Lipid and volatile profiles of Finnish oat batches of pure cultivars: Effect of storage on the volatile formation

Recent data showing the compositional variation and storage behavior among different oat batches for the purpose of food remains limited. Lipids of twenty oat flour samples of pure cultivars grown in Finland during 2019 were extracted and fractionated into neutral and polar-rich lipids. Flour was stored for nine months, and profiles of volatiles and tocols were analyzed to reveal oxidative stability. The lipid content was 5.9-8.9 g per 100 g of flour [DW] and consisted of 78.7 ± 2.5 % neutral and 21.3 ± 2.5 % polar lipids. Palmitic (16 %), oleic (36 %), and linoleic (39 %) acids were the most abundant fatty acids. Neutral lipids had more oleic and less linoleic and palmitic acids than polar lipids. The fresh samples correlated with tocols, pentanal, 2-pentylfuran, 2-heptanone, nonanal, 2-butanone, and heptanal, while stored samples were associated with 3-octen-2-one, 2-octenal, hexanal, and octanal. Lipid composition and oxidative stability are essential factors for selecting oat batches for food applications.

Chemoenzymatic Synthesis of ABC-Type Enantiostructured Triacylglycerols by the Use of the p-Methoxybenzyl Protective Group

This report demonstrates the first asymmetric synthesis of enantiopure structured triacylglycerols (TAGs) of the ABC type presenting three non-identical fatty acids, two of which are unsaturated. The unsaturated fatty acids included monounsaturated oleic acid (C18:1 n-9) and polyunsaturated linoleic acid (C18:2 n-6). This was accomplished by a six-step chemoenzymatic approach starting from (R)- and (S)-solketals. The highly regioselective immobilized Candida antarctica lipase (CAL-B) played a crucial role in the regiocontrol of the synthesis. The synthesis also benefited from the use of the p-methoxybenzyl (PMB) ether protective group, which enabled the incorporation of two different unsaturated fatty acids into the glycerol skeleton. The total of six such TAGs were prepared, four constituting the unsaturated fatty acids in the sn-1 and sn-2 positions, with a saturated fatty acid in the remaining sn-3 position of the glycerol backbone. In the two remaining TAGs, the different unsaturated fatty acids accommodated the sn-1 and sn-3 end positions, with the saturated fatty acid present in the sn-2 position. Enantiopure TAGs are urgently demanded as standards for the enantiospecific analysis of intact TAGs in fats and oils.

Influence of Dietary Triacylglycerol Structure on the Accumulation of Docosahexaenoic Acid [22:6(n-3)] in Organs in a Short-Term Feeding Trial with Mildly Omega-3 Deficient Rats

SCOPE

To study the effect of positional distribution of docosahexaenoic acid (DHA) in dietary triacylglycerols (TAG) on the tissue fatty acid content and composition of mildly (n-3) deficient rats.

METHODS AND RESULTS

In a 5-day feeding trial, mildly (n-3) deficient rats received 360 mg daily structured TAGs: sn-22:6(n-3)-18:0-18:0, sn-18:0-18:0-22:6(n-3), sn-18:0-22:6(n-3)-18:0, or tristearin. A fifth group receives standard (n-3) adequate feed AIN-93G from birth till the end of the trial. The DHA-fed groups show significantly higher DHA levels in the liver and visceral fat compared to the tristearin or normal feed groups showing that the dose and the short feeding period of DHA were sufficient to restore the DHA content in the organs of (n-3) deficient rats. Feeding sn-1 DHA resulted in higher levels of DHA in the liver TAG compared to sn-3 DHA feeding, although the difference did not reach statistical significance.

CONCLUSION

These findings indicated a possible difference in the tissue accumulation and/or metabolic fate of DHA from the sn-1 and sn-3 positions of TAG.

Metabolomic Investigation of Brain and Liver in Rats Fed Docosahexaenoic Acid in Regio- and Enantiopure Triacylglycerols

SCOPE

N-3 polyunsaturated fatty acids (n-3 PUFAs) play important roles in cognitive functions. However, there is a lack of knowledge on the metabolic impact of regio- and stereo-specific positioning of n-3 PUFAs in dietary triacylglycerols.

METHODS AND RESULTS

Rats in a state of mild n-3 PUFA deficiency are fed daily with 360 mg triacylglycerols containing DHA (docosahexaenoic acid) at sn (stereospecific numbering)-1, 2, or 3 positions and 18:0 at remaining positions, or an equal amount of tristearin for 5 days. Groups fed with n-3 deficient diet and normal n-3 adequate diet are included as controls. The metabolic profiles of the brain and liver are studied using NMR (nuclear magnetic resonance)-based metabolomics. Several metabolites of significance in membrane integrity and neurotransmission, and glutamate, in particular, are significantly lower in the brain of the groups fed with sn-1 and sn-3 DHA compared to the sn-2 DHA group. Further, the tristearin and DHA groups show a lower lactate level compared to the groups fed on normal or n-3 deficient diet, suggesting a prominent role of C18:0 in regulating energy metabolism.

CONCLUSION

This study sheds light on the impact of stereospecific positioning of DHA in triacylglycerols and the role of dietary stearic acid on metabolism in the brain and liver.

Metabolic fate of DHA from regio- and stereospecific positions of triacylglycerols in a long-term feeding trial in rats

This study investigated the impact of regio- and stereospecific position of docosahexaenoic acid (DHA) in dietary triacylglycerols (TAGs) on the fatty acid composition of tissues and organs in rats. Four-week feeding with TAGs containing DHA in sn-1, 2, or 3 position and palmitic acid in the remaining positions at a daily dosage of 500 mg TAG/kg body weight significantly increased the DHA content in all organs and tissues in rats, except in the brain, where the change in DHA level was not statistically significant. The group fed sn-1 DHA showed a significantly higher content of DHA in the plasma TAG than the group fed sn-3 DHA. The sn-3 DHA group had higher levels of DHA in the visceral fat compared to the sn-1, sn-2, as well as all other groups. This is the first study showing that DHA from sn-1 and sn-3 positions of dietary TAGs have differential accumulation in tissues. The new findings improved the current knowledge on the significance of TAG isomeric structure for the bioavailability and metabolic fate of DHA.

