Fatty acid profiles and antioxidants of organic and conventional milk from low- and high-input systems during outdoor period

A randomized control trial to test the effect of pegbovigrastim treatment at dry off on plasma and milk oxylipid profiles during early mammary gland involution and post-parturient period

The early period of mammary gland involution is a critical juncture in the lactation cycle that can have significant effects on milk production and mammary gland health. Pegbovigrastim (PEG) administered 1 wk prior and on the day of parturition can enhance immune function and reduce the incidence of mastitis in the early postpartum period. Oxylipids are potent metabolites of polyunsaturated fatty acids (PUFA) and are important mediators of inflammation. The objective of this study was to evaluate effects of PEG given 1 wk before and at the day of dry-off (D0) on concentrations of oxylipids in plasma and milk from 7 d before D0 to 14 after, as well as the effects during the first 14 d of the subsequent lactation. We hypothesized that both pro- and anti-inflammatory oxylipids would vary based on initiation of mammary gland involution and that pegbovigrastim would affect oxylipid concentration, particularly those related to leukocytes. A complete randomized blocked design was used to enroll cows into either a PEG treatment group (n = 10) or control group (n = 10; CON). Blood samples were collected -7, -2, -1, 0, 1, 2, 4, 7, 14 d relative to dry-off and 5, 10, and 14 d post-calving. Samples were analyzed for PUFA and oxylipids in milk and plasma by ultra-performance mass-spectrometry and liquid chromatography tandem quadrupole mass spectrometry, respectively. Overall, 30 lipid mediators were measured both in milk and plasma. Repeated measures analyses revealed a significant interaction of treatment by time for milk 8-iso-keto-15-prostaglandin E2, prostaglandin F2α, plasma 8,12-iso-prostaglandin FαVI, 11-hydroxyeicosatetraenoic acid, and 12-hydroxyheptadecatienoic acid. The majority of milk PUFA and oxylipids differed significantly during early mammary gland involution and into the early postpartum period. This study demonstrated changes in oxylipids in milk secretions and plasma during early involution and further investigation may illuminate multiple complex processes and reveal targets for optimization of mammary gland involution.

Effects of Production Systems and Seasons on Retail-Goat-Milk Fatty-Acid Composition and Nutritional Indices in Greece

Simple Summary

The consumption of goat milk is constantly increasing. However, there are not many studies on the nutritional profile of retail goat milk. This study examined the effects of production systems (conventional and organic) and seasons (spring, summer, autumn and winter) on the fatty acid composition and nutritional indices related to the healthy fat consumption of fluid goat milk sold in the supermarkets. The production system did not significantly affect milk fatty-acid composition nor its nutritional value, whereas seasonal effects were observed. Overall, retail goat milk had a desirable nutritional value, irrespective of production system and season.

Abstract

An increased consumer interest in goat milk has been registered in recent years due to its health-related benefits. This study aimed to investigate the effects of production systems and seasons on fatty-acid composition and nutritional indices for the healthy fat consumption of retail goat milk. The study lasted one year, and milk samples (n = 160) from 14 brands (10 conventional and 4 organic) were collected on a monthly basis. Organic milk had a marginally lower fat and protein content compared with conventionally produced milk according to the declared chemical composition. The production system did not significantly affect milk fatty-acid composition and its nutritional value, indicating that there were no major differences in the feeding strategies between conventionally and organically raised ewes. Seasonal effects were observed in the fatty-acid profile and the nutritional indices. Lower content of saturated fatty acids (SFAs), hypocholesterolemic/hypercholesterolemic ratio (h/H) and linoleic acid/α-linolenic acid (LA/ALA) ratio values were observed in summer. Retail goat milk had a desirable nutritional value, irrespective of production system and season, due to the following characteristics: low atherogenic index (AI) and LA/ALA ratio values, and high h/H ratio, desirable fatty acid (DFA) values and health-promoting index values. In conclusion, neither production nor season significantly impacted the fatty-acid composition and the fat-consumption nutritional indices of retail goat milk produced in Greece.

