Lipid supply and metabolism in infancy

Effects of mono- and di-glycerides/phospholipids (MDG/PL) on the bioaccessibility of lipophilic nutrients in a protein-based emulsion system

Lipophilic nutrients are known to have relatively poor absorption, thus limiting their bioaccessibility. Consequently, researchers in food and pharmaceutical areas are exploring different techniques to promote the efficient delivery of lipophilic nutrients. The effects of two polar lipids, namely mono-, di-glycerides (MDG) and lecithin (PL), on the bioaccessibility of lipophilic nutrients were investigated in this study with a protein-based emulsion model system. During the emulsion preparation and formation, the incorporation of MDG/PL was found to benefit the dissolution and stabilization of lipophilic nutrients, such as lutein, and could also modify the construction of the emulsion surface. An in vitro digestion study showed that the use of MDG/PL could significantly increase the bioaccessibility of lipophilic nutrients [lutein, vitamin E, and docosahexaenoic acid (DHA)] by 13.52%, 186.90%, and 36.17% in a protein-based emulsion system. The use of MDG and PL decreased the interfacial tension in all the samples: protein only 20.65 mN m^-1, protein-PL 6.47 mN m^-1, and protein-MDG/PL 4.23 mN m^-1, as well as 12.11 mN m^-1, 1.26 mN m^-1 and 1.16 mN m^-1 with the presence of bile salts. Caco-2 cell culture results showed that, with the application of MDG/PL, the absorption rate of micelles was higher than that in the other groups and this resulted in a 70% absorption increase for lutein. Therefore, MDG/PL can improve the lipophilic nutrient absorption via promoting the affinity of formed micelles to the enterocytes of the small intestine. This study exhibited the effectiveness of MDG/PL on improving the bioaccessibility of lipophilic nutrients in a protein-based emulsion system mimicking the digestion and absorption fate of breast milk in an infant's gastric intestinal tract, thus suggesting that MDG/PL can be used as a technical pathway to improve the absorption of lipophilic nutrients.

Do Thyroid Diseases during Pregnancy and Lactation Affect the Nutritional Composition of Human Milk?

OBJECTIVE

 To identify whether the effects of thyroid disease during pregnancy and lactation affect the nutritional composition of human milk.

METHODS

 Systematic review of the scientific literature using the Medical Literature Analysis and Retrieval System Online/MedLine databases to evaluate the association of thyroid diseases during pregnancy and lactation with the nutritional composition of human milk. There was no delimitation by period or by language, and the searches were completed in March 2019. The following descriptors were applied: human milk AND thyroid AND composition, using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol for data search, selection, and extraction. The flowchart proposed for bibliographic search resulted in 12 articles and, of these, four were selected.

RESULTS

 The articles elected for this review were published between 1976 and 2018. Two studies found significant differences in the nutritional composition of mothers' milk with hypothyroidism or overweight compared with the milk of those without hypothyroidism. Studies have shown that the presence of the disease led to changes in the nutritional composition of human milk, especially a higher concentration of human milk fat.

CONCLUSION

 It is extremely important that these women have continuous nutritional follow-up to minimize the impact of these morbidities on the nutritional composition of human milk.

Alteration of the colostrum whey proteome in mothers with gestational hypothyroidism

BACKGROUND

Gestational hypothyroidism (G-HypoT) is one of the most common thyroid diseases in pregnant women. Human milk, which closely links the mother with infant, is an important factor to the infant health. Here, we analyzed the colostrum whey proteome of women with or without G-HypoT.

METHODS AND RESULTS

Using high-mass accuracy and high-resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS), 1055 proteins were identified. Tandem Mass Tags (TMT) analysis identified differentially expressed proteins between G-HypoT and non-G-HypoT mothers. Of 44 proteins identified, 15 proteins were significantly increased in G-HypoT colostrum whey, while 29 were significantly decreased. Analysis revealed that enzymes involved in carbohydrate metabolism, and that reflect the metabolic activities in breastfeeding women, including fructose-1, 6-bisphosphatase 1, phosphoglycerate mutase 1 were down-regulated. Cell structural proteins, biomarkers of mammary integrity development, including Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and actin were lower in G-HypoT colostrum whey. However, immune protein fragments like Ig gamma-3 chain C region increased in G-HypoT colostrum whey.