Antioxidative Effect of Dihydrosphingosine (d18:0) and α-Tocopherol on Tridocosahexaenoin (DHA-TAG)

Sphingoid bases have shown promise as effective antioxidants in fish oils together with α-tocopherol, and the effect has been attributed to products resulting from amino-carbonyl reactions (lipation products) between the sphingoid base amine group and carbonyl compounds from lipid oxidation. In this study, the synergistic effect of dihydrosphingosine (d18:0) and α-tocopherol was studied on pure docosahexaenoic acid (DHA) triacylglycerols with an omics-type liquid- and gas-chromatographic mass spectrometric approach to verify the synergistic effect, to get a comprehensive view on the effect of d18:0 on the oxidation pattern, and to identify the lipation products. The results confirmed that d18:0 rapidly reacts further in the presence of lipid oxidation products and α-tocopherol. α-Tocopherol and d18:0 showed an improved antioxidative effect after 12 h of oxidation, indicating the formation of antioxidants through carbonyl-amine reactions. Imines formed from the carbonyls and d18:0 could be tentatively identified.

Correction: Kulkarni et al. Tissue-Specific Content of Polyunsaturated Fatty Acids in (n-3) Deficiency State of Rats. Foods 2021, 11, 208

The authors would like to make the following corrections to a published paper [...].

Lipid Structure Influences the Digestion and Oxidation Behavior of Docosahexaenoic and Eicosapentaenoic Acids in the Simulated Digestion System

Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for human health but prone to oxidation. While esterification location is known to influence the stability of omega-3 in triacylglycerols (TAGs) in oxidation trials, their oxidative behavior in the gastrointestinal tract is unknown. Synthesized ABA- and AAB-type TAGs containing DHA and EPA were submitted to static in vitro digestion for the first time. Tridocosahexaenoin and DHA as ethyl esters were similarly digested. Digesta were analyzed by gas chromatography, liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. Besides the formation of di- and monoacylglycerols, degradation of hydroperoxides was detected in ABA- and AAB-type TAGs, whereas oxygenated species increased in tridocosahexaenoin. Ethyl esters were mainly unaffected. EPA was expectedly less susceptible to oxidation prior to and during the digestion process, particularly in sn-2. These results are relevant for the production of tailored omega-3 structures to be used as supplements or ingredients.

In Vitro Bioactivities of Food Grade Extracts from Yarrow (Achillea millefolium L.) and Stinging Nettle (Urtica dioica L.) Leaves

Yarrow (Achillea millefolium L., AM) and nettle (Urtica dioica L., UD) are bioactive plants used commercially in functional food and supplement applications and traditionally to alleviate gastric disorders. In this work, the effects of food-grade optimized extracts of Finnish early-season AM and UD were tested on bacterial growth including potential beneficial and foodborne pathogens, as well as murine norovirus (MNV). The anti-inflammatory properties of the extracts were also tested in vitro by NF-κB reporter cells. The food-grade extraction was optimized with the response surface modelling in terms of total carotenoid, chlorophyll, and phenolic compounds contents and antioxidant capacities. The optimal food-grade extraction parameters were a 1-h extraction in 70% ethanol at 45 °C for AM, and at 49 °C for UD. There were no significant effects on the beneficial bacteria (Lacticaseibacillus and Bifidobacterium strains), and the extracts were more effective against gram-positive than gram-negative foodborne bacteria and potential pathogens. Listeria innocua was the most susceptible strain in the optimized extracts with a growth rate of 0.059 ± 0.004 for AM and 0.067 ± 0.006 for UD, p < 0.05 compared to control. The optimized extracts showed a logarithmic growth reduction of 0.67 compared to MNV. The hydroethanolic extracts were cytotoxic to both cell lines, whereas aqueous AM and UD extracts induced and reduced TLR4 signalling in a reporter cell line, respectively. The results provide novel food-grade extraction parameters and support the bioactive effects of AM and UD in functional food applications, but more research is needed to elucidate the precise biological activity in vivo for gastric health.

Breast Milk Lipidome Is Associated With Maternal Diet and Infants' Growth

Objectives

The fatty acid (FA) composition of breast milk is a relevant aspect related to the development of the lactating infant. The present study aimed at exploring correlations between dietary intake of macro- and micronutrients with the FA profile in breast milk, and the possible implication for infants' growth.

Study Design

Breast milk samples from a cohort of lactating women were collected 7–15 days postpartum. The FA profiles in triacylglycerol (TAG) and phospholipid (PL)-rich fractions were analyzed by gas chromatography. Diet was registered during the third trimester of pregnancy by means of a food frequency questionnaire (FFQ). In addition, anthropometric measurements of infants were collected from gestation and up to 12 months postpartum.

Results

The FA profile in breast milk was characterized by a median of 37.4, 41.3 and 16.8% of saturated, monounsaturated, and polyunsaturated FAs, respectively. From the dietary components, zinc, iron, and B group vitamins were correlated positively with the proportion of total n-3 FAs in TAG and C20:5 n-3 in PL. Lycopene, vitamin E, zinc, and vitamin B2 showed a similar correlation with total polyunsaturated fatty acid (PUFA), total n-6 FAs, C20:4 n-6, and C18:2 n-6 in TAG. Regarding food groups, nuts showed the strongest association with several PUFA both in TAG and PL, while the vegetable group was also positively associated with C18:3 n-3. Furthermore, the concentration of linolenic acid (C18:3 n-3) and palmitic acid (C16:0) were positively associated with increased length for age (LFA) and weight for age (WFA) at 12 months compared with birth [ΔLFA −0.16 (−0.85, 0.37); ΔWFA −0.26 (−0.77, 0.21)].