Assessing the validity of plasma phospholipid fatty acids as biomarkers of dairy fat intake using data from a randomized controlled intervention trial

BACKGROUND

Plasma phospholipid pentadecanoic acid (C15:0), heptadecanoic acid (C17:0), and trans-palmitoleic acid (trans-C16:1n-7) are correlates of dairy fat intake. However, their relative concentrations may be influenced by other endogenous factors, such as liver fat content, and their validity as biomarkers of dairy fat intake has yet to be established.

OBJECTIVES

We investigated whether liver fat content modifies relations between concentrations of C15:0, C17:0, and trans-C16:1n-7 (alone and in combination with iso-C17:0) and known dairy fat intake in the context of a randomized controlled intervention study. We further examined the proportion of dairy fat intake explained by these fatty acids on their own and when considering liver fat content.

METHODS

We used data from a 12-wk intervention trial in which participants (n = 62) consumed diets limited in dairy (0.3 g/d of dairy fat), rich in low-fat dairy (8.7 g/d of dairy fat), or rich in full-fat dairy (28.5 g/d of dairy fat). We used linear regression models to examine relations between relative fatty acid concentrations and grams per day of dairy fat intake, liver fat percentage, and their interaction.

RESULTS

Only trans-C16:1n-7 in isolation (β: 0.0004 ± 0.0002, P = 0.03) and combined with iso-C17:0 (β: 0.002 ± 0.0005, P < 0.0001) were consistently positively associated with dairy fat intake regardless of liver fat content. Trans-C16:1n-7 combined with iso-C17:0 also explained the greatest proportion of variation (35.4%) in dairy fat intake. C15:0 and C17:0 were not associated with dairy fat intake after adjusting for liver fat and were predicted to be higher in relation to increased dairy fat intake only among individuals with elevated liver fat.

CONCLUSIONS

The potential for liver fat to affect relative plasma phospholipid concentrations of C15:0 and C17:0 raises questions about their validity as biomarkers of dairy fat intake. Of the fatty acid measures tested, trans-C16:1n-7 combined with iso-C17:0, especially with adjustment of liver fat, age, and sex, may provide the most robust estimate of dairy fat consumption.

Review: Quality and authentication of organic animal products in Europe

The 'organic' label guarantees a production process that avoids the use of synthetic fertilisers, pesticides and hormones and minimises the use of veterinary drugs; however, consumers are demanding guarantees regarding food quality. This article reviews the current state of knowledge on the quality of organic animal products, including the authentication of their organic origin. Quality has been considered as an integrative combination of six core attributes: commercial value, and nutritional, sensory, technological, convenience and safety attributes. The comparison of these attributes between organic and conventional animal products shows high heterogeneity due to variability in farming pratices in both organic and conventional systems. To overcome this, we pinpoint the farming practices underlying the differences observed. This enables light to be shed on the consequences of possible trajectories of organic farming, if specifications are relaxed or tightened up on commitments concerning farming practices that impact product quality. Two recent meta-analyses showed better nutritional attributes in organic milk and meat linked to their higher poly-unsaturated fatty acid (PUFA) content, particularly n-3 PUFAs. Regarding safety, we point to a lack of integrated studies quantifying the balance between positive and negative effects. Organic farming reduces the risk of drug residues and antibiotic resistance, but both outdoor rearing and a frequently longer rearing period increase the animals' exposition to environmental contaminants and the risk of their bioaccumulation in milk, eggs, meat and fish flesh. We highlight antagonisms between quality attributes for certain animal products (lamb, pork). In general, attributes are more variable for organic products, which can be explained by lower genetic selection (poultry), lower inputs and/or greater variability in farming conditions. However, the literature does not address the implications of this greater variability for the consumers' acceptability and the necessary adaptation of manufacturing processes. Further research is needed to document the impacts on human nutritional biomarkers and health. Methods used to authenticate organic origin are based on differences in animal diet composition between organic and conventional systems, but their reliability is hampered by the variability in farming practices.

