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Metabolic Slowing and Reduced Oxidative Damage with Sustained Caloric Restriction Support the Rate of Living and Oxidative Damage Theories of Aging.
Redman, LM, Smith, SR, Burton, JH, Martin, CK, Il'yasova, D, Ravussin, E
Cell metabolism. 2018;27(4):805-815.e4
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Following a calorie-restricted diet while maintaining adequate nutrition is known to have a beneficial effect on increasing longevity and promoting healthy ageing. Oxidative stress resulting from reactive oxygen species formation in mitochondria plays a role in accelerating ageing by damaging DNA, proteins and lipids. A calorie-restriction diet can reduce oxidative stress and cause metabolic adaptations. In this ancillary study, non-obese participants were randomly assigned to either a calorie restriction group which followed 25% calorie restriction while getting adequate nutritional support through supplementation or to a control group which included ad libitum calorie intake. After 2 years of intervention, participants in the calorie restriction group achieved 15% calorie restriction, 8.7kg weight loss and a reduction in 24-hour energy expenditure and sleep energy expenditure beyond weight loss because of metabolic adaptation. Oxidative stress and thyroid axis activity were also reduced in the calorie restriction group. Further robust studies are required to evaluate the effectiveness of calorie restriction in metabolic adaptation and oxidative stress and its effects on ageing. The results of this study can be used by healthcare professionals to understand the benefits of a nutritionally adequate calorie restriction diet on adjusting metabolic processes.
Abstract
Calorie restriction (CR) is a dietary intervention with potential benefits for healthspan improvement and lifespan extension. In 53 (34 CR and 19 control) non-obese adults, we tested the hypothesis that energy expenditure (EE) and its endocrine mediators are reduced with a CR diet over 2 years. Approximately 15% CR was achieved over 2 years, resulting in an average 8.7 kg weight loss, whereas controls gained 1.8 kg. In the CR group, EE measured over 24 hr or during sleep was approximately 80-120 kcal/day lower than expected on the basis of weight loss, indicating sustained metabolic adaptation over 2 years. This metabolic adaptation was accompanied by significantly reduced thyroid axis activity and reactive oxygen species (F2-isoprostane) production. Findings from this 2-year CR trial in healthy, non-obese humans provide new evidence of persistent metabolic slowing accompanied by reduced oxidative stress, which supports the rate of living and oxidative damage theories of mammalian aging.
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A whole-grain diet reduces peripheral insulin resistance and improves glucose kinetics in obese adults: A randomized-controlled trial.
Malin, SK, Kullman, EL, Scelsi, AR, Haus, JM, Filion, J, Pagadala, MR, Godin, JP, Kochhar, S, Ross, AB, Kirwan, JP
Metabolism: clinical and experimental. 2018;82:111-117
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Literature shows that dietary whole-grain intake is associated with a lower incidence of type 2 diabetes. The aim of the study was to investigate the association between a whole-grain diet and insulin resistance and glucose use in individuals at risk for type 2 diabetes. The study was a randomized, double-blind, controlled crossover trial involving fourteen middle-aged, obese adults at risk for diabetes. Randomisation was carried out prior to metabolic testing. Results indicate that whole-grain intake as part of a mixed-meal diet significantly improved post-prandial (after a meal) glucose metabolism in middle-aged obese adults. Furthermore, both whole-grain and refined-grain interventions induced about 3–6% weight and fat loss. Authors conclude that whole-grain intake effectively promotes glycaemic control by improving insulin action.
