Perceived Barriers to Application of Glycaemic Index: Valid Concerns or Lost in Translation?

The term glycaemic-index (GI) originally appeared in the literature in the early 1980s. GI categorizes carbohydrate according to glycaemic effect postprandially. Since its inception, GI has obtained and maintained interest of academics and clinicians globally. Upon review of GI literature, it becomes clear that the clinical utility of GI is a source of controversy. Can and should GI be applied clinically? There are academics and clinicians on both sides of the argument. Certainly, this controversy has been a stimulus for the evolution of GI methodology and application research, but may also negatively impact clinicians’ perception of GI if misunderstood. This article reviews two assessments of GI that are often listed as barriers to application; the GI concept is (1) too complex and (2) too difficult for clients to apply. The literature reviewed does not support the majority of purported barriers, but does indicate that there is a call from clinicians for more and improved GI education tools and clinician GI education. The literature indicates that the Registered Dietitian (RD) can play a key role in GI knowledge translation; from research to application. Research is warranted to assess GI education tool and knowledge needs of clinicians and the clients they serve

Effect of adding the novel fiber, PGX®, to commonly consumed foods on glycemic response, glycemic index and GRIP: a simple and effective strategy for reducing post prandial blood glucose levels - a randomized, controlled trial

<p>Abstract</p> <p>Background</p> <p>Reductions in postprandial glycemia have been demonstrated previously with the addition of the novel viscous polysaccharide (NVP), PolyGlycopleX^®(PGX^®), to an OGTT or white bread. This study explores whether these reductions are sustained when NVP is added to a range of commonly consumed foods or incorporated into a breakfast cereal.</p> <p>Methods</p> <p>Ten healthy subjects (4M, 6F; age 37.3 ± 3.6 y; BMI 23.8 ± 1.3 kg/m²), participated in an acute, randomized controlled trial. The glycemic response to cornflakes, rice, yogurt, and a frozen dinner with and without 5 g of NVP sprinkled onto the food was determined. In addition, 3 granolas with different levels of NVP and 3 control white breads and one white bread and milk were also consumed. All meals contained 50 g of available carbohydrate. Capillary blood samples were taken fasting and at 15, 30, 45, 60, 90 and 120 min after the start of the meal. The glycemic index (GI) and the glycemic reduction index potential (GRIP) were calculated. The blood glucose concentrations at each time and the iAUC values were subjected to repeated-measures analysis of variance (ANOVA) examining for the effect of test meal. After demonstration of significant heterogeneity, differences between individual means was assessed using GLM ANOVA with Tukey test to adjust for multiple comparisons.</p> <p>Results</p> <p>Addition of NVP reduced blood glucose response irrespective of food or dose (p < 0.01). The GI of cornflakes, cornflakes+NVP, rice, rice+NVP, yogurt, yogurt+NVP, turkey dinner, and turkey dinner+NVP were 83 ± 8, 58 ± 7, 82 ± 8, 45 ± 4, 44 ± 4, 38 ± 3, 55 ± 5 and 41 ± 4, respectively. The GI of the control granola, and granolas with 2.5 and 5 g of NVP were 64 ± 6, 33 ± 5, and 22 ± 3 respectively. GRIP was 6.8 ± 0.9 units per/g of NVP.</p> <p>Conclusion</p> <p>Sprinkling or incorporation of NVP into a variety of different foods is highly effective in reducing postprandial glycemia and lowering the GI of a food.</p> <p>Clinical Trial registration</p> <p>NCT00935350.</p

Mindfulness meditation targets transdiagnostic symptoms implicated in stress-related disorders: Understanding relationships between changes in mindfulness, sleep quality, and physical symptoms

Mindfulness-Based Stress Reduction (MBSR) is an 8-week meditation program known to improve anxiety, depression, and psychological well-being. Other health-related effects, such as sleep quality, are less well established, as are the psychological processes associated with therapeutic change. This prospective, observational study (n=213) aimed to determine whether perseverative cognition, indicated by rumination and intrusive thoughts, and emotion regulation, measured by avoidance, thought suppression, emotion suppression, and cognitive reappraisal, partly accounted for the hypothesized relationship between changes in mindfulness and two health-related outcomes: sleep quality and stress-related physical symptoms. As expected, increased mindfulness following the MBSR program was directly correlated with decreased sleep disturbance (r=-0.21, p=0.004) and decreased stress-related physical symptoms (r=-0.38, p<0.001). Partial correlations revealed that pre-post changes in rumination, unwanted intrusive thoughts, thought suppression, experiential avoidance, emotion suppression, and cognitive reappraisal each uniquely accounted for up to 32% of the correlation between the change in mindfulness and change in sleep disturbance and up to 30% of the correlation between the change in mindfulness and change in stress-related physical symptoms. Results suggest that the stress-reducing effects of MBSR are due, in part, to improvements in perseverative cognition and emotion regulation, two “transdiagnostic” mental processes that cut across stress-related disorders

