Cholesterol-lowering effects of oat β-glucan

Dietary Fibre as a Unifying Remedy for the Whole Spectrum of Obesity-Associated Cardiovascular Risk

Obesity is a pandemic carrying the heavy burden of multiple and serious co-morbidities including metabolic syndrome, type 2 diabetes and cardiovascular diseases. The pathophysiological processes leading to the accumulation of body fat slowly evolve to fat accumulation in other body compartments than subcutaneous tissue. This abnormal fat deposition determines insulin resistance which in turn causes blood glucose and lipid metabolism derangement, non-alcoholic fatty liver disease, hypertension, and metabolic syndrome. All these conditions contribute to increase the cardiovascular risk of obese people. Several randomized clinical trials demonstrated that moderate weight loss (5⁻10%) in obese patients improves obesity-related metabolic risk factors and coexisting disorders. Therefore, nutritional strategies able to facilitate weight management, and in the meantime positively influence obesity-associated cardiovascular risk factors, should be implemented. To this aim, a suitable option could be dietary fibres that may also act independently of weight loss. The present narrative review summarizes the current evidence about the effects of dietary fibres on weight management in obese people. Moreover, all of the different cardiovascular risk factors are individually considered and evidence on cardiovascular outcomes is summarized. We also describe the plausible mechanisms by which different dietary fibres could modulate cardio-metabolic risk factors. Overall, despite both epidemiological and intervention studies on weight loss that show statistically significant but negligible clinical effects, dietary fibres seem to have a beneficial impact on main pathophysiological pathways involved in cardiovascular risk (i.e., insulin resistance, renin-angiotensin, and sympathetic nervous systems). Although the evidence is not conclusive, this suggests that fibre would be a suitable option to counteract obesity-related cardio-metabolic diseases also independently of weight loss. However, evidence is not consistent for the different risk factors, with clear beneficial effects shown on blood glucose metabolism and Low Density Lipoprotein (LDL) cholesterol while there is fewer, and less consistent data shown on plasma triglyceride and blood pressure. Ascribing the beneficial effect of some foods (i.e., fruits and vegetables) solely to their fibre content requires more investigation on the pathophysiological role of other dietary components, such as polyphenols.

β-glucan Salecan Improves Exercise Performance and Displays Anti-Fatigue Effects through Regulating Energy Metabolism and Oxidative Stress in Mice

Fatigue induced by prolonged exercise not only leads to the decrease of exercise capacity, but also might be the cause of many diseases. In consideration of the side effects of pharmacological drugs, dietary supplements seem to be a better choice to ameliorate exercise-induced fatigue. The present study aimed to investigate the anti-fatigue effect of Salecan, a novel water-soluble β-glucan, during exercise and explore the underlying mechanisms. Male Institute of Cancer Research (ICR) mice were divided into five groups, including the Rest group and the other four Swim-groups treated with Salecan at 0, 25, 50, and 100 mg/kg/day for four weeks. Salecan treatment markedly increased the exhaustive swimming time of mice in the forced swimming test. Exercise fatigue and injury-related biochemical biomarkers including lactate, blood urea nitrogen (BUN), creatinine kinase (CK), alanine transaminase (ALT), and aspartate transaminase (AST) were ameliorated by Salecan. Salecan reversed the decreased serum glucose levels and glycogen contents caused by exercise. In addition, Salecan improved oxidative stress induced by exercise through regulating Nrf2/HO–1/Trx signaling pathway. Thus, the beneficial effects of Salecan against fatigue may be due to its positive effects on energy metabolism and antioxidation defence. Our results suggest that Salecan could be a novel potential candidate for anti-fatigue dietary supplements.

Molecular Mechanism by which Prominent Human Gut Bacteroidetes Utilize Mixed-Linkage Beta-Glucans, Major Health-Promoting Cereal Polysaccharides

Microbial utilization of complex polysaccharides is a major driving force in shaping the composition of the human gut microbiota. There is a growing appreciation that finely tuned polysaccharide utilization loci enable ubiquitous gut Bacteroidetes to thrive on the plethora of complex polysaccharides that constitute "dietary fiber." Mixed-linkage β(1,3)/β(1,4)-glucans (MLGs) are a key family of plant cell wall polysaccharides with recognized health benefits but whose mechanism of utilization has remained unclear. Here, we provide molecular insight into the function of an archetypal MLG utilization locus (MLGUL) through a combination of biochemistry, enzymology, structural biology, and microbiology. Comparative genomics coupled with growth studies demonstrated further that syntenic MLGULs serve as genetic markers for MLG catabolism across commensal gut bacteria. In turn, we surveyed human gut metagenomes to reveal that MLGULs are ubiquitous in human populations globally, which underscores the importance of gut microbial metabolism of MLG as a common cereal polysaccharide.

Aluminum hydroxide colloid vaccine encapsulated in yeast shells with enhanced humoral and cellular immune responses

Aluminum salt (Alum) is one of the most important immune adjuvants approved for use in humans, however it is not suitable for vaccination against various chronic infectious diseases and cancers for not being able to induce cell-mediated (Th1) immunity. Here, we encapsulated an Alum colloid inside β-glucan particles (GPs), which are a type of natural particles derived from the yeast glucan shells, to prepare hybrid GP-Alum (GP-Al) adjuvant particles with a very uniform size of 2-4 μm. These hybrid particles can be used to load antigen proteins through a simple mixing procedure, and can be highly specifically targeted to antigen-presenting cells (APCs) and strongly activate dendritic cells (DCs) maturation and cytokine secretion. In an animal model, they elicit a strong Th1-biased immune response and extremely high antibody titer, and cause marked prophylactic and therapeutic effects against tumors. As Alum has been proven to be a safe adjuvant to induce strong humoral responses and β-glucans are safe for human use, this very uniform hybrid Alum particulate system could have important application as a vaccine carrier to stimulate humoral and cellular immune responses at the same time.