Abstract
BACKGROUND Whole-grain intake is associated with lower risk of type 2 diabetes but the mechanisms are unclear. PURPOSE We tested the hypothesis that a WG diet reduces insulin resistance and improves glucose use in individuals at risk for type 2 diabetes compared with an isocaloric-matched refined-grain diet. METHODS A double-blind, randomized, controlled, crossover trial of 14 moderately obese adults (Age, 38 ± 2 y; BMI, 34.0 ± 1.1 kg/m2). Insulin resistance and glucose metabolism was assessed using an oral glucose tolerance test combined with isotopic tracers of [6,6-2H2]-glucose and [U-13C]-glucose, and indirect calorimetry. Peripheral and hepatic insulin resistance was assessed as 1/(rate of disposal/insulin), and endogenous glucose rates of appearance (Ra) iAUC60-240 × insulin iAUC60-240, respectively. Both diets met ADA nutritional guidelines and contained either whole-grain (50 g per 1000 kcal) or equivalent refined-grain. All food was provided for 8 wk. with an 8-10 wk. washout period between diets. RESULTS Post-prandial glucose tolerance, peripheral insulin sensitivity, and metabolic flexibility (insulin-stimulated - fasting carbohydrate oxidation) improvements were greater after whole-grain compared to the refined-grain diet (P < 0.05). Compared to baseline, body fat (~2 kg) and hepatic Ra insulin resistance was reduced by both diets, while fasting glucose and exogenous glucose-meal were unchanged after both interventions. Changes in peripheral insulin resistance and metabolic flexibility correlated with improved glucose tolerance (P < 0.05). CONCLUSION Whole-grains reduced diabetes risk and the mechanisms appear to work through reduced post-prandial blood glucose and peripheral insulin resistance that were statistically linked to enhanced metabolic flexibility.
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Effective nationwide school-based participatory extramural program on adolescent body mass index, health knowledge and behaviors.
Heo, M, Jimenez, CC, Lim, J, Isasi, CR, Blank, AE, Lounsbury, DW, Fredericks, L, Bouchard, M, Faith, MS, Wylie-Rosett, J
BMC pediatrics. 2018;18(1):7
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Adolescent obesity is a major public health concern that affects health status not only during adolescence but also during adulthood. The aim of this study was to test whether the HealthCorps program would improve weight status represented by body mass index (BMI; kg/m2) z-score and obesity class. A secondary aim was to identify knowledge and health behaviour domains that would be increased with the program. The study design was a two parallel arm quasi-experimental pre-post comparison design. A total of 2279 students from 62 schools participated in the HealthCorps program. Results indicate that HealthCorps program participation resulted in BMI z-score improvement among overweight/obese female students. Participation also resulted in increased knowledge in most domains regardless of sex and improved a few behaviour domains. However, it did not improve weight status among male students. Authors conclude that the HealthCorps was effective for BMI z-score improvements among female students in addition to significant positive effects on knowledge and a few behaviors in both sexes.
Abstract
BACKGROUND Adolescent obesity is a major public health concern. Open to all high school students regardless of weight status, HealthCorps is a nationwide program offering a comprehensive high school-based participatory educational program to indirectly address obesity. We tested a hypothesis that the HealthCorps program would decrease BMI z-scores among overweight or obese students, and reduce obesity rates, and evaluated its effects on health knowledge and behaviors. METHODS HealthCorps aimed to improve student knowledge and behaviors regarding nutrition quality, physical activity, sleep, breakfast intake, and mental resilience. Participating students received through HealthCorps coordinators weekly or bi-weekly classroom lessons either for a semester or a year in addition to various during- and after-school health-promoting activities and mentorship. Self-reported height and weight were collected along with questionnaires assessing knowledge and behaviors during 2013-2014 academic year among 14 HealthCorps-participating New York City high schools. This quasi experimental two-arm pre-post trial included 611 HealthCorps and 221 comparison arm students for the analytic sample. Sex-specific analyses stratified by weight status were adjusted for age and Hispanic ethnicity with clustering effects of schools and students taken into account. RESULTS HealthCorps female overweight/obese and obese student had a significant decrease in BMI z-scores (post-pre delta BMI z-score = -0.16 (95%CI = (-0.26, -0.05), p = 0.004 for the former; and = -0.23 (-0.44, -0.03), p = 0.028, for the latter) whereas comparison female counterparts did not. The HealthCorps students, but not the comparison students, had a significant increase for all knowledge domains except for the breakfast realm, and reported a greater number of significant behavior changes including fruit and vegetable intake and physical activities. CONCLUSIONS The HealthCorps program was associated with reduced BMI z-score in overweight/obese and obese female adolescents, with enhanced health knowledge and behavior for both sexes. With its wide reach, this may be a promising program to help combat adolescent obesity in schools. TRIAL REGISTRATION This study is registered as a clinical trial at the ClinicalTrials.gov registry with trial number NCT02277496 on September 10, 2014 (Retrospectively registered).
