Meta-analysis of the effect of β-glucan intake on blood cholesterol and glucose levels

Objective

A meta-analysis was performed on epidemiologic studies to assess the relation between β-glucan consumption from oats and from barley on blood cholesterol level, triglyceride/triacylglycerol (TGL/TAG) level, and blood glucose level (BGL) in humans. In addition, the effect of β-glucan on total cholesterol (TC) and BGL was translated into an empirical dose–response model.

Methods

Thirty research articles that evaluated the effect of different exposure levels of β-glucan on blood cholesterol and BGL were analyzed, yielding 126 clinical studies.

Results

There was a significant inverse relation in TC (−0.60 mmol/L, 95% confidence interval [CI] −0.85 to −0.34), low-density lipoprotein (−0.66 mmol/L, 95% CI −0.96 to −0.36), and TGL/TAG (−0.04 mmol/L, 95% CI −0.15 to 0.07) after consumption of β-glucan. In contrast, an increase in high-density lipoprotein cholesterol was noted (0.03 mmol/L, 95% CI −0.06 to 0.13) with the random-effect model. The analysis showed a significant change in BGL (−2.58 mmol/L, 95% CI −3.22 to −1.84) with high heterogeneity between (I² = 97%) and across (τ² = 5.88) the studies. The fixed-effect model showed a significant change in TC, low-density lipoprotein, and BGL, whereas it showed no significant changes in high-density lipoprotein and TGL/TAG. The dose–response model showed that a 3-g/d dose of oat or barley β-glucan was sufficient to decrease TC.

Conclusion

Consumption of 3 g/d of oat or barley β-glucan is sufficient to decrease blood cholesterol, whereas the effect on BGL is still inconclusive, with high heterogeneity, and requires further clinical research studies with longer intervention periods.     

Conjugated linoleic acid improves glucose utilization in the soleus muscle of rats fed linoleic acid–enriched and linoleic acid–deprived diets

The effect that conjugated linoleic acid (CLA) has on glucose metabolism in experimental animals depends on nutritional conditions. Therefore, we hypothesized that CLA improves glucose utilization and insulin sensitivity in rats fed different levels of dietary linoleic acid (LA). We investigated the effect of CLA on the uptake, incorporation, and oxidation of glucose and glycogen synthesis in the soleus muscle of rats who were fed either LA-enriched (⁺LA) or LA-deprived (⁻LA) diets, under basal conditions and in the absence or presence of insulin and/or palmitate. For 60 days, male Wistar rats were fed 1 of 4 diets consisting of ⁺LA, ⁻LA, or ⁺LA and ⁻LA supplemented with CLA. Nutritional parameters and soleus glucose metabolism were evaluated. Under basal conditions, CLA enhanced soleus glucose oxidation, whereas increased glucose uptake and incorporation were observed in the ⁻LA + CLA group. Conjugated linoleic acid–supplemented rats presented a lower response to insulin on glucose metabolism compared with non–CLA-supplemented rats. Palmitate partially inhibited the effect of insulin on the uptake and incorporation of glucose in the ⁺LA and ^–LA groups but not in the ⁺LA + CLA or ⁻LA + CLA groups. Dietary CLA increased glucose utilization under basal conditions and prevented the palmitate-induced inhibition of glucose uptake and incorporation that is stimulated by insulin. The beneficial effects of CLA were better in LA-deprived rats. Conjugated linoleic acid may also have negative effects, such as lowering the insulin response capacity. These results demonstrate the complexities of the interactions between CLA, palmitate, and/or insulin to differentially modify muscle glucose utilization and show that the magnitude of the response is related to the dietary LA levels.     

