Influence of breast-feeding on the restoration of the low serum concentration of vitamin E and beta-carotene in the newborn infant

Scientific opinion on the tolerable upper intake level for vitamin E

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the revision of the tolerable upper intake level (UL) for vitamin E. As α-tocopherol is recognised as the only essential form of vitamin E, the Panel restricted its evaluation to α-tocopherol. Systematic reviews of the literature were conducted to assess evidence on priority adverse health effects of excess intake of vitamin E, namely risk of impaired coagulation and bleeding, cardiovascular disease and prostate cancer. The effect on blood clotting and associated increased risk of bleeding is considered as the critical effect to establish an UL for vitamin E. No new evidence has been published that could improve the characterisation of a dose-response. The ULs for vitamin E from all dietary sources, which were previously established by the Scientific Committee on Food, are retained for all population groups, i.e. 300 mg/day for adults, including pregnant and lactating women, 100 mg/day for children aged 1-3 years, 120 mg/day for 4-6 years, 160 mg/day for 7-10 years, 220 mg/day for 11-14 years and 260 mg/day for 15-17 years. A UL of 50 mg/day is established for infants aged 4-6 months and a UL of 60 mg/day for infants aged 7-11 months. ULs apply to all stereoisomeric forms of α-tocopherol. ULs do not apply to individuals receiving anticoagulant or antiplatelet medications (e.g. aspirin), to patients on secondary prevention for CVD or to patients with vitamin K malabsorption syndromes. It is unlikely that the ULs for vitamin E are exceeded in European populations, except for regular users of food supplements containing high doses of vitamin E.

Nutritional supplements and mother's milk composition: a systematic review of interventional studies

BACKGROUND

This study aims to systematically review the effects of maternal vitamin and/or mineral supplementation on the content of breast milk.

METHODS

We systematically searched electronic databases including Medline via PubMed, Scopus and ISI Web of Science till May 24, 2018. The following terms were used systematically in all mentioned databases: ("human milk" OR "breast milk" OR "breast milk composition" OR "human breast milk composition" OR "composition breast milk" OR "mother milk" OR "human breast milk" OR "maternal milk") AND ("vitamin a" OR "retinol" OR "retinal" OR "retinoic acid" OR "beta-carotene" OR "beta carotene" OR "ascorbic acid" OR "l-ascorbic acid" OR "l ascorbic acid" OR "vitamin c" OR "vitamin d" OR "cholecalciferol" OR "ergocalciferol" OR "calciferol" OR "vitamin e" OR "tocopherol" OR "tocotrienol" OR "alpha-tocopherol" OR "alpha tocopherol" OR "α-tocopherol" OR "α tocopherol" OR "vitamin k" OR "vitamin b" OR "vitamin b complex" OR "zinc" OR "iron" OR "copper" Or "selenium" OR "manganese" OR "magnesium") and we searched Medline via Medical subject Headings (MeSH) terms. We searched Google Scholar for to increase the sensitivity of our search. The search was conducted on human studies, but it was not limited to the title and abstract. Methodological quality and risk of bias of included studies were evaluated by Jadad scale and Cochrane risk of bias tools, respectively.

RESULTS

This review included papers on three minerals (zinc, iron, selenium) and 6 vitamins (vitamin A, B, D, C, E and K) in addition to multi-vitamin supplements. Although studies had different designs, e.g. not using random allocation and/or blinding, our findings suggest that maternal use of some dietary supplements, including vitamin A, D, vitamin B1, B2 and vitamin C might be reflected in human milk. Vitamin supplements had agreater effect on breast milk composition compared to minerals. Higher doses of supplements showed higher effects and they were reflected more in colostrum than in the mature milk.

CONCLUSION

Maternal dietary vitamin and/or mineral supplementation, particularly fat- soluble vitamins, vitamin B1, B2 and C might be reflected in the breast milk composition. No difference was found between mega dose and single dose administration of minerals.

Vitamin A and Breast-Feeding: A Comparison of Data from Developed and Developing Countries

The vitamin A status of lactating women, its effect on the vitamin A content of human milk, and the adequacy of human milk as a source of vitamin A for the infant were assessed, comparing data from developing countries with those from developed countries. The vitamin A concentration in breast milk during the first two weeks of lactation is nearly double that at one month. It is even higher in preterm milk than in term milk during the first several months. Human milk alone provides sufficient vitamin A to prevent clinical deficiency throughout the first 12 months of life, even in presumably more poorly nourished populations in developing countries. However, it is not sufficient to allow liver storage after about six months of lactation.

Effect of mono- and diglycerides on the digestion and absorption of lutein in lymph fistula rats

Breast milk lutein is better absorbed by infants than lutein delivered in infant formula. Therefore, we wanted to better understand the possible absorption differences of lutein in breast milk vs. that in infant formula by determining its bioavailability after gastric administration and whether the intestinal absorption of lutein can be improved by using new delivery vehicles. Study 1 compared the intestinal uptake,and the lymphatic and portal transport of lutein in conscious lymph fistula rats. Four groups of lymph- and portal vein-cannulated rats ( n = 8-10/group) were randomized to receive via gastric tube increasing doses (10, 20, 40, or 80 mg/kg) of 20% lutein in safflower oil (SO) suspension to assess whether there was a saturable level of lutein that could be absorbed and transported in lymph. Aliquots of hourly portal blood and lymph were taken for lutein and zeaxanthin analyses. The dose-response study showed that 20 mg/kg lutein was the saturable level of lymphatic lutein absorption with no lutein detected in portal circulation at any dosage level tested. Study 2 randomized five groups of lymph fistula rats ( n = 4-9/group) to receive 20 mg/kg lutein from either lutein in SO or lutein in four different mono- and diglyceride oils (MDGs). Gastric infusion of lutein suspended in MDG (20 mg/kg) significantly improved (71-211%, P < 0.05) lymphatic lutein output 2-6 h after lipid feeding vs. lutein in SO. Lymphatic zeaxanthin (10% of the lutein fed mixture) transport in both Study 1 and Study 2 followed that of lutein. We conclude that a mixture of MDGs helps solubilize lutein and facilitate gastrointestinal micelle formation, thus improving lymphatic lutein absorption compared with triglyceride oils. NEW & NOTEWORTHY This paper describes how lutein is digested and absorbed by the gastrointestinal tract by using the conscious lymph fistula rat model. Our dose-response study showed that absorption and lymphatic transport of lutein is a saturable process with no lutein detected in portal circulation at any dosage level tested. Our paper also provides insight into how this process can be improved by modifying the typical lipid mixtures carrying the lutein.

