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Type-4 Resistant Starch in Substitution for Available Carbohydrate Reduces Postprandial Glycemic Response and Hunger in Acute, Randomized, Double-Blind, Controlled Study.
Stewart, ML, Wilcox, ML, Bell, M, Buggia, MA, Maki, KC
Nutrients. 2018;10(2)
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Resistant starch is a combination of dietary fibre and carbohydrate that ‘resists’ digestion in the small intestine and is fermented in the large intestine by gut bacteria. It is associated with a number of health benefits, particularly the management of blood glucose levels. This small double-blind, randomised controlled trail allocated 36 healthy individuals (mostly female, average age 46 and BMI 26) to eat either a low-fibre scone or a scone with added resistant starch in the form of acid-hydrolyzed and heat treated maize starch. The response of blood glucose and blood insulin levels were measured, as well as participants feeling of fullness and intestinal comfort after eating the scones. The scone with the added resistant starch had significantly lower blood glucose (43-45% lower) and blood insulin (35-40% lower) levels after eating the scone, when compared to those eating the low-fibre scone. They also reported feeling fuller for longer and had no particular digestive symptoms. Whilst this is a small study, Nutrition Practitioners may want to investigate dietary sources of resistant starch when working with clients to balance blood glucose and insulin levels.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Based on the findings of the Predict Study, it is highly probable that the same meal will elicit a different glycaemic response in individuals with different gut microbial compositions.
- The gut microbiota, therefore, needs to be taken into consideration when assessing glycaemic responses to a meal.
- Healthcare practitioners may like to consider the use of resistant starches as an additional tool to balance blood sugar responses to a meal.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Dietary modulation of the gut microbiota impacts human health. This paper discusses the effects of a man-made type of resistant starch on the glycaemic response to a meal. Based on the initial findings of the Predict Study, it is highly probably that the same meal will elicit a different glycaemic (and wider metabolic) response in individuals with different gut microbial compositions. So this paper confirms the need to take the gut microbiota into consideration when assessing glycaemic responses to a meal, both in research and in clinical practice.
Clinical practice applications:
Not all fibres are equal, and not all starches are equal. Type 4 resistant starch is a novel addition to the already known types 1, 2, and 3 and provides with clinicians with an additional tool to balance their patient's blood sugar response to a meal based on the effect of resistant starch on the gut microbiota.
Considerations for future research:
Resistant starches are known for their ability to affect gut microbiota composition and short-chain fatty acid concentrations which, in turn, have the ability to modulate immune and metabolic functions in the host, including cholesterol, fasting glucose, glycosylated haemoglobin, and pro-inflammatory markers. Further studies on glycaemic and wider metabolic responses to a meal must take into consideration the effect of resistant starches on gut microbial composition. Not doing so may be skewing scientific findings.
Abstract
Resistant starch (RS) is a type of dietary fiber that has been acknowledged for multiple physiological benefits. Resistant starch type 4 (RS4) is a subcategory of RS that has been more intensively studied as new types of RS4 emerge in the food supply. The primary aim of this randomized, double-blind, controlled study was to characterize the postprandial glucose response in healthy adults after consuming a high fiber scone containing a novel RS4 or a low fiber control scone without RS4. Secondary aims included assessment of postprandial insulin response, postprandial satiety, and gastrointestinal tolerance. The fiber scone significantly reduced postprandial glucose and insulin incremental areas under the curves (43-45% reduction, 35-40% reduction, respectively) and postprandial glucose and insulin maximum concentrations (8-10% and 22% reduction, respectively). The fiber scone significantly reduced hunger and desire to eat during the 180 min following consumption and yielded no gastrointestinal side effects compared with the control scone. The results from this study demonstrate that a ready-to-eat baked-good, such as a scone, can be formulated with RS4 replacing refined wheat flour to yield statistically significant and clinically meaningful reductions in blood glucose and insulin excursions. This is the first study to report increased satiety after short-term RS4 intake, which warrants further investigation in long-term feeding studies.
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Food sources of fructose-containing sugars and glycaemic control: systematic review and meta-analysis of controlled intervention studies.
Choo, VL, Viguiliouk, E, Blanco Mejia, S, Cozma, AI, Khan, TA, Ha, V, Wolever, TMS, Leiter, LA, Vuksan, V, Kendall, CWC, et al
BMJ (Clinical research ed.). 2018;363:k4644
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With increasing evidence linking fructose to metabolic disease, current dietary guidelines recommend a reduction of added free sugars, especially fructose-containing sugars from sugars-sweetened beverages (SSBs). However, it is currently unclear whether the negative impact of fructose on metabolic health is as implicative in the context of an overall dietary consumption pattern. The aim of this study was to assess the effect of different sources of fructose-containing sugars on glycaemic control in people with and without diabetes. This review analysed 155 controlled intervention studies and found that fructose-containing sugars in the form of fruit do not have a harmful effect on glycaemic control when compared to energy-matched macronutrient substitutions. Further, harmful effects on glycaemic control were found when excess energy in the form of fructose-containing sugars from SSBs were added to the diet. The authors conclude the food source of fructose-containing sugars on glycemic control is important in the conversation of metabolic health and glycaemic control. While further research is needed to assess a wider variety of food sources, public health professionals should consider the influence of food sources when developing dietary recommendations for the prevention and management of diabetes and other metabolic conditions.
