Cholesterol-lowering effects of barley dietary fibre in humans: scientific support for a generic health claim

Effects of β-glucan Rich Barley Flour on Glucose and Lipid Metabolism in the Ileum, Liver, and Adipose Tissues of High-Fat Diet Induced-Obesity Model Male Mice Analyzed by DNA Microarray

We evaluated whether intake of β-glucan-rich barley flour affects expression levels of genes related to glucose and lipid metabolism in the ileum, liver, and adipose tissues of mice fed a high-fat diet. C57BL/6J male mice were fed a high-fat diet supplemented with high β-glucan barley, for 92 days. We measured the expression levels of genes involved in glucose and lipid metabolism in the ileum, liver, and adipose tissues using DNA microarray and q-PCR. The concentration of short-chain fatty acids (SCFAs) in the cecum was analyzed by GC/MS. The metabolic syndrome indices were improved by barley flour intake. Microarray analysis showed that the expression of genes related to steroid synthesis was consistently decreased in the liver and adipose tissues. The expression of genes involved in glucose metabolism did not change in these organs. In liver, a negative correlation was showed between some SCFAs and the expression levels of mRNA related to lipid synthesis and degradation. Barley flour affects lipid metabolism at the gene expression levels in both liver and adipose tissues. We suggest that SCFAs are associated with changes in the expression levels of genes related to lipid metabolism in the liver and adipose tissues, which affect lipid accumulation.

Effect of Different Amounts of Hybrid Barley in Diets on the Growth Performance and Selected Biochemical Parameters of Blood Serum Characterizing Health Status in Fattening Pigs

Simple Summary

The aim of the present study was to determine the effect of dietary hybrid barley and/or wheat on production parameters, selected biochemical parameters of blood serum characterizing health status in fattening pigs. The use of hybrid barley as the basic ingredient of diets for fattening pigs provided similar production parameters as those obtained with wheat. No significant differences were noted in case of performance results and meatiness of fatteners. However, usage of hybrid barley with high level in diet decreased level of total cholesterol and LDL (low-density lipoprotein fraction) fraction in blood. It means that barley had a beneficial effect on blood lipid indices.

Abstract

The aim of the study was to determine the effect of dietary hybrid barley and/or wheat on production parameters, selected biochemical parameters of blood serum characterizing health status in fattening pigs. In group I, hybrid barley constituted 80% of feed; in II—wheat and hybrid barley were used, each in amount of 40% feed; in III—contained 80% of wheat. No significant differences were noted in case of performance results (body weight gains, feed intake, and feed conversion ratio) and meatiness of fatteners. All estimated biochemical indices determined in serum were within normal range. Usage of 80% hybrid barley decreased concentration of total cholesterol, low-density lipoprotein fraction (LDL), and triglycerides in blood (p < 0.05). However, high-density lipoprotein fraction (HDL) content increased (p < 0.01) up to 1.04 mmol·dm⁻³, comparing to the group with 80% of wheat (0.84 mmol·dm⁻³). Summarized, the diet with high level of barley had a beneficial effect on blood lipid indices, what indicate a good health status of all animals.

Effect of thermally treated barley dietary fiber against hypercholesterolemia

Dietary fiber is a nondigestible constituent of vegetal foods, formed by insoluble and soluble dietary fiber. The intake of dietary fiber, especially soluble dietary fiber, is limited and demands researcher's attention. The modification of cereal's dietary fiber, predominantly insoluble fiber, could be one possible solution. The current study evaluated the comparative effects of several thermal treatments on the modification of insoluble dietary fiber in barley and explored their therapeutic potential in vivo against hypercholesterolemia. The two cultivars of barley, Haider-93 and Jau-87, were thermally treated using different techniques, and dietary fiber was extracted. Successively, the intake of these dietary fibers was evaluated for its antilipidemic activity in normal and hypercholesterolemic rats. In the first phase, thermal treatments especially cooking without soaking increased the soluble fiber (68.08%). The roasting all increased the soluble fiber contents, however, at relatively lower rate (53.91%). The results of efficacy study revealed that biochemical parameters in control animals were within the normal clinical ranges, thus appraising the safe status of the experimental diets. The thermally treated barley fiber decreased total cholesterol (12.14%-12.63%), low-density lipoprotein (14.12%-14.85%), and triglycerides (2.25%-4.32%). The study recorded increasing trends for high-density lipoprotein in both normal and hypercholesterolemic rats. In the nutshell, thermal modification of dietary fiber increased the ratio of soluble to insoluble dietary fiber that improved its hypocholesterolemic potential. The thermally treated barley dietary fiber is effective in reducing the lipid profile in Sprague-dawley rats than untreated dietary fiber and, therefore, can be considered as a functional food and ingredient to cope different lifestyle diseases.