Equivalent glycemic load (EGL): a method for quantifying the glycemic responses elicited by low carbohydrate foods

BACKGROUND: Glycemic load (GL) is used to quantify the glycemic impact of high-carbohydrate (CHO) foods, but cannot be used for low-CHO foods. Therefore, we evaluated the accuracy of equivalent-glycemic-load (EGL), a measure of the glycemic impact of low-CHO foods defined as the amount of CHO from white-bread (WB) with the same glycemic impact as one serving of food. METHODS: Several randomized, cross-over trials were performed by a contract research organization using overnight-fasted healthy subjects drawn from a pool of 63 recruited from the general population by newspaper advertisement. Incremental blood-glucose response area-under-the-curve (AUC) elicited by 0, 5, 10, 20, 35 and 50 g CHO portions of WB (WB-CHO) and 3, 5, 10 and 20 g glucose were measured. EGL values of the different doses of glucose and WB and 4 low-CHO foods were determined as: EGL = (F-B)/M, where F is AUC after food and B is y-intercept and M slope of the regression of AUC on grams WB-CHO. The dose-response curves of WB and glucose were used to derive an equation to estimate GL from EGL, and the resulting values compared to GL calculated from the glucose dose-response curve. The accuracy of EGL was assessed by comparing the GL (estimated from EGL) values of the 4 doses of oral-glucose with the amounts actually consumed. RESULTS: Over 0–50 g WB-CHO (n = 10), the dose-response curve was non-linear, but over the range 0–20 g the curve was indistinguishable from linear, with AUC after 0, 5, 10 and 20 g WB-CHO, 10 ± 1, 28 ± 2, 58 ± 5 and 100 ± 6 mmol × min/L, differing significantly from each other (n = 48). The difference between GL values estimated from EGL and those calculated from the dose-response curve was 0 g (95% confidence-interval, ± 0.5 g). The difference between the GL values of the 4 doses of glucose estimated from EGL, and the amounts of glucose actually consumed was 0.2 g (95% confidence-interval, ± 1 g). CONCLUSION: EGL, a measure of the glycemic impact of low-carbohydrate foods, is valid across the range of 0–20 g CHO, accurate to within 1 g, and at least sensitive enough to detect a glycemic response equivalent to that produced by 3 g oral-glucose in 10 subjects

Decreased symptoms of depression after mindfulness-based stress reduction: potential moderating effects of religiosity, spirituality, trait mindfulness, sex, and age

Objective: mindfulness-based stress reduction (MBSR) is a secular meditation training program that reduces depressive symptoms. Little is known, however, about the degree to which a participant's spiritual and religious background, or other demographic characteristics associated with risk for depression, may affect the effectiveness of MBSR. Therefore, this study tested whether individual differences in religiosity, spirituality, motivation for spiritual growth, trait mindfulness, sex, and age affect MBSR effectiveness.Methods: as part of an open trial, multiple regression was used to analyze variation in depressive symptom outcomes among 322 adults who enrolled in an 8-week, community-based MBSR program.Results: as hypothesized, depressive symptom severity decreased significantly in the full study sample (d=0.57; p&lt;0.01). After adjustment for baseline symptom severity, moderation analyses revealed no significant differences in the change in depressive symptoms following MBSR as a function of spirituality, religiosity, trait mindfulness, or demographic variables. Paired t tests found consistent, statistically significant (p&lt;0.01) reductions in depressive symptoms across all subgroups by religious affiliation, intention for spiritual growth, sex, and baseline symptom severity. After adjustment for baseline symptom scores, age, sex, and religious affiliation, a significant proportion of variance in post-MBSR depressive symptoms was uniquely explained by changes in both spirituality (?=?0.15; p=0.006) and mindfulness (?=?0.17; p&lt;0.001).Conclusions: these findings suggest that MBSR, a secular meditation training program, is associated with improved depressive symptoms regardless of affiliation with a religion, sense of spirituality, trait level of mindfulness before MBSR training, sex, or age. Increases in both mindfulness and daily spiritual experiences uniquely explained improvement in depressive symptom

Effect of varying molecular weight of oat β-glucan taken just before eating on postprandial glycemic response in healthy humans

To see if the molecular weight (MW) and viscosity of oat β-glucan (OBG) when taken before eating determine its effect on postprandial glycemic responses (PPRG), healthy overnight-fasted subjects (n = 16) were studied on eight separate occasions. Subjects consumed 200 mL water alone (Control) or with 4 g OBG varying in MW and viscosity followed, 2–3 min later, by 113 g white-bread. Blood was taken fasting and at 15, 30, 45, 60, 90, and 120 min after starting to eat. None of the OBG treatments differed significantly from the Control for the a-priori primary endpoint of glucose peak-rise or secondary endpoint of incremental area-under-the-curve (iAUC) over 0–120 min. However, significant differences from the Control were seen for glucose iAUC over 0–45 min and time to peak (TTP) glucose. Lower log(MW) and log(viscosity) were associated with higher iAUC 0–45 (p &lt; 0.001) and shorter TTP (p &lt; 0.001). We conclude that when 4 g OBG is taken as a preload, reducing MW does not affect glucose peak rise or iAUC0-120, but rather accelerates the rise in blood glucose and reduces the time it takes glucose to reach the peak. However, this is based on post-hoc calculation of iAUC0-45 and TTP and needs to be confirmed in a subsequent study.</p