Conclusions

Mothers' intake of nuts, dietary sources of zinc, iron, and B group vitamins were identified as potential predictors of a high-unsaturated FA profile in breast milk. In addition, linolenic and palmitic acids in breast milk were positively associated with infants' growth in the first year of life.

Similarity Index for the Fat Fraction between Breast Milk and Infant Formulas

The similarity of the fat fraction in infant formulas rich in either bovine milk fat (MF) or vegetable oil (VO) to breast milk was evaluated by analyzing their lipid composition. Milk fat-rich formulas were highly similar (average similarity index 0.68) to breast milk compared to the VO-rich formulas (average similarity index 0.56). The highest difference in the indices was found in the contents of cholesterol (0.66 vs 0.28 in MF- and VO-rich formulas, respectively, on average) and polar lipids (0.84 vs 0.53), the positional distribution of fatty acids in the sn-2 position of triacylglycerols (0.53 vs 0.28), and fatty acid composition (0.72 vs 0.54). The VO-based formulas were superior in similarity in n - 6 PUFA. Thus, the addition of bovine MF fractions is an effective way to increase the similarity between the lipid composition of infant formulas and human milk.

Tissue-Specific Content of Polyunsaturated Fatty Acids in (n-3) Deficiency State of Rats

The dietary intake of fatty acids (FAs) affects the composition and distribution of FAs in the body. Here, a first-generation (n-3)-deficiency study was conducted by keeping young (age 21 ± 2 days) Sprague-Dawley male rats on a peanut-oil-based diet for 33 days after weaning in order to compare the effect of mild (n-3)-deficiency on the lipid composition of different organs and feces. Soybean-oil-based diet was used as a control. The plasma FA levels corresponded to FAs levels in the organs. Lower docosahexaenoic acid (DHA) content was detected in the plasma, brain, testis, visceral fat, heart, and lungs of the (n-3)-deficient group, whereas the DHA content of the eye and feces did not differ between the experimental groups. The DHA content of the brains of the (n-3)-deficient group was 86% of the DHA content of the brains of the (n-3)-adequate group. The DHA level of the organs was affected in the order of visceral fat > liver triacylglycerols > lung > heart > liver phospholipids > testis > eye > brain, with brain being least affected. The low levels of (n-3) FAs in the liver, brain, eye, heart, and lung were offset by an increase in the (n-6) FAs, mainly arachidonic acid. These results indicate that, in rats, adequate maternal nutrition during pregnancy and weaning does not provide enough (n-3) FAs for 33 days of an (n-3)-deficient diet. Results of this study can be used also to evaluate the conditions needed to reach mild (n-3) deficiency in the first generation of rats and to evaluate the feasibility to collect data from a variety of organs or only selected ones.

Acylated anthocyanins: A review on their bioavailability and effects on postprandial carbohydrate metabolism and inflammation

Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.

Predicting the Properties of Industrially Produced Oat Flours by the Characteristics of Native Oat Grains or Non-Heat-Treated Groats

The aim of this study was to determine whether the properties of the native oat grain or non-heat-treated groats (laboratory-scale dehulling) can be used to predict the quality of the industrially produced oat flour produced from heat-treated groats. Quality properties such as the color, hectoliter weight, thousand seed weight and hull content of Finnish native grains (n = 30) were determined. Furthermore, the relationship between the properties of the native grains and the chemical composition of the raw oat materials before and after the milling process were studied. A significant relationship (p < 0.01) was observed between the thousand seed weight of the native oat groats and the chemical composition of the industrially produced oat flour. Furthermore, the protein content of the native grains measured by NIT correlated with the chemical composition of the oat flours. These results suggest that the properties of oat flour produced on an industrial scale, including heat treatment, could be predicted based on the properties of native oat grains.

Phenolic Metabolites in the Urine and Plasma of Healthy Men After Acute Intake of Purple Potato Extract Rich in Methoxysubstituted Monoacylated Anthocyanins

SCOPE

Structurally stable acylated anthocyanins have potential in various food applications but the effects of acylation and methoxysubstitution on anthocyanin metabolism are poorly understood. This is the first study thoroughly investigating phenolic metabolites, their time-wise changes, and pharmacokinetics following an acute intake of methoxysubstituted monoacylated anthocyanins.

METHODS AND RESULTS

Healthy male volunteers (n = 17) consumed a yellow potato meal with and without purple potato extract rich in acylated anthocyanins (152 mg) and hydroxycinnamic acid conjugates (140 mg). Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is used for identification and quantification of metabolites from serially collected urine and plasma. While the parent anthocyanins are not detected, 28 phenolic metabolites from urine and 14 from plasma are quantified, including hydroxybenzoic and hydroxycinnamic acids and protocatechuic acid sulfates and glucuronides; three (catechol, gallic acid-4-O-glucuronide, and 2-methoxybenzoic acid) are detected for the first time after anthocyanin-rich food. Urinary hippuric acid is the most abundant with an increase of 139 µM mM^-1 creatinine after the treatment. A large additional set of tentatively identified phenolic metabolites are detected. Late urinary peak time values suggest colonic degradation.

CONCLUSION

Acylated anthocyanins are more bioavailable than earlier reported after extensive degradation in human and/or colonial metabolism to phenolic metabolites, which may be further conjugated and demethylated.

