Evaluation of two dietary treatments in obese hyperinsulinemic adolescents

The Effectiveness of a Low Glycemic Index/Load Diet on Cardiometabolic, Glucometabolic, and Anthropometric Indices in Children with Overweight or Obesity: A Systematic Review and Meta-Analysis

(1) Background: This systematic review and meta-analysis aims to evaluate the impact of a low glycemic index (LGI) and low glycemic load (LGL) diet on children with overweight and obesity, analyzing any changes in anthropometric, cardiometabolic, and glucometabolic parameters. (2) Methods: Three electronic databases (PubMed, Scopus, CENTRAL), as well as clinical trial registries and reference lists of the included studies, were searched for eligible randomized control trials (RCTs). Two independent reviewers performed the screening of the studies, data extraction, and risk of bias assessment. Mean difference (MD) and 95% confidence intervals (CI) using a random effects model were calculated for each outcome. (3) Results: Eleven RCTs (n = 634) examining the effect of LGI diet versus control were identified. The synthesized data provided from the RCTs indicate no difference between intervention and control groups regarding primary outcomes (body weight (MD: -0.14; 95% CI -1.93 to 1.64, 5 trials), body mass index (BMI) (MD: -0.31; 95% CI -0.85 to 0.23, 6 trials), BMI z-score (MD: -0.03; 95% CI -0.09 to 0.02, 5 trials), and waist circumference (MD: -0.52; 95% CI -2.35 to 1.31, 5 trials)) and other measures of cardiometabolic and glucometabolic parameters. The majority of trials were classified as "some concerns". (4) Conclusions: LGI and LGL diets do not seem to be associated with changes in adiposity, cardiometabolic or glucometabolic markers in children with overweight or obesity. Further research comparing the LGI diet to a high glycemic index diet, with proper methodological standards, is required to clarify the benefits of a LGI diet in this population.

Prevalence of LDL-hypercholesterolemia and other cardiovascular risk factors in young people with type 1 diabetes

BACKGROUND

Mortality and morbidity in people with Type 1 diabetes (T1D) is mainly caused by cardiovascular disease (CVD). Early treatment of cardiovascular risk factors (CVRFs) is of great importance.

OBJECTIVE

To analyze the prevalence of LDL-hypercholesterolemia and other CVRFs in youth with T1D.

METHODS

Clinical and laboratory parameters, and vascular thickness measurement were obtained in youth with T1D (age 6-18 years, T1D duration >1 year) attending a diabetes clinic. LDL-hypercholesterolemia, microalbuminuria and arterial hypertension were defined as CVRFs.

RESULTS

A total of 333 youth (48% girls; age: 13.3 years [10.3-15.5], median [interquartile range]) participated in the study. The T1D duration was 5.9 years [3.5-9.4] with HbA1c of 7.4% [6.8-8.0]. Intima media thickness (N=223) was 538.0 µm [470.0-618.0]). LDL-hypercholesterolemia was present in 30 participants (9%; 18 girls; age: 14.3 years [11.2-15.7]). None of the participants had persistent microalbuminuria, although 59 (18.3%) had elevated albumin excretion in a random urine specimen. LDL-hypercholesterolemia was associated with increased blood pressure (p<0.05), insulin requirement (p<0.05), HbA1c (p<0.05), triglyceride (p<0.001) and total cholesterol (p<0.001), and a family history of premature CVD (p<0.001), but negatively correlated with HDL cholesterol levels (p<0.05). Sex, pubertal status, duration of diabetes, type of therapy, and physical activity did not differ between participants with and without LDL- hypercholesterolemia. Arterial hypertension was present in 11 participants (3.3%; 4 girls; age: 14.1 years [11.1-16.1]).

CONCLUSION

LDL-hypercholesterolemia affected 9% of youth with T1D in this cohort and was associated with other CVRFs. A holistic therapeutic concept for these young people is essential.

Low glycaemic index or low glycaemic load diets for people with overweight or obesity

BACKGROUND

The prevalence of obesity is increasing worldwide, yet nutritional management remains contentious. It has been suggested that low glycaemic index (GI) or low glycaemic load (GL) diets may stimulate greater weight loss than higher GI/GL diets or other weight reduction diets. The previous version of this review, published in 2007, found mainly short-term intervention studies. Since then, randomised controlled trials (RCTs) with longer-term follow-up have become available, warranting an update of this review.

OBJECTIVES

To assess the effects of low glycaemic index or low glycaemic load diets on weight loss in people with overweight or obesity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, one other database, and two clinical trials registers from their inception to 25 May 2022. We did not apply any language restrictions.

