Effectiveness of weight loss in the elderly with type 2 diabetes mellitus

Potential exerkines for physical exercise-elicited pro-cognitive effects: Insight from clinical and animal research

A sedentary lifestyle is now known as a critical risk factor for accelerated aging-related neurodegenerative disorders. In contract, having regular physical exercise has opposite effects. Clinical findings have suggested that physical exercise can promote brain plasticity, particularly the hippocampus and the prefrontal cortex, that are important for learning and memory and mood regulations. However, the underlying mechanisms are still unclear. Animal studies reveal that the effects of physical exercise on promoting neuroplasticity could be mediated by different exerkines derived from the peripheral system and the brain itself. This book chapter summarizes the recent evidence from clinical and pre-clinical studies showing the emerging mediators for exercise-promoted brain health, including myokines secreted from skeletal muscles, adipokines from adipose tissues, and other factors secreted from the bone and liver.

Influence of skeletal muscle mass and fat mass on the metabolic and inflammatory profile in sarcopenic and non-sarcopenic overfat elderly

BACKGROUND

Sarcopenic elderly present low muscle mass and strength, however, it is not clear if the inflammatory and metabolic profile is more related to low lean mass or high fat mass in sarcopenic and non-sarcopenic overfat elderly.

AIM

To verify the difference in inflammatory and metabolic responses in sarcopenic and non-sarcopenic overfat elderly and the relationship between these markers, body composition, and strength in this population.

METHODS

Fifty-seven elderly were divided into two groups: sarcopenic (n = 30) and non-sarcopenic (n = 27). Body composition was evaluated with octopolar bioimpedance. Total cholesterol, high-density lipoprotein cholesterol, triacylglycerol, glucose, cortisol, leptin, adiponectin, Plasminogen activator inhibitor-1 (PAI-1), TNF-α, IL-6, IL-8, and IL-10 were assessed. The handgrip test was used to evaluate strength.

RESULTS

When comparing the inflammatory profile, sarcopenic individuals showed greater adiponectin concentration (p = 0.019), adiponectin/fat mass ratio (p < 0.001), adiponectin/visceral fat (p < 0.001), and higher PAI-1 (p = 0.019) than non-sarcopenic overfat elderly. After adjusting the inflammatory profile by skeletal muscle mass the significant differences between groups were maintained (p < 0.05) but no significant differences between groups were observed when adjusting by fat mass, despite a tendency to a significant difference for adiponectin concentration (p = 0.06). In addition, after adjusting leptin by fat mass there was a statistically significant lower concentration in the sarcopenic compared to non-sarcopenic overfat elderly.

CONCLUSION

Non-sarcopenic overfat elderly presented lower anti-inflammatory and anti-atherogenic responses than sarcopenic elderly. Furthermore, fat mass but not skeletal muscle mass seem to change these responses.

Evidence-based diabetes care for older people with Type 2 diabetes: a critical review

In our ageing society diabetes imposes a significant burden in terms of the numbers of people with the condition, diabetes-related complications including disability, and health and social care expenditure. Older people with diabetes can represent some of the more complex and difficult challenges facing the clinician working in different settings, and the recognition that we have only a relatively small (but increasing) evidence base to guide us in diabetes management is a limitation of our current approaches. Nevertheless, in this review we attempt to explore what evidence there is to guide us in a comprehensive scheme of treatment for older adults, often in a high-risk clinical state, in terms of glucose lowering, blood pressure and lipid management, frailty care and lifestyle interventions. We strive towards individualized care and make a call for action for more high-quality research using different trial designs.

The relationship between regional abdominal fat distribution and both insulin resistance and subclinical chronic inflammation in non-diabetic adults

OBJECTIVE

Obesity is associated with a high risk of insulin resistance (IR) and its metabolic complications. It is still debated that distributions of adipose tissue relate to an excess risk of IR and chronic inflammation in different race. This study was designed to examine the relation between insulin sensitivity, chronic inflammation and central fat distribution in non-diabetic volunteers in Taiwanese.

METHODS

There were 328 volunteers without family history of diabetes mellitus and with normal oral glucose tolerance test enrolled. Total body fat and abdominal fat were measured. Abdominal fat was categorized into intraperitoneal (IP), retroperitoneal (RP) and subcutaneous (SC) fat. The IR index was estimated by homeostatic model assessment. Five inflammatory markers: adiponectin, leptin, tumor necrosing factor-α (TNF-α), resistin and high sensitive CRP (hs-CRP) were measured.

