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Dairy Protein Supplementation Modulates the Human Skeletal Muscle microRNA Response to Lower Limb Immobilization.
D'Souza, RF, Zeng, N, Figueiredo, VC, Markworth, JF, Durainayagam, BR, Mitchell, SM, Fanning, AC, Poppitt, SD, Cameron-Smith, D, Mitchell, CJ
Molecular nutrition & food research. 2018;(7):e1701028
Abstract
Limb immobilization results in a rapid loss of muscle size and strength. The resultant alterations in signaling pathways governing myogenesis, catabolism, and mitochondrial biogenesis are likely to include posttranscriptional regulation mediated by altered microRNAs (miRNAs). Given that protein ingestion exerts an anabolic action and may act as a countermeasure to mitigate muscle loss with immobilization, it is important to examine miRNA in this context. The objective of the study is therefore to characterize the vastus lateralis miRNA response to 14 days of disuse in males (45-60 years) randomized to receive supplementation with 20 g d-1 of dairy protein (n = 12) or isocaloric carbohydrate placebo (n = 13). Biopsies are collected before and after a 2-week immobilization period. Of the 24 miRNAs previously identified in myogenic regulation, seven (miR-133a, -206, -15a, -451a, -126, -208b, and let-7e) are increased with immobilization irrespective of group; five (miR-16, -494, let-7a, -7c, and 7d) increased only in the carbohydrate group; and eight (miR-1, -486, -23a, -23b, -26a, -148b, let-7b, and -7g) are divergently expressed between groups (suppressed with protein). The ability of protein supplementation to differentially regulate miRNAs involved in key muscle regulatory pathways following short-term limb immobilization reflects potential protective function in mitigating muscle loss during limb immobilization.
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2.
[Advances in the knowledge about human milk proteins].
Brunser, O
Revista chilena de pediatria. 2018;(2):261-269
Abstract
The mammary gland and maternal milk are the product of millions of years of evolution that resul ted in an optimal composition that sustains the growth and development of newborns and infants. Maternal milk supports the growth, adaptation and survival of this immature organism. Recent studies have detected 1606 different proteins in human milk, most of them synthesized in the acini of the glandular tissue while others originate from distant organs such as the lymphoid tissue and the digestive tract. Maternal milk enzymes modify its proteins and liberate peptides with antimicrobial, antihypertensive or stimulatory activities. This proteolytic activity occurs at specific sites in peptide chains. To prevent the extemporaneous activation of these proteolytic enzymes, that would result in inflammatory processes, maternal milk also contains inhibitory peptides that together with the stimulatory peptides conform a complex regulatory system. Some enzymes in maternal milk main tain their activity in the gastrointestinal tract of infants and compensate for the decreased activity of digestive tract enzymes in newborns. Thus, the milk enterokynase stimulates the release of pancreatic proteases as it induces the liberation of cholecystokynin/pancreozymin. The bile salt-activated lipase of human milk is activated in the duodenum by the infants' bile salts and partially compensates for the low levels of pancreatic lipase in newborns. These milk enzymes probably contribute to the nutrition of premature infants as they increase the availability of amino acids and peptides in their upper gastrointestinal tract; furthermore, as their intestinal epithelium is more permeable to peptides and partially digested protein this may help induce immune tolerance. The most relevant issues in the physiology and composition of the maternal milk are presented in this review.
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Protein-enriched, milk-based supplement to counteract sarcopenia in acutely ill geriatric patients offered resistance exercise training during and after hospitalisation: study protocol for a randomised, double-blind, multicentre trial.
Gade, J, Beck, AM, Bitz, C, Christensen, B, Klausen, TW, Vinther, A, Astrup, A
BMJ open. 2018;(2):e019210
Abstract
INTRODUCTION Age-related loss of muscle mass and strength, sarcopaenia, burdens many older adults. The process is accelerated with bed rest, protein intakes below requirements and the catabolic effect of certain illnesses. Thus, acutely ill, hospitalised older adults are particularly vulnerable. Protein supplementation can preserve muscle mass and/or strength and, combining this with resistance exercise training (RT), may have additional benefits. Therefore, this study investigates the effect of protein supplementation as an addition to offering RT among older adults while admitted to the geriatric ward and after discharge. This has not previously been investigated. METHODS AND ANALYSIS In a block-randomised, double-blind, multicentre intervention study, 165 older adults above 70 years, fulfilling the eligibility criteria, will be included consecutively from three medical departments (blocks of n=20, stratified by recruitment site). After inclusion, participants will be randomly allocated (1:1) to receive either ready-to-drink, protein-enriched, milk-based supplements (a total of 27.5 g whey protein/day) or isoenergetic placebo products (<1.5 g protein/day), twice daily as a supplement to their habitual diet. Both groups will be offered a standardised RT programme for lower extremity muscle strength (daily while hospitalised and 4×/week after discharge). The study period starts during their hospital stay and continues 12 weeks after discharge. The primary endpoint is lower extremity muscle strength and function (30 s chair-stand-test). Secondary endpoints include muscle mass, measures of physical function and measures related to cost-effectiveness. ETHICS AND DISSEMINATION Approval is given by the Research Ethic Committee of the Capital Region of Denmark (reference no. H-16018240) and the Danish Data Protection Agency (reference no. HGH-2016-050). There are no expected risks associated with participation, and each participant is expected to benefit from the RT. Results will be published in peer-reviewed international journals and presented at national and international congresses and symposiums. TRIAL REGISTRATION NUMBER NCT02717819 (9 March 2016).