Overview of Nutrients in Human Milk

The WHO recommends exclusive breastfeeding for the first 6 mo of life to promote optimal infant health and development. Understanding the micro- and macronutrient concentrations of human milk and how each nutrient fluctuates with lactational stage, maternal factors, and supplementation is imperative for supporting good breastfeeding practices. Where maternal undernutrition compromises human milk quality, a thorough awareness of the effectiveness of interventions can direct efforts to achieve both maternal and infant nutrient sufficiency. This review of current knowledge covers trends in nutrient concentrations over the course of lactation and describes the influence of maternal intake, status, supplementation, and other factors on human milk concentrations of each nutrient.

Retinol and α-tocopherol in human milk and their relationship with dietary intake during lactation

Human milk is considered as an optimal nutrition source for neonates, and vitamins A and E improve oxidative stress in offspring through breast milk.

Storage at -80°C preserves the antioxidant capacity of preterm human milk

BACKGROUND AND OBJECTIVE

It is essential to establish optimum parameters for maintaining the quality of stored milk until the moment of consumption with minimal deterioration of its properties. The aim of the study was to evaluate total antioxidant capacity (TAC) and total oxidation status (TOS) of fresh and freeze-stored samples (at -80°C) of preterm human milk (HM).

METHODS

Samples of colostrum were collected from 98 healthy women within the first 4 days after delivery. The total milk volume collected (6 ml) was divided in two aliquot parts: 3 ml for the fresh analysis which was done immediately after the extraction and 3 ml for storage under freezing conditions at -80°C for three months. The antioxidant status and oxidative stress of the fresh and stored breast milk were assessed via determination of TAC and TOS levels.

RESULTS

The mean gestational age and the birth weight of the infants were 31.26 ± 2.93 weeks and 1620 ± 581.91 g; respectively. There were no significant correlations between maternal age, route of delivery and milk oxidative stress. There was no significant difference between the levels of TAC, TOS and the oxidative stress index in fresh and freeze-stored samples of colostrum in preterm HM (p > 0.05).

CONCLUSION

Freeze storage of preterm HM at -80°C for three months preserves the antioxidant capacity without changing oxidative status of HM, which could be noteworthy for the preterm infant nutrition.

Resonance Raman based skin carotenoid measurements in newborns and infants

We describe Resonance Raman based skin carotenoid measurements in newborns and infants. Skin- and serum carotenoid levels correlate with high statistical significance in healthy newborns and infants, and with reduced accuracy also in prematurely born infants, who in general feature very low carotenoid levels and thin transparent skin giving rise to large background absorption effects. Skin carotenoid levels can be easily compared among subjects and/or tracked in longitudinal studies with the highly molecule-specific Raman method. It therefore holds promise as a rapid, non-invasive, carotenoid antioxidant assessment method for newborns and infants in the field of pediatrics.

Plasma carotenoid concentrations of infants are increased by feeding a milk-based infant formula supplemented with carotenoids

BACKGROUND

Human milk is the gold standard of infant nutrition and is a source of important substances, including carotenoids. Infant formulas are designed to mimic the composition and/or performance of human milk, although currently carotenoids are not routinely added to US infant formulas. The aim of this study was to assess plasma concentrations of β-carotene, lutein and lycopene 56 days after feeding infants milk-based infant formula without (CTRL) or with different concentrations of added carotenoids (L1 and L2).

RESULTS

Plasma carotenoid concentrations increased in infants fed carotenoid-supplemented formulas as compared with the control formula with no added carotenoids. At study day 56, infants fed the supplemented formulas (L1 and L2) had mean plasma lutein, β-carotene and lycopene concentrations that were within the range of a concurrent group of human milk-fed infants (HM). Anthropometric measurements were comparable among all study groups.

CONCLUSION

Plasma carotenoid concentrations of infants fed the supplemented formulas were within the range of the HM group and are consistent with reported plasma carotenoid ranges in human milk-fed infants. The experimental formulas were well tolerated and anthropometric measurements were comparable among all study groups.

Effect of carotenoid supplementation on plasma carotenoids, inflammation and visual development in preterm infants

OBJECTIVE

Dietary carotenoids (lutein, lycopene and β-carotene) may be important in preventing or ameliorating prematurity complications. Little is known about carotenoid status or effects of supplementation.

STUDY DESIGN

This randomized controlled multicenter trial compared plasma carotenoid levels among preterm infants (n=203, <33 weeks gestational age) fed diets with and without added lutein, lycopene and β-carotene with human milk (HM)-fed term infants. We assessed safety and health.

RESULT

Plasma carotenoid levels were higher in the supplemented group at all time points (P<0.0001) and were similar to those of term HM-fed infants. Supplemented infants had lower plasma C-reactive protein (P<0.001). Plasma lutein levels correlated with the full field electroretinogram-saturated response amplitude in rod photoreceptors (r=0.361, P=0.05). The supplemented group also showed greater rod photoreceptor sensitivity (least squares means 6.1 vs 4.1; P<0.05).