RESULTS

IR was related to IP fat (r = 0.23, p < 0.001), but not RP fat, SC fat or total body fat. After correcting for age and sex, IP fat was the only significant predictor of IR (r2 = 58%, p = 0.001). Leptin showed the strongest relationship with all fat compartments (IP fat: r = 0.44, p = 0.001; RP fat: r = 0.36, p = 0.005, SC fat: r = 0.54, p < 0.001; total body fat: r = 0.61, p < 0.001). The hs-CRP and adiponectin were closely related both to IP (r = 0.29, p = 0.004; r = -0.20, p = 0.046, respectively) and total body fat (r = 0.29, p = 0.004; r = -0.29, p = 0.005, respectively), but not RP, or SC fat. TNF-α and resistin were not correlated to any fat compartment. After correcting for age and sex, leptin variance was mostly explained by SC fat (41.3%), followed by IP fat (33.6%) and RP fat (25.3%). The hs-CRP and adiponectin variance were mostly explained by IP fat (40% and 49% respectively).

CONCLUSIONS

IP fat is better predictors of IR and subclinical chronic inflammation in Taiwanese adults. A disproportionate accumulation of abdominal fat is associated with increased risk of cardiovascular diseases.

The effects of exercise training on obesity-induced dysregulated expression of adipokines in white adipose tissue

Obesity is recognized as a risk factor for lifestyle-related diseases such as type 2 diabetes and cardiovascular disease. White adipose tissue (WAT) is not only a static storage site for energy; it is also a dynamic tissue that is actively involved in metabolic reactions and produces humoral factors, such as leptin and adiponectin, which are collectively referred to as adipokines. Additionally, because there is much evidence that obesity-induced inflammatory changes in WAT, which is caused by dysregulated expression of inflammation-related adipokines involving tumor necrosis factor- α and monocyte chemoattractant protein 1, contribute to the development of insulin resistance, WAT has attracted special attention as an organ that causes diabetes and other lifestyle-related diseases. Exercise training (TR) not only leads to a decrease in WAT mass but also attenuates obesity-induced dysregulated expression of the inflammation-related adipokines in WAT. Therefore, TR is widely used as a tool for preventing and improving lifestyle-related diseases. This review outlines the impact of TR on the expression and secretory response of adipokines in WAT.

Lifestyle factors increasing adiponectin synthesis and secretion

Adiponectin is an anti-inflammatory adipokine released from adipose tissue that is known to exert insulin-sensitizing effects in skeletal muscle and liver. Given that the secretion of adiponectin is impaired in obesity and related pathologies, strategies to enhance its synthesis and secretion are of interest. There is evidence that several lifestyle factors, including consumption of dietary long-chain n-3 PUFA, TZD administration, and weight loss can increase adiponectin synthesis and secretion. The effect of chronic exercise, independent of weight loss, is variable and less convincing. Potential mechanisms by which such lifestyle factors exert their favorable effects on adiponectin include activation of PPARγ and AMPK, regulation of posttranslational modifications, and changes in adipose tissue morphology and macrophage infiltration. As a clear role for adiponectin in mitigating obesity-related impairments in lipid metabolism and insulin sensitivity is evident, further research investigating factors that enhance adiponectin synthesis and secretion is distinctly warranted.

A carbohydrate-restricted diet during resistance training promotes more favorable changes in body composition and markers of health in obese women with and without insulin resistance

OBJECTIVE

To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels.

METHODS

221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m(2)) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline.

RESULTS

Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (-3.5 ± 3 kg), fat mass (-2.7 ± 3 kg), blood glucose (-3%), total cholesterol (-4.5%), low-density lipoproteins (-5%), triglycerides (-5.9%), systolic blood pressure (-2.6%), and waist circumference (-3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (-4.4 ± 3.6 kg vs -2.6 ± 2.9 kg), fat loss (-3.4 ± 2.7 kg vs -1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (-30.8% vs -10.8%) than those in the HC group. Participants in the HH (-14.1%) and HP-HH (-21.6%) groups observed the greatest reduction in serum blood glucose.

CONCLUSION

A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.

Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women

Background

This study's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss.

Methods

One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kg•m^-2, 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3x•week^-1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA with an alpha of 0.05 with LSD post-hoc analysis when appropriate.