Human milk metabolome is associated with symptoms of maternal psychological distress and milk cortisol

The composition of human milk is subject to considerable variation, but the effects of maternal stress are largely unknown. We studied differences in human milk metabolome between Finnish mothers (n = 120, secretors) with symptoms of prenatal symptoms of psychological distress and milk cortisol concentrations. Human milk samples acquired at 2.5 months postpartum were analyzed using targeted ¹H NMR metabolomics. Self-reported scores for depression (EPDS), overall anxiety (SCL-90), and pregnancy-related anxiety (PRAQ) were used to evaluate psychological distress. Prenatal psychological distress was positively associated with concentrations of short-chain fatty acids, caprate, and hypoxanthine (q < 0.0012). Milk cortisol was positively associated with lactate concentration (q < 0.05). Changes in the human milk metabolome were shown to be associated with maternal psychological distress and concentration of milk cortisol in a dissimilarly, suggesting alterations in bacterial and energy metabolism of the mother, respectively.

Strategy for stereospecific characterization of natural triacylglycerols using multidimensional chromatography and mass spectrometry

Stereoisomeric determination of individual triacylglycerols (TAGs) in natural oils and fats is a challenge due to similar physicochemical properties of TAGs with different fatty acid combinations. In this study, we present a strategy to resolve the enantiomeric composition of nutritionally important TAGs in sea buckthorn (Hippophaë rhamnoides) as an example food matrix. The targeted strategy combines 1) fatty acid profiling with GC, 2) separation of TAGs with RP-HPLC, 3) stereospecific separation with chiral-phase HPLC and 4) structural characterization with MS. Three major asymmetric diacid- and triacid-TAG species were analyzed in sea buckthorn pulp oil. Off-line coupling of RP-HPLC and chiral-phase HPLC allowed separation of several TAG regioisomers and enantiomers, which could not be resolved using one-dimensional techniques. Enantiomeric ratios were determined and specific structural analysis of separated TAGs was performed using direct inlet ammonia negative ion chemical ionization method. Of the TAG 16:0/16:1/16:1 palmitic acid (C16:0) was located predominantly in a primary position and the enantiomeric ratio of TAG sn-16:1-16:1-16:0 to sn-16:0-16:1-16:1 was 70.5/29.5. Among the TAGs 16:0/16:0/18:2 and 16:0/16:0/16:1, only ca 5% had C16:0 in the sn-2 position, thus, ca 95% were symmetric sn-16:0-18:2-16:0 and sn-16:0-16:1-16:0. The enantiomeric ratio of triacid-TAGs containing C16:0 and two unsaturated fatty acids (palmitoleic C16:1, oleic C18:1 or linoleic acids C18:2) could not be resolved due to lack of commercial enantiopure reference compounds. However, it became clear that the targeted strategy presented offer unique and convenient method to study the enantiomeric structure of individual TAGs.

Effect of oat β-glucan of different molecular weights on fecal bile acids, urine metabolites and pressure in the digestive tract - A human cross over trial

While the development of oat products often requires altered molecular weight (MW) of β-glucan, the resulting health implications are currently unclear. This 3-leg crossover trial (n = 14) investigated the effects of the consumption of oat bran with High, Medium and Low MW β-glucan (average > 1000, 524 and 82 kDa respectively) with 3 consequent meals on oat-derived phenolic compounds in urine (UHPLC-MS/MS), bile acids in feces (UHPLC-QTOF), gastrointestinal conditions (ingestible capsule), and perceived gut well-being. Urine excretion of ferulic acid was higher (p < 0.001, p < 0.001), and the fecal excretion of deoxycholic (p < 0.03, p < 0.02) and chenodeoxycholic (p < 0.06, p < 0.02) acids lower after consumption of Low MW β-glucan compared with both Medium and High MW β-glucan. Duodenal pressure was higher after consumption of High MW β-glucan compared to Medium (p < 0.041) and Low (p < 0.022) MW β-glucan. The MW of β-glucan did not affect gut well-being, but the perceptions between females and males differed.

Sensory Characteristics Contributing to Pleasantness of Oat Product Concepts by Finnish and Chinese Consumers

Oats are increasingly popular among consumers and the food industry. While data exist on sensory characteristics of oats as such, previous studies focusing on the pleasantness of oats, and especially investigations of a wide range of oat products by European and Asian consumers, are scarce. An online questionnaire was organized in Finland (n = 381; 83.7% Finnish) focusing on the liking and familiarity of oat products, followed by sensory tests in Finland (n = 65 and n = 73) and China (n = 103) using the Check-All-That-Apply method and hedonic ratings. A questionnaire revealed that the Finnish consumers rated the pleasantness and familiarity of several oat product categories, such as breads and porridges, higher compared to participants of other ethnicities. Sensory tests showed both similarities, e.g., porridges were described as “natural”, “healthy” and “oat-like”, and differences between countries, e.g., sweet biscuits, were described as “crispy” and “hard” by Finnish consumers and “strange” and “musty” by Chinese consumers. Sweet products were unanimously preferred. The ethnicity had an important role affecting the rating of pleasantness and familiarity of oat product categories, whereas food neophobia and health interest status also had an influence. The proved healthiness of oats was a crucial factor affecting the choices of consumers and their acceptance in both countries.

Effects of Anthocyanin Extracts from Bilberry (Vaccinium myrtillus L.) and Purple Potato (Solanum tuberosum L. var. 'Synkeä Sakari') on the Plasma Metabolomic Profile of Zucker Diabetic Fatty Rats

This study compared the effects of the nonacylated and acylated anthocyanin-rich extracts on plasma metabolic profiles of Zucker diabetic fatty rats. The rats were fed with the nonacylated anthocyanin extract from bilberries (NAAB) or the acylated anthocyanin extract from purple potatoes (AAPP) at daily doses of 25 and 50 mg/kg body weight for 8 weeks. ¹H NMR metabolomics was used to study the changes in plasma metabolites. A reduced fasting plasma glucose level was seen in all anthocyanin-fed groups, especially in the groups fed with NAAB. Both NAAB and AAPP decreased the levels of branched-chain amino acids and improved lipid profiles. AAPP increased the glutamine/glutamate ratio and decreased the levels of glycerol and metabolites involved in glycolysis, suggesting improved insulin sensitivity, gluconeogenesis, and glycolysis. AAPP decreased the hepatic TBC1D1 and G6PC messenger RNA level, suggesting regulation of gluconeogenesis and lipogenesis. This study indicated that AAPP and NAAB affected the plasma metabolic profile of diabetic rats differently.