CONCLUSION

Carotenoid supplementation for preterm infants raises plasma concentrations to those observed in HM-fed term infants. Carotenoid supplementation may decrease inflammation. Our results point to protective effects of lutein on preterm retina health and maturation.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

Plant stanol ester spreads as components of a balanced diet for pregnant and breast-feeding women: evaluation of clinical safety

Clinical safety of consuming plant stanol ester spreads during pregnancy and lactation, the impact on maternal and infant serum and breast-milk cholesterol and the ratios (μmol/mmol of cholesterol) of synthesis and absorption markers were evaluated. Pregnant women (n21) were randomised to control and dietary intervention groups, the intervention including advice to follow a balanced diet and to consume spreads enriched with plant stanol esters. Participants were followed during and after pregnancy and their infants up to 1 year of age. A mean 1·1 (sd0·4) g consumption of plant stanols during pregnancy and 1·4 (sd0·9) g 1 month post-partum increased sitostanol and the markers for cholesterol synthesis, lathosterol, lathosterol/campesterol and lathosterol/sitosterol, and reduced a marker for cholesterol absorption, campesterol, in maternal serum. In breast milk, desmosterol was lower in the intervention group, while no differences were detected between the groups in infants' serum. Plant stanol ester spread consumption had no impact on the length of gestation, infants' growth or serum β-carotene concentration at 1 and 6 months of age, but the cholesterol-adjusted serum β-carotene concentration was lowered at 1 month in the intervention group. Plant stanol ester spread consumption appeared safe in the clinical setting, except for potential lowering of infants' serum β-carotene concentration, and was reflected in the markers of cholesterol synthesis and absorption in mothers' serum, encouraging further studies in larger settings.

Evaluation of antioxidant capacity and aroma quality of breast milk

OBJECTIVE

It is important to understand the difference and similarity in antioxidant capacity and aroma quality between formula and breast milk for purposes of modifying infant formulas. We evaluated the antioxidant properties and aroma quality of infant formula and breast milk.

METHODS

Six breast milk samples and four infant formulas were used. Antioxidant properties were measured using the following methods: 2,2-diphenyl-1-picryhydrazyl free radical scavenging capacity, oxygen radical absorbance capacity, total phenolic content, and phenolic composition. Aroma quality was determined using the electronic nose.

RESULTS

The 2,2-diphenyl-1-picryhydrazyl free radical scavenging activity for formula and breast milk ranged from 45.3% to 61.8% and from 52.8% to 61.2%, respectively. Oxygen radical absorbance capacity ranged from 28.8 to 31.9 g/kg for formula and from 25.5 to 39.2 g/kg for breast milk. Total phenolic content ranged from 422 to 751 mg/kg and from 329to 797 mg/kg for formula and milk, respectively. p-Hydroxybenzoic acid, p-coumaric acid, and ferulic acid were detected with values ranging from 614 to 635, 1391 to 1444, and 1425 to 1490 microg/kg in breast milk and from 783 to 3594, 1449 to 1510, and 1447 to 1561 microg/kg in formulas. Electronic nose results indicated that the aroma quality of formula controls 2, 3, and 4 was similar to that of breast milk.

CONCLUSION

Differences and similarities in antioxidant properties and aroma quality were found among some of the formulas and breast milk. The contribution of phenolic acids to total antioxidant capacity was limited.

Antioxidants in bovine colostrum

Quality, content and properties of colostrum are crucial for the neonate and its further development. Due to essential differences between intrauterine and extrauterine environment, the neonate is exposed to oxidative stress conditions. Colostrum apart from nutrient and immunological components should contain antioxidative systems necessary for the protection against reactive oxygen species. This review describes available data on enzymatic and non-enzymatic antioxidants in colostrum. Due to the fact that the literature concerning bovine colostrum is scanty, the information based on bovine mature milk determinations as well as other species is provided. Bovine colostrum is used not only by calves, but also for the production of hyperimmunized colostrum, medicines or feed supplements. Quality of colostrum influences quality of mature milk. This is another reason, except from health of neonate, why antioxidative properties of bovine colostrum are of special importance and require further detailed elucidation.

Lamb serum vitamin E and immunoglobulin G concentrations in response to various maternal mineral and iodine supplementation regimens

The objective of the first of three studies (experiment 1) was to evaluate the effects of supplementing the pregnant ewe diet with high levels of minerals for the final 4 weeks of gestation on lamb serum vitamin E and immunoglobulin G (IgG) concentration at 24 h post partum. Sixty ewes were allocated to one of two treatments (no. =30) and offered a basal diet fortified with 52 g of supplementary minerals/vitamins containing Ca, Mg, Na, P, Co, I, Mn, Se, Zn and vitamin E (M1) for the final 4 weeks of pregnancy or no mineral/vitamin supplement was added (C1). Immediately after birth, lambs were allocated to one of four treatments in a 2×2 factorial design with the factors being ewe treatment (± minerals) and colostrum origin (± minerals). Irrespective of the colostrum origin, the progeny of the mineral supplemented ewes had lower serum vitamin E and IgG concentrations and IgG absorption efficiency at 24 h post partum (P<0·001). In a second study (experiment 2), 44 ewes were allocated to one of four treatments (no. =11) in week 13 of pregnancy and offered a basal diet in addition to one of the following mineral/vitamin fortifications: 0 g (C2), 52 g of a mineral supplement as in experiment 1 (M2), a supplement as in M1 but with iodine excluded (-I), iodine only offered at a rate (40 mg per ewe per day) equivalent to 52 g of minerals (IO). When iodine was offered either M2 (P<0·01) or (IO) (P<0·001) it resulted in the progeny having a reduced serum vitamin E concentration at 24 h post partum. The -I progeny had higher serum vitamin E concentrations at 24 h post partum than the progeny of treatments C2, M2 (P<0·01) and IO (P<0·001). In a third study (experiment 3) the effect of incremental levels of iodine supplementation on lamb serum vitamin E concentration was studied. Forty-eight ewes were allocated to one of four treatments (no. =12) and offered the following levels of supplementary dietary iodine: 0 mg (C3), 8·9 mg (LI), 17·7 mg (MI) or 26·6 mg (HI) for the final 6 weeks of pregnancy. There was a linear (P<0·001) reduction in lamb serum vitamin E concentration as maternal iodine supplementation increased. We conclude that when ewes are offered high levels of iodine during the final 6 weeks of gestation their progeny are pre-programmed in utero to have a reduced ability to absorb colostral vitamin E. These findings support our earlier studies and provide further evidence of the need to reduce the current toxicity values for iodine. for the ewe in late pregnancy.

