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Coingestion of Collagen With Whey Protein Prevents Postexercise Decline in Plasma Glycine Availability in Recreationally Active Men.
Aussieker, T, Janssen, TAH, Hermans, WJH, Holwerda, AM, Senden, JM, van Kranenburg, JMX, Goessens, JPB, Snijders, T, van Loon, LJC
International journal of sport nutrition and exercise metabolism. 2024;34(4):189-198
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Exercise increases muscle protein synthesis rates. Protein ingestion during recovery from exercise further increases postexercise muscle protein synthesis rates and can be applied as a nutritional strategy to further augment gains in muscle mass and strength following prolonged resistance exercise training. This study aimed to determine whether coingesting collagen with whey protein could prevent the decline in plasma glycine availability after exercise. This study was a randomised, double-blind, crossover study involving 14 recreationally active men. Participants ingested 30 grams of protein in different combinations of whey and collagen immediately after resistance exercise. Results showed that: - differences in postprandial plasma amino acid concentrations correspond well with the amino acid composition of different whey plus collagen protein blends; - ingestion of 30g whey protein immediately after exercise resulted in a decline in postprandial plasma glycine availability during the acute recovery period; - co-ingesting 5g collagen with 25g whey protein was sufficient to prevent the decline in plasma glycine availability and allowed maintenance of circulating plasma glycine concentrations above baseline values during recovery from a single bout of resistance exercise. Authors concluded that the co-ingestion of a small amount of collagen (5g) with whey protein (25g) is sufficient to prevent the decline in plasma glycine availability during recovery from a single bout of resistance exercise in healthy, young men.
Abstract
Whey protein ingestion during recovery from exercise increases myofibrillar but not muscle connective protein synthesis rates. It has been speculated that whey protein does not provide sufficient glycine to maximize postexercise muscle connective protein synthesis rates. In the present study, we assessed the impact of coingesting different amounts of collagen with whey protein as a nutritional strategy to increase plasma glycine availability during recovery from exercise. In a randomized, double-blind, crossover design, 14 recreationally active men (age: 26 ± 5 years; body mass index: 23.8 ± 2.1 kg·m-2) ingested in total 30 g protein, provided as whey protein with 0 g (WHEY), 5 g (WC05); 10 g (WC10), and 15 g (WC15) of collagen protein immediately after a single bout of resistance exercise. Blood samples were collected frequently over 6 hr of postexercise recovery to assess postprandial plasma amino acid kinetics and availability. Protein ingestion strongly increased plasma amino acid concentrations (p < .001) with no differences in plasma total amino acid availability between treatments (p > .05). The postprandial rise in plasma leucine and essential amino acid availability was greater in WHEY compared with the WC10 and WC15 treatments (p < .05). Plasma glycine and nonessential amino acid concentrations declined following whey protein ingestion but increased following collagen coingestion (p < .05). Postprandial plasma glycine availability averaged -8.9 ± 5.8, 9.2 ± 3.7, 23.1 ± 6.5, and 39.8 ± 11.0 mmol·360 min/L in WHEY, WC05, WC10, and WC15, respectively (incremental area under curve values, p < .05). Coingestion of a small amount of collagen (5 g) with whey protein (25 g) is sufficient to prevent the decline in plasma glycine availability during recovery from lower body resistance-type exercise in recreationally active men.
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Short-term removal of exercise impairs glycemic control in older adults: A randomized trial.