Diet, Perceived Intestinal Well-Being and Compositions of Fecal Microbiota and Short Chain Fatty Acids in Oat-Using Subjects with Celiac Disease or Gluten Sensitivity

A gluten-free diet may result in high fat and low fiber intake and thus lead to unbalanced microbiota. This study characterized fecal microbiota profiles by 16S MiSeq sequencing among oat-using healthy adult subjects (n = 14) or adult subjects with celiac disease (CeD) (n = 19) or non-celiac gluten sensitivity (NCGS) (n = 10). Selected microbial metabolites, self-reported 4d food diaries and perceived gut symptoms were compared. Subjects with NCGS experienced the highest amount of gut symptoms and received more energy from fat and less from carbohydrates than healthy and CeD subjects. Oat consumption resulted in reaching the lower limit of the recommended fiber intake. Frequent consumption of gluten-free pure oats did not result in microbiota dysbiosis in subjects with CeD or NCGS. Thus, the high number of gut symptoms in NCGS subjects was not linked to the microbiota. The proportion of fecal acetate was higher in healthy when compared to NCGS subjects, which may be linked to a higher abundance of Bifidobacterium in the control group compared to NCGS and CeD subjects. Propionate, butyrate and ammonia production and β-glucuronidase activity were comparable among the study groups. The results suggest that pure oats have great potential as the basis of a gluten-free diet and warrant further studies in minor microbiota disorders.

Interactions between cortisol and lipids in human milk

Background

Human breast milk is one of the key early postnatal biological exposures for the developing child. It includes bioactive compounds, such as cortisol and fatty acids, which may be linked via the mother’s lipid metabolism.

Methods

This study investigated the associations between cortisol and lipids in human milk at the infant age of 2.5 months. Human milk cortisol concentrations were measured using luminescence immunoassay, and two groups of milks (n = 50 each) were formed based on either high (> 10 nmol/L) or low (< 3 nmol/L) cortisol levels. Lipids, as fatty acid content and composition of neutral (triacylglycerol-rich) and polar (phospholipid-rich) lipids, were measured with gas chromatography. The samples originated from the FinnBrain Birth Cohort Study.

Results

The percentage of phospholipid-rich lipids of total lipids was 33.08% ± 1.33%. In triacylglycerol-rich lipids, high cortisol level in milk was associated with higher lauric (12:0, mass % and mg/mL), myristic (14:0, mass % and mg/mL), eicosenoic (20:1n − 9, mass %), docosenoic (22:1n − 9, mass %, and mg/mL) acids, and to lower palmitic acid (16:0, mass %) compared with low cortisol levels in milk. In phospholipid-rich lipids, high cortisol level was associated with higher myristic (14:0, mass %) and docosenoic (22:1n − 9, mass %) acids. After adjusting for pre-pregnancy BMI and sampling time by linear regression, the milk cortisol remained a significant predictor for lauric and myristic acids in triacylglycerol-rich lipids, and myristic and docosenoic acid in phospholipid-rich lipids (β = 0.23 to 0.38 and p < 0.05 for each).

Conclusions

This study revealed certain significant associations between milk cortisol and the fatty acid composition of human milk, indicating that cortisol might be one of the factors affecting the origin of the lipids in human milk.

Bioavailability of docosahexaenoic acid 22:6(n-3) from enantiopure triacylglycerols and their regioisomeric counterpart in rats

Lack of synthetic enantiospecific triacylglycerols (TAGs) has hindered our understanding of the impact of TAG structure on the absorption and metabolic fate of fatty acids (FAs). In a five-day feeding trial with mildly (n-3) deficient rats, the bioavailability of docosahexaenoic acid [22:6(n-3), DHA] and stearic acid (18:0) from the two different enantiomers of TAG: sn-22:6(n-3)-18:0-18:0 and sn-18:0-18:0-22:6(n-3), and their regioisomeric TAG: sn-18:0-22:6(n-3)-18:0 was compared. Less secretion of fecal DHA was detected from the sn-2 position compared with the sn-1 and sn-3 positions, but no difference was found in DHA content of the fasting plasma or in the weight of the body or organs. 18:0 was lost to feces mainly as cleaved from the primary positions but also as glycerol-bound. The 5-day intervention in rats was long enough to modify the fatty acid profile of plasma phospholipids.

Mycobiome Profiles in Breast Milk from Healthy Women Depend on Mode of Delivery, Geographic Location, and Interaction with Bacteria