Processing of oat: the impact on oat's cholesterol lowering effect

Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day-1) play a role in cholesterol reduction; and (3) unrefined β-glucan-rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient.

Antiobesity Effect of Exopolysaccharides Isolated from Kefir Grains

Physiological properties of water-soluble exopolysaccharides (EPS) and residues after EPS removal (Res) from the probiotic kefir were determined in high-fat (HF) diet-fed C57BL/6J mice. EPS solutions showed rheological properties and lower viscosity compared to those of β-glucan (BG). EPS significantly suppressed the adipogenesis of 3T3-L1 preadipocytes in a dose-dependent manner. Mice were fed HF diets containing 5% EPS, 5% BG, 8% Res, or 5% microcrystalline cellulose (control) for 4 weeks. Compared with the control, EPS supplementation significantly reduced HF diet-induced body weight gain, adipose tissue weight, and plasma very-low-density lipoprotein cholesterol concentration (P < 0.05). Res and BG significantly reduced body weight gain; however, reduction in adipose tissue weight was not statistically significant, suggesting that the antiobesity effect of EPS occurs due to viscosity and an additional factor. EPS supplementation significantly enhanced abundance of Akkermansia spp. in feces. These data indicate that EPS shows significant antiobesity effects possibly via intestinal microbiota alterations.

The impact of oat structure and β-glucan on in vitro lipid digestion

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The structure of oat tissue is an important factor for determining its influence on (in vitro) lipid digestion.

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β-glucan release from oat cell walls during digestion was not complete.

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Processing of oats affects the rate and extent of lipolysis.

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Viscosity is not the only factor affecting lipolysis.

Oat β-glucan has been shown to play a positive role in influencing lipid and cholesterol metabolism. However, the mechanisms behind these beneficial effects are not fully understood.

The purpose of the current work was to investigate some of the possible mechanisms behind the cholesterol lowering effect of oat β-glucan, and how processing of oat modulates lipolysis. β-Glucan release, and the rate and extent of lipolysis measured in the presence of different sources of oat β-glucan, were investigated during gastrointestinal digestion.

Only a fraction of the original β-glucan content was released during digestion. Oat flakes and flour appeared to have a more significant effect on lipolysis than purified β-glucan.

These findings show that the positive action of β-glucan is likely to involve complex processes and interactions with the food matrix. This work also highlights the importance of considering the structure and physicochemical properties of foods, and not just the nutrient content.

Identification and functional analysis of new peroxygenases in oat

Two new peroxygenases for the biosynthesis of epoxy fatty acids in oat were identified and functionally analyzed by heterologous expression along with rationally designed site-directed mutagenesis. Oat (Avena sativa L.) contains a large family of peroxygenases, a group of heme-containing monooxygenases catalyzing hydroperoxide-dependent epoxidation of unsaturated fatty acids. Here, we report identification and functional analysis of two new peroxygenases AsPXG2 and AsPXG3 from oat. The open reading frame (ORF) of AsPXG2 contains 702 bps encoding a polypeptide of 233 amino acids, while the ORF of AsPXG3 is 627 bps coding for 208 amino acids. Both AsPXG2 and AsPXG3 comprise a single transmembrane domain, conserved histidines for heme binding and a conserved EF-hand motif for calcium binding, but they only share about 50% amino acid sequence identity with each other. When expressed in Escherichia coli and Pichia pastoris, AsPXG3 showed high epoxidation activity, while AsPXG2 exhibited no activity in E. coli and low activity in P. pastoris. AsPXG3 could effectively epoxidize both mono- and polyunsaturated fatty acids with linolenic acid being the most preferred substrate. Site-directed mutagenesis was employed to investigate the structure-function relationship of oat peroxygenase on 12 conserved residues of AsPXG3. Replacement of two conserved histidines, the ligands to the prosthetic heme group of the peroxygenase, by alanine resulted in complete loss of activity. Substitution of three conserved residues surrounding the two histidines resulted in reduction of the enzymatic activity by more than 80%. These results imply that these conserved residues might be located in or near the catalytic pocket, where the two histidine residues coordinate the heme group and the surrounding residues define the shape and size of the pocket for interaction with the heme as well as two substrates.

Effect of Oral Pre-Meal Administration of Betaglucans on Glycaemic Control and Variability in Subjects with Type 1 Diabetes

We conducted a double-blind placebo-controlled crossover pilot study to investigate the effect of oat betaglucans (β-glucan) on glycaemic control and variability in adults with type 1 diabetes (T1D; n = 14). Stomacol^® tablets (1.53 g of β-glucan) or placebo (Plac) were administered three times daily before meals for two weeks. Glucose levels were monitored during the second week by continuous glucose monitoring (CGM). There was an increase in basic measures of glycaemic control (maximal glucose value 341 ± 15 vs. 378 ± 13 mg/dL for Plac and β-glucan, p = 0.004), and average daily risk range (62 ± 5 vs. 79 ± 4 mg/dL for Plac and β-glucan, p = 0.003) favouring Plac over β-glucan, but no increase in the M-value (the weighted average of the glucose values) or other more complex measures. Basic measures of glucose variability were also slightly increased during β-glucan treatment, with no difference in more complex measures. However, glycaemic variability increased between the first and last two CGM days on Plac, but remained unchanged on β-glucan. In conclusion, in this pilot study we were unable to demonstrate a general positive effect of β-glucan before meals on glucose control or variability in T1D.

