Dichotomous effect of dietary fiber in pediatrics: a narrative review of the health benefits and tolerance of fiber.

Dietary fibers are associated with favorable gastrointestinal, immune, and metabolic health outcomes when consumed at sufficient levels. Despite the well-described benefits of dietary fibers, children and adolescents continue to fall short of daily recommended levels. This gap in fiber intake (i.e., "fiber gap") might increase the risk of developing early-onset pediatric obesity and obesity-related comorbidities such as type 2 diabetes mellitus into adulthood. The structure-dependent physicochemical properties of dietary fiber are diverse. Differences in solubility, viscosity, water-holding capacity, binding capability, bulking effect, and fermentability influence the physiological effects of dietary fibers that aid in regulating appetite, glycemic and lipidemic responses, and inflammation. Of growing interest is the fermentation of fibers by the gut microbiota, which yields both beneficial and less favorable end-products such as short-chain fatty acids (e.g., acetate, propionate, and butyrate) that impart metabolic and immunomodulatory properties, and gases (e.g., hydrogen, carbon dioxide, and methane) that cause gastrointestinal symptoms, respectively. This narrative review summarizes (1) the implications of fibers on the gut microbiota and the pathophysiology of pediatric obesity, (2) some factors that potentially contribute to the fiber gap with an emphasis on undesirable gastrointestinal symptoms, (3) some methods to alleviate fiber-induced symptoms, and (4) the therapeutic potential of whole foods and commonly marketed fiber supplements for improved health in pediatric obesity.

Cardiometabolic Health in Adolescents with Obesity: The Role of Protein Intake, Diet Quality, and Physical Activity.

Background: Although adolescents with obesity have an increased risk of cardiometabolic disease, a subset maintains a healthy cardiometabolic profile. Unhealthy lifestyle behaviors may determine cardiometabolic risk. We aimed to characterize the lifestyle behaviors of adolescents with obesity, compare differences between metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO), and assess associations between lifestyle behaviors and cardiometabolic profiles. Methods: Participants aged 10-18 years with body mass index (BMI) ≥ 95th percentile were included. Dietary intake (DI) was estimated from 3-day food records, and diet quality (DQ) was assessed using the Healthy Eating Index-Canadian Adaptation. Physical activity (PA), body composition, anthropometrics, blood markers, and blood pressure (BP) were objectively measured. MUO was defined as having high triglycerides, BP, glucose, or low high-density lipoprotein. Regression analyses were performed between lifestyle behaviors and cardiometabolic markers. Results: Thirty-nine participants (BMI z-score 2.8 [2.5-3.5], age 12.5 [10.9-13.5] years, 56.4% female) were included. A high proportion of participants failed to meet lifestyle recommendations, particularly for DQ (94.7%, n = 36), fiber (94.7%, n = 36), and PA (90.9%, n = 30). No differences in lifestyle behaviors were found between MUO (59.0%, n = 22) and MHO (41.0%, n = 16). Protein intake was negatively associated with BMI and waist circumference z-scores, fat mass index, insulin resistance, low-density lipoprotein, and C-reactive protein, whereas higher DQ was associated with lower C-reactive protein. Higher light PA levels were associated with lower total cholesterol and triglycerides. Conclusion: Adolescents with either MUO or MHO displayed low adherence to DQ, DI, and PA recommendations; no differences in lifestyle behaviors were found. Protein intake, DQ, and PA were associated with a healthier cardiometabolic profile.

The metabolic load-capacity model and cardiometabolic health in children and youth with obesity.

BACKGROUND: The metabolic load-capacity index (LCI), which represents the ratio of adipose to skeletal muscle tissue-containing compartments, is potentially associated with cardiometabolic diseases. OBJECTIVES: To examine the associations between the LCI and cardiometabolic risk factors in children and youth with obesity. METHODS: This is a cross-sectional study including 10-18 years-old participants with a BMI of ≥95th . LCI by air-displacement plethysmography (ADP) was calculated as fat mass divided by fat-free mass, and LCI by ultrasound (US) as subcutaneous adipose tissue divided by skeletal muscle thickness. Sex-specific medians stratified participants into high versus low LCI. Single (inflammation, insulin resistance, dyslipidemia and hypertension) and clustered cardiometabolic risk factors were evaluated. Linear and logistic regression models tested the associations between these variables, adjusted for sexual maturation. RESULTS: Thirty-nine participants (43.6% males; 59% mid-late puberty) aged 12.5 (IQR: 11.1-13.5) years were included. LCI by ADP was positively associated with markers of inflammation and dyslipidemia; having a higher LCI predicted dyslipidemia in logistic regression. Similarly, LCI by US was positively associated with markers of dyslipidemia and blood pressure. In mid-late pubertal participants, LCI by US was positively associated with markers of insulin resistance and inflammation. CONCLUSIONS: Participants with unfavourable cardiometabolic profile had higher LCI, suggesting its potential use for predicting and monitoring cardiometabolic health in clinical settings.

Resistance Training Improves Muscle Strength and Function, Regardless of Protein Supplementation, in the Mid- to Long-Term Period after Gastric Bypass.

Inadequate protein intake and low levels of physical activity are common long-term sequelae after bariatric surgery and can negatively affect muscle strength (MS) and physical function (PF). The study investigated the effects of resistance training with or without protein supplementation on MS and PF. The study, which involved a 12-week controlled trial (n = 61) of individuals 2-7 years post-Roux-en-Y gastric bypass (RYGB), comprised four groups: whey protein supplementation (PRO; n = 18), maltodextrin placebo (control [CON]; n = 17), resistance training combined with placebo (RTP; n = 11), and resistance training combined with whey protein supplementation (RTP+PRO; n = 15). An isokinetic dynamometer was used to measure MS (peak torque at 60°/s and 180°/s). PF was measured with the 30-s sit-to-stand (30-STS), 6-min walk (6-MWT), and timed up-and-go (TUG) tests. There were improvements in the absolute and relative-to-bodyweight peak torque at 60°/s and 180°/s, TUG, 6-MWT and 30-STS in the RTP and RTP+PRO groups, but not in the CON and PRO groups. Changes in MS were significantly correlated with changes in PF between the pre- and post-intervention periods. A supervised resistance training program, regardless of protein supplementation, improved MS and PF in the mid-to-long-term period after RYGB and can lead to clinical benefits and improved quality of life.