Recent studies report the presence of fungal species in breast milk of healthy mothers, suggesting a potential role in infant mycobiome development. In the present work, we aimed to determine whether the healthy human breast milk mycobiota is influenced by geographical location and mode of delivery, as well as to investigate its interaction with bacterial profiles in the same samples. A total of 80 mature breast milk samples from 4 different countries were analyzed by Illumina sequencing of the internal transcribed spacer 1 (ITS1) region, joining the 18S and 5.8S regions of the fungal rRNA region. Basidiomycota and Ascomycota were found to be the dominant phyla, with Malassezia and Davidiella being the most prevalent genera across countries. A core formed by Malassezia, Davidiella, Sistotrema, and Penicillium was shared in the milk samples from the different origins, although specific shifts in mycobiome composition were associated with geographic location and delivery mode. The presence of fungi in the breast milk samples was further confirmed by culture and isolate characterization, and fungal loads were estimated by quantitative PCR (qPCR) targeting the fungal ITS1 region. Cooccurrence network analysis of bacteria and fungi showed complex interactions that were influenced by geographical location, mode of delivery, maternal age, and pregestational body mass index. The presence of a breast milk mycobiome was confirmed in all samples analyzed, regardless of the geographic origin.IMPORTANCE During recent years, human breast milk has been documented as a potential source of bacteria for the newborn. Recently, we have reported the presence of fungi in breast milk from healthy mothers. It is well known that environmental and perinatal factors can affect milk bacteria; however, the impact on milk fungi is still unknown. The current report describes fungal communities (mycobiota) in breast milk samples across different geographic locations and the influence of the mode of delivery. We also provide novel insights on bacterium-fungus interactions, taking into account environmental and perinatal factors. We identified a core of four genera shared across locations, consisting of Malassezia, Davidiella, Sistotrema, and Penicillium, which have been reported to be present in the infant gut. Our data confirm the presence of fungi in breast milk across continents and support the potential role of breast milk in the initial seeding of fungal species in the infant gut.

Low-FODMAP vs regular rye bread in irritable bowel syndrome: Randomized SmartPill® study

AIM

To compare the effects of regular vs low-FODMAP rye bread on irritable bowel syndrome (IBS) symptoms and to study gastrointestinal conditions with SmartPill^®.

METHODS

Our aim was to evaluate if rye bread low in FODMAPs would cause reduced hydrogen excretion, lower intraluminal pressure, higher colonic pH, different transit times, and fewer IBS symptoms than regular rye bread. The study was a randomized, double-blind, controlled cross-over meal study. Female IBS patients (n = 7) ate study breads at three consecutive meals during one day. The diet was similar for both study periods except for the FODMAP content of the bread consumed during the study day. Intraluminal pH, transit time, and pressure were measured by SmartPill, an indigestible motility capsule.

RESULTS

Hydrogen excretion (a marker of colonic fermentation) expressed as area under the curve (AUC)_{(0-630 min)} was [median (range)] 6300 (1785-10800) ppm∙min for low-FODMAP rye bread and 10 635 (4215-13080) ppm∙min for regular bread (P = 0.028). Mean scores of gastrointestinal symptoms showed no statistically significant differences but suggested less flatulence after low-FODMAP bread consumption (P = 0.063). Intraluminal pressure correlated significantly with total symptom score after regular rye bread (ρ = 0.786, P = 0.036) and nearly significantly after low-FODMAP bread consumption (ρ = 0.75, P = 0.052). We found no differences in pH, pressure, or transit times between the breads. Gastric residence of SmartPill was slower than expected. SmartPill left the stomach in less than 5 h only during one measurement (out of 14 measurements in total) and therefore did not follow on par with the rye bread bolus.

CONCLUSION

Low-FODMAP rye bread reduced colonic fermentation vs regular rye bread. No difference was found in median values of intraluminal conditions of the gastrointestinal tract.

Effects of Insect Herbivory on Bilberry Production and Removal of Berries by Frugivores

The evolutionary purpose of a fleshy fruit is to attract seed dispersers and get the seeds dispersed by frugivorous animals. For this reason, fruits should be highly rewarding to these mutualists. However, insect herbivory can alter plant reproductive success e.g. by decreasing fruit yield or affecting the attractiveness of the fruits to mutualistic seed dispersers. Under natural conditions, we tested the effects of experimental larval-defoliation on berry ripening and consumption of a non-cultivated dwarf shrub, the bilberry (Vaccinium myrtillus L.), which produces animal-dispersed berries with high sugar and anthocyanin concentration. Bilberry ramets with high fruit yield were most likely to have their berries foraged, indicating that frugivores made foraging choices based on the abundance of berries. Moreover, the probability for berries being foraged was the lowest for non-defoliated ramets that grew adjacent to larval-defoliated ramets, even though larval-defoliation did not affect the biochemical composition (total concentrations of anthocyanins, sugars and organic acids) or the probability of ripening of berries. We hypothesise that the lower probability for berries being foraged in these ramets may be a consequence of rhizome- or volatile-mediated communication between ramets, resulting in a priming effect of the herbivore defence and lower attractiveness of the non-defoliated ramets.

Breast Milk Polyamines and Microbiota Interactions: Impact of Mode of Delivery and Geographical Location

Background/Aims: The aim of the present study was to identify and quantify the polyamine levels in human milk obtained from different countries and through different modes of delivery, and to investigate their association with breast milk microbes. Methods: Mature breast milk samples were obtained from 78 healthy mothers after 1 month of lactation from 4 different geographical locations: Finland, Spain (Europe); South Africa (Africa); and China (Asia). Polyamines were determined using HPLC after dansyl derivatization and milk microbiota was obtained by 16S rRNA gene sequencing. Results: The mean values of polyamines in breast milk were 70.0, 424.2, and 610.0 nmol/dL for putrescine, spermidine and spermine, respectively, and 1,170.9 nmol/dL of total polyamines. The levels of putrescine were significantly higher in Spain (p < 0.05) and spermidine levels were significantly higher in Finland (p < 0.05) compared with other countries. Cesarean delivery had an impact on polyamine levels and it was related to an increase in the putrescine concentration being significant in Spanish samples (p < 0.01). Furthermore, putrescine levels were correlated positively with Gammaproteobacteria (r = 0.46, p < 0.001), especially with Pseudomonas fragi (r = 0.40, p < 0.001). Conclusions: The results demonstrate significant effect of geographical variations in human milk polyamine concentrations, being correlated with human milk microbiota composition. These differences may have an impact on infant development during lactation.