Lipid Lowering with Soluble Dietary Fiber

Consumption of dietary soluble fibers has been associated with health benefits such as reduced lipid levels, lower blood pressure, improved blood glucose control, weight loss, improved immune function, and reduced inflammation. Many of these health benefits relate to a reduced risk of developing cardiovascular disease. In this paper, we have reviewed recent studies on the hypocholesterolemic effects of dietary soluble fibers as well as fiber-rich foods. Findings include the following: (a) consumption of water-soluble, viscous-forming fibers can reduce total and low-density lipoprotein cholesterol levels by about 5-10 %; (b) minimal changes of high-density lipoprotein cholesterol or triglyceride levels were observed; (c) cholesterol-lowering properties of soluble fibers depend on their physical and chemical properties; and (d) medium to high molecular weight fibers are more effective in reducing lipid levels. Hypocholesterolemic benefits were also observed with some fiber-rich foods, such as whole oats, whole barley, legumes, peas, beans, flax seeds, apples, and citrus foods.

Effect of dietary interventions during weaning period on parental practice and lipoproteins and vitamin D status in two-year-old children

Objective: Evaluate if a two-day course for parents on nutrition and applied baby food preparation had an effect on child’s intake of home-made foods, lipid concentration, and vitamin D status.

Design: Randomized controlled trial at age 6 months and follow-up at ages 15 and 24 months.

Setting: Four health care clinics in Kristiansand, Norway.

Subjects: Thirty-nine pairs of 6-month-old children and their parents in the intervention group and 20 pairs in the control group.

Results: At age 15 months, the intervention group had lower intakes of ready-made porridge (2.0 vs. 5.8 servings per week (p < 0.05)), lower intake of canned baby food (2.9 vs. 6.3 servings per week (p < 0.05)) and higher intakes of home-made porridge (4.8 servings vs. 0.9 servings per week (p < 0.001)) compared with the control group. The intervention group had higher HDL cholesterol concentrations at 2 years than the control group, 1.08 mol/l compared to 0.89 mol/l (p < 0.05).

Conclusions: This is the first study to show that providing dietary information and applied baby food preparation to parents during the weaning period may have impact on the children’s diet at 15 and 24 months and improve their lipid profile. Our results call for studies with more power and longer follow-up.

Effects of 3 g of soluble fiber from oats on lipid levels of Asian Indians - a randomized controlled, parallel arm study

Background

Cardiovascular diseases are more prevalent and severe in Asian Indians. Simple diet-based strategies are important for prevention of cardiovascular diseases.The aim of the present study was to evaluate the effects of oats consumption on lipid parameters in mildly hypercholesterolemic Asian Indians living in India.

Methods

A short-term, prospective, open-labeled, randomized controlled, parallel group study was conducted. Mildly hypercholesterolemic (total cholesterol >200 mg/dL and <240 mg/dL) subjects (n = 80) were randomized into two groups: intervention (n = 40) and usual diet (n = 40). Sample size was calculated for a two-group parallel superiority randomized control trial. Out of 80 enrolled subjects 69 subjects completed the study; 33 in the control group and 36 in the intervention group. In the intervention group, patients were served 70 g of oats twice a day in the form of porridge and upma (A thick porridge from oats with seasonings and vegetables) under observation at the study site. Lipid parameters were assessed at baseline and after 4 weeks of intervention.

Results

There was a reduction of 3.1% in total cholesterol levels in the control group as against 8.1% reduction in the intervention group (p < 0.02). Greater reductions were also seen in low-density lipoprotein cholesterol in the intervention group (11.6%) as compared to control group (4.1%, p < 0.04) over a period of 28 days.

Conclusion

Daily consumption of 3 g of soluble fiber from 70 g of oats leads to beneficial effects on the lipid parameters, specifically total cholesterol and low-density lipoprotein cholesterol in hypercholesterolemic Asian Indians. Large scale studies over a longer period of intervention are required to further establish the cholesterol-lowering effect of oat fiber.

Trial registration

The study was retrospectively registered at clinicaltrials.gov (dated: 25th Februrary.2015) with registration number NCT02376660.

Impact of hydrothermal and mechanical processing on dissolution kinetics and rheology of oat β-glucan

Oat mixed-linkage β-glucan has been shown to lower fasting blood cholesterol concentrations due notably to an increase in digesta viscosity in the proximal gut. To exert its action, the polysaccharide has to be released from the food matrix and hydrated. The dissolution kinetics of β-glucan from three oat materials, varying in their structure, composition and degree of processing, was investigated by incubating the oats at 37°C over multiple time points (up to 72h). The samples were analysed for β-glucan content, weight-average molecular weight and rheological behaviour. Regardless of the materials studied and the processing applied, the solubilisation of β-glucan was not complete. Mechanical and hydrothermal processing led to differences in the viscosity flow curves of the recovered solutions, with the presence of particulates having a marked effect. This study revealed that the structure and processing methods applied to oat materials resulted in varied and complex rheological properties, especially when particulates are present.

