were collected using a 3-day food record method, covering 2 weekdays and 1 weekend day. Milk fatty acids were analyzed using a gas chromatography method. Trans fat consumption was assessed using the Nutrition Data System for Research or calculating the intake based on percentage of trans fatty acids in the breast milk. Linoleic acid, α-linolenic acid, arachidonic acid, and docosahexaenoic acid in breast milk were 16.23%, 1.52%, 0.59%, and 0.66% total milk lipids, respectively. Mean daily intakes of total fat, saturated fatty acids, monounsaturated fatty acids, were 79, 24, 29, and 18 g, respectively. Total trans fat intake was estimated to be 1.15-1.20 g daily and accounted for 0.50-0.52% total energy. Breast milk of Hong Kong Chinese lactating women contained relatively higher contents of arachidonic and docosahexaenoic acids compared with those of Western countries. Compared with the previous study conducted in 1995, breast milk total trans fatty acids in 2018 still remained low. Total trans fat intake by Hong Kong lactating women in 2018 was a half of WHO's recommendation that total trans fat intake should be <1% total energy.

Benefits of the inclusion of açai oil in the diet of dairy sheep in heat stress on health and milk production and quality.

The objective of this study was to determine whether the addition of açai (Euterpe oleracea) oil in the diets of lactating sheep under heat stress exerted beneficial effects on health as well as milk production and quality. Eighteen multiparous Lacaune sheep (2 or 3 parities; 28-30 days of lactation; average milk production of 1.7 L/sheep/day) were stratified by parity and milk production and were assigned randomly to 1 of 2 treatments (9 sheep/treatment): diet supplemented with 2% of soybean oil (SOY) or 2% of açai oil (AÇAI) in the concentrate for 14 days. The amount of oil added in the diet was equivalent to 0.65% of the total diet (dry matter basis). Blood and milk samples were collected on days 1, 10 and 14. On day 14, the AÇAI group sheep had lower serum concentrations of leukocytes, neutrophils, and lymphocytes than did the SOY group sheep. On day 14, AÇAI group sheep had lower serum concentration of triglycerides and urea, milk concentration of fat and total solid and milk lipid peroxidation than did SOY group sheep. However, on day 14, AÇAI group sheep had higher serum concentrations of glucose and globulin, serum and milk antioxidant capacity against peroxyl radicals, milk production and productive efficiency than did SOY group sheep. The fatty acids profile in milk did not differ between groups. These data suggest that açai oil improved the antioxidant activity in serum and milk and improved milk production and quality in dairy sheep under heat stress.

Vesicle properties and health benefits of milk phospholipids: a review

Phospholipids are important ingredients in milk. They serve as bioactive components with processing functionalities, despite representing only a small proportion of total milk lipids. There has been increasing interest in vesicle properties and health effects of milk phospholipids. However, there are limited reports on industry-scale manufacturing of related commercial products. This contribution aims to elucidate the industrial processes of manufacturing milk phospholipid products including phospholipid extraction and fraction as well as summarizing determination assays of milk phospholipids. In addition to industrial production, this review elaborates on application aspects, such as the biological properties of milk phospholipids and their technical importance as delivery vesicles of liposomes and phytosomes. In addition, new insights on large-scale production of milk phospholipids and new applications such as phytosomes and antioxidant properties are discussed.

Dietary linseed supplementation affects the fatty acid composition of the sn-2 position of triglycerides in sheep milk