The role of point-of-care β-hydroxybutyrate testing in the diagnosis of diabetic ketoacidosis: a review

The number of patients with diabetes and diabetes-related complications is increasing. Rapid and accurate diagnosis is key to efficiently providing the appropriate level of care for patients with diabetes. When faced with a hyperglycemic patient (ie, blood glucose level > 250 mg/dL), the prevailing attitude among health care providers is to "think worst first," and common clinical practice is to perform an evaluation for diabetic ketoacidosis (DKA). Traditionally, diagnosing DKA in accordance with the American Diabetes Association guidelines requires performing ≥ 2 (possibly 3) tests to obtain measurements for blood glucose, serum bicarbonate, serum pH, and serum anion gap levels, as well as measurements of either urine or serum ketone bodies. Recently, commercial point-of-care β-hydroxybutyrate measurement devices have become readily accessible and less expensive. These devices offer the potential to simplify clinicians' diagnostic approach to hyperglycemic patients. In this evidence-based literature review, we describe the use of point-of-care β-hydroxybutyrate testing for diagnosing DKA, and discuss its limitations in determining DKA severity.     

Effect of a low molecular weight, high-purity β-glucan on in vitro digestion and glycemic response

β-Glucans are believed to lower postprandial glycemia due to their ability to increase viscosity and slow down gastric emptying. The effect of high-purity barley β-glucan (Glucagel) was tested on in vitro starch digestibility and glycemic response of chapattis. In a randomized controlled crossover trial, 10 healthy human subjects consumed chapattis containing 0, 4 and 8% β-glucan on different occasions. Capillary blood samples were collected before and at 0, 15, 30, 45, 60, 90 and 120 min after consuming the chapattis. There was no significant difference either in the amount of glucose released after in vitro digestion or in the glycemic response to chapattis with 0, 4 and 8% β-glucan (P>0.05). It may be concluded that low molecular weight barley β-glucan, although of 75% purity, was not effective in lowering glycemic response possibly due to its inability to influence starch digestion and particle breakdown during in vitro digestion.     

A Comparison of the Effects of the Opioid Antagonists Naltrexone,Naltrindole, and β-Funaltrexamine on Ethanol Consumption in the Rat

The effects of the universal opioid antagonist naltrexone were compared to the δ-selective opioid antagonist naltrindole and the μ-selective opioid antagonist β-funaltrexamine on ethanol consumption in the absence of food or fluid deprivation using a limited access procedure in Wistar rats. Both naltrexone, at doses of 0.1, 0.25, 0.5, 1.0, 3.0, and 10 mg/kg, and β-funaltrexamine, at doses of 5.0 and 20.0 mg/kg, significantly decreased consumption of a 6% ethanol solution compared to saline control groups. Naltrindole, at doses of 5.0 and 15.0 mg/kg, failed to significantly reduce ethanol consumption. In addition, the highest doses of naltrexone, which antagonize δ as well as μ-opioid receptors, did not differ significantly from the lowest doses in their ability to reduce ethanol consumption. These data suggest that ethanol consumption using the limited access paradigm in the outbred rat is modulated by μ rather than δ-opioid receptors. Although this is not consistent with other data showing that δ antagonists decrease ethanol consumption, it is suggested that these difference may be related to the alcohol-preferring rats used in those experiments.     

Drug treatment and the control of malaria in Africa: a time of hope?

A wide selection of drugs is available to treat malaria. In many countries, however, the resistance of Plasmodium falciparum to drug therapy is problematic. For example, resistance to chloroquine is a problem in most tropical areas. Sulphadoxine/pyrimethamine, quinine, mefloquine, and artemisinin remain available and effective in many scenarios. Malarone and benflumetol/artemether are new drug combinations to apply against malaria infection. Each country needs an agreed-upon antimalarial drugs policy which takes into account the epidemiological factors affecting parasite distribution and the pattern of drug resistance. The prevailing health service characteristics, including the levels of health care at which different drugs are available, the risks and benefits of different drug regimens, compliance factors, and the logistics and cost of drug delivery must also be considered. Policy should be to reduce malaria mortality and morbidity and the development of drug resistance, while remaining within the limits of each country's budgetary and staffing capacity. Indications for treatment, genotyping and the reinfection problem in drug evaluation, amodiaquine reappraisal, new drug combinations, the role of drugs in preventing mosquito infection, and molecular biology in the surveillance of drug resistance are discussed.     