Fragility of epidermis in newborns, children and adolescents

Within their first days of life, newborns' skin undergoes various adaptation processes needed to accommodate the transition from the wet uterine environment to the dry atmosphere. The skin of newborns and infants is considered as a physiological fragile skin, a skin with lower resistance to aggressions. Fragile skin is divided into four categories up to its origin: physiological fragile skin (age, location), pathological fragile skin (acute and chronic), circumstantial fragile skin (due to environmental extrinsic factors or intrinsic factors such as stress) and iatrogenic fragile skin. Extensive research of the past 10 years have proven evidence that at birth albeit showing a nearly perfect appearance, newborn skin is structurally and functionally immature compared to adult skin undergoing a physiological maturation process after birth at least throughout the first year of life. This article is an overview of all known data about fragility of epidermis in 'fragile populations': newborns, children and adolescents. It includes the recent pathological, pathophysiological and clinical data about fragility of epidermis in various dermatological diseases, such as atopic dermatitis, acne, rosacea, contact dermatitis, irritative dermatitis and focus on UV protection.

Phytochemical Pharmacokinetics and Bioactivity of Oat and Barley Flour: A Randomized Crossover Trial

While dietary fiber plays an important role in the health benefits associated with whole grain consumption, other ingredients concentrated in the outer bran layer, including alkylresorcinols, lignans, phenolic acids, phytosterols, and tocols, may also contribute to these outcomes. To determine the acute bioavailability and pharmacokinetics of the major phytochemicals found in barley and oats, we conducted a randomized, three-way crossover trial in 13 healthy subjects, aged 40–70 years with a body mass index (BMI) of 27–35.9 kg/m². After a two-day run-in period following a diet low in phytochemicals, subjects were randomized to receive muffins made with either 48 g whole oat flour, whole barley flour, or refined wheat flour plus cellulose (control), with a one-week washout period between each intervention. At the same time, an oral glucose tolerance test was administered. In addition to plasma phytochemical concentrations, glucose and insulin responses, biomarkers of antioxidant activity, lipid peroxidation, inflammation, and vascular remodeling were determined over a 24-h period. There was no significant effect on acute bioavailability or pharmacokinetics of major phytochemicals. Administered concurrently with a glucose bolus, the source of whole grains did not attenuate the post-prandial response of markers of glucoregulation and insulin sensitivity, inflammation, nor vascular remodeling compared to the refined grain control. No significant differences were observed in the bioavailability or postprandial effects between whole-oat and whole-barley compared to a refined wheat control when administered with a glucose challenge. These null results may be due, in part, to the inclusion criteria for the subjects, dose of the whole grains, and concurrent acute administration of the whole grains with the glucose bolus.

The impact of oat (Avena sativa) consumption on biomarkers of renal function in patients with chronic kidney disease: A parallel randomized clinical trial

BACKGROUND & OBJECTIVE

Animal studies report that oat (Avena sativa L) intake has favorable effects on kidney function. However, the effects of oat consumption have not been assessed in humans. The aim of this study was to examine the impact of oat intake on biomarkers of renal function in patients with chronic kidney disease (CKD).

METHODS

Fifty-two patients with CKD were randomly assigned to a control group (recommended to reduce intake of dietary protein, phosphorus, sodium and potassium) or an oat consumption group (given nutritional recommendations for controls +50 g/day oats). Blood urea nitrogen (BUN), serum creatinine (SCr), urine creatinine, serum albumin, serum potassium, parathyroid hormone (PTH), serum klotho and urine protein concentration were measured at baseline and after an eight-week intervention. Creatinine clearance was calculated using urine creatinine concentration.

RESULTS

Within group analysis showed a significant increase in BUN (P = 0.02) and serum potassium (P = 0.01) and a marginally significant increment in SCr (P = 0.08) among controls. However, changes in the oat group were not significant. In a multivariate adjusted model, we observed a significant difference in change of serum potassium (-0.03 mEq/L for oat group and 0.13 mEq/L for control group; P = 0.01) and a marginally significant difference in change of serum albumin (0.01 g/dl for oat group and -0.08 for control group; P = 0.08) between the two groups. There was no change in PTH concentration.

CONCLUSION

Intake of oats may have a beneficial effect on serum albumin and serum potassium in patients with CKD.

REGISTRATION CODE

Present study registered under IRCT.ir identifier no. IRCT2015050414551N2.

Volatile Compounds Produced by Lactobacillus paracasei During Oat Fermentation

This study investigated the profiles of volatile compounds produced by Lactobacillus paracasei during oat fermentation using gas chromatography-mass spectrometry coupled with headspace solid-phase microextraction method. A total of 60 compounds, including acids, alcohols, aldehydes, esters, furan derivatives, hydrocarbons, ketones, sulfur-containing compounds, terpenes, and other compounds, were identified in fermented oat. Lipid oxidation products such as 2-pentylfuran, 1-octen-3-ol, hexanal, and nonanal were found to be the main contributors to oat samples fermented by L. paracasei with the level of 2-pentylfuran being the highest. In addition, the contents of ketones, alcohols, acids, and furan derivatives in the oat samples consistently increased with the fermentation time. On the other hand, the contents of degradation products of amino acids, such as 3-methylbutanal, benzaldehyde, acetophenone, dimethyl sulfide, and dimethyl disulfide, decreased in oat samples during fermentation. Principal component analysis (PCA) was applied to discriminate the fermented oat samples according to different fermentation times. The fermented oats were clearly differentiated on PCA plots. The initial fermentation stage was mainly affected by aldehydes, whereas the later samples of fermented oats were strongly associated with acids, alcohols, furan derivatives, and ketones. The application of PCA to data of the volatile profiles revealed that the oat samples fermented by L. paracasei could be distinguished according to fermentation time.