Reynolds, LJ, Williams, TM, Harden, JE, Twiddy, HM, Kearney, ML
Physiological reports. 2023;11(2):e15591
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Advancements in glucose monitoring make assessing free-living postprandial blood glucose levels convenient and feasible. Continuous glucose monitoring systems assess blood glucose levels 24h a day and have been demonstrated to enhance diabetes management. Both acutely and chronically, physical activity and/or exercise is a powerful modulator of glycaemic control. The aim of this study was to examine if the alterations in glycaemic control in older adults who exercise were different compared to young adults who exercise, in response to short-term removal of exercise. This study was a randomised, cross-over, exploratory study design which included 20 participants (9 young, active participants and 11 older, active participants). Participants had glycaemic control assessed for 3 days while performing their normal habitual exercise and for 3 days while refraining from habitual exercise. Results show that three days of exercise removal impairs glycaemic control in older adults as well as young adults. In fact, older adults (even though they have worse glycaemic control than younger adults) do not experience a greater impairment in glycaemic control compared to young adults. Authors conclude that their findings support the overall need for regular, daily exercise in adults, particularly older adults, who have a worse glycaemic profile.
Abstract
Postprandial glycemia (PPG) predicts cardiovascular disease, and short-term physical inactivity increases PPG in young, active adults. Whether this occurs in older, active adults who may be more prone to bouts of inactivity is unknown. This study determined if postprandial interstitial glucose (PPIG) was impaired in active older adults following the removal of exercise for 3 days (NOEX) compared to active young adults. In this randomized, crossover study, 11 older (69.1 ± 1.9 years) and 9 young (32.8 ± 1.8 years) habitually active (≥90 min/week of exercise) adults completed 3-days of NOEX and 3-days of normal habitual exercise (EX), separated by ≥1 week. Diet was standardized across phases. Glycemic control (3-day average) was assessed via continuous glucose monitoring during both phases. Significant main effects of age and phase were detected (p < 0.05), but no interaction was found for steps/day (p > 0.05) (old EX: 6283 ± 607, old NOEX 2380 ± 382 and young EX: 8798 ± 623, young NOEX 4075 ± 516 steps/day). Significant main effects of age (p = 0.002) and time (p < 0.001) existed for 1-h PPIG, but no effect of phase or interactions was found (p > 0.05). Significant main effects (p < 0.05) of age (old: 114 ± 1 mg/dl, young: 106 ± 1 mg/dl), phase (NOEX: 112 ± 1 mg/dl, EX: 108 ± 1 mg/dl), and time (0 min: 100 ± 2, 30 min: 118 ± 2, 60 min: 116 ± 2, 90 min: 111 ± 2, 120 min: 108 ± 2 mg/dl) in 2-h PPIG were detected, but no interaction was found (p > 0.05). However, only significant main effects of phase (NOEX: 14 ± 1 and EX:12 ± 1, p > 0.05) were found for 24-h blood glucose standard deviation. Older adults appear to have impaired glycemic control compared to young adults and exercise removal impairs glycemic control in both populations. Yet, the impairment in glycemic control with exercise removal is not different between old and young adults.
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Impact of dietary interventions on pre-diabetic oral and gut microbiome, metabolites and cytokines.
Shoer, S, Shilo, S, Godneva, A, Ben-Yacov, O, Rein, M, Wolf, BC, Lotan-Pompan, M, Bar, N, Weiss, EI, Houri-Haddad, Y, et al
Nature communications. 2023;14(1):5384
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Pre-diabetes, a condition characterized by elevated blood glucose levels but below diabetes thresholds, is a significant risk factor for the development of type 2 diabetes, as well as other comorbidities including cardiovascular and kidney diseases. Diet plays a critical role in the development of hyperglycaemia and the onset of pre-diabetes. The aim of this study was to assess the impact of a personalized postprandial glucose-targeting diet (PPT), as well as the standard of care Mediterranean diet (MED), on the oral and gut microbiome, metabolites and cytokines in 200 pre-diabetic individuals. This study was a biphasic, randomised, controlled, single-blind dietary intervention. Phase one included a six-month intervention that compared two diets targeting glycaemic control, while phase two included a six-month follow-up period. Participants (n = 225) were randomly assigned in a 1:1 ratio to a PPT (n = 113) or a MED (n = 112). Results showed that participants assigned to the PPT diet had significant changes in 19 gut microbial species, 14 gut and one oral microbial pathway, 86 serum metabolites and four cytokines. Participants assigned to the MED diet showed significant changes in five gut and one oral microbial species, 18 gut microbial pathways, 27 serum metabolites and four cytokines. Authors conclude that dietary interventions can affect the microbiome, cardiometabolic profile and immune response of the host. Thus, diets such as the PPT used in this study, which takes into account microbiome features, could be designed to affect the microbiome and inflict desired metabolic outcomes.