Distinct Patterns in Human Milk Microbiota and Fatty Acid Profiles Across Specific Geographic Locations

Breast feeding results in long term health benefits in the prevention of communicable and non-communicable diseases at both individual and population levels. Geographical location directly impacts the composition of breast milk including microbiota and lipids. The aim of this study was to investigate the influence of geographical location, i.e., Europe (Spain and Finland), Africa (South Africa), and Asia (China), on breast milk microbiota and lipid composition in samples obtained from healthy mothers after the 1 month of lactation. Altogether, 80 women (20 from each country) participated in the study, with equal number of women who delivered by vaginal or cesarean section from each country. Lipid composition particularly that of polyunsaturated fatty acids differed between the countries, with the highest amount of n-6 PUFA (25.6%) observed in the milk of Chinese women. Milk microbiota composition also differed significantly between the countries (p = 0.002). Among vaginally delivered women, Spanish women had highest amount of Bacteroidetes (mean relative abundance of 3.75) whereas Chinese women had highest amount of Actinobacteria (mean relative abundance 5.7). Women who had had a cesarean section had higher amount of Proteobacteria as observed in the milk of the Spanish and South African women. Interestingly, the Spanish and South African women had significantly higher bacterial genes mapped to lipid, amino acid and carbohydrate metabolism (p < 0.05). Association of the lipid profile with the microbiota revealed that monounsaturated fatty acids (MUFA) were negatively associated with Proteobacteria (r = -0.43, p < 0.05), while Lactobacillus genus was associated with MUFA (r = -0.23, p = 0.04). These findings reveal that the milk microbiota and lipid composition exhibit differences based on geographical locations in addition to the differences observed due to the mode of delivery.

Comparison of the postprandial effects of purple-fleshed and yellow-fleshed potatoes in healthy males with chemical characterization of the potato meals

The aim of the current study was to characterize the anthocyanin content and composition of a purple potato landrace cultivar (Solanum tuberosum 'Synkeä Sakari') and to compare the postprandial effects of purple-fleshed potatoes, yellow-fleshed potatoes and bilberries in potato starch on postprandial glycemia and insulinemia in healthy males. The purple potato meal caused smaller insulinemia than the yellow potato meal (iAUC 120 min 1347 and 2226, respectively, p = 0.012 and iAUC 240 min 1448 and 2403, p = 0.007) or the bilberry meal (iAUC 120 min 1920, p = 0.027). The purple potato meal caused a smaller plasma glucose at 40 min postprandially compared with the yellow potato meal (p = 0.044). The results of this study suggest that anthocyanin-containing purple-fleshed potatoes influence the postprandial insulinemia positively. Since potatoes are the world's largest non-grain commodity, replacing yellow-fleshed potatoes with purple-fleshed potatoes as staple food could have large potential in maintaining public health.

Triacylglycerol biosynthesis in developing Ribes nigrum and Ribes rubrum seeds from gene expression to oil composition

Oils with sufficient contents of fatty acids, which can be metabolized into precursors of anti-inflammatory eicosanoids, have potential health effects. Ribes sp. seed oil is rich in α-linolenic, γ-linolenic and stearidonic acids belonging to this fatty acid group. Only a few previous studies exist on Ribes sp. gene expression. We followed the seed oil biosynthesis of four Ribes nigrum and two Ribes rubrum cultivars at different developmental stages over 2 years in Southern and Northern Finland with a 686 km latitudinal difference. The species and the developmental stage were the most important factors causing differences in gene expression levels and oil composition. Differences between cultivars were detected in some cases, but year and location had only small effects. However, expression of the gene encoding Δ(9)-desaturase in R. nigrum was affected by location. Triacylglycerol biosynthesis in Ribes sp. was distinctly buffered and typically followed a certain path, regardless of growth environment.

Comparison of the bioavailability of docosapentaenoic acid (DPA, 22:5n-3) and eicosapentaenoic acid (EPA, 20:5n-3) in the rat

Based on the results from a human study which showed significantly reduced incorporation of DPA compared with EPA into chylomicrons, this study was designed to test if dietary DPA was significantly less absorbed than EPA. Male Sprague Dawley rats were randomly assigned to three groups of six, and were fed a semi-synthetic high fat diet (23.5% fat) for 9 days. The test omega 3 fatty acids (EPA and DPA, 250mg/animal/day, free fatty acid form) or olive oil (250mg/animal/day) were added to the high fat diet on days 5, 6 and 7. Dietary EPA and DPA appeared in the faeces on days 6, 7 and 8, with the total amount of DPA excreted being 4.6-fold greater than that of EPA. The total amount of faecal fat did not differ significantly between the groups. At the conclusion of the study (day 9), it was found that liver DPA, EPA and total n-3 LC-PUFA levels were significantly increased by both DPA and EPA feeding compared with the olive oil fed control group. In the heart, DPA feeding increased the DPA content and both DPA and EPA feeding increased the total n-3 LC-PUFA levels. This study showed that DPA and EPA, both provided in free form, are metabolised differently, despite being chemically similar.

Tandem mass spectrometric analysis of human milk triacylglycerols from normal weight and overweight mothers on different diets

The composition and structures of TAGs in the human milk from mothers with different food choices and prepregnancy body mass index were determined with two tandem mass spectrometric methods (negative APCI-MS/MS and positive UHPLC/ESI-MS/MS) at the infant's age of three months. The normal weight mothers with recommended food choices had more 18:3n-3 and less 18:0 in their milk than normal weight mothers with non-recommended food choices. A significant difference between the normal weight mothers on the non-recommended food choices and the other groups was seen in acyl carbon number: number of double bond (ACN:DB)-groups 54:6, 54:5, 54:3 and 54:2. In ACN:DB 52:7 and 52:6 the two recommended food choices-groups differed significantly from the two non-recommended food choices-groups. The regioisomerism of TAGs varied little despite differences in mother's weight and diet with sn-18:1-16:0-18:1 as the most prevalent regioisomer in the milk (13.8±2.7%). The results of this study highlight the importance of structure specific human milk substitutes and the careful selection of the MS/MS methods for analysis of mixtures of several isobaric TAGs.