Beta-glucan contamination of pharmaceutical products: How much should we accept?

Beta-glucans are large polysaccharides produced by a range of prokaryotic and eukaryotic organisms. They have potential immunostimulatory properties and have been used with therapeutic intent as anti-microbial and anti-tumour agents. A range of other potentially beneficial effects have been described, and oral forms of beta-glucans are widely available over-the-counter and online. Parenteral formulations are popular in parts of Asia and are the subject of ongoing trials, worldwide. Beta-glucans are also potential contaminants of pharmaceutical products, and high levels have been described in some blood products. However, little is known about the clinical effects of such contamination, considerable uncertainty exists over the level at which immunostimulation may occur, and there are no guidelines available on acceptable levels. We encountered beta-glucan contamination of one of our products, and we suspect that others may encounter similar issues since the origin of beta-glucan contamination includes commonly used filters and solutions applied in the manufacture of biotherapeutic agents. It is likely that regulators will increasingly enquire about beta-glucan levels in pharmaceutical products, especially those with an immunomodulatory mechanism of action. Here, we review the literature on beta-glucans in pharmaceutical products and propose an acceptable level for therapeutic agents for parenteral use.

TNF-α modulation by natural bioactive molecules in mouse RAW 264.7 macrophage cells

BACKGROUND

The present study was designed to examine the anti-inflammatory effects of plant-derived products marketed for human health benefits.

METHODS

The tumor necrotic factor-α (TNF-α) was used as a proinflammatory biomarker generated by mouse macrophage RAW 264.6 cells. The in vitro tested plant products include Saskatoon berry (SKB), quercetin, purified oat beta-glucan (OBG), curcumin, and turmeric. Quantification of TNF-α in cell culture supernatants was carried out using mouse TNF-α assay kit and the cell proliferation was determined by MTT (3-(4, 5-dimethylthiazolyl-2)-2,5- diphenyltetrazolium bromide) assay. The cells were grown in Dulbecco's modified Eagle's medium supplemented with 10% heat-inactivated fetal bovine serum and 100 U/mL penicillin and 100 µg/mL streptomycin. Bacterial lipopolysaccharide (LPS) at a concentration of 500 ng/mL was employed to stimulate the TNF-α production in mouse macrophage cells.

RESULTS

Results showed that curcumin at 10 µM (3.7 µg/mL) level effectively attenuated the LPS-induced inflammatory response, and at 100 µM completely inhibited macrophage RAW cell growth (p<0.05). The aqueous turmeric extract caused inhibitory effect on TNF-α at 25, 50, 100, and 500 µg/mL. SKB inhibited TNF-α production at 50, 100, 500, and 1,000 µg/mL. On the other hand, at 10, 25, 500, and 1,000 µg/mL SKB promoted significant cell growth/proliferation. Quercetin at 10, 25, 50 and 100 µg/mL inhibited TNF-α, but at 500 and 1,000 µg/mL stimulated cell growth. OBG at 10, 25, and 50 µg/mL inhibited TNF-α, but in some cases OBG stimulated TNF-α At 1,000 and 10,000 µg/mL OBG proved to be extremely toxic or lethal to the macrophage cells.

CONCLUSIONS

Overall, the plant products showed anti-inflammatory effects as well as cell proliferation or inhibition in the in vitro system used in this investigation. The underlying mechanisms of dualistic actions caused by plant-derived ingredients, viz., macrophage cellular growth stimulation or retardation, remain to be elucidated.

Short- and Long-Term Effects of Wholegrain Oat Intake on Weight Management and Glucolipid Metabolism in Overweight Type-2 Diabetics: A Randomized Control Trial

Glycemic control and weight reduction are primary goals for the management of overweight and obese type 2 diabetes mellitus (T2DM). Effective management cannot be achieved without an appropriate diet. Our study aimed to evaluate the short- and long-term effects of oat intake and develop a reasonable dietary plan for overweight T2DM patients. A randomized control trial, registered under ClinicalTrials.gov (Identification code: NCT01495052), was carried out among adult T2DM patients. A subgroup of 298 overweight subjects was selected and received a 30-day centralized intervention and 1-year free-living follow-up. Participants were randomly allocated to one of the following four groups. The usual care group (n = 60) received no intervention; the healthy diet group (n = 79) received a low-fat and high-fiber diet (“healthy diet”); the 50 g-oats group (n = 80) and 100 g-oats group (n = 79) received the “healthy diet” with the same amount of cereals replaced by 50 g and 100 g oats respectively. Anthropometric, blood glycemic and lipid variables were measured. For the 30-day intervention, significant differences in the changes of FPG (fasting plasma glucose), PPG (postprandial plasma glucose), HbA1c (glycosylated hemoglobin), HOMA-IR (homeostasis model assessment of insulin resistance), TC (total cholesterol), TG (total triglycerides), and LDL-c (low-density lipoprotein cholesterol) were observed among the four groups. Compared to the healthy diet group, the 50 g-oats group had a bigger reduction in PPG (mean difference (MD): −1.04 mmol/L; 95% CI: −2.03, −0.05) and TC (MD: −0.24 mmol/L; 95% CI: −0.47, −0.01); the 100 g-oats group had a bigger reduction in PPG (MD: −1.48 mmol/L; 95% CI: −2.57, −0.39), HOMA-IR (MD: −1.77 mU·mol/L²; 95% CI: −3.49, −0.05), TC (MD: −0.33 mmol/L; 95% CI: −0.56, −0.10) and LDL-c (MD: −0.22 mmol/L; 95% CI: −0.41, −0.03). In the 1-year follow-up, greater effects in reducing weight (MD: −0.89 kg; 95% CI: −1.56, −0.22), HbA1c (MD: −0.64%; 95% CI: −1.19, −0.09) and TG (MD: −0.70 mmol/L; 95% CI: −1.11, −0.29) were observed in the 100 g-oats group. In conclusion, short- and long-term oat intake had significant effects on controlling hyperglycemia, lowering blood lipid and reducing weight. Our study provided some supportive evidence for recommending oat as a good whole grain selection for overweight diabetics.