CONCLUSION

These results implied that G-HypoT may changed human colostrum whey protein in composition level, decreasing levels of metabolic proteins and cell-structure proteins, while increasing levels of immune-related proteins, which may compromise or reflect mothers' and infants' health.

Maternal DHA Status during Pregnancy Has a Positive Impact on Infant Problem Solving: A Norwegian Prospective Observation Study

Docosahexaenoic acid (DHA, 22:6, n-3) is a long-chain polyunsaturated fatty acid necessary for normal brain growth and cognitive development. Seafood and dietary supplements are the primary dietary sources of DHA. This study addresses the associations between DHA status in pregnant women and healthy, term-born infant problem-solving skills assessed using the Ages and Stages Questionnaire. The fatty acid status of maternal red blood cells (RBCs) was assessed in the 28th week of gestation and at three months postpartum. The infants’ fatty acid status (RBC) was assessed at three, six, and twelve months, and problem-solving skills were assessed at six and twelve months. Maternal DHA status in pregnancy was found to be positively associated with infants’ problem-solving skills at 12 months. This association remained significant even after controlling for the level of maternal education, a surrogate for socio-economic status. The infants’ DHA status at three months was associated with the infants’ problem solving at 12 months. The results accentuate the importance for pregnant and lactating women to have a satisfactory DHA status from dietary intake of seafood or other sources rich in DHA.

Omega 3 polyunsaturated fatty acids and body weight

In animal studies, n-3 PUFA have been shown to influence body composition and to reduce the accumulation of body fat, thereby affecting body weight homeostasis. In addition, it has been suggested that an additional supply of n-3 PUFA during pregnancy or lactation, or both, would have a beneficial effect on birth weight and infant growth and development. The purpose of the present study was to systematically review interventional clinical trials on the effects of dietary n-3 PUFA supplementation on body weight in adult subjects and in infants whose mothers were supplemented with these fatty acids during pregnancy and/or lactation. A systematic search, focused on n-3 PUFA and body weight, and limited to controlled clinical trials, was performed in different databases. The quality of all included studies was assessed against set criteria, and results of eligible trials were compared. There were few studies targeting this topic. In adults, all of the five studies included, except for one, show no change in body weight by dietary supplementation with n-3 PUFA. Within those trials conducted in pregnant and/or lactating women in which a main outcome was birth weight or growth in infancy, two showed a modest increase in birth weight and the rest showed no effect. None of the trials showed an effect of maternal n-3 PUFA supplementation on infant's weight at the short term. However, it should be noted that a number of limitations, including a variety of experimental designs, type and doses of n-3 PUFA, and high attrition rates, among others, make impossible to draw robust conclusions from this review.

Compartmental analyses of 2H5-alpha-linolenic acid and C-U-eicosapentaenoic acid toward synthesis of plasma labeled 22:6n-3 in newborn term infants

BACKGROUND

During early postnatal development, the nervous system accretes docosahexaenoic acid (DHA; 22:6n-3), a highly unsaturated n-3 (omega-3) fatty acid (FA) used in the formation of neural cell membranes. DHA, which is present in human breast milk, may also be biosynthesized from n-3 FAs such as 18:3n-3 [alpha-linolenic acid (ALA)] or 20:5n-3 [eicosapentaenoic acid (EPA)]. An important concern is to what extent these precursors can supply DHA to the developing infant.

OBJECTIVE

We analyzed measurements of fractional percentages of plasma (2)H(5)-ALA and (13)C-U-EPA directed toward the synthesis of labeled 22:6n-3 in 11 newborn infants by using compartmental modeling procedures.

DESIGN

One-week-old infants received doses of (2)H(5)-ALA and (13)C-U-EPA ethyl esters enterally. We drew blood from the infants periodically and analyzed the plasma for endogenous and labeled n-3 FAs. From the time-course concentrations of the labeled FAs, we determined rate constant coefficients, fractional synthetic rates, and plasma turnover rates of n-3 FAs.

RESULTS

In infants, approximately 0.04% of the (2)H(5)-ALA dose converted to plasma (2)H(5)-EPA. Plasma (2)H(5)-EPA and (2)H(5)-22:5n-3 [docosapentaenoic acid (DPA)] efficiently converted to (2)H(5)-DPA and (2)H(5)-DHA, respectively. The percentage of plasma (13)C-U-EPA directed toward the synthesis of (13)C-DHA was lower than the percentage of plasma (2)H(5)-EPA that originated from (2)H(5)-ALA.