Postprandial metabolism of docosapentaenoic acid (DPA, 22:5n-3) and eicosapentaenoic acid (EPA, 20:5n-3) in humans

The study of the metabolism of docosapentaenoic acid (DPA, 22:5n-3) in humans has been limited by the unavailability of pure DPA and the fact that DPA is found in combination with eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) in natural products. In this double blind cross over study, pure DPA and EPA were incorporated in meals served to healthy female volunteers. Mass spectrometric methods were used to study the chylomicron lipidomics. Plasma chylomicronemia was significantly reduced after the meal containing DPA compared with the meal containing EPA or olive oil only. Both EPA and DPA were incorporated into chylomicron TAGs, while there was less incorporation into chylomicron phospholipids. Lipidomic analysis of the chylomicron TAGs revealed the dynamic nature of chylomicron TAGs. The main TAG species that EPA and DPA were incorporated into were EPA/18:1/18:1, DPA/18:1/16:0 and DPA/18:1/18:1. There was very limited conversion of DPA and EPA to DHA and there were no increases in EPA levels during the 5h postprandial period after the DPA meal. In conclusion, EPA and DPA showed different metabolic fates, and DPA hindered the digestion, ingestion or incorporation into chylomicrons of the olive oil present in the meal.

Lipidomic profiling of chylomicron triacylglycerols in response to high fat meals

Using lipidomic methodologies the impact that meal lipid composition and metabolic syndrome (MetS) exerts on the postprandial chylomicron triacylglycerol (TAG) response was examined. Males (9 control; 11 MetS) participated in a randomised crossover trial ingesting two high fat breakfast meals composed of either dairy-based foods or vegetable oil-based foods. The postprandial lipidomic molecular composition of the TAG in the chylomicron-rich (CM) fraction was analysed with tandem mass spectrometry coupled with liquid chromatography to profile CM TAG species and targeted TAG regioisomers. Postprandial CM TAG concentrations were significantly lower after the dairy-based foods compared with the vegetable oil-based foods for both control and MetS subjects. The CM TAG response to the ingested meals involved both significant and differential depletion of TAG species containing shorter- and medium-chain fatty acids (FA) and enrichment of TAG molecular species containing C16 and C18 saturated, monounsaturated and diunsaturated FA. Furthermore, there were significant changes in the TAG species between the food TAG and CM TAG and between the 3- and 5-h postprandial samples for the CM TAG regioisomers. Unexpectedly, the postprandial CM TAG concentration and CM TAG lipidomic responses did not differ between the control and MetS subjects. Lipidomic analysing of CM TAG molecular species revealed dynamic changes in the molecular species of CM TAG during the postprandial phase suggesting either preferential CM TAG species formation and/or clearance.

The fiber and/or polyphenols present in lingonberries null the glycemic effect of the sugars present in the berries when consumed together with added glucose in healthy human volunteers

This study was undertaken on the broad hypothesis that lingonberry (Vaccinium vitis-idaea L.) has potential to reduce postprandial glycemic and lipemic response. More specifically, 2 postprandial crossover studies with healthy normal-weight male subjects were conducted to study the influence of commercial lingonberry powder on postprandial glycemia and lipemia. The test meals contained fat-free yoghurt with either glucose (50 g) or triacylglycerols (35 g) with or without (control) the lingonberry powder. The lingonberry powder provided the meals with a known amount of fiber and a known amount and composition of sugars, and it was a rich source of polyphenols. Postprandial glucose, insulin, and triacylglycerol responses were analyzed. There were no significant differences in the postprandial glucose concentration between the meals in the glycemia trial despite the fact that the lingonberry meal contained more glucose and fructose. When the meal did not contain added sugar but, instead, added triacylglycerol, no glycemia or lipemia-lowering effect was detected. On the contrary, there were indications of higher glycemic and insulinemic effect after the lingonberry meal. The results of this study indicate that the fibers and/or polyphenols present in lingonberries null the glycemic effect of the sugars present in the berries when consumed together with added glucose. By contrast, the lingonberry powder did not affect the postprandial lipemic response.

Black currant seed oil and fish oil supplements differ in their effects on fatty acid profiles of plasma lipids, and concentrations of serum total and lipoprotein lipids, plasma glucose and insulin

European diets provide a suboptimal intake of eicosapentaenoic (20:5n3) and docosahexaenoic (22:6n3) acids, which are derived mainly from fish oils. The present study indicates that black currant seed oil, which contains 14.5% alpha-linolenic (18:3n3), 12.6% gamma-linolenic (18:3n6), 47.5% linoleic (18:2n6) and 2.7% stearidonic (18:4n3) acids, could potentially serve as alternative to fish oil as a n3 fatty acid source. Fifteen healthy females participated in a randomized, double-blind, crossover study including two 4-week periods with either 3 g/day of black currant seed oil or 2.8 g/day of fish oil separated by a 4-week washout period. The results show that black currant seed oil supplementation increased the proportion of 18:3n6 in triacylglycerols (TAG) and cholesteryl esters (CE), and that of dihomo-gamma-linolenic (20:3n6) in TAGs, CEs and glycerophospholipids (GPL) (P<.05). Proportion of 18:3n6 was higher (P<.05) after black currant seed oil than after fish oil in TAGs and CEs, and that of 20:3n6 in TAGs, CEs and GPLs. Black currant seed oil supplementation caused only minor changes in the proportions of 20:5n3 or 22:6n3. Serum levels of LDL cholesterol were lower (P<.05) after black currant seed oil compared to fish oil. Plasma glucose concentration decreased during the fish oil supplementation (P<.05).