Antihyperlipidemic effect of Acanthopanax senticosus (Rupr. et Maxim) Harms leaves in high-fat-diet fed mice

BACKGROUND

Metabolic syndrome is a major risk factor for a variety of obesity-related diseases. Recently, the effects of functional foods have been investigated on lipid metabolism as a means to reduce lipid content in the blood, liver and adipose tissues associated with carnitine O-palmitoyltransferase (CPT) activity. Acanthopanax senticosus (Rupr. et Maxim) Harms (AS) is a medicinal herb possessing a wide spectra of functions including antioxidant, anti-inflammatory and anti-fatigue actions. Despite much research being focused on the cortical roots of AS, little information is available regarding its leaves, which are also expected to promote human health, for example by improving abnormal lipid metabolism. Here, we explored whether AS leaves affect lipid metabolism in mice fed a high-fat diet.

RESULTS

The administration of AS to BALB/c mice fed a high-fat diet significantly decreased plasma triglycerides (TG). CPT activity in the liver of these mice was significantly enhanced by AS treatment.

CONCLUSION

These findings indicate that AS leaves have the potential to alleviate increase in plasma TG levels due to high-fat diet intake in mice, possibly by increasing mitochondrial fatty acid β-oxidation, especially via CPT activation. Consequently, daily intake of AS leaves could promote beneficial health effects including the prevention of metabolic syndrome. © 2015 Society of Chemical Industry.

Whole grain foods: is sensory liking related to knowledge, attitude, or intake?

Purpose

The health benefits of whole grains are well established, yet intake remains below recommendations. Knowledge and familiarity with whole grains may increase short-term intake, but sensory properties can limit consumption. These factors usually are researched separately, thus, this study aims to explore the relationships among sensory liking, knowledge, attitudes and intake.

Design/methodology/approach

This cross-sectional study had 69 college students participate in four tasks: sensory liking of whole vs refined grain bread, rice, pasta and tortillas; bitter taster status; knowledge and attitudes; and intake of whole grains.

Findings

Whole wheat bread and tortillas were liked, as well as their refined grain counterparts. However, white rice and pasta were liked significantly more than the whole grain products (p < 0.05), which are less familiar to most people. Higher consumers of whole grain foods preferred those samples to the refined product for some sensory attributes (p < 0.05). Bitter taster status was not related to sensory preferences. Understanding and recognition of whole grains was low, but attitudes were generally positive. Whole grain intake was overestimated by the food frequency questionnaire because of problems with the instrument and also subjects’ lack of understanding about these foods.

Research limitations/implications

The link between preference and consumption warrants further study. The survey used to measure whole grain intake was a limitation and demonstrates the need for an accurate and efficient tool. Although knowledge about whole grains is limited, the positive attitudes expressed by participants can strategically inform outreach. If people believe that they consume more whole grains than they actually do, they may have a false sense of security. Further research with different age groups and a wider variety of foods is needed.

Practical implications

Participants overestimated their consumption of whole grain foods, indicating that consumers may think that they are meeting recommended amounts but they are actually deficient in whole grain intake; thus, improved education and promotional efforts are needed.

Originality/value

Few studies examine the inter-relationships among sensory preference, bitter taster status, knowledge, attitude and intake of whole grains.

Pharmacological research on natural substances in Latvia: Focus on lunasin, betulin, polyprenol and phlorizin

In this concise review the current research in plant bioactive compound studies in Latvia is described. The paper summarizes recent studies on substances from edible plants (e.g., cereals and apples) or their synthetic analogues, such as peptide lunasin, as well as substances isolated from inedible plants (e.g., birch and conifer), such as pentacyclic triterpenes (e.g., betulin, betulinic acid, and lupeol) and polyprenols. Latvian researchers have been first to demonstrate the presence of lunasin in triticale and oats. Additionally, the impact of genotype on the levels of lunasin in cereals was shown. Pharmacological studies have revealed effects of lunasin and synthetic triterpenes on the central nervous system in rodents. We were first to show that synthetic lunasin causes a marked neuroleptic/cataleptic effect and that betulin antagonizes bicuculline-induced seizures (a GABA A receptor antagonist). Studies on the mechanisms of action showed that lunasin binds to dopamine D1 receptors and betulin binds to melanocortin and gamma-aminobutyric acid A receptors therefore we suggest that these receptors play an essential role in lunasin's and betulin's central effects. Recent studies on conifer polyprenols demonstrated the ability of polyprenols to prevent statin-induced muscle weakness in a rat model. Another study on plant compounds has demonstrated the anti-hyperglycemic activity of phlorizin-containing unripe apple pomace in healthy volunteers. In summary, research into plant-derived compounds in Latvia has been focused on fractionating, isolating and characterizing of lunasin, triterpenes, polyprenols and phlorizin using in vitro, and in vivo assays, and human observational studies.