Abstract
Diabetes and associated comorbidities are a global health threat on the rise. We conducted a six-month dietary intervention in pre-diabetic individuals (NCT03222791), to mitigate the hyperglycemia and enhance metabolic health. The current work explores early diabetes markers in the 200 individuals who completed the trial. We find 166 of 2,803 measured features, including oral and gut microbial species and pathways, serum metabolites and cytokines, show significant change in response to a personalized postprandial glucose-targeting diet or the standard of care Mediterranean diet. These changes include established markers of hyperglycemia as well as novel features that can now be investigated as potential therapeutic targets. Our results indicate the microbiome mediates the effect of diet on glycemic, metabolic and immune measurements, with gut microbiome compositional change explaining 12.25% of serum metabolites variance. Although the gut microbiome displays greater compositional changes compared to the oral microbiome, the oral microbiome demonstrates more changes at the genetic level, with trends dependent on environmental richness and species prevalence in the population. In conclusion, our study shows dietary interventions can affect the microbiome, cardiometabolic profile and immune response of the host, and that these factors are well associated with each other, and can be harnessed for new therapeutic modalities.
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Gut microbiome modulates the effects of a personalised postprandial-targeting (PPT) diet on cardiometabolic markers: a diet intervention in pre-diabetes.
Ben-Yacov, O, Godneva, A, Rein, M, Shilo, S, Lotan-Pompan, M, Weinberger, A, Segal, E
Gut. 2023;72(8):1486-1496
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Diet is a major contributor to cardiometabolic health and plays a fundamental role in the prevention, management and even reversal of many chronic diseases. The gut microbiota has a central role in human health and disease. Specifically, its role in cardiometabolic health has been studied extensively in recent years. The aim of this study was to evaluate the interplay between dietary modifications, microbiome composition and cardiometabolic health outcomes. This study was a randomised controlled trial of a 6-month dietary intervention comparing a personalised postprandial-targeting (PPT) diet versus Mediterranean (MED) diet in 200 adults with pre-diabetes. Results showed that: - PPT intervention induced greater changes in multiple dietary features compared with MED intervention. - PPT intervention increased microbiome diversity and richness and exerted specific microbiome species changes that associate with clinical outcomes. - Changes in specific gut microbiome species partially mediated the effects of dietary modifications on clinical outcomes. Authors conclude that the PPT diet prompted greater changes in gut microbiota composition, consistent with overall greater dietary modifications, as compared with the MED intervention.