Abstract
OBJECTIVE To assess the effect of different food sources of fructose-containing sugars on glycaemic control at different levels of energy control. DESIGN Systematic review and meta-analysis of controlled intervention studies. DATA SOURCES Medine, Embase, and the Cochrane Library up to 25 April 2018. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Controlled intervention studies of at least seven days' duration and assessing the effect of different food sources of fructose-containing sugars on glycaemic control in people with and without diabetes were included. Four study designs were prespecified on the basis of energy control: substitution studies (sugars in energy matched comparisons with other macronutrients), addition studies (excess energy from sugars added to diets), subtraction studies (energy from sugars subtracted from diets), and ad libitum studies (sugars freely replaced by other macronutrients without control for energy). Outcomes were glycated haemoglobin (HbA1c), fasting blood glucose, and fasting blood glucose insulin. DATA EXTRACTION AND SYNTHESIS Four independent reviewers extracted relevant data and assessed risk of bias. Data were pooled by random effects models and overall certainty of the evidence assessed by the GRADE approach (grading of recommendations assessment, development, and evaluation). RESULTS 155 study comparisons (n=5086) were included. Total fructose-containing sugars had no harmful effect on any outcome in substitution or subtraction studies, with a decrease seen in HbA1c in substitution studies (mean difference -0.22% (95% confidence interval to -0.35% to -0.08%), -25.9 mmol/mol (-27.3 to -24.4)), but a harmful effect was seen on fasting insulin in addition studies (4.68 pmol/L (1.40 to 7.96)) and ad libitum studies (7.24 pmol/L (0.47 to 14.00)). There was interaction by food source, with specific food sources showing beneficial effects (fruit and fruit juice) or harmful effects (sweetened milk and mixed sources) in substitution studies and harmful effects (sugars-sweetened beverages and fruit juice) in addition studies on at least one outcome. Most of the evidence was low quality. CONCLUSIONS Energy control and food source appear to mediate the effect of fructose-containing sugars on glycaemic control. Although most food sources of these sugars (especially fruit) do not have a harmful effect in energy matched substitutions with other macronutrients, several food sources of fructose-containing sugars (especially sugars-sweetened beverages) adding excess energy to diets have harmful effects. However, certainty in these estimates is low, and more high quality randomised controlled trials are needed. STUDY REGISTRATION Clinicaltrials.gov (NCT02716870).
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Cardio-Metabolic Benefits of Plant-Based Diets.
Kahleova, H, Levin, S, Barnard, N
Nutrients. 2017;9(8)
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Chronic disease, which includes cardiovascular disease, obesity, type 2 diabetes, hypertension, hyperlipidaemia and stroke, is the underlying cause of many health and economic burdens. There is ample evidence that proper nutrition, specifically plant-based diets (PBDs), are an effective strategy for reducing the burden of chronic disease. The aim of this narrative review is to summarise the most recent evidence on the efficacy of PBDs on various cardio-metabolic disease risk factors. This review found consistent, convincing evidence around PBDs improving body weight, glycaemic control, blood pressure and blood lipid profile, thus reducing the overall risk factors associated with chronic disease. Based on these findings, the authors conclude properly planned PBDs are an effective tool for preventing and treating cardio-metabolic disease and encourage PBDs to be recommended and promoted.
Abstract
Cardio-metabolic disease, namely ischemic heart disease, stroke, obesity, and type 2 diabetes, represent substantial health and economic burdens. Almost one half of cardio-metabolic deaths in the U.S. might be prevented through proper nutrition. Plant-based (vegetarian and vegan) diets are an effective strategy for improving nutrient intake. At the same time, they are associated with decreased all-cause mortality and decreased risk of obesity, type 2 diabetes, and coronary heart disease. Evidence suggests that plant-based diets may reduce the risk of coronary heart disease events by an estimated 40% and the risk of cerebral vascular disease events by 29%. These diets also reduce the risk of developing metabolic syndrome and type 2 diabetes by about one half. Properly planned vegetarian diets are healthful, effective for weight and glycemic control, and provide metabolic and cardiovascular benefits, including reversing atherosclerosis and decreasing blood lipids and blood pressure. The use of plant-based diets as a means of prevention and treatment of cardio-metabolic disease should be promoted through dietary guidelines and recommendations.