β-glucans: ex vivo inflammatory and oxidative stress results after pasta intake

BACKGROUND

It is well known that Mediterranean Diet can positively influence the health of each individual, in particular it is know that fibers have an important role. However, in Mediterranean cities most people do not have a close adherence to Mediterranean diet. Thus, in our study, we considered fibers like β-glucans that have been added to pasta with a percentage of 6 %. Our study aimed to evaluate the capacity of β-glucans intake on oxidative stress and inflammation in a cohort of middle aged slightly overweight subjects.

METHODS

We used a longitudinal study design. The study lasted 30 days during which time, each participant acted with no food restriction. Participants underwent morning fasting blood venous sample for blood chemistry and other biological parameters at the beginning of the study and after 30 days of pasta supplemented with 6 % of β-glucan intake 4 times a week. We performed anthropometric, biochemical, oxidative stress and cytokine analysis at the beginning and the end of study.

RESULTS

After the 30 days of pasta intake we obtained a significant decrease of LDL-cholesterol, IL-6 and AGEs levels.

CONCLUSION

The results confirmed a capacity of β-glucans intake to lower oxidative stress. Additional longitudinal observation on community-based cohorts are needed to confirm these data and investigate the biological mechanisms through which effects are induced, and to fully explore the therapeutic potential of β-glucans.

Effects of dietary oat proteins on cholesterol metabolism of hypercholesterolaemic hamsters

BACKGROUND

The aim of present study was to investigate the hypocholesterolaemic effects of oat proteins (OP) in hamsters fed with a hypercholesterolaemic diet. The hamsters were divided into five groups and fed with the experimental diets containing oat, OP, oat β-glucan (OG), or OP+OG for 30 days.

RESULTS

OP and the OG significantly lowered the concentrations of plasma low-density lipoprotein-cholesterol and liver total cholesterol (TC), and increased the excretion of faecal bile acid and TC. Plasma and liver TC in the OP+OG group were significantly lower than those in the OP or OG groups. Both OP and OG increased the activity of liver cholesterol 7α-hydroxylase (CYP7A1), while its activity in the OP+OG group was strongly increased compared with the OP or OG groups.

CONCLUSION

These results indicated that dietary OP could improve hypercholesterolaemia, while dietary OP and OG together would have better hypocholesterolaemic effects.

New Horizons for the Study of Dietary Fiber and Health: A Review

Dietary fibre has been consumed for centuries with known health benefits, but defining dietary fibre is a real challenge. From a functional perspective, dietary fibre is described as supporting laxation, attenuating blood glucose responses and assisting with cholesterol lowering. The problem is different types of dietary fibre have different effects, and new effects are increasingly observed, such as the influence on gut microbiota. Thus, a single definition may need to be described in more generic terms. Rather than being bound by a few functional definitions, we may need to embrace the possibilities of new horizons, and derive a working definition of dietary fibre based on a set of conceptual principles, rather than the limited definitions we have to date. To begin this process, a review of individual fibre types and their physiological effects would be helpful. Dietary fibre is a complex group of substances, and there is a growing interest in specific effects linked to fibre type. Different fractions of dietary fibre have different physiological properties, yet there is a paucity of literature covering the effects of all fibres. This paper describes a range of individual fibre types and identifies gaps in the literature which may expose new directions for a working definition of dietary fibre.

Oats-From Farm to Fork

Oats have a long history of use as human food and animal feed. From its origins in the Fertile Crescent, the oat has adapted to a wide range of climatic conditions and geographic regions. Its unique macro-, micro-, and phytonutrient composition, high nutritional value, and relatively low agricultural input requirements makes oats unique among cereal crops. The health benefits of the oats are becoming well established. While the connection between oat β-glucan fiber in reducing the risk of cardiovascular disease and controlling glycemia have been unequivocally established, other potential benefits including modulation of intestinal microbiota and inflammation continue to be explored. Advances in food technology are continuing to expand the diversity of oat-based foods, creating opportunities to deliver the health benefits of oats to a larger segment of the population.

Randomised controlled pilot study to assess the feasibility of a Mediterranean Portfolio dietary intervention for cardiovascular risk reduction in HIV dyslipidaemia: a study protocol

INTRODUCTION

HIV drug treatment has greatly improved life expectancy, but increased risk of cardiovascular disease remains, potentially due to the additional burdens of infection, inflammation and antiretroviral treatment. The Mediterranean Diet has been shown to reduce cardiovascular risk and mortality in the general population, but no evidence exists for this effect in the HIV population. This study will explore the feasibility of a randomised controlled trial (RCT) to examine whether a Mediterranean-style diet that incorporates a portfolio of cholesterol-lowering foods, reduces cardiovascular risk in people with HIV dyslipidaemia.