Effect of Farming System (Organic vs. Conventional) and Season on Composition and Fatty Acid Profile of Bovine, Caprine and Ovine Milk and Retail Halloumi Cheese Produced in Cyprus

The present work aimed to evaluate the effect of farming practices and season on the fat and protein content and fatty acid (FA) profile of milk and Halloumi cheese produced in Cyprus. Over a year, raw bulk-tank milk samples from cow, goat, and sheep farms were collected seasonally from all organic (11) and representative conventional (44) dairy farms, whereas Fresh Halloumi cheese samples were collected monthly from retail outlets (48 organic and 48 conventional samples in total). The different farming practices did not affect the milk fat content of ruminants, while protein levels were decreased in organic bovine and caprine milk. Under organic farming practices, milk and cheese contained increased values of total mono-unsaturated FA (MUFA) and poly-unsaturated FA (PUFA), and specific FA, such as oleic, conjugated linoleic, linoleic, and α-linolenic acids. Total saturated FA (SFA) levels were particularly decreased in organic samples and, consequently, the atherogenic indices of milk and cheese were decreased. Season influenced milk and Halloumi cheese FA profile; spring samples had lower SFA and higher PUFA and MUFA concentrations. Overall, the organic farm practices improved the lipid profile of milk and Halloumi cheese, which is more likely attributed to the different feeding strategies applied in organic dairy farms.

The Mode of Grass Supply to Dairy Cows Impacts on Fatty Acid and Antioxidant Profile of Milk

The optimization of milk production includes a rational use of forages, respect for the environment and offers the best quality to consumers. Milk production based on grass and forages produces healthier milk and it is widely spread throughout the Atlantic arc to maximize milk yield per hectare. However, the mode of offering the grass can have a major influence on milk composition. The aim of this study was to evaluate the effect of grass supply mode (grazing, zero-grazing or ensiling) on dairy cows’ performance, with particular reference to fatty acids and fat-soluble antioxidants concentration. A three by three Latin square experiment was performed with 18 dairy cows. Experimental treatments consisted of exclusive feeding with grass silage and zero-grazing, both offered ad libitum indoors, or grazing for 24 h. The results showed that grazing cows had a higher dry matter intake and greater milk yield than cows feeding on grass silage and zero-grazing, as well as higher concentrations of protein, lactose, nonfat-solids and urea in milk than housed cows. Milk fat from grazing cows had a higher proportion of unsaturated fatty acids than from cows feeding on grass silage and zero-grazing, with significant differences in the proportion of vaccenic and rumenic acids. The 18:1 trans-11 to 18:1 trans-10 ratio is proposed as biomarker to identify the milk produced from the management system of grazing cattle. Milk from grazing cows had a greater proportion of lutein than cows eating grass silage, with the zero-grazing system having intermediate values. In conclusion, the mode of grass supply affects fatty acid and antioxidant profiles of milk.

Cow's milk: Composition, nutritional, biological and cardioprotective benefits

Since several years, dairy products have been at the heart of nutritional deba-tes. High-fat dairy products can aggravate dyslipidemia and the consumption of satura-ted, and trans fats is associated with an increased cardiovascular diseases risk. In this re-gard, current dietary guidelines recommend a low fat content, and a significant reduc-tion in trans fatty acid intake. However, recent controversial epidemiological studies show that high-fat dairy products consumption may reduce diabetes, metabolic syndro-me, and the risk of cardiovascular diseases. This dairy paradox has led to a dietary guidelines re-evaluation.

Fatty Acid Content of Retail Cow's Milk in the Northeastern United States-What's in It for the Consumer?