Abstract
OBJECTIVE To explore the interplay between dietary modifications, microbiome composition and host metabolic responses in a dietary intervention setting of a personalised postprandial-targeting (PPT) diet versus a Mediterranean (MED) diet in pre-diabetes. DESIGN In a 6-month dietary intervention, adults with pre-diabetes were randomly assigned to follow an MED or PPT diet (based on a machine-learning algorithm for predicting postprandial glucose responses). Data collected at baseline and 6 months from 200 participants who completed the intervention included: dietary data from self-recorded logging using a smartphone application, gut microbiome data from shotgun metagenomics sequencing of faecal samples, and clinical data from continuous glucose monitoring, blood biomarkers and anthropometrics. RESULTS PPT diet induced more prominent changes to the gut microbiome composition, compared with MED diet, consistent with overall greater dietary modifications observed. Particularly, microbiome alpha-diversity increased significantly in PPT (p=0.007) but not in MED arm (p=0.18). Post hoc analysis of changes in multiple dietary features, including food-categories, nutrients and PPT-adherence score across the cohort, demonstrated significant associations between specific dietary changes and species-level changes in microbiome composition. Furthermore, using causal mediation analysis we detect nine microbial species that partially mediate the association between specific dietary changes and clinical outcomes, including three species (from Bacteroidales, Lachnospiraceae, Oscillospirales orders) that mediate the association between PPT-adherence score and clinical outcomes of hemoglobin A1c (HbA1c), high-density lipoprotein cholesterol (HDL-C) and triglycerides. Finally, using machine-learning models trained on dietary changes and baseline clinical data, we predict personalised metabolic responses to dietary modifications and assess features importance for clinical improvement in cardiometabolic markers of blood lipids, glycaemic control and body weight. CONCLUSIONS Our findings support the role of gut microbiome in modulating the effects of dietary modifications on cardiometabolic outcomes, and advance the concept of precision nutrition strategies for reducing comorbidities in pre-diabetes. TRIAL REGISTRATION NUMBER NCT03222791.
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Differential Responders to a Mixed Meal Tolerance Test Associated with Type 2 Diabetes Risk Factors and Gut Microbiota-Data from the MEDGI-Carb Randomized Controlled Trial.
Skantze, V, Hjorth, T, Wallman, M, Brunius, C, Dicksved, J, Pelve, EA, Esberg, A, Vitale, M, Giacco, R, Costabile, G, et al
Nutrients. 2023;15(20)
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Type 2 diabetes (T2D) is a growing worldwide health problem. Increased blood sugars and a corresponding increase in the production of the hormone insulin, which functions to lower blood sugar are risk factors for T2D development. However, it has been shown that everyone has an individual response to the food and the production of differing levels of blood sugar and insulin when eating the same meals has been shown. This secondary analysis of a 12-week randomised control trial of 155 individuals aimed to determine relationships between gut microbiota composition and the glucose response to high and low glycaemic index Mediterranean diets. The results identified two distinct types of response amongst the participants. Cluster A individuals had a lower but more rapid glucose response following food and were deemed to have a better glucose control than cluster B individuals. The clusters also differed in the gut microbiota composition. Cluster A had a higher proportion of Clostridium sensu stricto 1 and a lower proportion of Blautia, than cluster B. It was concluded that the glucose response to a standardised meal can differ between individuals and are associated with differing gut microbiota and risk for T2D. This study could be used by healthcare professionals to understand that diet recommendations are not one size fits all and that the recommendation of certain diets may have differing success. Understanding and differentiating individuals and tailor making recommendations may be of benefit, however further understanding is required on different glucose responses following a meal.
Abstract
The global prevalence of type 2 diabetes mellitus (T2DM) has surged in recent decades, and the identification of differential glycemic responders can aid tailored treatment for the prevention of prediabetes and T2DM. A mixed meal tolerance test (MMTT) based on regular foods offers the potential to uncover differential responders in dynamical postprandial events. We aimed to fit a simple mathematical model on dynamic postprandial glucose data from repeated MMTTs among participants with elevated T2DM risk to identify response clusters and investigate their association with T2DM risk factors and gut microbiota. Data were used from a 12-week multi-center dietary intervention trial involving high-risk T2DM adults, comparing high- versus low-glycemic index foods within a Mediterranean diet context (MEDGICarb). Model-based analysis of MMTTs from 155 participants (81 females and 74 males) revealed two distinct plasma glucose response clusters that were associated with baseline gut microbiota. Cluster A, inversely associated with HbA1c and waist circumference and directly with insulin sensitivity, exhibited a contrasting profile to cluster B. Findings imply that a standardized breakfast MMTT using regular foods could effectively distinguish non-diabetic individuals at varying risk levels for T2DM using a simple mechanistic model.
