The Effects of Exercise and Restriction of Sugar-Sweetened Beverages on Muscle Function and Autophagy Regulation in High-Fat High-Sucrose-Fed Obesity Mice

The association between healthy beverage index and sarcopenia in Iranian older adults: a case-control study

BACKGROUND

Sarcopenia is a progressive disease with age-related loss of skeletal muscle mass, strength, and function. No study has investigated the association between healthy beverage index (HBI) and sarcopenia in older adults. Therefore, the present study aimed to investigate the association between HBI and sarcopenia in Iranian older adults.

METHODS

In the present case-control study, 80 sarcopenic and 80 non-sarcopenic participants matched in sex were included. Body composition was measured using bioelectrical impedance analysis. Handgrip strength (HGS), skeletal muscle mass index (SMI), and gait speed were utilized to confirm sarcopenia. Also, a food frequency questionnaire was used to evaluate food intake. HBI score was calculated based on ten sub-components of the total beverages. Moreover, logistic regression was applied to assess the association between HBI and sarcopenia.

RESULTS

In the crude model, we observed no significant association between HBI and the odds of sarcopenia. Still, after adjusting the confounders, the odds of developing sarcopenia decreased significantly in the second and last tertiles (T) (T2- odds ratio (OR) = 0.04, 95% confidence interval (CI): 0.01-0.25 and T3- OR = 0.10, 95% CI: 0.01-0.60).

CONCLUSIONS

Our findings indicated that HBI is inversely related to the chance of sarcopenia. Therefore, to reduce the odds of sarcopenia, it is recommended to consume healthy drinks such as fruit juices and milk.

Mitochondrial Dysfunction, Oxidative Stress, and Inter-Organ Miscommunications in T2D Progression

Type 2 diabetes (T2D) is a heterogenous disease, and conventionally, peripheral insulin resistance (IR) was thought to precede islet β-cell dysfunction, promoting progression from prediabetes to T2D. New evidence suggests that T2D-lean individuals experience early β-cell dysfunction without significant IR. Regardless of the primary event (i.e., IR vs. β-cell dysfunction) that contributes to dysglycemia, significant early-onset oxidative damage and mitochondrial dysfunction in multiple metabolic tissues may be a driver of T2D onset and progression. Oxidative stress, defined as the generation of reactive oxygen species (ROS), is mediated by hyperglycemia alone or in combination with lipids. Physiological oxidative stress promotes inter-tissue communication, while pathological oxidative stress promotes inter-tissue mis-communication, and new evidence suggests that this is mediated via extracellular vesicles (EVs), including mitochondria containing EVs. Under metabolic-related stress conditions, EV-mediated cross-talk between β-cells and skeletal muscle likely trigger mitochondrial anomalies leading to prediabetes and T2D. This article reviews the underlying molecular mechanisms in ROS-related pathogenesis of prediabetes, including mitophagy and mitochondrial dynamics due to oxidative stress. Further, this review will describe the potential of various therapeutic avenues for attenuating oxidative damage, reversing prediabetes and preventing progression to T2D.

Association between sugar-sweetened beverage consumption frequency and muscle strength: results from a sample of Chinese adolescents

BACKGROUND

Although sugar-sweetened beverage consumption has become an important and widespread concern, there are few studies on the association between sugar-sweetened beverage consumption frequency and muscle strength in Chinese adolescents. The objective of this study was to analyze the association between sugar-sweetened beverage consumption frequency and muscle strength in Chinese adolescents.

METHODS

A stratified whole-group sampling method was used to survey 25,893 adolescents aged 13-15 years old in China for sugar-sweetened beverage consumption frequency and muscle strength for grip strength and standing long jump. The subjects' basic information, body mass index (BMI), and covariates were investigated. The association between sugar-sweetened beverage consumption frequency and muscle strength was analyzed by multivariate logisitc regression analysis.

RESULTS

The proportions of Chinese adolescents who consumed sugar-sweetened beverage ≥ 3 times/week, 1-2 times/week, and < 1 time/week were 12.23%, 52.79%, and 34.98%, respectively. The differences in sugar-sweetened beverage consumption frequency were statistically significant when compared across gender, parental education, duration of physical activity, snacks, and mode of commuting to school (χ² values = 228.570, 51.422, 275.552, 3165.656, 10.988, P < 0.01). Logistic regression analysis showed that overall Chinese adolescents with sugary drinks 1-2 times/week (OR = 1.207, 95% CI:1.132-1.287) and sugary drinks ≥ 3 times/week (OR = 1.771, 95% CI:1.611-1.947) were associated with lower muscle strength compared to sugary drinks < 1 time/week showed a positive association (P < 0.01). The same trend was found for boys and girls.