Bioactive oat β-glucan reduces LDL cholesterol in Caucasians and non-Caucasians

<p>Abstract</p> <p>Background</p> <p>There is increasing global acceptance that viscous soluble fibers lower serum LDL cholesterol (LDL-C), but most evidence for this comes from studies in Caucasians. To see if oat β-glucan lowers LDL-C in Caucasians and non-Caucasians we conducted a post-hoc analysis of the results of a randomized, controlled, double-blind, multi-center clinical trial whose primary aim was to determine if molecular-weight (MW) influenced the LDL-C-lowering effect of oat β-glucan.</p> <p>Results</p> <p>Caucasian and non-Caucasian subjects with LDL-C-C ≥ 3.0 and ≤ 5.0 mmol/L (n = 786 screened, n = 400 ineligible, n = 19 refused, n = 367 randomized, n = 345 completed, n = 1 excluded for missing ethnicity) were randomly assigned to consume cereal containing wheat-fiber (Control, n = 74:13 Caucasian:non-Caucasian) or 3 g high-MW (3H, 2,250,000 g/mol, n = 67:19), 4 g medium-MW (4 M, 850,000 g/mol, n = 50:17), 3 g medium-MW (3M, 530,000 g/mol, n = 54:9) or 4 g low-MW (4 L, 210,000 g/mol, n = 51:12) oat β-glucan daily for 4 weeks. LDL-C after 4 weeks was influenced by baseline LDL-C (p < 0.001) and treatment (p = 0.003), but not ethnicity (p = 0.74). In all subjects, compared to control, 3 H, 4 M and 3 M reduced LDL-C significantly by 4.8 to 6.5%, but 4 L had no effect. Compared to control, the bioactive oat β-glucan treatments (3H, 4M and 3M) reduced LDL-C by a combined mean (95% CI) of 0.18 (0.06, 0.31) mmol/L (4.8%, n = 171, p = 0.004) in Caucasians, a value not significantly different from the 0.37 (0.09, 0.65) mmol/L (10.3%, n = 45, p = 0.008) reduction in non-Caucasians.</p> <p>Conclusion</p> <p>We conclude that oat β-glucan reduces LDL-C in both Caucasians and non-Caucasians; there was insufficient power to determine if the magnitude of LDL-C-lowering differed by ethnicity.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00981981">NCT00981981</a></p

Concentrated oat β-glucan, a fermentable fiber, lowers serum cholesterol in hypercholesterolemic adults in a randomized controlled trial

BACKGROUND: Soluble fibers lower serum lipids, but are difficult to incorporate into products acceptable to consumers. We investigated the physiological effects of a concentrated oat β-glucan on cardiovascular disease (CVD) endpoints in human subjects. We also compared the fermentability of concentrated oat β-glucan with inulin and guar gum in a model intestinal fermentation system. METHODS: Seventy-five hypercholesterolemic men and women were randomly assigned to one of two treatments: 6 grams/day concentrated oat β-glucan or 6 grams/day dextrose (control). Fasting blood samples were collected at baseline, week 3, and week 6 and analyzed for total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, glucose, insulin, homocysteine and C-reactive protein (CRP). To estimate colonic fermentability, 0.5 g concentrated oat β-glucan was incubated in a batch model intestinal fermentation system, using human fecal inoculum to provide representative microflora. Fecal donors were not involved with the β-glucan feeding trial. Inulin and guar gum were also incubated in separate serum bottles for comparison. RESULTS: Oat β-glucan produced significant reduction from baseline in total cholesterol (-0.3 ± 0.1 mmol/L) and LDL cholesterol (-0.3 ± 0.1 mmol/L), and the reduction in LDL cholesterol were significantly greater than in the control group (p = 0.03). Concentrated oat β-glucan was a fermentable fiber and produced total SCFA and acetate concentrations similar to inulin and guar gum. Concentrated oat β-glucan produced the highest concentrations of butyrate at 4, 8, and 12 hours. CONCLUSION: Six grams concentrated oat β-glucan per day for six weeks significantly reduced total and LDL cholesterol in subjects with elevated cholesterol, and the LDL cholesterol reduction was greater than the change in the control group. Based on a model intestinal fermentation, this oat β-glucan was fermentable, producing higher amounts of butyrate than other fibers. Thus, a practical dose of β-glucan can significantly lower serum lipids in a high-risk population and may improve colon health