SELECTION CRITERIA

We included RCTs with a minimum duration of eight weeks comparing low GI/GL diets to higher GI/GL diets or any other diets in people with overweight or obesity.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We conducted two main comparisons: low GI/GL diets versus higher GI/GL diets and low GI/GL diets versus any other diet. Our main outcomes included change in body weight and body mass index, adverse events, health-related quality of life, and mortality. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

In this updated review, we included 10 studies (1210 participants); nine were newly-identified studies. We included only one study from the previous version of this review, following a revision of inclusion criteria. We listed five studies as 'awaiting classification' and one study as 'ongoing'. Of the 10 included studies, seven compared low GI/GL diets (233 participants) with higher GI/GL diets (222 participants) and three studies compared low GI/GL diets (379 participants) with any other diet (376 participants). One study included children (50 participants); one study included adults aged over 65 years (24 participants); the remaining studies included adults (1136 participants). The duration of the interventions varied from eight weeks to 18 months. All trials had an unclear or high risk of bias across several domains.  Low GI/GL diets versus higher GI/GL diets Low GI/GL diets probably result in little to no difference in change in body weight compared to higher GI/GL diets (mean difference (MD) -0.82 kg, 95% confidence interval (CI) -1.92 to 0.28; I2 = 52%; 7 studies, 403 participants; moderate-certainty evidence). Evidence from four studies reporting change in body mass index (BMI) indicated low GI/GL diets may result in little to no difference in change in BMI compared to higher GI/GL diets (MD -0.45 kg/m2, 95% CI -1.02 to 0.12; I2 = 22%; 186 participants; low-certainty evidence)at the end of the study periods. One study assessing participants' mood indicated that low GI/GL diets may improve mood compared to higher GI/GL diets, but the evidence is very uncertain (MD -3.5, 95% CI -9.33 to 2.33; 42 participants; very low-certainty evidence). Two studies assessing adverse events did not report any adverse events; we judged this outcome to have very low-certainty evidence. No studies reported on all-cause mortality.    For the secondary outcomes, low GI/GL diets may result in little to no difference in fat mass compared to higher GI/GL diets (MD -0.86 kg, 95% CI -1.52 to -0.20; I2 = 6%; 6 studies, 295 participants; low certainty-evidence). Similarly, low GI/GL diets may result in little to no difference in fasting blood glucose level compared to higher GI/GL diets (MD 0.12 mmol/L, 95% CI 0.03 to 0.21; I2 = 0%; 6 studies, 344 participants; low-certainty evidence).  Low GI/GL diets versus any other diet Low GI/GL diets probably result in little to no difference in change in body weight compared to other diets (MD -1.24 kg, 95% CI -2.82 to 0.34; I2 = 70%; 3 studies, 723 participants; moderate-certainty evidence). The evidence suggests that low GI/GL diets probably result in little to no difference in change in BMI compared to other diets (MD -0.30 kg in favour of low GI/GL diets, 95% CI -0.59 to -0.01; I2 = 0%; 2 studies, 650 participants; moderate-certainty evidence). Two adverse events were reported in one study: one was not related to the intervention, and the other, an eating disorder, may have been related to the intervention. Another study reported 11 adverse events, including hypoglycaemia following an oral glucose tolerance test. The same study reported seven serious adverse events, including kidney stones and diverticulitis. We judged this outcome to have low-certainty evidence. No studies reported on health-related quality of life or all-cause mortality. For the secondary outcomes, none of the studies reported on fat mass. Low GI/GL diets probably do not reduce fasting blood glucose level compared to other diets (MD 0.03 mmol/L, 95% CI -0.05 to 0.12; I2 = 0%; 3 studies, 732 participants; moderate-certainty evidence).  AUTHORS' CONCLUSIONS: The current evidence indicates there may be little to no difference for all main outcomes between low GI/GL diets versus higher GI/GL diets or any other diet. There is insufficient information to draw firm conclusions about the effect of low GI/GL diets on people with overweight or obesity. Most studies had a small sample size, with only a few participants in each comparison group. We rated the certainty of the evidence as moderate to very low. More well-designed and adequately-powered studies are needed. They should follow a standardised intervention protocol, adopt objective outcome measurement since blinding may be difficult to achieve, and make efforts to minimise loss to follow-up. Furthermore, studies in people from a wide range of ethnicities and with a wide range of dietary habits, as well as studies in low- and middle-income countries, are needed.