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The Short-Term Variation of Human Gut Mycobiome in Response to Dietary Intervention of Different Macronutrient Distributions.
Tian, Y, Gou, W, Ma, Y, Shuai, M, Liang, X, Fu, Y, Zheng, JS
Nutrients. 2023;15(9)
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The human gut is inhabited by a diverse and complex community of microbes, such as bacteria, viruses, and fungi, which are critical in maintaining human health. Gut mycobiome is less diverse and abundant than bacteria in the gut, which comprises approximately 0.1% of the total gut microbes and inhabits symbiotically with bacteria as a commensal in the human gut. The aim of this study was to explore short-term gut mycobiome variations in response to a high-carbohydrate, low-fat (HC) diet and a low-carbohydrate, high-fat (LC) diet. This study was a cross-over N-of-1 feeding trial among 30 participants over 72 days (WE-MACNUTR). A total of 28 participants were included in the final analysis. Results showed that the HC diet, but not the LC diet, may increase the fungal alpha diversity at the populational level. Both dietary interventions may affect the gut fungal community structure (i.e., beta diversity). Furthermore, the dietary environment influenced the relationship between gut mycobiome and glycaemic phenotypes. Authors concluded that their findings provide novel evidence on how the gut mycobiome structure and composition change in response to the HC and LC dietary interventions and reveals diet-specific changes in the fungal genera.
Abstract
While the human gut is home to a complex and diverse community of microbes, including bacteria and fungi, research on the gut microbiome has largely focused on bacteria, with relatively little attention given to the gut mycobiome. This study aims to investigate how diets with different dietary macronutrient distributions impact the gut mycobiome. We investigated gut mycobiome response to high-carbohydrate, low-fat (HC) and low-carbohydrate high-fat (LC) diet interventions based on a series of 72-day feeding-based n-of-1 clinical trials. A total of 30 participants were enrolled and underwent three sets of HC and LC dietary interventions in a randomized sequence. Each set lasted for 24 days with a 6-day washout period between dietary interventions. We collected and analyzed the fungal composition of 317 stool samples before and after each intervention period. To account for intra-individual variation across the three sets, we averaged the mycobiome data from the repeated sets for analysis. Of the 30 participants, 28 (aged 22-34 years) completed the entire intervention. Our results revealed a significant increase in gut fungal alpha diversity (p < 0.05) and significant changes in fungal composition (beta diversity, p < 0.05) after the HC dietary intervention. Specifically, we observed the enrichment of five fungal genera (Pleurotus, Kazachstania, Auricularia, Paraphaeosphaeria, Ustilaginaceae sp.; FDR < 0.052) and depletion of one fungal genus (Blumeria; FDR = 0.03) after the HC intervention. After the LC dietary intervention, one fungal genus was enriched (Ustilaginaceae sp.; FDR = 0.003), and five fungal genera were depleted (Blumeria, Agaricomycetes spp., Malassezia, Rhizopus, and Penicillium; FDR < 0.1). This study provides novel evidence on how the gut mycobiome structure and composition change in response to the HC and LC dietary interventions and reveals diet-specific changes in the fungal genera.
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The Effect of Walnut (Juglans regia) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Mirzababaei, A, Daneshvar, M, Abaj, F, Daneshzad, E, Hosseininasab, D, Clark, CCT, Mirzaei, K
Clinical nutrition research. 2022;11(2):120-132
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The main characteristics of type 2 diabetes mellitus (T2DM) are hyperinsulinemia, insulin resistance, and β-cells decline, concomitant to dyslipidaemia. The latter includes abnormalities in concentrations of triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), or total cholesterol (TC), which are major risk factors for cardiovascular diseases. The aim of this study was to evaluate the effect of Juglans regia leaf extract (JRLE) on glycaemic control and lipid profile in T2DM patients. This study is a systematic review and meta-analysis of four randomised controlled studies. All studies were conducted in Iran, on T2DM patients, and both genders. Results show that JRLE supplementation did not have any significant effect on TC, LDL-C, and HDL-C; however, it significantly reduced fasting blood glucose and significantly increased alanine transaminase [enzyme]. Authors conclude that their findings strengthen the available evidence of JRLE as an alternative adjunctive therapy to better control glycaemic targets and lipid parameters.