Effect of PolyGlycopleX (PGX) Consumption on Blood Lipid Profiles in Healthy, Low CVD Risk Overweight Adults

Raised blood lipid levels are associated with a risk of a cardiovascular disease (CVD). Moderate reductions in several CVD factors such as total, low-density lipoprotein (LDL) cholesterol and non-high-density lipoprotein (non-HDL) cholesterol concentrations may be more effective in reducing overall risk than a major reduction in just one. A blind, randomised controlled trial was conducted with 120 healthy overweight (BMI 25⁻30) adults aged 25⁻70 years who were non-smokers, not diabetic and of low risk of cardiovascular disease, as assessed by the Framingham risk equation. Participants consumed 4.5 g PolyGlycopleX (PGX) as softgel capsules (PGXS) or 5 g PGX granules (PGXG) or 5 g rice flour (RF) with meals three times a day for 12 weeks. Total, LDL and non-HDL cholesterol were all significantly reduced (-6%, -5% and -3.5%, respectively) post the PGX granule treatment; however, PGX in softgel capsule form did not affect blood lipid profiles. Daily consumption of PGX granules in overweight low CVD risk adults produced lipid changes indicating a CVD preventative benefit.

Processing and Prebiotics Characteristics of β-Glucan Extract from Highland Barley

β-glucan extract (GE) was obtained from highland barley bran using alkaline–acid–alcohol extraction method. The stability, solubility, foaming ability, and prebiotics characteristics of GE were assessed consecutively. GE demonstrated excellent heat stability (hardly degraded at 220 °C) and pH stability, especially at neutral or alkaline condition, and its solubility was significantly influenced by temperature instead of pH or NaCl, achieving 0.91 g/100 g at 100 °C. Good foaming ability and foam stability of GE were observed during low temperatures (≤40 °C), neutral or alkaline condition. GE indicated a strong anti-digestibility capacity of resisting the hydrolysis of α-amylase and simulated human gastric acid. Interestingly, GE could effectively promote the growth of Lactobacillus bulgaricus and Bifidobacterium adolescentis, which was close to fructooligosaccharide. The results of this study could offer valuable information for the application of β-glucan from highland barley as prebiotics in promoting human intestinal health metabolism.

Barley Products of Different Fiber Composition Selectively Change Microbiota Composition in Rats

Scope

Several dietary fiber properties are suggested to be important for the profiling of the microbiota composition, but those characteristics are rather unclear. Whether different physico‐chemical properties of barley dietary fiber influence the gut microbiota composition is investigated.

Methods and results

Seven diets containing equal amounts of dietary fiber from barley malts, brewer's spent grain (BSG), and barley extracts, resulting in varying amounts of β‐glucan, soluble arabinoxylan, and insoluble arabinoxylan in the diets were given to conventional rats. Malts increased microbiota alpha diversity more than BSG and the extracts. The intake of soluble arabinoxylan was related to Akkermansia and propionic acid formation in the cecum of rats, whereas β‐glucan and/or insoluble arabinoxylan were attributed to some potentially butyrate‐producing bacteria (e.g., Lactobacillus, Blautia, and Allobaculum).

Conclusion

This study demonstrates that there is a potential to stimulate butyrate‐ and propionate‐producing bacteria in the cecum of rats with malt products of specific fiber properties. Moreover, BSG, a by product from beer production, added to malt can possibly be used to further modulate the microbiota composition, toward a higher butyric acid formation. A complex mixture of fiber as in the malts is of greater importance for microbiota diversity than purer fiber extracts.

Health claims in the labelling and marketing of food products:

Since 1990 certain health claims in the labelling and marketing of food products have been allowed in Sweden within the food sector's Code of Practice. The rules were developed in close dialogue with the authorities. The legal basis was a decision by the authorities not to apply the medicinal products’ legislation to “foods normally found on the dinner table” provided the rules defined in the Code were followed. The Code of Practice lists nine well-established diet–health relationships eligible for generic disease risk reduction claims in two steps and general rules regarding nutrient function claims. Since 2001, there has also been the possibility for using “product-specific physiological claims (PFP)”, subject to premarketing evaluation of the scientific dossier supporting the claim. The scientific documentation has been approved for 10 products with PFP, and another 15 products have been found to fulfil the Code's criteria for “low glycaemic index”. In the third edition of the Code, active since 2004, conditions in terms of nutritional composition were set, i.e. “nutrient profiles”, with a general reference to the Swedish National Food Administration's regulation on the use of a particular symbol, i.e. the keyhole symbol. Applying the Swedish Code of practice has provided experience useful in the implementation of the European Regulation on nutrition and health claims made on foods, effective from 2007.

A Review of Extraction and Analysis of Bioactives in Oat and Barley and Scope for Use of Novel Food Processing Technologies

Oat and barely are cereal crops mainly used as animal feed and for the purposes of malting and brewing, respectively. Some studies have indicated that consumption of oat and barley rich foods may reduce the risk of some chronic diseases such as coronary heart disease, type II diabetes and cancer. Whilst there is no absolute consensus, some of these benefits may be linked to presence of compounds such as phenolics, vitamin E and β-glucan in these cereals. A number of benefits have also been linked to the lipid component (sterols, fatty acids) and the proteins and bioactive peptides in oats and barley. Since the available evidence is pointing toward the possible health benefits of oat and barley components, a number of authors have examined techniques for recovering them from their native sources. In the present review, we summarise and examine the range of conventional techniques that have been used for the purpose of extraction and detection of these bioactives. In addition, the recent advances in use of novel food processing technologies as a substitute to conventional processes for extraction of bioactives from oats and barley, has been discussed.