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Variation in the Protein Composition of Human Milk during Extended Lactation: A Narrative Review.
Verd, S, Ginovart, G, Calvo, J, Ponce-Taylor, J, Gaya, A
Nutrients. 2018;(8)
Abstract
The aim of this review is to evaluate changes in protein parameters in the second year postpartum. There is considerable agreement among authors about the declining trend of human milk protein concentrations, but most research on protein content in breast milk focuses on the first year of life and comes from developed countries. Whereas this is the case for exclusive breastfeeding or for breastfeeding into the first year of life, the opposite applies to weaning or extended breastfeeding. This review is predominantly based on observational epidemiological evidence and on comparative research linking breast milk composition with cutting down on breastfeeding. Studies dating back several decades have shown an increase in the proportion of immunoglobulins, lactoferrin, and serum albumin during weaning. According to the limited data available, it seems likely that the regulation of milk protein composition during involution can be ascribed to alterations in tight junctions. In studies on humans and other mammalian species, offspring suckle more from mothers that produce more dilute milk and the increase in milk protein concentration is positively correlated to a decrease in suckling frequency during weaning. High milk protein contents were first reported in nonindustrial communities where breastfeeding is sustained the longest, but recent papers from urbanized communities have taken credit for rediscovering the increase in protein content of human milk that becomes evident with prolonged breastfeeding. This review presents an overview of the changes in breast milk protein parameters in the second year postpartum to enable milk banks' practitioners to make informed nutritional decisions on preterm infants.
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Maternal intake of milk and milk proteins is positively associated with birth weight: A prospective observational cohort study.
Mukhopadhyay, A, Dwarkanath, P, Bhanji, S, Devi, S, Thomas, A, Kurpad, AV, Thomas, T
Clinical nutrition ESPEN. 2018;:103-109
Abstract
BACKGROUND A striking number of low birth weight (LBW) Indian babies are born annually. Previous studies have confirmed the positive association between milk intake and birth weight. However, the relations between protein and vitamin B12 from milk and birth weight have not been systematically explored. AIMS We examined the relations between birth weight and maternal intake of milk, protein from milk and vitamin B12 from milk. METHODS This prospective, observational cohort study was conducted in an urban South Indian hospital. The dietary intakes of milk and milk products were assessed using validated food frequency questionnaire and at delivery birth outcomes were measured. The relations between milk products, milk protein, and vitamin B12 from milk with birth weight and gestational weight gain were assessed in 2036 births with first trimester dietary and delivery data. RESULTS Median consumption of milk products in the first trimester was 310 g·day-1 and average birth weight was 2876 g. Birth weight was positively associated with intake of milk products and of % protein from milk products (%milk protein) in the first trimester [β = 86.8, 95% confidence interval (CI): 29.1, 144.6; β = 63.1, 95% CI: 10.8, 115.5; P < 0.001 for both]. Intake of milk products and of %milk protein in the third trimester was positively associated with gestational weight gain (GWG) between the second and third trimester (One-way ANOVA, P < 0.001 and = 0.001, respectively). Neither birth weight nor GWG were associated with %vitamin B12 from milk products. CONCLUSIONS These findings indicate that intake of milk products in the first trimester and especially, protein from milk products is positively associated with birth weight in this South Asian Indian population.
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Post-resistance exercise ingestion of milk protein attenuates plasma TNFα and TNFr1 expression on monocyte subpopulations.