Abstract
Numerous clinical trials have examined the beneficial effects of Juglans regia leaf extract (JRLE) in patients with type 2 diabetes mellitus (T2DM); however, the results of these studies are inconsistent. Therefore, we conducted the current systematic review and meta-analysis to evaluate the effect of JRLE on glycemic control and lipid profile in T2DM patients. We searched online databases including PubMed, Scopus, EMBASE, and Web of Science for randomized controlled clinical trials that examined the effect of JRLE on glycemic and lipid indices in T2DM patients. Data were pooled using both fixed and random-effect models and weighted mean difference (WMD) was considered as the overall effect size. Of the total records, 4 eligible studies, with a total sample size of 195 subjects, were included. The meta-analysis revealed that JRLE supplementation significantly reduces fasting blood glucose (WMD, -18.04; 95% confidence interval [CI], -32.88 mg/dL, -3.21 mg/dL; p = 0.017) and significantly increases fasting insulin level (WMD, 1.93; 95% CI, 0.40 U/L, 3.45 U/L; p = 0.014). Although the overall effect of JRLE supplementation on hemoglobin A1c was not significant, a significant reduction was seen in studies with an intervention duration of > 8 weeks (WMD, -0.64; 95% CI, -1.16%, -0.11%; p = 0.018). Moreover, we also found no significant change in lipid parameters. Our findings revealed a beneficial effect of JRLE supplementation on glycemic indices in T2DM patients, but no significant improvement was found for lipid profile parameters.
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Effect of Aqueous Cinnamon Extract on the Postprandial Glycemia Levels in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial.
Rachid, AP, Moncada, M, Mesquita, MF, Brito, J, Bernardo, MA, Silva, ML
Nutrients. 2022;14(8)
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Type 2 diabetes mellitus (DM2) is characterised by high levels of blood glucose due to relative insulin deficiency caused through pancreatic beta-cell dysfunction and insulin resistance. The use of traditional plants as complementary therapies has been growing due to their effect on health, including antioxidant and anti-inflammatory activity as well as their effect against diabetes mellitus and cardiovascular disease. The aims of this study were to investigate (1) the effect of aqueous cinnamon extract (6 g cinnamon burmannii/100 mL) on postprandial glycaemia levels in adults with DM2 and (2) the total phenols content and antioxidant evaluation. This study is a single-blind randomised controlled clinical trial. Participants were randomly assigned to intervention (n = 18) or control group (n = 18). The control group was given only a glucose solution for an oral glucose tolerance test (OGTT) and the intervention group was given a glucose solution for an OGTT immediately followed by a cinnamon aqueous extract. Results show that the ingestion of aqueous cinnamon extract (6 g) has no significant effect on postprandial glycaemia over time in patients with DM2 compared with the control group. However, the phenol content analysis showed that cinnamon extract possesses a considerable antioxidant activity and inhibition capacity of reactive oxygen species. Authors conclude by recommending the intake of aqueous cinnamon extract as a source of natural antioxidants due to its high content in these compounds and respective antioxidant activity.