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Body-composition changes in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE)-2 study: a 2-y randomized controlled trial of calorie restriction in nonobese humans.
Das, SK, Roberts, SB, Bhapkar, MV, Villareal, DT, Fontana, L, Martin, CK, Racette, SB, Fuss, PJ, Kraus, WE, Wong, WW, et al
The American journal of clinical nutrition. 2017;105(4):913-927
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Aging is associated with a decline in both the quantity and quality of fat-free mass (FFM) in parallel with increases in body weight and adiposity. Calorie restriction (CR) is the only dietary intervention that has shown promise regarding a reduction in the rate of biological aging in many nonhuman species. The aim of this study was to examine differential effects of CR on men and women and in normal-weight compared with overweight individuals. CALERIE-2 was a 2-year, multicentre, parallel-group, randomised controlled trial. The participants were randomly assigned to one of the two groups; CR group or the ad libitum control. Results show that at the end of the 2-year CR period, - body composition was relatively higher in FFM and lower in fat mass (FM) [72% FFM, 28% FM] compared with baseline [67% FFM, 33% FM]. - large improvements were observed in indexes of central adiposity, including smaller waist circumference and reductions in percentage of trunk fat in this nonobese population. Authors conclude that body composition is not adversely affected by CR in the absence of prescribed exercise. In fact, maintaining a sustained level of physical activity during CR may be required to help preserve body-composition profiles commensurate with healthy aging.
Abstract
Background: Calorie restriction (CR) retards aging and increases longevity in many animal models. However, it is unclear whether CR can be implemented in humans without adverse effects on body composition.Objective: We evaluated the effect of a 2-y CR regimen on body composition including the influence of sex and body mass index (BMI; in kg/m2) among participants enrolled in CALERIE-2 (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), a multicenter, randomized controlled trial.Design: Participants were 218 nonobese (BMI: 21.9-28.0) adults aged 21-51 y who were randomly assigned to 25% CR (CR, n = 143) or ad libitum control (AL, n = 75) in a 2:1 ratio. Measures at baseline and 12 and 24 mo included body weight, waist circumference, fat mass (FM), fat-free mass (FFM), and appendicular mass by dual-energy X-ray absorptiometry; activity-related energy expenditure (AREE) by doubly labeled water; and dietary protein intake by self-report. Values are expressed as means ± SDs.Results: The CR group achieved 11.9% ± 0.7% CR over 2-y and had significant decreases in weight (-7.6 ± 0.3 compared with 0.4 ± 0.5 kg), waist circumference (-6.2 ± 0.4 compared with 0.9 ± 0.5 cm), FM (-5.4 ± 0.3 compared with 0.5 ± 0.4 kg), and FFM (-2.0 ± 0.2 compared with -0.0 ± 0.2 kg) at 24 mo relative to the AL group (all between-group P < 0.001). Moreover, FFM as a percentage of body weight at 24 mo was higher, and percentage of FM was lower in the CR group than in the AL. AREE, but not protein intake, predicted preservation of FFM during CR (P < 0.01). Men in the CR group lost significantly more trunk fat (P = 0.03) and FFM expressed as a percentage of weight loss (P < 0.001) than women in the CR group.Conclusions: Two years of CR had broadly favorable effects on both whole-body and regional adiposity that could facilitate health span in humans. The decrements in FFM were commensurate with the reduced body mass; although men in the CR group lost more FFM than the women did, the percentage of FFM in the men in the CR group was higher than at baseline. CALERIE was registered at clinicaltrials.gov as NCT00427193.
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In a randomized trial in prostate cancer patients, dietary protein restriction modifies markers of leptin and insulin signaling in plasma extracellular vesicles.