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Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial.
Trepanowski, JF, Kroeger, CM, Barnosky, A, Klempel, MC, Bhutani, S, Hoddy, KK, Gabel, K, Freels, S, Rigdon, J, Rood, J, et al
JAMA internal medicine. 2017;177(7):930-938
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Restricting calories every second day to as low as 500 calories (alternate day fasting) has become popular in recent years as a weight loss strategy. This randomised clinical trial of 69 obese, but otherwise healthy, individuals aimed to assess the impact of alternate day fasting for 6 months on weight loss and risk factors for heart disease, in comparison to more traditional daily calorie restriction. The study results showed that average weight loss was similar for the alternate day fasting group and daily calorie restriction group, compared to control. Average HDL cholesterol levels were higher at month 6 and average LDL cholesterol levels were higher at month 12 in the alternate day fasting group, compared to the daily calorie restriction group. There were no other statistically significant differences between the 2 groups for other markers of heart disease. Drop out rates were highest in the alternate day fasting group, suggesting that it is a harder diet to stick to in the longer term. Nutrition practitioners practising individualised nutrition can use the results of this trial to work with overweight clients in choosing the best dietary strategy for weight loss in relation to their clients’ goals and lifestyle.
Abstract
Importance: Alternate-day fasting has become increasingly popular, yet, to date, no long-term randomized clinical trials have evaluated its efficacy. Objective: To compare the effects of alternate-day fasting vs daily calorie restriction on weight loss, weight maintenance, and risk indicators for cardiovascular disease. Design, Setting, and Participants: A single-center randomized clinical trial of obese adults (18 to 64 years of age; mean body mass index, 34) was conducted between October 1, 2011, and January 15, 2015, at an academic institution in Chicago, Illinois. Interventions: Participants were randomized to 1 of 3 groups for 1 year: alternate-day fasting (25% of energy needs on fast days; 125% of energy needs on alternating "feast days"), calorie restriction (75% of energy needs every day), or a no-intervention control. The trial involved a 6-month weight-loss phase followed by a 6-month weight-maintenance phase. Main Outcomes and Measures: The primary outcome was change in body weight. Secondary outcomes were adherence to the dietary intervention and risk indicators for cardiovascular disease. Results: Among the 100 participants (86 women and 14 men; mean [SD] age, 44 [11] years), the dropout rate was highest in the alternate-day fasting group (13 of 34 [38%]), vs the daily calorie restriction group (10 of 35 [29%]) and control group (8 of 31 [26%]). Mean weight loss was similar for participants in the alternate-day fasting group and those in the daily calorie restriction group at month 6 (-6.8% [95% CI, -9.1% to -4.5%] vs -6.8% [95% CI, -9.1% to -4.6%]) and month 12 (-6.0% [95% CI, -8.5% to -3.6%] vs -5.3% [95% CI, -7.6% to -3.0%]) relative to those in the control group. Participants in the alternate-day fasting group ate more than prescribed on fast days, and less than prescribed on feast days, while those in the daily calorie restriction group generally met their prescribed energy goals. There were no significant differences between the intervention groups in blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, insulin resistance, C-reactive protein, or homocysteine concentrations at month 6 or 12. Mean high-density lipoprotein cholesterol levels at month 6 significantly increased among the participants in the alternate-day fasting group (6.2 mg/dL [95% CI, 0.1-12.4 mg/dL]), but not at month 12 (1.0 mg/dL [95% CI, -5.9 to 7.8 mg/dL]), relative to those in the daily calorie restriction group. Mean low-density lipoprotein cholesterol levels were significantly elevated by month 12 among the participants in the alternate-day fasting group (11.5 mg/dL [95% CI, 1.9-21.1 mg/dL]) compared with those in the daily calorie restriction group. Conclusions and Relevance: Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction. Trial Registration: clinicaltrials.gov Identifier: NCT00960505.
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A 12-week low-carbohydrate, high-fat diet improves metabolic health outcomes over a control diet in a randomised controlled trial with overweight defence force personnel.
Zinn, C, McPhee, J, Harris, N, Williden, M, Prendergast, K, Schofield, G
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2017;42(11):1158-1164
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A global rise in overweight and obesity has created uncertainty around the efficacy of current nutritional guidelines that favour a high-carbohydrate, low-fat (HCLF) diet. Evidence has shown a low-carbohydrate, high-fat (LCHF) diet, compared with a HCLF diet, is at least as effective in reducing body weight and waist circumference and is more effective for improving metabolic health. The aim of this study was evaluate changes in weight and metabolic health between these two dietary approaches among 26 overweight and obese defence force personnel. Participants were randomly allocated to a HCLF or LCHF diet for 12 weeks. Weight, waist circumference, fasting lipids and glycaemic markers were assessed at baseline and 12 weeks. Both study groups demonstrated a significant reduction in weight and waist circumference, and the LCHF group showed further improvements in metabolic markers. Based on these results, the authors conclude a high-fat dietary approach shows promise for short-term weight loss and improved metabolic health compared with current dietary guidelines among the defence force population.