In the human intestine, lipids are absorbed as sn-2 monoglycerides (sn-2, also named β-position), produced mainly by pancreatic lipases, which hydrolysate the triglyceride molecule in positions 1 and 3 (sn-1,3, α-position). The fatty acids esterified in sn-2 are thus preferentially absorbed, which means that the bioavailability of a single fatty acid is affected by its position on the triglyceride. This experiment is carried out with the milk used to make cheese applied in a study with 42 human volunteers. In that study the authors detected an improvement in the blood lipid profile. The aim of the present study was to examine the effectiveness of this kind of cheese in improving human health by studying how linseed supplementation affects the milk fatty acid composition of the 3 different triglyceride positions and thus the fatty acid bioavailability. The sn-2 were obtained by reacting total milk lipids with swine pancreatic lipase. The milk came from 24 sheep fed a control diet and 24 sheep fed a diet containing 200 g of extruded linseed per day. The sn-2 were separated by thin-layer chromatography. The fatty acid composition of total lipids and sn-2 was obtained by a gas chromatography-flame ionization detector apparatus equipped with a high polar 100 m length capillary column. The bioavailability of the fatty acids was evaluated by a putative preferential intestinal absorption index (PPIAi), where PPIAi <0 indicated a disadvantageous nutritional condition and PPIAi >0 indicated a preferential intestinal absorption. With regard to the fatty acid composition of triglycerides, the linseed group showed a significantly higher content of both linolenic acid and rumenic acid compared with the control. As a consequence of linseed supplementation, the linolenic and rumenic acid content esterified in the β-position increased greatly. This was highlighted by the PPIAi. The results of the present study suggest that the linolenic acid and conjugated linoleic acid affinity for lyso-phosphatidic acid acyl-transferase increased with its tissue availability.

Supplementing dams with both arachidonic and docosahexaenoic acid has beneficial effects on growth and immune development

Omega-3 long-chain polyunsaturated fatty acids (LCPUFAS) modulate immune cells in vitro and in vivo. This study investigated the effects of enriching the maternal diet with the n-6 and n-3 LCPUFAs, arachidonic (20:4n-6, 0.6%wt ARA) and docosahexaenoic acid (22:6n-3, 0.32%wt DHA), or 1:1 and 2:1 ratios (ARA: DHA) on total lipids in milk, total lipids, and immunophenotypes in plasma, lymph nodes, and spleen from isolated immune cells from 28d old pups. From day 15 of gestation to day 3 pp, Sprague-Dawley dams were fed a commercial chow. On day 3 pp litters were culled and pups (4 males and 2 females) randomly cross-fostered to dams who were randomized to one of the 5 experimental diets resulting in 20 male and 10 female pups/diet group. Dams fed ARA or ARA: DHA had 28–36% more 20:4n-6 in milk and feeding DHA or ARA: DHA doubled 22:6n-3 in milk lipids (P<0.05). Feeding 1:1 or 2:1 ARA: DHA resulted in greater pup weight at weaning (P<0.05). Compared to the control pups, ARA + DHA fed pups had a lower proportion of splenic CD45RA+ lymphocytes. In summary, postpartum supplementation with a combination of ARA + DHA, compared to ARA or DHA alone, resulted in a higher content of ARA and DHA in dam's milk and tissues and had positive effects on growth, accompanied by evidence of progression toward a mature immune phenotype, and suggests a need for ARA when DHA is supplemented in the early diet. Additional investigations are needed of ARA immunomodulation to better understand and estimate nutritional requirements for LCPUFAs during early development.

Supplementing dams with both arachidonic acid and docosahexaenoic acid has beneficial effects on growth and immune development beyond single fatty acid supplementation

Abstract Omega-3 long-chain polyunsaturated fatty acids (LCPUFAS) modulate immune cells in vitro and in vivo. This study investigated the effects of enriching the maternal diet with the n-6 and -3 LCPUFAs, arachidonic (20:4n-6, 0.6%wt ARA) and docosahexaenoic acid (22:6n-3, 0.32%wt DHA), or a 2:1 ratio (2ARA:1DHA) on total lipids in milk, total lipids, and immunophenotypes in plasma, lymph nodes, and spleen from isolated immune cells from 28d old pups. From day 15 of gestation to post-partum day (ppd)3, Sprague-Dawley dams were fed a commercial chow. On ppd3 litters were culled and pups (4 males and 2 females) randomly cross-fostered to dams who were randomized to one of the 3 experimental diets resulting in 20 male and 10 female pups/diet group. Dams fed ARA or ARA:DHA had 28–36% more 20:4n-6 in milk and feeding DHA or 2:1 ARA:DHA doubled 22:6n-3 in milk lipids (P&amp;lt;0.05). Feeding 2ARA:1DHA or ARA alone resulted in greater pup weight at weaning (P&amp;lt;0.05). Feeding ARA (-DHA) resulted in lower DHA in plasma and spleen while feeding DHA (-ARA) resulted in higher DHA in plasma (P&amp;lt;0.05). Compared to the 2ARA:1DHA pups, there was general trend for ARA fed pups to have higher and DHA fed pups to have lower total, T helper, T cytotoxic, and B lymphocytes in blood, and spleen. In summary, perinatal supplementation with 2ARA:1DHA, compared to ARA or DHA alone, resulted in a higher content of ARA and DHA in breast milk and tissues and had positive effects on growth. DHA without ARA increased 22:6n-3 in milk, plasma, spleen, and reduced 20:4n-6 in milk. Manipulation of dietary LCPUFAs was reflected by lipid content in tissues, and accompanied by evidence of effects on immunophenotype. These changes suggest functional effects but this remains to be confirmed by future investigations.