The fatty acid (FA) composition and content of whole milk (3.25% fat) from organic, omega-3 (n-3) FA fortified, and conventional retail brands available in the northeastern U.S. were assessed monthly via gas chromatography. Among the retail labels, organic milk stood out as it contained a distinct and more healthful FA profile, consistently comprising a higher content of unique bioactive FAs (short-chain FAs, odd- and branched-chain FAs, vaccenic acid, and conjugated linoleic acids) per serving, particularly during the warm season. The total content of saturated FAs did not differ by retail label. While organic and n-3 fortified milk contained a similar content of total n-3 FAs, the proportion of individual n-3 FAs differed significantly (organic milk: 18:3 n-3; n-3 fortified milk: 20:6 n-3) as a result of the production system and process, respectively. Overall, per serving, the FA profile of organic milk may provide added nutritional and health benefits.

Effect of raw milk consumption on perceived health, mood and immune functioning among US adults with a poor and normal health: A retrospective questionnaire based study

INTRODUCTION

Raw milk consumption is controversially discussed, and people are looking for raw milk due to expected positive health impacts. The purpose of this consumer survey was to evaluate health conditions prior to and after consuming of raw milk (RM).

METHODS

An on-line survey was distributed in Spring 2018 among existing consumers of raw milk. One-Item health score, 1-item immunity score, immune status (ISQ), mood, bowel and skin conditions were rated retrospectively based on validated questionnaires. Data from 327 participants (age 54 years) were included, of which 156 (48%) were allocated to the poor health group after they reported being immune depressed or suffering from a chronic disease. Others were allocated to the normal health group. Milk consumption pattern before and after changing of the milk diet were recorded. All health outcomes were evaluated according a linear mixed model in SPSS.

RESULTS

Health, perceived immunity, bowel and mood scores increased post RM consumption with around 35% in the poor health group (P < 0.001), and around 9% in the normal health group (P < 0.001). Bowel and mood scores were overall lower in women than in men. Outcomes were independent of the origin of raw farm milk.

CONCLUSIONS

This consumer survey suggests that positive health and mood changes are associated with the consumption of raw milk. Effects were strongest in people with a self-reported poor health status as well as in women.

Milk processing increases the allergenicity of cow's milk-Preclinical evidence supported by a human proof-of-concept provocation pilot

Background

Several studies demonstrated the adverse effect of milk processing on the allergy‐protective capacity of raw cow's milk. Whether milk processing also affects the allergenicity of raw milk is hardly investigated.

Objective

To assess the allergenicity of raw (unprocessed) and processed cow's milk in a murine model for food allergy as well as in cow's milk allergic children.

Methods

C3H/HeOuJ mice were either sensitized to whole milk (raw cow's milk, heated raw cow's milk or shop milk [store‐bought milk]) and challenged with cow's milk protein or they were sensitized and challenged to whey proteins (native or heated). Acute allergic symptoms, mast cell degranulation, allergen‐specific IgE levels and cytokine concentrations were determined upon challenge. Cow's milk allergic children were tested in an oral provocation pilot with organic raw and conventional shop milk.

Results

Mice sensitized to raw milk showed fewer acute allergic symptoms upon intradermal challenge than mice sensitized to processed milk. The acute allergic skin response was low (103 ± 8.5 µm vs 195 ± 17.7 µm for heated raw milk, P < 0.0001 and vs 149 ± 13.6 µm for shop milk, P = 0.0316), and there were no anaphylactic shock symptoms and no anaphylactic shock‐induced drop in body temperature. Moreover, allergen‐specific IgE levels and Th2 cytokines were significantly lower in raw milk sensitized mice. Interestingly, the reduced sensitizing capacity was preserved in the isolated native whey protein fraction of raw milk. Besides, native whey protein challenge diminished allergic symptoms in mice sensitized to heated whey proteins. In an oral provocation pilot, cow's milk allergic children tolerated raw milk up to 50 mL, whereas they only tolerated 8.6 ± 5.3 mL shop milk (P = 0.0078).

Conclusion and Clinical Relevance

This study demonstrates that raw (unprocessed) cow's milk and native whey proteins have a lower allergenicity than their processed counterparts. The preclinical evidence in combination with the human proof‐of‐concept provocation pilot provides evidence that milk processing negatively influences the allergenicity of milk.