CONCLUSIONS

Endogenously synthesized EPA was efficiently converted to DHA. In comparison, preformed EPA was less efficiently used for DHA biosynthesis, which suggests a differential metabolism of endogenous EPA compared with exogenous EPA. However, on a per mole basis, preformed EPA was 3.6 times more effective toward DHA synthesis than was ALA. Newborns required an intake of approximately 5 mg preformed DHA. kg(-1) x d(-1) to maintain plasma DHA homeostasis.

Compartmental analyses of plasma 13C- and 2H-labeled n-6 fatty acids arising from oral administrations of 13C-U-18:2n-6 and 2H5-20:3n-6 in newborn infants

Efficacy of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 toward synthesis of labeled-20:4n-6 was studied in newborn infants utilizing compartmental models of plasma labeled n-6 fatty acids (FA). Ten infants received oral doses of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 ethyl esters (100 and 2 mg/kg, respectively). Rate constant coefficients and half-lives (t((1/2))) of n-6 FA were determined from the time-course concentrations of labeled-FA. Plasma n-6 FA values approximated steady state concentrations. Synthetic and utilization rates were calculated. Eight percent (range, 2-21%) of plasma (13)C-U-18:2n-6 was used for synthesis of (13)C-18:3n-6, -20:2n-6, and -20:3n-6. Seventy percent of (13)C-20:3n-6 (mean, CV: 0.26) was available for synthesis of (13)C-20:4n-6. The percentage of (2)H(5)-20:3n-6 converted to (2)H(5)-20:4n-6 was lower (mean: 26%, p < 0.02) than the (13)C-labeled analogue. Turnover of 18:2n-6 in subjects and of 20:4n-6 in plasma was 4.2 g/kg/d (CV: 0.58) and 4.3 mg/kg/d (CV: 0.81), respectively. Intake of 18:2n-6 and 20:4n-6 were estimated to be 3.0 g/kg/d (+/-1.7) and 2.8 mg/kg/d (+/- 2.2), respectively. Infants required additional 18:2n-6 and 20:4n-6 (mean: 1.2 g and 1.5 mg/kg/d) above predicted intake amounts to maintain plasma concentrations of 18:2n-6 and 20:4n-6, in order to spare FA from fat stores.

Effect of n-3 long-chain polyunsaturated fatty acid supplementation of women with low-risk pregnancies on pregnancy outcomes and growth measures at birth: a meta-analysis of randomized controlled trials

BACKGROUND

It is hypothesized that the intake of long-chain polyunsaturated fatty acids (LC-PUFAs) throughout pregnancy is important to maternal health and fetal and infant development.

OBJECTIVE

The objective was to evaluate systematically the effect of LC-PUFA supplementation of pregnant women's diets on pregnancy outcomes and growth measures at birth.

DESIGN

We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Library through August 2005 and also searched the references in reviewed articles for randomized controlled trials (RCTs) comparing LC-PUFA supplementation with placebo or no supplementation.

RESULTS

Of 6 included RCTs, only 1 was judged to be at low risk of bias. Supplementation with n-3 LC-PUFAs in these 6 RCTs (1278 infants) was associated with a significantly greater length of pregnancy [weighted mean difference (WMD): 1.57 d; 95% CI: 0.35, 2.78 d; findings stable on sensitivity analysis] than in control subjects. We found no evidence that supplementation influenced the percentage of preterm deliveries, the rate of low-birth-weight infants, or the rate of preeclampsia or eclampsia. We found no significant difference in the 6 RCTs (1278 infants) in birth weight (WMD: 54 g; 95% CI: -3.1, 111 g) and no significant difference in 5 RCTs (1262 infants) in birth length (WMD: 0.23 cm; 95% CI: -0.04, 0.5 cm), but, in 4 RCTs (729 infants), there was a significant increase in head circumference (WMD: 0.26 cm; 95% CI: 0.02, 0.49 cm; significance was lost on sensitivity analysis).

CONCLUSIONS

n-3 LC-PUFA supplementation during pregnancy may enhance pregnancy duration and head circumference, but the mean effect size is small. The implications of these findings for later growth and development remain to be elucidated.