Wellness Check: Nutrition

Long-term nutritional interventions improve some physical development parameters in children

1. In this systematic review and meta-analysis, there was a significant improvement in weight-for-height and weight-for-age z scores in children who received nutritional interventions for ≥6 months compared to controls.

2. However, there were no improvements in body mass index (BMI)-for-age or height-for-age z scores in children who received nutritional interventions or in weight-for-height and weight-for-age z scores in children who received the intervention for <6 months.

Evidence Rating Level: 1 (Excellent)

It is well known that diet and physical development in children are tightly linked. Dietary interventions are often recommended for improving nutrition status in children. However, the role of these interventions in improving growth and development outcomes in children is poorly understood. Thus, the purpose of the present study was to evaluate the evidence regarding the impact of dietary interventions on physical development in children.

Of 429 identified records, 8 studies (n= 6,645 children) were included from five databases between January 2007 and December 2022. Randomized controlled trials with participants <8 years old that compared an intervention group that received nutritional guidance or supplementation to a control group, and evaluated outcomes including body mass index (BMI)-for age z score, relative weight-for-height z score, height-for-age z score, and weight-for-age z score were included. Studies that included participants with other underlying diseases were excluded. The study was conducted according to PRSIMA guidelines. The primary outcomes were BMI-for-age, weight-for-height, height-for-age, and weight-for age z scores.

The results demonstrated that when a nutritional intervention was implemented for ≥6 months, there was a significant improvement in weight-for-height and weight-for-age z scores compared to controls. However, there were no improvements in BMI-for-age or height-for-age z scores for any length of intervention or in weight-for-height and weight-for-age z scores in children who received the intervention for <6 months. Despite these findings, the review was limited by the fact that only 2 studies used dietary interventions lasting >6 months, which may have influenced the results. Nonetheless, the study demonstrated that long-term nutritional interventions may positively impact some growth parameters in young children.

Habitual diet choices may be linked to exercise-related abdominal complaints

1. In this cross-sectional study, it was found that habitual dietary intake of fat, tea, and unhealthy foods was positively associated with abdominal complaints (AC) during running.

2. Additionally, several personal characteristics were positively associated with exercise-related AC, including female sex, younger age, and running at a higher intensity.

Evidence Rating Level: 2 (Good)

Abdominal complaints (AC) are common among runners, both during and after physical activity. Although certain foods are known to play a role in the development and frequency of AC during activity, the impact of day-to-day nutritional intake on exercise-related AC is poorly understood. As a result, the present study investigated the dietary habits of a cohort of runners to elucidate the impact of daily nutrition on AC during physical activity.

The study enlisted a cohort of 1139 runners recruited through athletics clubs in the Netherlands and Belgium, social media, and following participation of the 2022 Rotterdam Marathon. Participants 18 years of age or older who had run at least once in the past year were included. Participants who reported an implausible dietary intake on the food frequency questionnaire (FFQ), defined as <800 and >4200kcal for men, and <500 and >3500kcal for women, were excluded. Information on general characteristics, running habits, AC, and habitual dietary intake was obtained through a general questionnaire and a FFQ completed by the participants once throughout the study. The primary outcome was the difference in habitual dietary intake in runners with and without AC.

The results demonstrated that certain habitual diet factors were positively associated with AC in runners, including a higher intake of fat, tea, and unhealthy foods. Furthermore, most participants with AC reported that eating too much before running and eating during running increased AC. Several personal characteristics were also associated with exercise-associated AC, including female sex, younger age, and running at a higher intensity. Despite this, the study was limited by the self-reported nature, which may have introduced bias in the dietary intake results. Nonetheless, the study demonstrated that the reduction of certain nutrients and food groups may reduce AC during exercise.

Consuming a low-carbohydrate breakfast improves glucose management in patients with type 2 diabetes

1. In this randomized controlled trial, HbA1c was significantly reduced in type 2 diabetes (T2D) patients that ate a low-carbohydrate (LC) breakfast at the end of the study, compared to the start.

2. Furthermore, T2D patients who ate the LC breakfast exhibited improvements in mean and maximum glucose, glycemic variability, and time above range compared to the control group.

Evidence Rating Level: 1 (Excellent)

It is well known that hyperglycemic episodes are a predictor of complications in patients with type 2 diabetes (T2D). Consumption of carbohydrates can result in a spike in blood glucose for patients with T2D, particularly in the morning when glucose intolerance is the greatest. As a result, a high-carbohydrate breakfast can have a significant impact on hyperglycemia. Therefore, the purpose of this study was to determine if consumption of a low-carbohydrate (LC) breakfast could lead to better glycemic control in patients with T2D.

The study included 127 participants from Canada and Australia who responded to online advertisements between October 2020 and March 2022. Participants aged 20-79 years old were included if they had physician-diagnosed T2D for ≥1 year, a current HbA1C <8.5%, body mass index (BMI) >25 kg/m2, and blood pressure < 160/99 mmHg. Participants who were smokers, undergoing medical treatment for various diseases, had allergies or dietary restrictions that prevented adherence to the study intervention, or were using exogenous insulin, >3 glucose-lowering medications, HRT, corticosteroids, or anti-inflammatory medications were excluded from the study. Participants were randomized 1:1 to either the LC or low-fat control (CTL) breakfast group for the 12-week study period. Blood samples were taken at baseline and after the 12-week Food records and anthropomorphic measures were provided by self-reports. The primary outcome was the change in HbA1c.

The results demonstrated that HbA1c was significantly reduced in the LC breakfast group at the end of the 12-week study period compared to the start. Meanwhile, the difference in HbA1c between the intervention and control groups was not statistically significant. However, mean and maximum glucose, glycemic variability, and time above range were all lower in the LC group compared to the CTL group. Despite these findings, the study was limited by the self-reported nature of diet and anthropomorphic measures, which could have impacted the results. Nonetheless, the study demonstrated that consuming a LC breakfast could be a helpful lifestyle intervention for improving glucose control in patients with T2D.

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