Patterns of Biodynamic Milk Fatty Acid Composition Explained by A Climate-Geographical Approach

BACKGROUND

Biodynamic dairy production is based on a land-related animal production without the additional input of N-fertilizers. The concentrate level per cow is low. This affects the yield level of animals and product quality outcomes.

METHODS

We examined the milk fatty acid (FA) composition of European biodynamic farms in relation to the ecological region of production and the farm's climate conditions. Climate data were derived from existing maps describing ecological vegetation zones within Europe. Additionally, biodynamic shop milk was compared to conventional shop milk, based on a regional comparison.

RESULTS

The largest differences in the FA composition were between biodynamic summer and winter milk. We found increased proportions of conjugated linoleic acid (CLA), alpha-linolenic acid (ALA-n3), monounsaturated FA (MUFA), and polyunsaturated FA (PUFA) in the summer milk. A principal component analysis expressed the structure that was present in the biodynamic farm milk samples, based on clusters of a single FA within four components. The components could be correlated with the season of production, the amount of precipitation, the elevation of the farm above sea level, and the length of the grazing season. Biodynamic shop milk in the summer had a lower n6/n3 PUFA ratio compared to the conventional shop milk in all regions of production. Mean values were 1.37 and 1.89, respectively.

CONCLUSIONS

The differentiation of biodynamic milk FA composition is consistent with the existing knowledge about the effects of fresh grass, fodder, and ratio composition on the milk's FA composition. Based on the n6/n3 PUFA ratio, the average biodynamic dairy cow had a high intake (>82%) of fresh grass and conserved roughage (hay and grass silage), especially in the summer.

In vitro and in vivo antioxidant potential of milks, yoghurts, fermented milks and cheeses: a narrative review of evidence

The antioxidant potential (AP) is an important nutritional property of foods, as increased oxidative stress is involved in most diet-related chronic diseases. In dairy products, the protein fraction contains antioxidant activity, especially casein. Other antioxidants include: antioxidant enzymes; lactoferrin; conjugated linoleic acid; coenzyme Q10; vitamins C, E, A and D3; equol; uric acid; carotenoids; and mineral activators of antioxidant enzymes. The AP of dairy products has been extensively studied in vitro, with few studies in animals and human subjects. Available in vivo studies greatly differ in their design and objectives. Overall, on a 100 g fresh weight-basis, AP of dairy products is close to that of grain-based foods and vegetable or fruit juices. Among dairy products, cheeses present the highest AP due to their higher protein content. AP of milk increases during digestion by up to 2·5 times because of released antioxidant peptides. AP of casein is linked to specific amino acids, whereas β-lactoglobulin thiol groups play a major role in the AP of whey. Thermal treatments such as ultra-high temperature processing have no clear effect on the AP of milk. Raw fat-rich milks have higher AP than less fat-rich milk, because of lipophilic antioxidants. Probiotic yoghurts and fermented milks have higher AP than conventional yoghurt and milk because proteolysis by probiotics releases antioxidant peptides. Among the probiotics, Lactobacillus casei/acidophilus leads to the highest AP. The data are insufficient for cheese, but fermentation-based changes appear to make a positive impact on AP. In conclusion, AP might participate in the reported dairy product-protective effects against some chronic diseases.

Antioxidant status and gut microbiota change in an aging mouse model as influenced by exopolysaccharide produced by Lactobacillus plantarum YW11 isolated from Tibetan kefir