Cholesterol Transport and Regulation in the Mammary Gland

The milk-producing alveolar epithelial cells secrete milk that remains after birth the principal source of nutrients for neonates. Milk secretion and composition are highly regulated processes via integrated actions of hormones and local factors which involve specific receptors and downstream signal transduction pathways. Overall milk composition is similar among mammalian species, although the content of individual constituents such as lipids may significantly differ from one species to another. The milk lipid fraction is essentially composed of triglycerides, which represent more than 95 % of the total lipids in human and commercialized bovine milk. Though sterols, including cholesterol, which is the major milk sterol, represent less than 0.5 % of the total milk lipid fraction, they are of key importance for several biological processes. Cholesterol is required for the formation of biological membranes especially in rapidly growing organisms, and for the synthesis of sterol-based compounds. Cholesterol found in milk originates predominantly from blood uptake and, to a certain extent, from local synthesis in the mammary tissue. The present review summarizes current knowledge on cellular mechanisms and regulatory processes determining intra- and transcellular cholesterol transport in the mammary gland. Cholesterol exchanges between the blood, the mammary alveolar cells and the milk, and the likely role of active cholesterol transporters in these processes are discussed. In this context, the hormonal regulation and signal transduction pathways promoting active cholesterol transport as well as potential regulatory crosstalks are highlighted.

Fatty acid composition of breastmilk of Israeli mothers

We conducted this study to determine the fatty acid composition of breastmilk of Israeli women and compare it with baby milk substitutes. Samples of mature breast milk, from 29 lactating Israeli Jewish mothers were collected during feedings. Total milk lipids extracts were transmethylated and analyzed by using an improved gas-chromatographic method. About 72% of the total fatty acids in the investigated breast milk comprised oleic (18:1c; 31±4%), palmitic (16:0; 21±4%), and linoleic (18:2n-6; 20±4%) acids. Total saturated fatty acids represented 42±7% of total fatty acids. The monounsaturated fatty acids content was 33±5%, of which 94% was oleic acid, and the polyunsaturated fatty acids content was about 24±4%, of which 85% was linoleic acid. The a-linolenic acid level found in this study, 2.0±0.6%, was higher than the range of values reported for the world population (0.10-1.4%). The main fatty acids composition of the milk substitutes has very similar composition to the breast milk. Docosahexaenoic acid levels are particularly low among the population of Jewish nursing mothers in relation to the milk substitutes, containing docosahexaenoic acid in their formulations.

Milk Composition during Lactation Suggests a Mechanism for Male Biased Allocation of Maternal Resources in the Tammar Wallaby (Macropus eugenii)

Recent research has found empirical evidence in support of the Trivers-Willard Hypothesis that offspring sex allocation is correlated with maternal investment. Tammar wallabies birthing sons have higher investment ability; however a mechanism for sex specific differential allocation of maternal resources in wallabies remains elusive. In metatherians the majority of maternal investment is during lactation. To examine if differential allocation occurs during lactation, we measured total milk protein, lipid and carbohydrates, from mothers with male and female pouch young, during phase 2B (100–215 days post partum) and phase 3 (215–360 days post partum) of lactation. Mothers of sons allocated significantly higher levels of protein than mothers of daughters during phase 2B of lactation, however no sex specific difference in maternal allocation was found for lipids, carbohydrates, or any milk component during phase 3 of lactation. We were unable to measure milk production to establish any differences in the amount of milk allocated. However, with the production of more milk comes a dilution effect on milk components. Given that we find no apparent dilution of milk components may suggest equality in milk production. Offspring body weight at 14 months of age was related to protein allocation during phase 2B of lactation, providing a maternal mechanism for differential allocation with fitness consequences. We believe collection of earlier phase 2A (0–100 days post partum) milk may yield important results given that differential investment in metatherians may be most apparent early in lactation, prior to any significant maternal investment, when a decision on termination of investment can be made with very little energetic loss to the mother. Interestingly, small mothers did not birth sons and better maternal condition was associated with raising sons. These data are in support of TWH and demonstrate a potential mechanism through which condition dependent and sex specific maternal investment may occur.