Vitamins A and E: metabolism, roles and transfer to offspring

Vitamins A and E are essential, naturally occurring, fat-soluble nutrients that are involved in several important biological processes such as immunity, protection against tissue damage, reproduction, growth and development. They are extremely important during the early stages of life and must be transferred adequately to the young during gestation and lactation. The present article presents an overview of their biological functions, metabolism and dynamics of transfer to offspring in mammals. Among other topics, the review focuses on the biochemical aspects of their intestinal absorption, blood transport, tissue uptake, storage and catabolism. It also describes their different roles as well as their use as preventive and therapeutic agents. Finally, the mechanisms involved in their transfer during gestation and lactation are discussed.

Vitamin E During Pre‐ and Postnatal Periods

Vitamin E is a fat-soluble nutrient that is extremely important during the early stages of life, from the time of conception to the postnatal development of the infant. The mechanisms involved in its placental and mammary uptake appear to be allowed by the presence of lipoprotein receptors (LDL-receptor, VLDL-receptor, scavenger receptor class B type I) together with lipoprotein lipase at the placental and mammary barriers. In addition, alpha-tocopherol transfer protein has been described as playing an essential role in the selective transfer of RRR-alpha-tocopherol across the placenta. Lower alpha-tocopherol concentrations are found in cord blood as compared to maternal circulation. The ingestion of colostrum which contains very high levels of vitamin E is therefore of utmost importance to supply the newborn with an essential defense against oxygen toxicity. Pregnancy is sometimes associated with complications that may lead to a premature delivery of the baby. Preterm infants are usually facing an oxidative stress that is among others related to a deficiency in alpha-tocopherol, as it accumulates mainly during the third trimester of pregnancy. Despite vitamin E supplementation, preterm infants usually require significantly longer to replenish their serum alpha-tocopherol levels than full-term infants. The use of vitamin E as a therapeutic agent in preeclampsia, which induces high maternal and fetal morbidity and mortality, has been discussed in numerous papers. This disorder is indeed associated with an important oxidative stress in the placenta and maternal circulation. However, the most recent studies did not show a beneficial effect of vitamin E administration in this pathology.

β-Carotene breakdown products may impair mitochondrial functions — potential side effects of high-dose β-carotene supplementation

Beta-carotene (BC) and other carotenoids are mainly considered as belonging to the group of micronutrients. As they are contained in fruit and vegetables and thus part of human diet, a regular low-dose intake from natural sources is normally assured. In the last decade high-dose supplementation with synthetic carotenoids has been used successfully in the treatment of diseases believed to be associated with oxidative stress. However, in a few clinical studies harmful effects have been observed as well, e.g., a higher incidence of lung cancer after BC was given in high doses to smokers. Our studies aim at shedding light on the causal mechanisms of the known side effects that we have investigated. Possibilities of preventing them are discussed. Obviously, on certain conditions of high-dose carotenoid supplementation, both the antioxidant and prooxidant reactions may arise. Carotenoid breakdown products (CBP) including very reactive aldehydes and epoxides are formed during oxidative attack in the course of antioxidative action. Carotenoid breakdown products inhibit state 3 respiration of isolated rat liver mitochondria at concentrations between 0.5 and 20 microM. In vivo stimulated neutrophils might represent an important source for the generation of CBP, and the lung might be a critical organ in CBP formation. The inhibition of mitochondrial state 3 respiration by CBP is accompanied by a reduced content of protein sulfhydryl groups, decreasing glutathione levels and redox state, and also elevated accumulation of malondialdehyde. Changes in mitochondrial membrane potential favour functional deterioration of the adenine nucleotide translocator (ANT). The findings reflect a basic mechanism of the side effects of BC supplementation in circumstances of severe oxidative stress induced by CBP representing a class of lipid oxidation products. We are striving for safe conditions of carotenoid supplementation in order to protect patients in need of this kind of medical treatment from possible side effects, such as unwanted prooxidative reactions.

Serum alpha- and gamma-tocopherol levels in atopic mothers and their infants are correlated

BACKGROUND

Vitamin E may have immunomodulatory properties beyond its antioxidant function. The objective here was to assess the alpha- and gamma-tocopherol status and its correlation between atopic mothers and their infants.

METHODS

Mothers with atopic disease were recruited at the end of gestation and their infants were followed up. Serum samples from mothers and infants were collected at the infants' age of 1 month. Atopic dermatitis was diagnosed during the 1st year of life and skin prick tests were performed at 1 year.

RESULTS

Infants' serum gamma- and alpha-tocopherol to fat ratios were significantly correlated with maternal serum ratios (r=0.70, p<0.0001 and r=0.52, p=0.004, respectively). In infants the serum alpha-tocopherol/fat was higher and the gamma-tocopherol/fat ratio lower than in mothers. Serum tocopherol levels were not associated with skin prick test reactions or atopic dermatitis in the infants.

CONCLUSIONS

Maternal tocopherol status determines that of the infant. Different tocopherol forms may have different serum levels and roles in the regulation of inflammatory diseases.

A review of the effects of breastfeeding on respiratory infections, atopy, and childhood asthma

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.

Effect of storage on breast milk antioxidant activity

BACKGROUND

Human milk, which contains compounds beneficial to infants, is often expressed and stored before use. Changes in its antioxidant activity with storage have not been studied.

OBJECTIVES

To measure antioxidant activity of fresh, refrigerated (4 degrees C), and frozen human milk (-20 degrees C), stored for two to seven days; to compare the antioxidant activity of milk from mothers delivering prematurely and at term; to compare the antioxidant activity of infant formulas and human milk.