Carbohydrates and increases in obesity: does the type of carbohydrate make a difference?

With the prevalence of obesity increasing in the U.S. and elsewhere, the place of carbohydrates in the diet has recently been under closer examination. This has led to the development of methods for analyzing the effects of dietary carbohydrate. Primary among these methods is the glycemic index, a measure of a food's effect on blood glucose levels, which was initially designed as a method for determining suitable carbohydrates for people with diabetes. However, the glycemic index does not address other metabolic issues related to excess sugar consumption. Prominent among these issues is the use of low glycemic index sweeteners, particularly fructose, which is increasingly present in processed food. Fructose is associated with increased adiposity, which may result from its effects on hormones associated with satiety. Other methods of determining "good" carbohydrates have also been developed. The common theme among them is increased nonstarchy vegetables and higher-fiber legumes.     

Effects of cannabinoids on neuropeptide Y and β-endorphin expression in the rat hypothalamic arcuate nucleus

The control of appetite and satiety is extremely complex and involves a balance between neurotransmitters and neuropeptides to stimulate and/or inhibit feeding behaviour. The effect of cannabinoids on food intake is well established, but little is known about the mechanism of action underlying their activity. In the present report, the effect of pharmacological manipulation of the cannabinoid receptor on the expression of hypothalamic neuropeptides is investigated. We used an immunohistochemical approach to examine the effect of intracerebroventricular administration of the cannabinoid receptor agonist WIN55,212-2 and the inverse agonist AM251 on neuropeptide Y (NPY) and the β-endorphin (β-end) neuronal hypothalamic systems. Double immunohistochemistry (c-fos/β-end) was used to assess the number of β-end neurons activated by the cannabinoid agonist. The present results showed that 1?μg WIN 55,212-2 increases β-end immunoreactivity within the arcuate nucleus while no significant changes were noted in the NPY-immunoreactive nerve fibres network in comparison to the control group. Injection of 1?μg AM251 decreases both NPY and β-end immunoreactivity within the arcuate nucleus. The number of β-end neurons exhibiting c-fos increased significantly in WIN 55,212-2 compared with the control group. These results suggest that cannabinoids affect the expression of hypothalamic neuropeptides, notably the NPY and β-end systems, which may have implications in the orexigenic action of cannabinoids.     

Removal of a Nexplanon® implant located in the biceps muscle using a combination of ultrasound and fluoroscopy guidance

Despite modifications to avoid deep insertions, clinical experience with Nexplanon® demonstrates that deep insertions still occur. We present a case of a Nexplanon® found in the biceps muscle that was successfully removed with a small incision using a combination of ultrasound and fluoroscopy guidance by interventional radiologists.     

Alterations in liver ultrastructure and induction of UDP-glucuronyltransferase in the rat following prenatal exposure to 3,4,3′,4′-tetrachlorobiphenyl

Prenatal exposure of rats to 3,4,3,4-tetrachlorobiphenyl (4CB) at 3 mg/kg/day from day 6 through day 18 of gestation produced a high incidence of perinatal mortality. Although the fine structure of fetal liver at day 19 appeared normal, significant changes were manifest in newborn pups. These alterations included a distention of cisternae of the rough endoplasmic reticulum and conspicuous proliferation of smooth membrane elements, which persisted in survivors for several weeks. In addition, mitochondria often appeared condensed with an atypical distribution of cristae. These changes were accompanied by a postnatal induction in the activity of liver UDP-glucuronyltransferase. In treated litters, 3-week-old pups had activity levels of the enzyme three times that of the controls.     