Wells, AJ, Jajtner, AR, Varanoske, AN, Church, DD, Gonzalez, AM, Townsend, JR, Boone, CH, Baker, KM, Beyer, KS, Mangine, GT, et al
Amino acids. 2017;(8):1415-1426
Abstract
Attenuating TNFα/TNFr1 signaling in monocytes has been proposed as a means of mitigating inflammation. The purpose of this study was to examine the effects of a milk protein supplement on TNFα and monocyte TNFr1 expression. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) ingested supplement (SUPP) or placebo (PL) immediately post-exercise in a randomized, cross-over design. Blood samples were obtained at baseline (BL), immediately (IP), 30-min (30P), 1-h (1H), 2-h (2H), and 5-h (5H) post-exercise to assess plasma concentrations of myoglobin; tumor necrosis factor-alpha (TNFα); and expression of tumor necrosis factor receptor 1 (TNFr1) on classical, intermediate, and non-classical monocytes. Magnitude-based inferences were used to provide inferences on the true effects of SUPP compared to PL. Plasma TNFα concentrations were "likely attenuated" (91.6% likelihood effect) from BL to 30P in the SUPP group compared with PL (d = 0.87; mean effect: 2.3 ± 2.4 pg mL-1). TNFr1 expressions on classical (75.9% likelihood effect) and intermediate (93.0% likelihood effect) monocytes were "likely attenuated" from BL to 2H in the SUPP group compared with PL (d = 0.67; mean effect: 510 ± 670 RFU, and d = 1.05; mean effect: 2500 ± 2300 RFU, respectively). TNFr1 expression on non-classical monocytes was "likely attenuated" (77.6% likelihood effect) from BL to 1H in the SUPP group compared with PL (d = 0.69; mean effect: 330 ± 430 RFU). Ingestion of a milk protein supplement immediately post-exercise appears to attenuate both plasma TNFα concentrations and TNFr1 expression on monocyte subpopulations in resistance-trained men.
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Effects of Postexercise Protein Intake on Muscle Mass and Strength During Resistance Training: Is There an Optimal Ratio Between Fast and Slow Proteins?
Fabre, M, Hausswirth, C, Tiollier, E, Molle, O, Louis, J, Durguerian, A, Neveux, N, Bigard, X
International journal of sport nutrition and exercise metabolism. 2017;(5):448-457
Abstract
While effects of the two classes of proteins found in milk (i.e., soluble proteins, including whey, and casein) on muscle protein synthesis have been well investigated after a single bout of resistance exercise (RE), the combined effects of these two proteins on the muscle responses to resistance training (RT) have not yet been investigated. Therefore, the aim of this study was to examine the effects of protein supplementation varying by the ratio between milk soluble proteins (fast-digested protein) and casein (slow-digested protein) on the muscle to a 9-week RT program. In a double-blind protocol, 31 resistance-trained men, were assigned to 3 groups receiving a drink containing 20g of protein comprising either 100% of fast protein (FP(100), n = 10), 50% of fast and 50% of slow proteins (FP(50), n = 11) or 20% of fast protein and 80% of casein (FP(20), n = 10) at the end of training bouts. Body composition (DXA), and maximal strength in dynamic and isometric were analyzed before and after RT. Moreover, blood plasma aminoacidemia kinetic after RE was measured. The results showed a higher leucine bioavailability after ingestion of FP(100) and FP(50) drinks, when compared with FP(20) (p< .05). However, the RT-induced changes in lean body mass (p < .01), dynamic (p < .01), and isometric muscle strength (p < .05) increased similarly in all experimental groups. To conclude, compared with the FP(20) group, the higher rise in plasma amino acids following the ingestion of FP(100) and FP(50) did not lead to higher muscle long-term adaptations.
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Protein ingestion preserves proteasome activity during intense aseptic inflammation and facilitates skeletal muscle recovery in humans.
Draganidis, D, Chondrogianni, N, Chatzinikolaou, A, Terzis, G, Karagounis, LG, Sovatzidis, A, Avloniti, A, Lefaki, M, Protopapa, M, Deli, CK, et al
The British journal of nutrition. 2017;(3):189-200
Abstract
The ubiquitin-proteasome system (UPS) is the main cellular proteolytic system responsible for the degradation of normal and abnormal (e.g. oxidised) proteins. Under catabolic conditions characterised by chronic inflammation, the UPS is activated resulting in proteolysis, muscle wasting and impaired muscle function. Milk proteins provide sulphur-containing amino acid and have been proposed to affect muscle inflammation. However, the response of the UPS to aseptic inflammation and protein supplementation is largely unknown. The aim of this study was to investigate how milk protein supplementation affects UPS activity and skeletal muscle function under conditions of aseptic injury induced by intense, eccentric exercise. In a double-blind, cross-over, repeated measures design, eleven men received either placebo (PLA) or milk protein concentrate (PRO, 4×20 g on exercise day and 20 g/d for the following 8 days), following an acute bout of eccentric exercise (twenty sets of fifteen eccentric contractions at 30°/s) on an isokinetic dynamometer. In each trial, muscle biopsies were obtained from the vastus lateralis muscle at baseline, as well as at 2 and 8 d post exercise, whereas blood samples were collected before exercise and at 6 h, 1 d, 2 d and 8 d post exercise. Muscle strength and soreness were assessed before exercise, 6 h post exercise and then daily for 8 consecutive days. PRO preserved chymotrypsin-like activity and attenuated the decrease of strength, facilitating its recovery. PRO also prevented the increase of NF-κB phosphorylation and HSP70 expression throughout recovery. We conclude that milk PRO supplementation following exercise-induced muscle trauma preserves proteasome activity and attenuates strength decline during the pro-inflammatory phase.