Mastitis Is Associated with Increased Free Fatty Acids, Somatic Cell Count, and Interleukin-8 Concentrations in Human Milk

Research in bovine lactation has demonstrated that milk produced by a mammary gland displaying inflammation-based symptoms of mastitis has increased levels of free fatty acids (FFAs) compared with milk produced by a contralateral asymptomatic gland. However, the effects of mastitis on lipid classes in milk have not been investigated in humans. The study described here compared milk collected from the symptomatic breast of women with mastitis (n=14) with that collected from the contralateral asymptomatic breast to determine if mastitis caused alterations in the quantity of total lipids, FFAs, and phospholipids (PLs), as well as the fatty acid profiles of these lipid classes. To assess their efficacy as biomarkers of mastitis, samples were also analyzed for selected markers of local inflammation: sodium, somatic cell count (SCC), and interleukin-8 (IL-8). FFAs were higher in milk from the mastitic breast compared with that from the healthy breast (1.31 vs. 1.07 ± 0.10 g/100 g of lipid, p<0.05). Similarly, SCC and IL-8 were elevated roughly 10-fold in milk from mastitic breasts, compared with milk from healthy breasts, and sodium tended to be higher in milk from mastitic breasts (p<0.10). However, there were no differences in total lipid, PLs, or fatty acid profiles within each lipid class. In summary, mastitis is associated with increased lipolysis in the human breast but not alterations in milk fat synthesis, as evidenced by a lack of alteration in total milk lipids. Additionally, these results indicate that SCC and IL-8 may be better indicators of mammary inflammation than sodium content.

Milk composition in free‐ranging polar bears (Ursus maritimus) as a model for captive rearing milk formula

The goals of this study were to have an improved understanding of milk composition and to help create a suitable milk formula for cubs raised in captivity. Milk samples were evaluated for fat, fatty acids, carbohydrate, vitamin D(3), 25(OH)D(3), vitamin A (retinol), vitamin E (α-tocopherol), protein, and amino acids. Total lipids in milk did not differ for cubs (mean ± SEM = 26.60 ± 1.88 g/100 ml vs. yearlings 27.80 ± 2.20 g/100 ml). Milk lipids were of 23.6% saturated fatty acid for cubs and 22.4% for yearlings. Milk consumed by cubs and yearlings contained 43.8 and 42.0% mono-unsaturated fatty acids and 23.4 and 21.9% polyunsaturated fatty acids, respectively. Carbohydrate content was higher in milk for cubs (4.60 ± 0.64 g/100 ml) than for yearlings (2.60 ± 0.40 g/100 ml). Vitamin D(3) concentration of milk was 18.40 ± 5.00 ng/ml in early lactation compared with 7.60 ± 2.00 ng/ml for mid-lactation. 25(OH)D(3) was lower in milk consumed by cubs (162.00 ± 6.70 pg/ml) than in milk consumed by yearlings (205.00 ± 45.70 pg/ml). Vitamin A concentrations were 0.06 ± 0.01 and 0.03 ± 0.01 µg/ml for cubs and yearlings, respectively. Vitamin E was higher in milk consumed by cubs (20.16 ± 4.46 µg/ml) than by yearlings (7.30 ± 1.50 µg/ml). Protein content did not differ in milk available to cubs (11.40 ± 0.80 g/100 ml compared with milk for yearlings 11.80 ± 0.40 g/100 ml). Taurine was the most abundant free amino acid at 3,165.90 ± 192.90 nmol/ml (0.04% as fed basis).