Efficiency of barley bran and oat bran in ameliorating blood lipid profile and the adverse histological changes in hypercholesterolemic male rats

The efficiency of oat bran and barley bran in lowering the induced hyperlipidemia and hypercholesterolemia in blood of male Albino rats (Rattus rattus) was studied. Twenty rats were divided into four groups each consisted of five rats and fed the specified test diets for eight weeks. The first group (G1) is the negative group which was fed basal diet, the second group (G2) was fed 1.0% cholesterol, was the third group (G3) fed 1.0% cholesterol and 10% oats bran, and the fourth group (G4) was fed 1.0% cholesterol and 10% barley bran. Feeding rats on 1% cholesterol significantly increased serum total cholesterol, low density lipoprotein, and very low density lipoprotein and triglyceride and decreased serum high density lipoprotein. Furthermore, enzyme activity of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase was increased, and lipid peroxide was increased, whereas catalase and glutathione-S-transferase were decreased. Kidney functions parameters in the cholesterol supplemented group were elevated compared with the negative control. In addition, histological alteration in kidney, liver, heart, and testes was observed, compared with the negative control. Hypercholesterolemic rats supplemented with oat bran and barley bran showed significant decrease in lipid parameters, significant increase in high density lipoprotein-cholesterol, improved antioxidant enzyme, and improved histopathology of kidney, liver, heart, and testes. In conclusion, both oat bran and barley bran had protective effects against induced hyperlipidemia and improved histological alterations. Oat bran appeared more efficient than barley bran in lowering the lipid profile levels in hypercholesterolemic rats.

Barley intake induces bile acid excretion by reduced expression of intestinal ASBT and NPC1L1 in C57BL/6J mice

To investigate the hypocholesterolemic mechanism of barley in vivo, six-week-old C57BL/6J mice were fed a high-fat diet (HFD) or high-fat diet containing barley (HFD-B) for seven weeks. Total and LDL cholesterol concentrations were significantly reduced in the HFD-B group while fecal cholesterol and bile acid was increased. Real-time PCR and immunoblot analysis revealed the induction of FXR expression, which in turn suppressed the expression of ASBT and NPC1L1 in the HFD-B group compared with the controls. In the liver, the expression of HMG-CoA reductase was significantly reduced while LDL receptor expression was unaltered in the HFD-B group compared with the controls. Our data suggest that the hypocholesterolemic effects of barley are primarily the result of reduced dietary cholesterol uptake and bile acid resorption. Reduced expression of intestinal ASBT and NPC1L1 may play a key role in the regulation of dietary cholesterol and bile acid metabolism in mice consuming a diet containing barley.

Phytochemical and dietary fiber components in barley varieties in the HEALTHGRAIN Diversity Screen

Ten different barley varieties grown in one location were studied for their content of tocols, folate, plant sterols, alkylresorcinols, and phenolic acids, as well as dietary fiber components (arabinoxylan and beta-glucan). The samples included hulled and hull-less barley types and types with normal, high-amylose, and waxy starch. The aim was to study the composition of raw materials, and therefore the hulls were not removed from the hulled barleys. A large variation was observed in the contents of all phytochemicals and dietary fibers. Two varieties from the INRA Clermont Ferrand barley program in France (CFL93-149 and CFL98-398) had high content of tocopherols and alkylresorcinols, whereas the variety Dicktoo was highest in dietary fiber content and phenolics. Positive correlations were found between 1000 kernel weight, alkylresorcinols, and tocols, as well as between dietary fiber content and phenolic compounds. The results demonstrate that the levels of phytochemicals in barley can likely be affected by breeding and that the contents of single phytochemicals may easily be adjusted by a right selection of a genotype.

Issues surrounding health claims for barley

Government-approved health claims support dietary intervention as a safe and practical approach to improving consumer health and provide industry with regulatory guidelines for food product labels. Claims already allowed in the United States, United Kingdom, Sweden, and The Netherlands for reducing cholesterol through consumption of oat or barley soluble fiber provide a basis for review, but each country may have different criteria for assessing clinical evidence for a physiological effect. For example, the FDA-approved barley health claim was based on a petition that included 39 animal model studies and 11 human clinical trials. Since then, more studies have been published, but with few exceptions, clinical data continue to demonstrate that the consumption of barley products is effective for lowering total and LDL cholesterol. More research is needed to fully understand the mechanism of cholesterol reduction and the role of beta-glucan molecular weight, viscosity, and solubility. In an assessment of the physiological efficacy of a dietary intervention, consideration should also be given to the potential impact of physical and thermal food-processing treatments and genotypic variation in the barley source. New barley cultivars have been generated specifically for food use, possessing increased beta-glucan, desirable starch composition profiles, and improved milling/processing traits. These advances in barley production, coupled with the establishment of a government-regulated health claim for barley beta-glucan, will stimulate new processing opportunities for barley foods and provide consumers with reliable, healthy food choices.