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Lipid-Based Nutrient Supplements During Pregnancy and Lactation Did Not Affect Human Milk Oligosaccharides and Bioactive Proteins in a Randomized Trial.
Jorgensen, JM, Arnold, C, Ashorn, P, Ashorn, U, Chaima, D, Cheung, YB, Davis, JC, Fan, YM, Goonatilleke, E, Kortekangas, E, et al
The Journal of nutrition. 2017;(10):1867-1874
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Abstract
BACKGROUND Human milk oligosaccharides (HMOs) and bioactive proteins are beneficial to infant health. Recent evidence suggests that maternal nutrition may affect the amount of HMOs and proteins in breast milk; however, the effect of nutrient supplementation on HMOs and bioactive proteins has not yet been well studied. OBJECTIVE We aimed to determine whether lipid-based nutrient supplements (LNSs) affect milk bioactive protein and HMO concentrations at 6 mo postpartum in women in rural Malawi. These are secondary outcomes of a previously published randomized controlled trial. METHODS Women were randomly assigned to consume either an iron and folic acid capsule (IFA) daily from ≤20 wk gestation until delivery, followed by placebo daily from delivery to 6 mo postpartum, or a multiple micronutrient (MMN) capsule or LNS daily from ≤20 wk gestation to 6 mo postpartum. Breast milk concentrations of total HMOs, sialylated HMOs, fucosylated HMOs, lactoferrin, lactalbumin, lysozymes, antitrypsin, immunoglobulin A, and osteopontin were analyzed at 6 mo postpartum (n = 647). Between-group differences in concentrations and in proportions of women classified as having low concentrations were tested. RESULTS HMO and bioactive protein concentrations did not differ between groups (P > 0.10 for all comparisons). At 6 mo postpartum, the proportions of women with low HMOs or bioactive proteins were not different between groups except for osteopontin. A lower proportion of women in the IFA group had low osteopontin compared with the LNS group after adjusting for covariates (OR: 0.5; 95% CI: 0.3, 0.9; P = 0.016). CONCLUSION The study findings do not support the hypothesis that supplementation with an LNS or MMN capsule during pregnancy and postpartum would increase HMO or bioactive milk proteins at 6 mo postpartum among Malawian women. This trial was registered at clinicaltrials.gov as NCT01239693.
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Milk-derived bioactive peptides and their health promoting effects: a potential role in atherosclerosis.
Marcone, S, Belton, O, Fitzgerald, DJ
British journal of clinical pharmacology. 2017;(1):152-162
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Abstract
Bioactive peptides derived from milk proteins are food components that, in addition to their nutritional value, retain many biological properties and have therapeutic effects in several health disorders, including cardiovascular disease. Amongst these, atherosclerosis is the underlying cause of heart attack and strokes. It is a progressive dyslipidaemic and inflammatory disease where accumulation of oxidized lipids and inflammatory cells leads to the formation of an atherosclerotic plaque in the vessel wall. Milk-derived bioactive peptides can be released during gastrointestinal digestion, food processing or by enzymatic and bacterial fermentation and are considered to promote diverse beneficial effects such as lipid lowering, antihypertensive, immnomodulating, anti-inflammatory and antithrombotic effects. In this review, an overview of the diverse biological effects of these compounds is given, particularly focusing on their beneficial properties on cardiovascular disease and proposing novel mechanisms of action responsible for their bioactivity. Attempts to prevent cardiovascular diseases target modifications of several risk factors such as high blood pressure, obesity, high blood concentrations of lipids or insulin resistance. Milk-derived bioactive peptides are a source of health-enhancing components and the potential health benefit of these compounds has a growing commercial potential. Consequently, they have been incorporated as ingredients in functional foods, as dietary supplements and as pharmaceuticals to promote health and reduce risk of chronic diseases.