An energy-restricted high-protein diet supplemented with β-cryptoxanthin alleviated oxidative stress and inflammation in nonalcoholic fatty liver disease: a randomized controlled trial

The efficacy of β-cryptoxanthin (BCX), a high-protein diet (HPD), or both in reducing oxidative stress and inflammation in nonalcoholic fatty liver disease (NAFLD) has never been examined within a randomized controlled trial (RCT). Thus, we aimed to assess the efficacy of an energy-restricted HPD supplemented with BCX in alleviating these conditions in NAFLD in an RCT design. We hypothesized that this combination may improve oxidative stress and inflammation in NAFLD as compared to a standard energy-restricted diet. Ninety-two ultrasonographically confirmed overweight/obese adult NAFLD patients attending an outpatient clinic in Ahvaz, Iran, were recruited for this 12-week, single-center, parallel-group, double-blind RCT from 2017 to 2018. Subjects were randomized into 4 equal groups (n = 23): HPD-BCX (energy-restricted HPD + BCX), HPD (energy-restricted HPD + placebo), BCX (standard energy-restricted diet + BCX), and control (standard energy-restricted diet + placebo). Serum levels of oxidative stress– and inflammation-related markers, as primary outcome measures, were determined at baseline and at the study end point. The 1-way analysis of covariance models in the intention-to-treat population (N = 92) showed that the HPD-BCX group achieved greater 12-week reductions in malondialdehyde, high-sensitivity C-reactive protein, interleukin-6, and total cytokeratin-18 (CK18-M65) but higher increases in total antioxidant capacity and adiponectin compared to the control group (mean differences for malondialdehyde, high-sensitivity C-reactive protein, interleukin-6, total cytokeratin-18, total antioxidant capacity, and adiponectin were −1.9 nmol/mL, −1.0 mg/L, −2.0 ng/L, −270.9 ng/L, 2.5 U/mL, and 1.9 mg/L, respectively; all P < .001). These results show that an energy-restricted HPD supplemented with BCX more efficaciously alleviates oxidative stress and inflammation in NAFLD as compared to a standard energy-restricted diet.     

Expanding the concept of parental control: a role for overt and covert control in children's snacking behaviour?

The existing literature on parental control and children's diets is confusing. The present paper reports two studies to explore an expanded conceptualisation of parental control with a focus on overt control which 'can be detected by the child' and covert control which 'cannot be detected by the child'. In study 1, 297 parents of children aged between 4 and 11 completed a measure of overt control and covert control alongside ratings of their child's snacking behaviour as a means to assess who uses either overt or covert control and how these aspects of parental control relate to a child's snacking behaviour. The results showed that lighter parents and those with children perceived as heavier were more likely to use covert control and those from a higher social class were more likely to use overt control. Further, whilst greater covert control predicted a decreased intake of unhealthy snacks, greater overt control predicted an increased intake of healthy snacks. In study 2, 61 parents completed the same measure of overt and covert control alongside the three control subscales of the Child Feeding Questionnaire [Birch, L.L., Fisher, J.O., Grimm-Thomas, Markey, C.N., Sawyer, R. (2001). Confirmatory factor analysis of the Child Feeding Questionnaire: A measure of parental attitudes, beliefs and practices about child feeding and obesity proneness. Appetite, 36, 201-210] to assess degrees of overlap between these measures. The results showed that although these five measures of control were all positively correlated, the correlations between the new and existing measures indicated a maximum of 21% shared variance suggesting that covert and overt control are conceptually and statistically separate from existing measures of control. To conclude, overt and covert control may be a useful expansion of existing ways to measure and conceptualise parental control. Further, these constructs may differentially relate to snacking behaviour which may help to explain some of the confusion in the literature.     