METHODS

Sixteen breast milk samples (term and preterm) were collected from mothers within 24 hours of delivery and divided into aliquots. Fresh samples were immediately tested for antioxidant activity, and the rest of the aliquots were stored at -20 degrees C or 4 degrees C to be analysed at 48 hours and seven days respectively. The assay used measures the ability of milk samples to inhibit the oxidation of 2,2'-azino-di-3-(ethylbenzthiazolinesulphonate) to its radical cation compared with Trolox.

RESULTS

Antioxidant activity at both refrigeration and freezing temperatures was significantly decreased. Freezing resulted in a greater decrease than refrigeration, and storage for seven days resulted in lower antioxidant activity than storage for 48 hours. There was no difference in milk from mothers who delivered prematurely or at term. Significantly lower antioxidant activity was noted in formula milk than in fresh human milk.

CONCLUSIONS

To preserve the antioxidant activity of human milk, storage time should be limited to 48 hours. Refrigeration is better than freezing and thawing.

Influence of sources of dietary vitamin E on the maternal transfer of alpha-tocopherol to fetal and neonatal guinea pigs as determined by a stable isotopic technique

The accepted biological potencies of vitamin E (United States Phamacopeia, 1985) for 1 mg all-rac-alpha-tocopheryl acetate (synthetic form) is 1.00 IU and that of 1 mg (RRR)-alpha-tocopheryl acetate (natural form) is 1.36 IU. In the present study, a stable isotopic (2H) technique was employed to evaluate the bioavailability of natural v. synthetic forms of vitamin E and to determine whether the potency of the forms is the stated relationship of 1.36:1.00 (RRR)-alpha-tocopheryl acetate:all-rac-alpha-tocopheryl acetate. Sixty female in-bred guinea pigs received either 40 or 80 mg vitamin E/kg diet with equal levels of (RRR)-alpha-tocopheryl acetate and all-rac-alpha-tocopheryl acetate throughout gestation and lactation. At late-term pregnancy (day 50 or 60) and during early lactation, dams and their corresponding fetuses or neonates were killed and various tissues collected for subsequent alpha-tocopherol analysis. Vitamin E analysis of fetal and neonatal tissues indicated a substantial transfer of 2H-labelled alpha-tocopherol across the placenta and through the mammary gland. Total alpha-tocopherol concentrations were significantly influenced by tissue type and dose level, but not by stage of gestation or lactation. The relative bioavailability (d3:d6) across fetal and neonatal tissues was on average 1.81:1.00, with a range from 1.62:1.00 to 2.01:1.00. Maternal tissues had a mean ratio of 1.77:1.00. A higher relative bioavailability (P<or=0.05) was observed with natural compared with synthetic alpha-tocopherol as shown by a higher d3:d6 ratio in all tissues examined. Vitamin E was highest in colostrum on day 2 then declined through to day 5. Results from this present experiment further question the accepted biological potencies of natural:synthetic alpha-tocopheryl acetate of 1.36:1.00.

Vitamin E supplementation for prevention of morbidity and mortality in preterm infants

BACKGROUND

Treating very low birth weight (VLBW) infants with pharmacologic doses of vitamin E as an antioxidant agent has been proposed for preventing or limiting retinopathy of prematurity, intracranial hemorrhage, hemolytic anemia, and chronic lung disease. However, excessive doses of vitamin E may result in side effects.

OBJECTIVES

The aim of this systematic review was to assess the effects of vitamin E supplementation on morbidity and mortality in preterm infants.

SEARCH STRATEGY

We searched MEDLINE (October 2002), EMBASE (March 2002), the Cochrane Controlled Trials Register (CCTR) from the Cochrane Library, 2003, Issue 1, and personal files for clinical trials assessing vitamin E in preterm infants.

SELECTION CRITERIA

We selected trials analyzing primary outcomes (mortality or combined long-term morbidity) or secondary outcomes (other morbidity) in infants with gestational age less than 37 weeks or birth weight less than 2500 grams. The intervention was allocation to routine supplementation with vitamin E in the treatment group versus placebo, no treatment or another type, dose or route of administration of vitamin E.

DATA COLLECTION AND ANALYSIS

We used standard methods of the Cochrane Collaboration and of the Cochrane Neonatal Review Group.

MAIN RESULTS

Twenty-six randomized clinical trials fulfilled entry criteria. No study assessed combined long-term morbidity. Routine vitamin E supplementation significantly reduced the risk of germinal/intraventricular hemorrhage (typical relative risk [RR] 0.85, 95% confidence interval [CI] 0.73, 0.99), increased the risk of sepsis (typical RR 1.52, CI 1.13, 2.04) and increased hemoglobin concentration by a small amount, but did not significantly affect mortality and other morbidity. In VLBW infants, vitamin E supplementation increased the risk of sepsis, and reduced the risk of severe retinopathy and blindness among those examined. Subgroup analyses in VLBW infants showed (1) an association between serum tocopherol levels greater than 3.5 mg/dl and increased risk of sepsis and reduced risk for severe retinopathy among those examined; and (2) an association between intravenous, high-dose administration of vitamin E and increased risk of sepsis.

REVIEWER'S CONCLUSIONS

Vitamin E supplementation in preterm infants reduced the risk of intracranial hemorrhage but increased the risk of sepsis. In very low birth weight infants it increased the risk of sepsis, and reduced the risk of severe retinopathy and blindness among those examined. Evidence does not support the routine use of vitamin E supplementation by intravenous route at high doses, or aiming at serum tocopherol levels greater than 3.5 mg/dl.

Development and validation of a fast and sensitive chromatographic assay for all-trans-retinol and tocopherols in human serum and plasma using liquid-liquid extraction

A sensitive HPLC assay for all-trans-retinol, alpha-tocopherol, and gamma-tocopherols in human serum and plasma is reported. Sample preparation is performed in one step and involves precipitation of proteins and extraction of lipids with two volumes of an ethanol-chloroform mixture (3:1, v/v) without I.S. addition. After removal of the precipitated protein, 20 microl aliquots of the supernatant (equivalent to 6.7 microl of serum or plasma) were injected into the HPLC system and analyzed using fluorometric detection. RP-HPLC was performed using a C(18) S3 ODS2 column with a methanol-water step gradient (97:3 to 100) at 1.0 ml/min. The quantification limit expressed as nanograms of analyte per milliliter of serum or plasma was approximately 30 ng for all-trans-retinol, 300 ng for alpha-tocopherol and 250 ng for gamma- and delta-tocopherol. The method was validated and applied to human serum and plasma from a total of 120 subjects. This procedure requires a small volume of serum or plasma and can therefore be a valuable tool for measuring low concentrations of these vitamins in preterm infants with sensitivity, precision and accuracy.