Targeted dietary approaches for the management of obesity and severe obesity in children and adolescents: A systematic review and meta-analysis

There is a need for a detailed understanding of effective dietary interventions for children with obesity. This systematic review examined the effectiveness of diets of varying energy content as a component of weight treatment in children and adolescents with obesity, severe obesity and obesity-related comorbidity. A systematic search of six databases, from 2000 to 2021, for intervention studies of targeted dietary treatment for obesity in children aged 2-18 years identified 125 studies. Dietary interventions were grouped according to diet type and energy target. Risk of bias was assessed using the Effective Public Healthcare Panacea Project assessment tool. Meta-analysis examined change in body mass index (BMI) at intervention end. A broad array of diet types were effective at reducing BMI in children with obesity. When dietary types were considered by energy target, a gradient effect was observed. Very-low energy diets were most effective with a - 4.40 kg/m² (n = 3; 95% CI -7.01 to -1.79). While dietary interventions with no specified energy target were ineffective, resulting in a BMI gain of +0.17 kg/m² (n = 22; 95% CI 0.05 to 0.40). Practical definitions of dietary energy target in the management of obesity and severe obesity are urgently required to ensure treatment seeking children have timely access to efficacious interventions.

Effects of low-glycemic index diet on plasma adipokines in obese children

BACKGROUND

A low-glycemic index (GI) diet may modulate adipocyte-produced adipokines linking to insulin resistance.

METHODS

The stored plasma samples from the RCT of a low-GI vs. conventional diet in obese children were analyzed for adipokines: leptin, adiponectin, resistin, and visfatin. Their relationships with clinical outcomes were assessed.

RESULTS

Fifty-two participants completed the 6-month intervention trial (mean age: 12.0 ± 2.0 years, 35 boys). Both groups had significantly decreased BMI z-scores from baseline whereas the low-GI group had significant reduction in fasting insulin and HOMA-IR. There were no differences in adipokines between the groups before and after the intervention. However, there was an association between baseline leptin and the change of fat mass index (FMI) but not the insulin resistance in both groups. The higher the baseline leptin was, the lower the changes were for FMI after the intervention.

CONCLUSION

Despite no demonstrable effect of low-GI diet on plasma adipokines, the higher baseline leptin was correlated with lower reduction of fat mass. Leptin resistance may have a detrimental effect on the reduction of adiposity in obese children. Baseline leptin could be a useful predictor of the change in body composition in an obesity intervention trial.

IMPACT

Leptin resistance may have a detrimental effect in reducing the adiposity in obese children. This study is the first of its kind to compare the plasma adipokine concentrations of obese children on low-GI diet and conventional diet. We found that serum leptin was significantly correlated with the reduction of BMI z-score and FMI in both groups. Baseline leptin could be a useful predictor of the change in body composition in an obesity intervention trial.

Association between diet quality index and cardiometabolic risk factors in adolescents: Study of Cardiovascular Risks in Adolescents (ERICA)

OBJECTIVE

This study evaluated the association between diet quality, assessed by the Diet Quality Index for Adolescents adapted for Brazilians (DQIA-BR), and cardiometabolic markers in adolescents.

METHODS

The DQIA-BR and cardiometabolic markers were assessed in 36 956 Brazilian adolescents (12-17 y old) enrolled in the Study of Cardiovascular Risks in Adolescents (ERICA), a national school-based cross-sectional multicenter study in Brazil. For analyses, the sample was stratified by sex and nutritional status. Multiple linear regressions were used to investigate the association between DQIA-BR and cardiometabolic markers (total cholesterol, HDL-c, LDL-c, triglycerides, fasting glucose and HOMA-IR). Adjusted models were constructed with two input levels of covariates. The first model was adjusted for sex, age, and socioeconomic status; in the second model, total energy intake, physical activity, and sedentary behavior were included.

RESULTS

A higher DQIA-BR score was associated with a better cardiometabolic profile in girls with normal weight; however, no association was observed in those with overweight/obesity. In boys with overweight/obesity, a better quality of diet was associated with lower concentrations of total cholesterol (β = -0.338, 95% confidence interval [CI]: -0.611 to -0.066) and LDL-c (β = -0.227, 95% CI: -0.448 to -0.005), but only LDL-c remained significant in those with normal weight (β = -0.115, 95% CI: -0.224 to 0.005).

CONCLUSION

The effects of diet quality on cardiometabolic risk factors differ according to sex and the presence of overweight/obesity. Overall, DQIA-BR is a suitable tool to evaluate the association between diet quality and cardiometabolic markers in normal-weight adolescents, but not for adolescents, especially girls, with overweight/obesity.