Abstract
Overweight, obesity, and poor health is becoming a global concern for defence force personnel. Conventional nutrition guidelines are being questioned for their efficacy in achieving optimal body composition and long-term health. This study compared the effects of a 12-week low-carbohydrate, high-fat diet with a conventional, high-carbohydrate, low-fat diet on weight reduction and metabolic health outcomes in at-risk New Zealand Defence Force personnel. In this randomised controlled trial, 41 overweight personnel were assigned to intervention and control groups. Weight, waist circumference, fasting lipids, and glycaemic control were assessed at baseline and at 12 weeks. Within-group change scores were analysed using the t statistic and interpreted using a p < 0.05 level of statistical significance. Between-group mean differences and confidence intervals were analysed using effect sizes and magnitude-based inferences. Twenty-six participants completed the trial (14 intervention, 12 control). Both groups showed statistically significant weight and waist circumference reductions; the intervention group significantly reduced triglycerides and serum glucose and significantly increased high-density lipoprotein cholesterol (HDLc). Relative to control, the intervention group showed small, possibly to likely beneficial effects for weight, triglycerides, glucose, insulin, and homeostasis model assessment of insulin resistance; moderate, likely beneficial effects for HDL cholesterol, triglyceride:HDLc ratio and HbA1c; and a small, likely harmful effect for low-density lipoprotein cholesterol. This dietary approach shows promise for short-term weight loss and improved metabolic health outcomes conditions compared with mainstream recommendations. It should be offered to defence force personnel at least as a viable alternative means to manage their weight and health.
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Effects of fasting and preoperative feeding in children.
Yurtcu, M, Gunel, E, Sahin, TK, Sivrikaya, A
World journal of gastroenterology. 2009;15(39):4919-22
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Preoperative fasting is usually carried out to prevent the risk of vomiting during anaesthesia. The study investigated whether children should have a long period of fasting before surgery. Eight groups of 10 children (aged 1-10 years) with disorders of groin and scrotum were orally fed normal liquid food (NLF) or a high calorie diet (HCD) in 2 divided doses at 6 hour intervals, then fasted for 2, 3, 4 or 5 hours prior to surgery. Four groups had NLF and 4 groups had HCD. All children had their glucose, prealbumin and cortisol levels measured twice, just after the oral feeding and just before surgery. Once anaesthesia was sufficient and stable, gastric liquid was collected and measured. Patients with disease that could delay gastric emptying, had high acid production or were on medication were excluded from the trial. The researchers found that there was no significant difference in blood prealbumin levels in all groups. There was significant increase in blood cortisol in 4 groups when fasted (NLF-2h fasted, HCD-2h fasted, NLF-3h fasted and HCD-5h fasted). Stomach aid residue liquids were at tolerable levels of 1-2ml in all children. Anaesthesia was uneventful, with no coughing, laryngospasm or vomiting reported, and outcomes of surgery and wound healing were not affected. The authors noted that drinking clear liquids up to 2 hours before surgery was unlikely to substantially affect the volume of gastric fluids, and did not appear to increase the risk of vomiting in normal, healthy children. Glucose and insulin infusions appeared to minimise endocrine stress response and normalised post-op insulin sensitivity. Additionally, there may be a psychological benefit for children as irritability appeared to decrease prior to surgery. The study concluded that there was no need for fasting longer than 2 hours prior to inguinoscrotal region surgery.
Abstract
AIM: To investigate whether children should undergo surgery without a long period of fasting after feeding. METHODS Eighty children with inguinoscrotal disorders (aged 1-10 years) were studied prospectively. They were divided into eight groups that each contained 10 children who were fed normal liquid food (NLF) and a high-calorie diet (HCD) 2, 3, 4 and 5 h before surgery, in two doses at 6-h intervals. NLF was given to four groups and HCD to the other four. In all groups, glucose, prealbumin and cortisol levels in the blood were measured twice: just after oral feeding and just before the operation. After the establishment of adequate anesthesia, gastric residue liquid was measured with a syringe. RESULTS Blood glucose levels in all patients fed NLF and HCD were high, except in patients in the HCD-4 group. There was no significant difference in the blood prealbumin levels. There was a significant increase in the blood cortisol levels in the NLF-2 (14.4 +/- 5.7), HCD-2 (13.2 +/- 6.0), NLF-3 (10.9 +/- 6.4), and HCD-5 (6.8 +/- 5.7) groups (P < 0.05). CONCLUSION The stress of surgery may be tolerated by children when they are fed up to 2 h before elective surgery.