CONCLUSION

Chinese adolescents' sugar-sweetened beverage consumption is common, and high-frequency sugar-sweetened beverage consumption is associated with lower muscle strength. In the future, we should control the use of sugar-sweetened beverages and increase muscular strength training in Chinese adolescents to promote healthy growth.

Interplay of skeletal muscle and adipose tissue: sarcopenic obesity

Sarcopenic obesity is becoming a global health concern, owing to the rising older population, causing cardiometabolic morbidity and mortality. Loss of muscle exceeding normal age-related changes has been revealed to be associated with obesity, aggravating each other through complex interactions. Physiological regeneration and proliferation of muscle tissue are achieved through harmonious processes of regulated inflammation, autophagy, muscle satellite cell proliferation, and signaling molecule function. Adipokines and myokines are signaling molecules from adipose tissue and muscle, respectively, that exert autocrine, paracrine, and endocrine effects on fat and muscle tissues. These signaling molecules interact with each other to regulate metabolic homeostasis. However, excessive adiposity creates pro-inflammatory conditions, leading to metabolic disorders and the disorganization of systemic homeostasis. Therefore, obesity impedes muscle tissue regeneration and induces the loss of muscle mass and function. Numerous studies have attempted to demonstrate the pathophysiological interaction between sarcopenia and obesity, but the interwoven matrix of the relationship between myokines and adipokines has made it difficult for researchers to understand them. This review briefly describes updated information about the crosstalk between muscle and adipose tissue.

Muscle strength and prediabetes progression and regression in middle-aged and older adults: a prospective cohort study

BACKGROUND

Prediabetes progression is associated with increased mortality while its regression decreases it. It is unclear whether muscle strength is related to prediabetes progression or regression. This study investigated the associations of muscle strength, assessed by grip strength and chair-rising time, with prediabetes progression and regression based on the China Health and Retirement Longitudinal Study (CHARLS) enrolling middle-aged and older adults.

METHODS

We included 2623 participants with prediabetes from CHARLS, who were followed up 4 years later with blood samples collected for measuring fasting plasma glucose and haemoglobin A1c. Grip strength (normalized by body weight) and chair-rising time were assessed at baseline and categorized into tertiles (low, middle, and high groups). Prediabetes at baseline and follow-up was defined primarily using the American Diabetes Association (ADA) criteria and secondarily using the World Health Organization (WHO) and International Expert Committee (IEC) criteria. Multinomial logistic regression analysis was applied to obtain the odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The mean age of included participants was 59.0 ± 8.6 years, and 46.6% of them were males. During follow-up, 1646 participants remained as prediabetes, 379 progressed to diabetes, and 598 regressed to normoglycaemia based on ADA criteria. Participants who progressed to diabetes had lower normalized grip strength than those who remained as prediabetes (0.49 ± 0.15 vs. 0.53 ± 0.15, P < 0.001), but participants who regressed to normoglycaemia showed the opposite (0.55 ± 0.16 vs. 0.53 ± 0.15, P = 0.003). However, chair-rising time was comparable across different groups (P_overall  = 0.17). Compared with participants in low normalized grip strength or high chair-rising time group, those in high normalized grip strength or low chair-rising time group had decreased odds of progression to diabetes (OR 0.62, 95% CI 0.44 to 0.87; and OR 0.69, 95% CI 0.51 to 0.93, respectively) after multivariable adjustment. However, both were unrelated to the odds of regression to normoglycaemia (OR 0.94, 95% CI 0.71 to 1.25; and OR 0.84, 95% CI 0.65 to 1.07, respectively). These outcomes remained generally comparable when prediabetes was defined by WHO or IEC criteria. Higher normalized grip strength but not lower chair-rising time was prospectively associated with lower blood pressure, better glycaemic condition, and lower inflammation (all P ≤ 0.04).

CONCLUSIONS

High muscle strength is associated with reduced odds of progression to diabetes but does not predict regression to normoglycaemia in prediabetes. Future studies are warranted to assess whether increases in muscle strength promote prediabetes regression.