Low glycaemic index diets as an intervention for obesity: a systematic review and meta-analysis

OBJECTIVES

Low glycaemic index (GI) diets may aid in weight loss by reducing postprandial blood glucose excursions, leading to more stable blood glucose concentrations and therefore a reduction in hunger. To test this hypothesis, we conducted a systematic review and meta-analysis of randomized controlled trials comparing low GI diets with other diet types.

METHODS

We included 101 studies involving 109 study arms and 8,527 participants. We meta-analysed the studies using a random-effects model and conducted subgroup analyses and meta-regression based on control diet, blood glucose control, baseline BMI and dietary GI.

RESULTS

Low GI diets resulted in small but significant improvements in body weight, BMI, LDL and total cholesterol overall, although no individual control diet was significantly different from low GI diets. Studies in people with normal blood glucose who achieved a difference in GI of 20 points or more resulted in a larger reduction in body weight (SMD = -0.26; 95% CIs [-0.43, -0.09]), and total cholesterol (SMD = -0.24; 95% CIs [-0.42, -0.05]) than studies that only achieved a smaller reduction in GI.

CONCLUSIONS

Low GI diets, especially diets achieving a substantial decrease in GI, were moderately effective in lowering body weight. However, efforts should be made to increase compliance with low GI diets, in order for them to be effective in people with overweight and obesity.

New Insights about How to Make an Intervention in Children and Adolescents with Metabolic Syndrome: Diet, Exercise vs. Changes in Body Composition. A Systematic Review of RCT

OBJECTIVE

To record which interventions produce the greatest variations in body composition in patients ≤19 years old with metabolic syndrome (MS).

METHOD

search dates between 2005 and 2017 in peer reviewed journals, following the PRISMA method (Preferred Reporting Items for Systematic reviews and Meta-Analyses). The selection criteria were: diagnostic for MS or at least a criterion for diagnosis; randomized clinical trials, ≤19 years of age; intervention programs that use diet and/or exercise as a tool (interventions showing an interest in body composition).

RESULTS

1781 clinical trials were identified under these criteria but only 0.51% were included. The most frequent characteristics of the selected clinical trials were that they used multidisciplinary interventions and were carried out in America. The most utilized parameters were BMI (body mass index) in kg/m² and BW (body weight) in kg.

CONCLUSIONS

Most of the clinical trials included had been diagnosed through at least 2 diagnostic criteria for MS. Multidisciplinary interventions obtained greater changes in body composition in patients with MS. This change was especially prevalent in the combinations of dietary interventions and physical exercise. It is proposed to follow the guidelines proposed for patients who are overweight, obese, or have diabetes type 2, and extrapolate these strategies as recommendations for future clinical trials designed for patients with MS.

Effectiveness of educational and lifestyle interventions to prevent paediatric obesity: systematic review and meta-analyses of randomized and non-randomized controlled trials

OBJECTIVE

This review and meta-analysis aim at updating a previous meta-analysis carried out by Waters et al. on the efficacy of interventions aimed at preventing childhood obesity and at identifying predictors of outcome.

METHODS

Using an ad-hoc search string, PubMed database was searched for studies assessing body mass index reduction associated with programmes lasting ≥12 weeks in overweight and obese children aged 2-18 years. Studies designed for children with eating disorders or relevant comorbidities were excluded. Studies meeting inclusion criteria were classified according to patient age (<6, 6-12 and 13-18 years), and intervention type (physical activity, diet or both), setting (educational, family or both) and duration (≤1 or >1 year). The search was also extended to other databases. Hand-searching techniques were also applied. The Cochrane 'risk of bias' was applied for quality assessment.

RESULTS

Seventy-two studies were meta-analysed. Overall, the best results were achieved by programmes combining diet and physical activity (n = 39). With regard to the setting, programmes involving both school and family and lasting ≤1 year were the most efficacious for 6- to 12-year-old children (n = 26); family-based-only interventions were also effective in children <6 years old (n = 2), although results have to be interpreted cautiously because of the small number of patients enrolled and the high study heterogeneity. In 13- to 18-year-old patients, interventions delivered at school (n = 8) were substantially unsuccessful.

CONCLUSIONS

Interventions for childhood obesity prevention should include both diet and physical activity, be preferentially targeted towards school age children and involve both the school and family setting. However, because of the important methodological limitations associated with currently available literature, additional studies are needed to draw definite conclusions.