Abstract
Cinnamon is a spice used in traditional cuisine that has been investigated due to hypoglycemic properties. The objective of this study was to investigate the effect of aqueous cinnamon extract on postprandial glycemia levels in type 2 diabetes mellitus (DM2) adults. This clinical trial enrolled 36 adults with DM2, randomly allocated in two groups: the control group (n = 18) took only an oral glucose tolerance test (OGTT) and the intervention group (n = 18) took OGTT immediately followed by aqueous cinnamon extract (6 g/100 mL) ingestion. Blood glucose levels were measured on fasting and after 30, 60, 90 and 120 min in both groups. The chemical analysis of the aqueous cinnamon extract included total phenols content determination and antioxidant activity assessment through FRAP and DPPH methods. The data reveal that aqueous cinnamon extract ingestion did not show a significant difference in the incremental area under the curve (p = 0.834), maximum glucose concentration (p = 0.527) and glucose concentration variation (p = 0.873) compared with the control group. Cinnamon extract possess a total phenol content of 1554.9 mg/L gallic acid equivalent and a strong antioxidant capacity, revealed by the DPPH (5125.0 µmol Trolox/L) and FRAP (3658.8 µmol Trolox/L) tests. Aqueous cinnamon extract did not significantly influence postprandial glucose response in diabetic patients during an OGTT.
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Effect of a Personalized Diet to Reduce Postprandial Glycemic Response vs a Low-fat Diet on Weight Loss in Adults With Abnormal Glucose Metabolism and Obesity: A Randomized Clinical Trial.
Popp, CJ, Hu, L, Kharmats, AY, Curran, M, Berube, L, Wang, C, Pompeii, ML, Illiano, P, St-Jules, DE, Mottern, M, et al
JAMA network open. 2022;5(9):e2233760
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Postprandial glycaemic response (PPGR) to foods can be different from person to person. This could be the reason why people experience different weight loss outcomes with standardised diets such as a low glycaemic index diet, low-fat diet or a low carbohydrate diet. In this single-centre, population-based, randomised, blinded clinical trial, 204 participants with irregular glucose metabolism and obesity were randomised to consume either a low-fat or personalised diet for six months in combination with fourteen behavioural change counselling sessions. The participants in the personalised diet group received a colour-coded meal score to indicate their estimated PPGR for different foods. The results of this study showed no significant weight reduction in the personalised diet group compared to the low-fat diet. Further robust studies are required to develop appropriate precision nutrition interventions for weight loss and energy balance. However, healthcare professionals can use the results of this study to understand that both a low-fat diet and a personalised diet, coupled with behavioural counselling, may be effective in promoting weight loss in obese populations with irregular glucose metabolism.
Abstract
IMPORTANCE Interindividual variability in postprandial glycemic response (PPGR) to the same foods may explain why low glycemic index or load and low-carbohydrate diet interventions have mixed weight loss outcomes. A precision nutrition approach that estimates personalized PPGR to specific foods may be more efficacious for weight loss. OBJECTIVE To compare a standardized low-fat vs a personalized diet regarding percentage of weight loss in adults with abnormal glucose metabolism and obesity. DESIGN, SETTING, AND PARTICIPANTS The Personal Diet Study was a single-center, population-based, 6-month randomized clinical trial with measurements at baseline (0 months) and 3 and 6 months conducted from February 12, 2018, to October 28, 2021. A total of 269 adults aged 18 to 80 years with a body mass index (calculated as weight in kilograms divided by height in meters squared) ranging from 27 to 50 and a hemoglobin A1c level ranging from 5.7% to 8.0% were recruited. Individuals were excluded if receiving medications other than metformin or with evidence of kidney disease, assessed as an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration equation, to avoid recruiting patients with advanced type 2 diabetes. INTERVENTIONS Participants were randomized to either a low-fat diet (<25% of energy intake; standardized group) or a personalized diet that estimates PPGR to foods using a machine learning algorithm (personalized group). Participants in both groups received a total of 14 behavioral counseling sessions and self-monitored dietary intake. In addition, the participants in the personalized group received color-coded meal scores on estimated PPGR delivered via a mobile app. MAIN OUTCOMES AND MEASURES The primary outcome was the percentage of weight loss from baseline to 6 months. Secondary outcomes included changes in body composition (fat mass, fat-free mass, and percentage of body weight), resting energy expenditure, and adaptive thermogenesis. Data were collected at baseline and 3 and 6 months. Analysis was based on intention to treat using linear mixed modeling. RESULTS Of a total of 204 adults randomized, 199 (102 in the personalized group vs 97 in the standardized group) contributed data (mean [SD] age, 58 [11] years; 133 women [66.8%]; mean [SD] body mass index, 33.9 [4.8]). Weight change at 6 months was -4.31% (95% CI, -5.37% to -3.24%) for the standardized group and -3.26% (95% CI, -4.25% to -2.26%) for the personalized group, which was not significantly different (difference between groups, 1.05% [95% CI, -0.40% to 2.50%]; P = .16). There were no between-group differences in body composition and adaptive thermogenesis; however, the change in resting energy expenditure was significantly greater in the standardized group from 0 to 6 months (difference between groups, 92.3 [95% CI, 0.9-183.8] kcal/d; P = .05). CONCLUSIONS AND RELEVANCE A personalized diet targeting a reduction in PPGR did not result in greater weight loss compared with a low-fat diet at 6 months. Future studies should assess methods of increasing dietary self-monitoring adherence and intervention exposure. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03336411.