Dietary β-glucan regulates the levels of inflammatory factors, inflammatory cytokines, and immunoglobulins in interleukin-10 knockout mice

β-Glucan is known to have anti-inflammatory properties, and several studies have demonstrated the beneficial effects of dietary β-glucan on inflammatory bowel disease (IBD). However, it is unknown how β-glucan mediates its protective effects on IBD. Therefore, we used a well-established mouse model for IBD, interleukin (IL)-10(-/-) mice, to explore the protective effects of β-glucan on IBD-like symptoms caused by IL-10 deficiency. The mice were divided into two groups: IL-10(-/-) and IL-10(-/-)?+?β-glucan treatment groups. IL-10(-/-) mice treated with dietary β-glucan exhibited less inflammation within the colon. The levels of immunoglobulins A and E were lower in the serum, spleen, mesenteric lymph nodes, and Peyer's patches in the IL-10(-/-) mice compared with the IL-10(-/-)?+?β-glucan mice. Also, the expression of pro-inflammatory cytokines was lower in the IL-10(-/-)?+?β-glucan mice compared with the IL-10(-/-) mice. Histological analysis also revealed that administration of dietary β-glucan in IL-10(-/-) mice reduced colonic tissue damage. Finally, the expression of the pro-inflammatory cytokine tissue necrosis factor-α was significantly lower with dietary β-glucan treatment in IL-10(-/-) mice. In conclusion, dietary β-glucan reduces the inflammation associated with IBD caused by IL-10 deficiency.     

The cannabinoid system: a role in both the homeostatic and hedonic control of eating?

Knowledge of the cannabinoid system and its components has expanded greatly over the past decade. There is increasing evidence for its role in the regulation of food intake and appetite. Cannabinoid system activity in the hypothalamus is thought to contribute to the homeostatic regulation of energy balance, under the control of the hormone leptin. A second component of cannabinoid-mediated food intake appears to involve reward pathways and the hedonic aspect of eating. With the cannabinoid system contributing to both regulatory pathways, it presents an attractive therapeutic target for the treatment of both obesity and eating disorders.     

Has a mixture of amino acids and micronutrients influence on glucose metabolism and dietary fatty acid pattern in chronic psychosocially stressed persons? A pilot study

Brain food, e.g. L-tryptophan, antioxidative substances, B vitamins and magnesium are thought to be beneficial for obesity, inflammation and insulin resistance. In the present pilot study we hypothesised that a specific amino acid mixture with micronutrients improves the cardiometabolic situation of chronically stressed persons. Cardiovascular and metabolic parameters were analysed as per protocol in 32 patients. Chronic stress disorders in the same patients were assessed by a psychological neurological questionnaire (PNF). After dietary intervention a reduction of the fasting serum insulin concentrations occurred in the treatment group. An association was found between PNF values, insulin concentrations at baseline and an insulin reduction after 12 weeks. The results support the use of our specific dietary supplement for improved stress management and a decrease in metabolic dysfunction.     

Does glutamine act as a substrate for transamination reactions in the liver of fed and fasted sheep?

The present study investigated the relative importance of glutamine as a transamination source in the ovine liver by examination of the labelling of amino acids (AA) in the hepatic free pool, mixed liver and plasma proteins of fed and fasted sheep, following infusion of isotopically-labelled glutamine. In a cross-over design four sheep were either fasted for 3 d or fed to maintenance and finally euthanased. At each intake, the sheep were infused for 6 h with [2-15N]glutamine (150 micromol/h) and samples of total plasma protein isolated. Following the terminal infusion, liver tissue total proteins were prepared and hydrolysed and 15N-enrichments in seventeen AA were determined by GC-combustion-isotope-ratio mass spectrometry. All AA were enriched (relative to natural abundance) except lysine and threonine, with the lowest enrichments in phenylalanine and histidine. There was no effect of the fed v. fasted state, except for leucine and isoleucine in liver protein Enrichments in liver protein were greater than in plasma protein except proline) and probably reflect the faster turnover rate of hepatic constitutive proteins compared with export proteins. Amination to methionine was greater than that to phenylalanine suggesting a mechanism for preferentially protecting the former. This factor could be important for ruminant production, as methionine is often considered to be the first limiting AA for animals offered certain silages and conserved forages. Enrichments in all AA (except for glutamine, alanine and aspartate) were less than that for glutamate and thus transaminations may have occurred with glutamine directly or via glutamate, following the action of hepatic glutaminase.