Results

All dieting groups exhibited adequate compliance to their prescribed diet regimen as energy and macronutrient amounts and distributions were close to prescribed amounts. Those groups that followed a diet and exercise program reported significantly greater anthropometric (waist circumference and body mass) and body composition via DXA (fat mass and % fat) changes. Caloric restriction initially reduced energy expenditure, but successfully returned to baseline values after 10 weeks of dieting and exercising. Significant fitness improvements (aerobic capacity and maximal strength) occurred in all exercising groups. No significant changes occurred in lipid panel constituents, but serum insulin and HOMA-IR values decreased in the VLCHP group. Significant reductions in serum leptin occurred in all caloric restriction + exercise groups after 14 weeks, which were unchanged in other non-diet/non-exercise groups.

Conclusions

Overall and over the entire test period, all diet groups which restricted their caloric intake and exercised experienced similar responses to each other. Regular exercise and modest caloric restriction successfully promoted anthropometric and body composition improvements along with various markers of muscular fitness. Significant increases in relative energy expenditure and reductions in circulating leptin were found in response to all exercise and diet groups. Macronutrient distribution may impact circulating levels of insulin and overall ability to improve strength levels in obese women who follow regular exercise.

The Why WAIT program: improving clinical outcomes through weight management in type 2 diabetes

Targeting body weight, as an alternative model to targeting hemoglobin A(1c), is emerging as a viable and potentially cost-effective approach to diabetes management in clinical practice. Why WAIT (Weight Achievement and Intensive Treatment) is a 12-week multidisciplinary program for weight control and intensive diabetes management specifically designed for application in routine diabetes practice. The program, which is generally covered by insurance, is followed by continuous support aimed at long-term maintenance of weight loss and diabetes control. This model was effective in improving key metabolic abnormalities observed in diabetic patients. Eighty-two percent of participants achieved the target hemoglobin A(1c) of less than 7% on less diabetes medications. The achieved weight reduction after 12 weeks of intervention was maintained for an additional year. Future dissemination of this intervention model in routine clinical practice may require wider endorsement by third-party payers and support of governmental health care agencies to halt the progression of the epidemic of obesity and diabetes in the United States.

Effects of exercise on adiponectin: a systematic review

Secreted from white adipose tissue, circulating concentrations of adiponectin are reduced in the presence of metabolic and cardiovascular disease such as obesity and type 2 diabetes. The aim of this systematic review is to assess the body of evidence critically for the effects of exercise on adiponectin levels. Literature searches using the Medline, CINAHL, Cochrane Controlled Trials registry, EMBASE, and SportDiscus databases were conducted from 1966 to September 2006 using keywords pertaining to "adiponectin" and "exercise." Thirty-three trials met the inclusion criteria. Study designs consisted of 5 cross-sectional studies, 7 trials of acute exercise, 11 uncontrolled trials, 2 non-randomized controlled trials, and 8 randomized controlled trials (RCTs). Exercise of varying prescription has been shown to increase serum adiponectin in 38% of RCTs, demonstrating small-to-moderate effect sizes (ESs). One study reported a dose-response effect of resistance training intensity and the augmentation of adiponectin. Inconsistent support in the literature exists for increasing adiponectin levels after short-term exposure to robust aerobic or resistance training of moderate-to-high intensities. Particular attention should be directed toward high-risk cohorts, in whom augmentation of the anti-inflammatory cytokine adiponectin may assume critical importance.

Diabetes, aging and physical activity

Diabetes mellitus (DM) is a metabolic disease affecting the regulation of insulin and glucose causing a disruption in the normal control of counterregulatory hormones and macronutrients, resulting in blood glucose accumulation. Metabolic deregulation leads to the production of noxious substances that have a particular propensity for damaging vascular and nervous structures. Physiological changes observed with aging are correlated with a concomitant increase in DM and its associated complications. Long-term complications, including peripheral and central neuropathies, micro- and macrovascular damage, retinopathy, and nephropathy are the major causes of mortality in diabetics [cardiovascular disease (CVD) being the primary complication causing death in this population]. All-cause mortality is three to four times greater in the DM population; hence, management of DM is of timely importance, particularly with a projected prevalence increase of 134% within the next 25 years among individuals over the age of 65 years. Exercise modalities, including endurance and resistance training, were employed to improve glycemic/metabolic control and to ameliorate the progression of DM-related complications. Several risk factors, including glucose levels, blood pressure, lipid/cholesterol profile, and BMI, are reportedly improved with these modes of exercise. However, not all studies demonstrate an improvement in risk factors, but consistently note improvement in complications and a reduction of DM incidence. There is convincing evidence that exercise, with or without specific improvements to traditional DM-related risk factors, is an effective therapy for the management of DM.