Carotenoid composition of human milk during the first month postpartum and the response to beta-carotene supplementation

BACKGROUND

Information is lacking regarding normal changes in milk carotenoid concentrations in healthy, well-nourished women during the first month of lactation.

OBJECTIVES

This study investigated milk carotenoid concentrations during days 4-32 postpartum and assessed the effects of maternal beta-carotene supplementation.

DESIGN

Subjects (n = 21; aged 19-39 y) were randomly assigned to receive beta-carotene (30 mg/d) or placebo from days 4 to 32 postpartum. Each subject provided 8 diet records and 8 milk samples during the study. Diet records were analyzed for energy, macronutrients, vitamins A and E, and carotenoids. Milk samples were analyzed with HPLC for concentrations of carotenoids, retinol, and alpha-tocopherol. Data were analyzed by using repeated-measures analysis and orthogonal contrasts.

RESULTS

No significant differences in average dietary intakes, body mass index, age, or parity were found between groups at baseline or after supplementation. Milk carotenoid concentrations decreased over time (P < 0.01), as did retinol and alpha-tocopherol concentrations (P < 0.003). Concentrations of most carotenoids decreased to those reported for mature milk by day 32 postpartum. Milk lutein concentrations remained elevated throughout the study compared with values reported for mature milk, whereas plasma lutein concentrations decreased significantly over time. beta-carotene supplementation did not significantly change the milk concentrations of beta-carotene, the other carotenoids, retinol, or alpha-tocopherol.

CONCLUSIONS

The lack of increase in milk beta-carotene despite supplementation suggests that transitional milk may be already nearly saturated with beta-carotene. The elevated milk lutein concentration and simultaneous decrease in plasma lutein suggest that lutein metabolism may be altered during early lactation.

Anti-inflammatory characteristics of human milk: how, where, why

When first proposed, the hypothesis that human milk was anti-inflammatory was supported by 2 observations: poor function of milk leukocytes and the presence in milk of components that could modify inflammatory processes. This hypothesis is now supported by studies documenting anti-inflammatory effects in animal models and suppression of humoral and cellular components of inflammation in vitro. To date, two mechanisms have been demonstrated: alteration of leukocyte function and modification of cytokine biology. It is not clear whether these mechanisms are only topical effects in the digestive tract, or whether absorption of milk components results in systemic effects. While inflammation benefits the host as a defense mechanism and precursor to immune responses, it also contributes to the clinical manifestations of illness and is an important early component of wound-healing responses that result in scar. The biological effects of milk's anti-inflammatory character may be to minimize clinical symptomatology without losing immunoresponsiveness for the breast-fed infant, and to minimize scar formation during healing responses.

Vitamin E status and the dynamics of its transfer between mother and pup during lactation in grey seals (Halichoerus grypus)

Concentrations of vitamin E, a powerful antioxidant, were measured in milk and serum of 18 grey seal (Halichoerus grypus) mothers and in the serum of their pups sampled up to 6 times between parturition and weaning on the Isle of May, Scotland, in 1998 and 2000. The vitamin E concentration in colostrum (89.4 ± 22.5 mg/kg milk; mean ± SD) was 4.5 times greater than that in later milk (20.9 ± 5.0 mg/kg milk). It then remained constant until the end of lactation. The decline in concentration of vitamin E in grey seal milk corresponded to a drop in the vitamin E concentration in mothers' serum between parturition (14.0 ± 4.8 mg/L serum) and the second half of the lactation period during which the serum vitamin E concentration remained stable (9.6 ± 3.2 mg/L serum). Circulating vitamin E concentrations varied significantly among mothers but there was no relationship with mother's age. Despite these differences between mothers, individuals produced milk with very similar vitamin E concentrations. The vitamin E concentration in grey seal pups' serum was low at birth (lowest concentration 3.1 mg/L serum) but increased sharply to a peak around days 1–3 (31.2 ± 5.2 mg/L serum). It then fell, before stabilizing until the end of lactation (21.1 ± 4.5 mg/L serum), reflecting the changes reported in the milk.

Vitamin E and vitamin A contents, fatty acid profiles, and gross composition of harp and hooded seal milk through lactation

This study reports fatty acid profiles and vitamin A and vitamin E contents of the milk of the harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) throughout the lactation period, as well as standard compositional analyses. The milk for this study was collected from harp and hooded seals breeding on the pack ice in the Gulf of St. Lawrence. Mother-pup pairs were serially captured, or point-sampled, in order to obtain milk samples during different lactation stages. Milk lipids showed the respective species' typical patterns during lactation, with a significant increase for harp seal milk and a relatively constant value for hooded seal milk. The profiles of most of the milk fatty acids remained relatively stable over the course of lactation in both species. Vitamin A content was also quite stable through lactation. By contrast, vitamin E content underwent a dramatic drop between the day of birth and early lactation for harp seals and from birth to midlactation for hooded seals. It then continued to decrease at a slower rate until the end of lactation in both species. The highest vitamin E content of colostrum reached 125 mg/kg of milk for harp seals and 200 mg/kg of milk for hooded seals. These concentrations subsequently dropped to 20-50 mg/kg of milk by early or mid lactation. These changes in this lipophilic, antioxidizing vitamin were not correlated with milk lipid content or its polyunsaturated fatty acid profiles.