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Acute Flaxseed Intake Reduces Postprandial Glycemia in Subjects with Type 2 Diabetes: A Randomized Crossover Clinical Trial.
Moreira, FD, Reis, CEG, Welker, AF, Gallassi, AD
Nutrients. 2022;14(18)
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Glucose levels tend to rise postprandially in patients with type 2 diabetes. Flaxseeds are known to have glycaemic control-improving properties and are rich in dietary fibre, alpha-linolenic acid which is an omega-3 fatty acid and phenolic compounds such as phenolic acids, lignans, flavonoids and tocopherols. Therefore, this randomised cross-over clinical trial evaluated the effects of ground raw golden flaxseeds on postprandial glycaemia induced by the consumption of complex carbohydrates in Type 2 diabetic patients. To assess the 2-hour postprandial glycaemic curve, 19 male Type 2 diabetics were randomly assigned either to consume 15 grams of ground raw gold flaxseeds 15 minutes before eating a standardised balanced breakfast or to consume a standardised balanced breakfast without ground flaxseeds. Compared to men who did not consume ground flaxseeds before their breakfast meal, those who ate 15 grams of ground flaxseed were able to lower their postprandial glucose levels by 24% and reduce their peak glucose levels by 17%. In order to generalise the results for the general population, further robust long-term studies are required to examine the beneficial effects of flaxseed on postprandial glycaemic excursions. This study can, however, assist healthcare professionals in implementing dietary strategies that include flaxseed to manage postprandial blood sugar levels in patients with type 2 diabetes.
Abstract
BACKGROUND Postprandial glycemic excursions are associated with impairment control of diabetes mellitus. Long-term consumption of flaxseed can lower blood glucose levels; however, its effects on the postprandial glycemic response remain unknown. Therefore, this study aimed to evaluate the acute effects of raw flaxseed consumption on the 2 h postprandial glycemic curve in men with type 2 diabetes mellitus (T2DM). METHODS This was a randomized crossover clinical trial. Nineteen men with T2DM were randomly assigned a standardized breakfast without (control) or with a previous intake of 15 g of ground raw golden flaxseed (flax). Glycemia was measured at fasting and postprandial at 15, 30, 45, 60, 90, and 120 min. Palatability markers (visual appeal, smell, and pleasantness of taste) and taste intensity (sweetness, saltiness, bitterness, sourness, and creaminess) were evaluated. RESULTS The peak glucose rise and the 2 h AUC glycemic response reduced in the flax group by 17% (p = 0.001) and 24% (p < 0.001), respectively. The glucose peak time, palatability, and taste parameters did not differ between the two groups. CONCLUSIONS Ingestion of 15 g of ground raw golden flaxseed before breakfast decreases the 2 h postprandial glycemic response in men with T2DM.