METHODS AND ANALYSIS

60 adults with stable HIV infection on antiretroviral treatment and low-density lipoprotein cholesterol >3 mmol/L will be recruited from 3 West Midlands HIV services. Participants will be randomised 1:1 to 1 of 2 dietary interventions, with stratification by gender and smoking status. Participants allocated to Diet1 will receive advice to reduce saturated fat intake, and those to Diet2 on how to adopt the Mediterranean Portfolio Diet with additional cholesterol-lowering foods (nuts, stanols, soya, oats, pulses). Measurements of fasting blood lipids, body composition and arterial stiffness will be conducted at baseline, and month 6 and 12 of the intervention. Food intake will be assessed using the Mediterranean Diet Score, 3-day food diaries and metabolomic biomarkers. Questionnaires will be used to assess quality of life and process evaluation. Qualitative interviews will explore barriers and facilitators to making dietary changes, and participant views on the intervention. Qualitative data will be analysed using the Framework Method. Feasibility will be assessed in terms of trial recruitment, retention, compliance to study visits and the intervention. SD of outcomes will inform the power calculation of the definitive RCT.

ETHICS

The West Midlands Ethics Committee has approved this study and informed consent forms. This trial is the first to test cholesterol-lowering foods in adults with HIV.

TRIAL REGISTRATION NUMBER

ISRCTN32090191; Pre-results.

Dietary fiber and satiety: the effects of oats on satiety

This review examines the effect of β-glucan, the viscous soluble fiber in oats, on satiety. A literature search for studies that examined delivery of the fiber in whole foods or as an extract was conducted. Viscosity interferes with the peristaltic mixing process in the small intestine to impede digestion and absorption of nutrients, which precipitates satiety signals. From measurements of the physicochemical and rheological properties of β-glucan, it appears that viscosity plays a key role in modulating satiety. However, the lack of standardized methods to measure viscosity and the inherent nature of appetite make it difficult to pinpoint the reasons for inconsistent results of the effects of oats on satiety. Nevertheless, the majority of the evidence suggests that oat β-glucan has a positive effect on perceptions of satiety.

Hypolipidaemic effects of oat flakes and β-glucans derived from four Chinese naked oat (Avena nuda) cultivars in Wistar-Lewis rats

BACKGROUND

β-Glucan is widely considered to be the major ingredient responsible for the hypolipidaemic effects of oat. Determination of the β-glucan content in naked oat cultivars in China has been largely performed for breeding and food processing. Since oat is generally consumed as oat flakes in China, evaluation of the bioactivity of oat flakes might be more direct and comprehensive than determination of the internal β-glucan. However, the hypolipidaemic activity of oat flakes processed from Chinese oat cultivars has rarely been reported.

RESULTS

The nutritional components of four naked oat cultivars were analysed before they were processed to oat flakes. The hypolipidaemic effects of oat flakes and the extracted β-glucans were tested on rats fed a high-fat diet for 30 days. Oat flakes and β-glucans of different origins showed different preventative effects on hyperlipidaemia. Among the four cultivars, β-glucan of 'Bayou-1' showed the greatest hypolipidaemic effect. However, oat flake processed from 'Dingyou-7' showed the best bioactivity to mediate the increase of serum lipid.

CONCLUSION

The hypolipidaemic effect of oat might not only depend on β-glucan, but might also be related to other components. 'Dingyou-7' might be suitable for oat flake processing because of its superior bioactivity.

Sodium alginate decreases the permeability of intestinal mucus

In the small intestine the nature of the environment leads to a highly heterogeneous mucus layer primarily composed of the MUC2 mucin. We set out to investigate whether the soluble dietary fibre sodium alginate could alter the permeability of the mucus layer. The alginate was shown to freely diffuse into the mucus and to have minimal effect on the bulk rheology when added at concentrations below 0.1%. Despite this lack of interaction between the mucin and alginate, the addition of alginate had a marked effect on the diffusion of 500 nm probe particles, which decreased as a function of increasing alginate concentration. Finally, we passed a protein stabilised emulsion through a simulation of oral, gastric and small intestinal digestion. We subsequently showed that the addition of 0.1% alginate to porcine intestinal mucus decreased the diffusion of fluorescently labelled lipid present in the emulsion digesta. This reduction may be sufficient to reduce problems associated with high rates of lipid absorption such as hyperlipidaemia.

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There are no specific interactions between alginate and intestinal mucus.

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Mucus rheology was hardly altered by small additions of alginate.

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Alginate freely diffused into mucus and reduced diffusion of 500 nm beads.

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Intestinal mucus permeability was decreased by a factor of two.

Profiling of Nutritional and Health-Related Compounds in Oat Varieties

The use of oats in the human diet has decreased over the past 70 years. This is an unfortunate development from the perspective of human health because oats have a high nutritional value and contain many compounds, including β-glucan, polyphenols, vitamins, and unsaturated fatty acids that are able to maintain or may even improve consumer’s health. In addition, oats fit into a gluten-free diet of celiac disease patients because they lack the T-cell stimulating epitopes from wheat, rye, and barley. We focused on the presence of health-related compounds in oats and how their levels vary among varieties in response to the type of soil. Ten oat varieties were grown in the Netherlands in sandy and clay soil and were analyzed for the presence and concentration of healthy compounds (β-glucan, fatty acids, vitamin E, and antioxidant activity), avenin composition, total protein and starch content, and agronomical characteristics. Principal component analysis showed that genetic background influenced the levels of all analyzed components. Protein, starch, β-glucan, and antioxidants were also affected by the type of soil. The obtained results showed that this kind of analysis can be used to profile oat varieties in general and enables the selection of specific varieties with specific compound characteristics.