Expression of functional immunomodulatory and anti-inflammatory factors in human milk

In addition to well-recognized antimicrobial substances, a growing body of evidence has accrued during the last decade regarding the presence and function of immunomodulatory and anti-inflammatory factors present in human milk and their role in protecting the mature newborn as well as the premature infant against infections. In addition, it is now appreciated that a number of these factors present in human milk may actively modulate the synthesis and maturation of the recipient immune system. This complex and interactive system of bioactive substances in human milk appears ideally to be designed to function by noninflammatory mechanisms, to operate often in a complementary or synergistic manner, to resist the digestive process in the recipient gastrointestinal tract, and to supplement developmentally delayed immune factors of the infant. The in vivo fate and effects of these immune factors in human milk, however, are still poorly understood. Clinical studies in conjunction with a broader use of experimental animal models and basic research are needed in the future to address these questions.

Influence of caesarean delivery and maternal factors on fat-soluble vitamins in blood from cord and neonates

We measured plasma and erythrocyte vitamin E (VE) and plasma vitamin A (VA) profiles in 48 full-term and 8 preterm pairs of neonates and their mothers at birth and we determined whether there is any relationship between maternal and umbilical cord for the nutrients measured. At the same time, we assessed the influence of the delivery type and neonate anthropometric measurements on maternal and cord blood VA and VE levels. We measured vitamin levels in vein and arterial blood in order to establish differences due to fetal metabolism. To determine the influence of pregnancy on vitamin levels, we compared the maternal results with data from a group of 13 non-pregnant women. Cord blood had lower plasma VE (arterial 275.8+/-71.7 microg/dl and vein 282.89+/-64.4 microg/dl values), erythrocyte VE (arterial 256.96+/-50.41 microg/dl packet cells and vein 257.41+/-44.35 microg/dl values), and VA levels (arterial 26.72+/-11.83 microg/dl and 27.15+/-10.05 microg/dl values) and a lower vitamin E/total lipids ratio (VE/LT) (arterial 1.60+/-0.4 and vein 1.62+/-0.3 values) than maternal blood (1474.62+/-424.51 microg/dl, 305.94+/-54.75 microg/dl packet cells, 41.03+/-18.83 microg/dl, 2.34+/-0.5, respectively). VA levels were higher in preterm than full-term neonates (P<0.05). Plasma and erythrocyte VE levels were not correlated in maternal blood but were correlated in neonates and infants (r>0.40; P<0.01). We found a good correlation between erythrocyte tocopherol of maternal and cord blood (r>0.40; P<0.01), although there was no correlation with plasma VE values. Cord vein plasma VE levels were higher than cord arterial blood measurements (P<0.01). The plasma VE and VE/LT of the mother and cord following vaginal delivery were higher than measurements from caesarean delivery (P<0.05), although erythrocyte levels were similar. The plasma VE level was higher in mothers at delivery than non-pregnant women.

Simultaneous determination of low plasma concentrations of retinol and tocopherols in preterm infants by a high-performance liquid chromatographic micromethod

A method for the simultaneous determination of low concentrations of retinol and tocopherols from 100 microliters plasma using isocratic reversed-phase HPLC is described. Retinol is quantified with a programmable UV-Vis detector, whereas tocopherols are quantified by fluorescence detection using tocol as the internal standard. Intra- and inter-assay precision are 3.7 and 4.3% for retinol and 2.3 and 6.1% for alpha-tocopherol, respectively. The accuracy as determined with standard material from the US National Institute of Standards and Technology with low, medium and high concentrations is in the range of 0.2-6.0% bias for retinol and of -3.0 to 5.5% for alpha-tocopherol, respectively. This method is highly sensitive and selective and has a good precision and accuracy for measuring low concentrations of vitamins in small plasma volumes.

Arachidonic acid supply and metabolism in human infants born at full term

Infants need arachidonic acid (AA; C20:4n-6) for eicosanoid synthesis and deposition in growing tissues, including brain. Human milk supplies preformed AA in amounts considered to meet accretion in membrane-rich tissues, but vegetable oil-based infant formulas do not contain AA. We studied two groups of ten healthy infants, each fed human milk or formula, and analyzed plasma lipid composition. Percentage contributions of AA to plasma phospholipids were stable over two months after birth in breast-fed infants, but infants fed formula developed significantly (P < 0.05) lower levels at the ages of two weeks (formula 6.9% vs. breast 9.4%, w/w), one month (6.2 vs. 9.1%), and two months (5.7 vs. 8.4%). In a second trial, we randomized infants to receive (from birth to age four months) formula without or with both AA and docosahexaenoic acid (DHA; C22:6n-3) at levels typical for mature human milk. Infants fed conventional formula showed a continuous decrease of phospholipid AA over time, whereas feeding of formula supplemented with AA and DHA led to significantly higher AA levels, similar to those in breast-fed infants (two months: supplemented 9.6% vs. unsupplemented 7.1%; four months: 8.7 vs. 6.6%). In order to estimate infantile capacity for endogenous synthesis of AA, we fed four term neonates with newly diagnosed phenylketonuria (mean age 18 d) a formula with all fat contributed by corn oil, which has a higher natural 13C-enrichment than European human milk or formula. Analysis of 13C-enrichment in plasma fatty acids over four days allowed us to estimate infantile AA synthesis. We found an increased 13C-value in plasma AA of all infants, which indicates that term neonates can synthesize AA. However, with a simplified isotope balance equation, we estimate that endogenous synthesis contributed only about 23% of total plasma arachidonic acid by day four. We conclude that full-term infants fed formula may require a dietary supply of some preformed AA if the biochemical status of breast-fed infants is to be achieved.