Lipid content and fatty acids composition of mature human milk in rural North China

To determine the lipid content and fatty acid (FA) composition of breast milk from fifty-two lactating women between ninth and twelfth lactation weeks in rural North China. The mothers were questioned on their dietary habits. Total milk lipids extracts were transmethylated and analysed using GLC to determine FA contents. The mean lipid content was 40.21 (sd 1.43) g/l. SFA constituted 35.92 % of the total FA. Medium-chain and long-chain SFA presented levels of 10.91 and 25.01 %, respectively. MUFA and PUFA constituted 32.59 and 19.97 % of the total FA, respectively. Oleic, linoleic and alpha-linolenic acid (ALA) presented contents of 31.26, 17.73 and 1.03 %, respectively. Arachidonic acid had a content of 0.30 %, while DHA content was 0.19 %. Not any form of trans FA were found in human milk samples. A maternal diet transition is proceeding in China. Further investigation on the analysis of human milk FA composition is needed to upgrade the human milk database in China.

TransFatty Acids and Fatty Acid Composition of Mature Breast Milk in Turkish Women and Their Association with Maternal Diet's

The aim of this study was to determine the fatty acid composition and trans fatty acid and fatty acid contents of breast milk in Turkish women and to find the effect of breastfeeding mothers' diet on trans fatty acid and fatty acid composition. Mature milk samples obtained from 50 Turkish nursing women were analyzed. Total milk lipids extracts were transmethylated and analyzed by using gas liquid chromatography to determine fatty acids contents. A questionnaire was applied to observe eating habits and 3 days dietary records from mothers were obtained. Daily dietary intake of total energy and nutrients were estimated by using nutrient database. The mean total trans fatty acids contents was 2.13 +/- 1.03%. The major sources of trans fatty acids in mothers' diets were margarines-butter (37.0%), bakery products and confectionery (29.6%). Mothers who had high level of trans isomers in their milk consumed significantly higher amounts of these products. Saturated fatty acids, polyunsaturated fatty acids and monounsaturated fatty acids of human milk constituted 40.7 +/- 4.7%, 26.9 +/- 4.2% and 30.8 +/- 0.6% of the total fatty acids, respectively. The levels of fatty acids in human milk may reflect the current diet of the mother as well as the diet consumed early in pregnancy. Margarines, bakery products and confectionery are a major source of trans fatty acids in maternal diet in Turkey.

Influence of maternal dietary n-3 fatty acids on breast milk and liver lipids of rat dams and offspring–a preliminary study

The impact of triacylglycerol (TAG) structure and level of n-3 fatty acids on the fatty acid profile of total breast milk lipids and total liver phospholipids (PL) of dams and offspring (1, 3 and 13 weeks of age), when administered during development, was examined. Pregnant rats were fed experimental diets from the 8 th day of pregnancy throughout lactation. After weaning and until 13 weeks of age, the offspring were fed the same diet as their dams. The experimental diets contained either a specific structured oil, linseed oil or fish oil. In the specific structured oil, α-linolenic acid (18:3n-3) was predominantly located in the sn-2 position of the TAG and the level of 18:3n-3 was 2 mol% or 10 mol%. In the linseed oil diets the level of 18:3n-3 was 2 mol% or 10 mol% as well. Finally, the fish oil diet contained 18:3n-3 as well as 20:5n-3 and 22:6n-3 adding up to a total of 2 mol% n-3 fatty acids. Samples from three animals in each group were analyzed. The highest level of 22:6n-3 in the breast milk was obtained with diets containing this fatty acid itself. The fatty acid profile of rat dam liver PL was very different from the milk lipids indicating that the maternal dietary fats and the fatty acid synthesis in the mammary gland are the major determinants of the fatty acid profile of breast milk, whereas the liver does not significantly add to this. The 20:4n-6 was decreased in breast milk lipids and liver PL of dams and offspring when 18:3n-3 was increased in the diet. When the diet was based on 10 mol% 18:3n-3 from structured lipid trace levels of 22:6n-3 occurred in breast milk. The 22:6n-3 in liver PL of 1 week old offspring was significantly higher when the diet was based on the specific structured oil (2 mol%) compared to linseed oil. The metabolism of fatty acids may therefore be related to their positions in the dietary TAG. In liver PL of 1 week old offspring 22:6n-3 was highest in the groups, in which the breast milk contained pre-formed 22:6n-3. This demonstrates that the milk fatty acids influence the fatty acid composition of liver PL in young offspring. The results showed, furthermore, that dietary 22:6n-3 is a more effective precursor of tissue 22:6n-3 than an equivalent amount of dietary 18:3n-3.