This study investigated the effect of exopolysaccharide (EPS) produced by Lactobacillus plantarum YW11 on the oxidative status and gut microbiota in an aging mouse model induced with d-galactose. The in vitro assay of the antioxidant activity of the EPS showed concentration-dependent (0.25-3.0 mg/mL) activities. At 3.0 mg/mL, the EPS reached the highest scavenging activities with half maximal inhibitory concentration values against hydroxyl radicals at 75.10% and 1.22 mg/mL, superoxide anion at 62.71% and 1.54 mg/mL, 2, 2-diphenyl-1-picrylhydrazyl at 35.11% and 0.63 mg/mL, and the maximal chelating rate on ferrous ion and the half-maximal chelating concentration of the EPS at 41.09% and 1.07 mg/mL, respectively. High doses of EPS (50 mg/kg per day) effectively relieved the oxidative stress in the aging mice with increased levels of glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity in mice serum by 21.55, 33.14, 61.09, and 38.18%, respectively, and decreased malondialdehyde level from 11.69 to 5.89 mmol/mL compared with those in the untreated aging mice model. The analysis of pyrosequencing sequence data from the gut microbiota revealed that the EPS could recover the microbiota diversity and phylotypes decreased or eliminated by the d-galactose treatment. The EPS could selectively decrease the abundance of Flexispira (37.5 fold), and increase the abundance of Blautia (36.5 fold) and Butyricicoccus (9.5 fold), which correspondingly decreased the content of nitrogen oxides to 9.87% and increased the content of short-chain fatty acids by 2.23 fold, thereby improving the oxidative and health conditions of the host intestinal tract. Further correlation analysis of core-microbiota variation induced by different treatments showed a strong correlation with oxidative phenotypes [catalase, goodness of prediction (Q²) = 0.49; total antioxidant capacity, Q² = 0.45; nitrogen oxides, Q² = 0.67; short-chain fatty acids, Q² = 0.55]. The fermented milk with L. plantarum YW11 containing EPS also showed favorable antioxidant and gut microbiota regulating activities. The present finding provided new insights into the functional mechanism of probiotics bioactivity.

Milk fat biomarkers and cardiometabolic disease

PURPOSE OF REVIEW

Dairy is a major food group with potential impact on cardiometabolic health. Self-reported dairy intake has limitations that can partly be avoided by using biomarkers. This review aims to summarize the evidence of odd-chain saturated fatty acids (OCFAs), that is, pentadecanoic acid (C15 : 0) and heptadecanoic acid (17 : 0), as biomarkers of dairy fat intake. In addition, the associations of OCFA biomarkers with cardiometabolic disease will be overviewed.

RECENT FINDINGS

Adipose tissue 15 : 0 is the preferred biomarker but also circulating 15 : 0, and to a weaker extent 17 : 0, reflects both habitual and changes in dairy intake. Whereas results from studies assessing cardiovascular outcomes are inconsistent, OCFA biomarkers are overall associated with lower diabetes risk. Residual confounding should however be considered until interventional data and mechanisms are available. Although OCFA biomarkers mainly reflect dairy fat intake, recently proposed endogenous synthesis and metabolism do motivate further research.

SUMMARY

Taking into account the study population diet and limitations of OCFA biomarkers, both adipose and circulating levels of 15 : 0, in particular, are useful for estimating total dairy fat intake. OCFA biomarkers are overall not linked to cardiovascular disease risk, but a possible beneficial role of dairy foods in diabetes prevention warrant further study.

Development of a QuEChERS-Based Stable-Isotope Dilution LC-MS/MS Method To Quantitate Ferulic Acid and Its Main Microbial and Hepatic Metabolites in Milk

Forage plants of the Poaceae family are grown as pasturage or used for the production of hay, straw, corn stover, etc. Although ferulic acid contents of grasses are generally high, the amount of ingested ferulic acid differs depending on the type of forage, resulting in varying contents of ferulic acid and its microbial and hepatic metabolites in milk. Concentrations and patterns of these metabolites may be used as markers to track different forages in livestock feeding. Therefore, we developed a stable isotope dilution assay to quantitate ferulic acid, 12 ferulic acid-based metabolites, p-coumaric acid, and cinnamic acid in milk. Because most analytes were not commercially available as stable isotope labeled standard compounds, they were synthesized as ¹³C- or deuterium-labeled standard compounds. A modification of the QuEChERS method, a Quick, Easy, Cheap, Effective, Rugged, and Safe approach usually applied to analyze pesticides in plant-based products, was used to extract the phenolic acids from milk. Determination was carried out by LC-ESI-MS/MS in scheduled multiple reaction monitoring modus. By using three different milk samples, the applicability of the validated approach was demonstrated.

Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids

The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid.

Free Maillard Reaction Products in Milk Reflect Nutritional Intake of Glycated Proteins and Can Be Used to Distinguish "Organic" and "Conventionally" Produced Milk

Using LC-MS/MS and isotopically labeled standard substances, quantitation of free Maillard reaction products (MRPs), namely, N(ε)-(carboxymethyl)lysine (CML), 5-(hydroxymethyl)-1H-pyrrole-2-carbaldehyde (pyrraline, PYR), N(δ)-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H), and N(ε)-fructosyllysine (FL), in bovine milk was achieved. Considerable variations in the amounts of the individual MRPs were found, most likely as a consequence of the nutritional uptake of glycated proteins. When comparing commercial milk samples labeled as originating from "organic" or "conventional" farming, respectively, significant differences in the content of free PYR (organic milk, 20-300 pmol/mL; conventional milk, 400-1000 pmol/mL) were observed. An analysis of feed samples indicated that rapeseed and sugar beet are the main sources for MRPs in conventional farming. Furthermore, milk of different dairy animals (cow, buffalo, donkey, goat, ewe, mare, camel) as well as for the first time human milk was analyzed for free MRPs. The distribution of their concentrations, with FL and PYR as the most abundant in human milk and with a high individual variability, also points to a nutritional influence. As the components of concentrated feed do not belong to the natural food sources of ruminants and equidae, free MRPs in milk might serve as indicators for an adequate animal feeding in near-natural farming and can be suitable parameters to distinguish between an "organic" and "conventional" production method of milk.

Effects of a dietary intervention with conjugated linoleic acid on immunological and metabolic parameters in children and adolescents with allergic asthma--a placebo-controlled pilot trial

Background

Circumstantial evidence suggests that conjugated linoleic acid (CLA) beneficially modulates immune function in allergic subjects. C9,t11-CLA, naturally occurring in ruminant fats, is suggested to be the effective isomer. In contrast, for the t10,c12-CLA isomer, which is naturally found only in traces but usually constitutes a relevant part in commercial CLA mixtures, adverse effects have been reported. Aim of this study was to assess putative immunomodulatory effects of highly enriched c9,t11-CLA in allergic subjects. To our best knowledge, our study is the first in that a CLA preparation was used for such purpose which was free of t10,c12-CLA.

Design

Twenty-nine asthmatic children and adolescents (age 6–18 y) with diagnosed allergic sensitization against grass pollen, house dust mite, or cat hair/epithelia consumed daily a portion of yoghurt containing either 3 g CLA (75 % c9,t11-CLA, 87 % purity) or placebo (safflower oil) over a period of 12 weeks. At study start and end, lung function parameters, specific IgE, in vitro allergen-induced cytokine production in peripheral blood mononuclear cells (PBMC), plasma ECP, urinary 8-oxodG as marker of oxidation, fatty acid profiles of erythrocytes, and routine haematological parameters were determined. Prior to blood samplings, 3-days dietary records were requested. Throughout the study, the participants documented daily their peak expiratory flow and kept protocol about their allergy symptoms and usage of demand medication.

Results

In contrast to the CLA group, PBMC-produced IFN-γ and IL-4 increased significantly and by trend, respectively, in the placebo group. Moreover, plasma ECP tended to increase in the placebo group. In the pollen subgroup, FEV1 improved upon both CLA and placebo oil supplementation. In both intervention groups, the n-6/n-3 PUFA ratio in red blood cells decreased, mainly due to an increase in n-3 PUFA. Moreover, 8-oxodG excretion increased in both groups. No changes occurred regarding specific IgE concentrations, allergy symptoms, and volume parameters.

Conclusion

Our results indicate that CLA modestly dampens the inflammatory response on the cellular level. A clinically relevant amelioration of the symptoms could not be proved in atopic manifest patients.

Trial registration

NCT01026506.