Growth, fatty acid composition of plasma lipid classes, and plasma retinol and alpha-tocopherol concentrations in full-term infants fed formula enriched with omega-6 and omega-3 long-chain polyunsaturated fatty acids

Full-term infants fed formula without dietary long-chain polyunsaturated fatty acids (LCF) exhibit significantly lower plasma LCP values than breast-fed infants. We studied prospectively two groups of healthy full-term infants fed conventional infant formula without LCP (F, n = 10) or the same formula enriched with both omega-6 and omega-3 LCP (LCP-F, n = 12). Anthropometric data were obtained and fatty acid (FA) compositions of plasma phospholipids, triglycerides and sterol esters as well as plasma retinol and alpha-tocopherol concentrations were determined at 5 days and 1, 2, 3 and 4 months of age. Gains in weight, length and head circumference did not differ between the two groups throughout the study period. Plasma FA values did not differ at 5 days of age. Between 1 and 4 months of age, plasma phospholipids of infants fed LCP-F consistently had significantly (p < 0.05) higher percentages of arachidonic acid (1 month: 9.7 (0.8) versus 7.0 (1.3) %wt/wt, 4 months: 8.7 (0.5) versus 6.6 (1.0) %wt/wt, median (interquartile range), LCP-F versus F) and docosahexaenoic acid (1 month: 2.9 (0.5) versus 1.6 (0.3) %wt/wt; 4 months: 2.9 (0.4) versus 0.9 (0.3) %wt/wt). Plasma retinol and alpha-tocopherol concentrations did not differ between the two groups throughout the study. We conclude that this form of LCP enrichment of formula for full-term infants effectively enhances plasma LCP contents without detectable adverse effects. The potential effects on functional outcome need to be studied carefully in prospective clinical trials.

Distribution of vitamin E between tissues during periods of hyperoxic and nutritional stress in the preterm guinea pig

1. Using a preterm guinea pig model we examined the impact of oxidative and nutritional stress on the vitamin E status of a number of immature tissues. 2. Liver, brain, lung, red blood cell and plasma alpha-tocopherol concentrations were measured in fed and fasted, preterm guinea pigs exposed to 21 or 95% oxygen for 48 hr. 3. Exposure to hyperoxia did not influence plasma, red blood cell, lung or brain vitamin E status of preterm pups. Liver alpha-tocopherol content was reduced 20% following 48 hr hyperoxic exposure (P < 0.05). 4. Food restriction (48 hr) alone reduced liver (41%) and red blood cell (32%) alpha-tocopherol concentrations in preterm animals while plasma, lung and brain vitamin E levels were unaffected. Combined with hyperoxic exposure, food restriction resulted in a (50%) fall in liver alpha-tocopherol concentration (P < 0.01). 5. The findings of this study suggest that the liver acts as a reservoir for vitamin E in the perinatal period, releasing increased quantities of this lipid soluble antioxidant for use by non-hepatic tissues during periods of hyperoxic and nutrient stress.

Dietary supplementation of vitamin E fails to prevent the development of hyperoxic lung injury in the premature guinea pig

1. The benefit of dietary vitamin E supplementation in preventing oxidative-induced lung injury was investigated. Three day preterm guinea pig pups were exposed to hyperoxic (85% O2) or normoxic (21% O2) conditions. The animals were fed either a standard low birthweight human infant formula milk (6.4 mg/l vitamin E), or a vitamin E supplemented milk (100 mg/l) for up to 7 days. 2. After 3 days vitamin E supplementation, plasma but not erythrocyte vitamin E concentrations were elevated, while following 7 days both plasma and erythrocyte vitamin E concentrations were significantly increased. 3. Lung and liver vitamin E concentrations were elevated at both 3 and 7 days. At 3 days the increase in lung vitamin E was oxygen-dependent, suggesting that the lung increases uptake of vitamin E in response to oxidative stress. 4. Despite an increase in the vitamin E concentration of the lungs of preterm guinea pigs, no amelioration of the lung injury was observed. These results suggest that although vitamin E is a potent antioxidant, it is unable to protect adequately the lungs from reactive oxygen species in the absence of sufficient primary enzymatic antioxidant defences.

Enzymatic conversion of all-trans-beta-carotene to retinal

Enzymatic conversion of all-trans-beta-carotene to retinal by a partially purified enzyme from rabbit, rat, and human neonatal intestinal mucosa has been demonstrated. The enzymatic product was characterized based on the following evidence. First, the product gave rise to its O-ethyl oxime by treatment with O-ethylhydroxylamine with an absorption maximum at 363 nm in ethanol characteristic of authentic retinal (O-ethyl) oxime. High-performance liquid chromatography of this derivative yielded a sharp peak with a retention time of 7.99 min, corresponding to the authentic compound. The enzyme blank and boiled enzyme blank failed to show any significant HPLC peaks corresponding to retinal (O-ethyl) oxime or retinal or retinol. Second, the mass spectrum of the O-ethyl oxime of the enzymatic product was identical to that of authentic retinal (O-ethyl) oxime (m/z 327, 45%; m+ and m/z 282, 100%, methoxy). Third, the 14C radioactivity persisted to constant specific activity even after repeated crystallization of the retinal (O-ethyl) oxime isolated from the enzyme reaction with purified beta-[14C]carotene. Fourth, the enzymatic product exhibited an absorption maximum at 370 nm in light petroleum characteristic of authentic retinal. Furthermore, it was reduced by horse liver alcohol dehydrogenase to retinol with an absorption maximum at 326 nm in light petroleum. This retinol was enzymatically esterified to retinyl palmitate by rat pancreatic esterase with a retention time of 10 min on HPLC, corresponding to authentic retinyl palmitate. Thus, the enzymatic product of beta-carotene cleavage by the partially purified intestinal enzyme has been unequivocally confirmed to be retinal. Similarly, enzymatic conversion of all-trans-beta-carotene to retinal by an intestinal mucosal enzyme from autopsy samples of human neonates has also been demonstrated. Based on the observed activities among intestinal samples from 12 premature infants, the BCC enzyme activity ranged from 3.3 to 1210 pmol/mg mucosal protein/hr. However, the observed activities in the human autopsy samples may be markedly underestimated, presumably because of marked loss of enzyme activity from the time of death to the time of assay. Therefore, the true activity of the enzyme can be assessed only after the extent of the loss of its activity on storage of the human samples can be accurately measured. Nonetheless, the demonstration of BCC enzyme activity in human neonates shows that beta-carotene may be an important source of vitamin A nutrition during gestation.