Maternal and infant essential fatty acid status in Havana, Cuba

Adequate intake of essential fatty acids (EFAs) is required for optimal development of the central nervous system and visual acuity in infants. Little information exists regarding the EFA status of vulnerable populations living in Southern regions. We examined the adequacy of EFA status in Cuban breast-feeding mothers and their infants. Blood and breast-milk samples were obtained from a cross-sectional sample of mothers and term infants in Havana at 2 mo postpartum. We determined the fatty acid profiles of total lipids in breast milk, plasma, and erythrocytes and assessed infant visual acuity by using Teller acuity cards. Of the 56 mothers and infants examined, none showed biochemical signs of poor EFA status. Compared with values reported in the literature, mothers had an adequate EFA profile in their breast milk, plasma, and erythrocytes. The docosahexaenoic acid (DHA) concentration in breast milk was 0.43 +/- 0.26% of total fatty acids. It appeared that these breast-fed infants had an adequate dietary supply of DHA, as reflected by the mean plasma and erythrocyte DHA concentrations (2.82 +/- 0.84% and 7.41 +/- 1.16% of total fatty acids, respectively). Infant visual acuity testing showed a mean of 2.00 +/- 0.68 cycles/degree, which is within the normal range of mean binocular acuities for 2-mo-old term infants. The data did not show any relation between EFA concentrations and visual acuity. The results suggest that n-3 fatty acid deficiency and potential related deficits in early visual neural development are rare, if they exist at all, in breast-feeding women and their infants in Havana.

Fatty acids and lipids of camel milk and colostrum.

Total fat content was 32.8 +/- 14 g/L in camel milk (10-240 days post partum) or 30.1 +/- 19.5 g/L in colostrum (1-7 days post partum). Triacylglycerols accounted for 96% of the total lipids in milk. Triacyglycerols of camel milk contained saturated fatty acids (66.1%) and unsaturated fatty acids (30.5%). The predominant saturated fatty acids were 16:0 (34.9%) 14:0 (14.5%) and 18:0 (9.7%). The content of these fatty in acids in colostrum was lower (52.4%) than that of mature milk. The colsotrum contained a relatively high amount of 18:1 (25.4%), and 16:1 (13.9%), with the remainder being a mixture of dienoic and trienoic long-chain fatty acids. Triacylglycerols contained low amount of short-chain fatty acids (C4-C8). There is a high content of polyunsaturated fatty acids in camel colostrum and milk.

Changes in the Concentration of Carotenoids, Vitamin A, Alpha-Tocopherol and Total Lipids in Human Milk throughout Early Lactation

Background: In mammals the composition of milk changes during early lactation showing a rapid decline in fat-soluble vitamins and a continuous increase in total lipids. Changes in the concentrations of carotenoids, vitamin A, α-tocopherol and total lipids in human milk (colostrum, transitory and mature milk) were studied to understand this not well characterised phenomenon. Methods: Colostrum, transitory and mature milk was collected from 21 women and analysed for carotenoids, vitamin A and α-tocopherol by HPLC. Results: Total lipids increased from the lowest levels in colostrum (1.5 ± 1.6 mg/ml) to the highest in transitory milk (3.6 ± 2.5 mg/ml, p < 0.01). Contrary to this, levels of total carotenoids (236.7 ± 121.9 ng/ml), vitamin A (1.02 ± 0.56 µg/ml) and α-tocopherol (11.8 ± 6.3 µg/ml) were highest in colostrum and declined significantly during the first weeks of lactation (63.2 ± 23.3 ng/ml, 0.33 ± 0.14 µg/ml, 2.7 ± 1.1 µg/ml, respectively; p < 0.001). Conclusions: The magnitude of decrease was not the same for all carotenoids and was dependent on the polarity of the carotenoid with the smallest decrease in the polar carotenoids. This might be due to differences in the distribution of carotenoids among plasma lipoproteins and might point to possible selective mechanisms being involved in the transfer of these components in early human milk.