Dietary restriction in obese children and its relation with eating behavior, fibroblast growth factor 21 and leptin: a prospective clinical intervention study

BACKGROUND

Obesity is significant problem involving eating behavior and peripheral metabolic conditions. The effect of carbohydrate and fat restriction on appetite regulation, fibroblast growth factor 21 (FGF21) and leptin in children has not been defined. Our objective was to compare the effect of both diets.

METHODS

One hundred and twenty children with body mass index (BMI) higher than the equivalent of 30 kg/m(2) for an adult, as corrected for gender and age were randomly assigned to (n = 60) a low-carbohydrate (L-CHO) diet or (n = 60) a low-fat (L-F) diet for 2 months. Fifty-three (88.3 %) subjects on the low-carbohydrate-diet and 45 (75 %) on the low-fat diet completed the study. Anthropometric measures, leptin and FGF21 levels were measured before and after the intervention. Comparison of the data for both of the diet groups was carried out using the t-test for independent variables. Intragroup comparisons before and after of each of the dietary treatments were performed using ANOVA for repeated measures. Factors associated with FGF21, leptin levels and satiety, were analyzed by multiple regression.

RESULTS

After both of the diets, weight, leptin, food responsiveness, and enjoyment of food significantly decreased and high density lipoprotein cholesterol (HDL) increased, but FGF21 decreased. Before and after both of the interventions FGF21 was associated with triglycerides. Before the diet, satiety was associated with lower screen time (p < 0.04) and insulin levels (p < 0.05).

CONCLUSIONS

Both dietary restrictions improved the metabolic and hormonal parameters of obese children. FGF21 is an indicator of a beneficial metabolic response in younger children. After 2 months an adaptation of the eating behavior to food restriction was observed.

Carbohydrates, glycemic index, and pregnancy outcomes in gestational diabetes

This review critically evaluates the current evidence regarding the effect of the dietary glycemic index (GI) on pregnancy outcomes in gestational diabetes mellitus (GDM). Current evidence, although limited, consistently supports the advantages of, and has demonstrated no disadvantages of, a low-GI diet. We conclude that pregnant women with GDM are likely to benefit from following a low-GI meal pattern, with no significant side effects, and consideration of the GI should be given when formulating a diet for GDM. However, until larger scale intervention trials are completed, an exclusive low-GI diet should not replace the current recommended diets for GDM from relevant government and health agencies. Further studies that intervene at an earlier stage of pregnancy are required.

Estimated insulin sensitivity and cardiovascular disease risk factors in adolescents with and without type 1 diabetes

OBJECTIVE

To test the hypothesis that cardiovascular disease (CVD) risk factors are similar in nondiabetic (non-DM) adolescents compared with those with type 1 diabetes (T1D) in the most insulin-sensitive (IS) tertile, and that CVD risk factors are more atherogenic with decreasing IS in adolescents with T1D.

STUDY DESIGN

IS for adolescents with T1D (n = 292; age = 15.4 ± 2.1 years; duration = 8.8 ± 3.0 years, hemoglobin A1c = 8.9% ± 1.6%) and non-DM controls (n = 89; age = 15.4 ± 2.1 years) was estimated using the model: log(e)IS = .64725 - 0.02032 (waist [cm]) - 0.09779 (hemoglobin A1c [%]) - 0.00235 (triglycerides [mg/dL]). CVD risk factors (blood pressure, fasting total and low- and high-density lipoprotein-cholesterol (HDL-c), high sensitivity C-reactive protein, and body mass index z score) were compared between all non-DM adolescents and those with T1D in the most IS tertile, and then examined for a linear trend by IS tertile in adolescents with T1D, adjusted for sex, race/ethnicity, and Tanner stage.

RESULTS

Estimated IS was significantly lower in adolescents with T1D compared with those without (T1D = 7.8 ± 2.4, non-DM = 11.5 ± 2.9; P < .0001). CVD risk factors were similar for non-DM compared with the adolescents with T1D with the most IS, except for higher (HDL-c) and diastolic blood pressure in adolescents with T1D (P < .05). Among adolescents with T1D, all CVD risk factors except for (HDL-c), were more atherogenic across decreasing IS tertiles in linear regression analysis (P < .05).

CONCLUSION

Adolescents with T1D who are the most IS have similar CVD risk factors compared with non-DM adolescents. CVD risk factors are inversely associated with IS in adolescents with T1D. IS may be an important therapeutic target for reducing CVD risk factors in adolescents with T1D.