Eitan, E, Tosti, V, Suire, CN, Cava, E, Berkowitz, S, Bertozzi, B, Raefsky, SM, Veronese, N, Spangler, R, Spelta, F, et al
Aging cell. 2017;16(6):1430-1433
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Obesity and insulin resistance are associated with accelerated aging and increased risk of many age-related diseases. The risk of many cancers, including prostate cancer, increases with age and being overweight further increases the risk. The aim of the study is to investigate the inhibition of tumour growth through the effect of protein restriction diets and hence, levels of circulating amino acids. The participants of the study were men (n=38) with prostate cancer awaiting prostatectomy surgery. Most of the subjects were overweight with a BMI of 30.45 ± 5.8. They were randomly assigned to either a control diet or a protein restricted diet. In comparison to the control diet, results show that protein restriction increased the levels of receptors (a protein molecule that receives chemical signals from outside a cell) responsible of leptin, the hormone that controls hunger. The results also show that protein restriction can improve the body’s sensitivity to the effects of the insulin in neurons (a nerve cell specialised to transmit information throughout the body). Authors conclude that protein restriction can counteract major age-related diseases.
Abstract
Obesity, metabolic syndrome, and hyperleptinemia are associated with aging and age-associated diseases including prostate cancer. One experimental approach to inhibit tumor growth is to reduce dietary protein intake and hence levels of circulating amino acids. Dietary protein restriction (PR) increases insulin sensitivity and suppresses prostate cancer cell tumor growth in animal models, providing a rationale for clinical trials. We sought to demonstrate that biomarkers derived from plasma extracellular vesicles (EVs) reflect systemic leptin and insulin signaling and respond to dietary interventions. We studied plasma samples from men with prostate cancer awaiting prostatectomy who participated in a randomized trial of one month of PR or control diet. We found increased levels of leptin receptor in the PR group in total plasma EVs and in a subpopulation of plasma EVs expressing the neuronal marker L1CAM. Protein restriction also shifted the phosphorylation status of the insulin receptor signal transducer protein IRS1 in L1CAM+ EVs in a manner suggestive of improved insulin sensitivity. Dietary PR modifies indicators of leptin and insulin signaling in circulating EVs. These findings are consistent with improved insulin and leptin sensitivity in response to PR and open a new window for following physiologic responses to dietary interventions in humans.
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Changes in Visceral Adiposity, Subcutaneous Adiposity, and Sex Hormones in the Diabetes Prevention Program.
Kim, C, Dabelea, D, Kalyani, RR, Christophi, CA, Bray, GA, Pi-Sunyer, X, Darwin, CH, Yalamanchi, S, Barrett-Connor, E, Golden, SH, et al
The Journal of clinical endocrinology and metabolism. 2017;102(9):3381-3389
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It is not currently known to what extent changes in different types of fat stores (visceral fat that surrounds organs and subcutaneous fat that sits under the surface of the skin) relate to changes in sex hormones. This study was a secondary analysis of a randomised controlled trial including 555 individuals. It examined whether changes to visceral and subcutaneous fat were associated with changes in sex hormones (DHEA, testosterone, oestrogen and sex hormone binding globulin - SHBG) among overweight individuals with glucose intolerance under the care of a diabetes program. Participants were randomly assigned to an intensive lifestyle modification programme (goals for weight reduction and 150 mins exercise weekly), medication (metformin) or placebo for 12 months. The authors found that among men, reductions in both types of fat were associated with significant increases in total testosterone and SHBG. Among women, reductions in both types of fat were associated with increases in SHBG and associations with estrone differed by menopausal status. No associations were found between changes in fat stores and estradiol or DHEA. The authors conclude that weight loss may affect sex hormone profiles via reductions in visceral and subcutaneous fat. -
Abstract
Context: The degree to which changes in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) relate to corresponding changes in plasma sex steroids is not known. Objective: We examined whether changes in VAT and SAT areas assessed by computed tomography were associated with changes in sex hormones [dehydroepiandrosterone sulfate (DHEAS), testosterone, estradiol, estrone, and sex hormone binding globulin (SHBG)] among Diabetes Prevention Program participants. Design: Secondary analysis of a randomized trial. Participants: Overweight and glucose-intolerant men (n = 246) and women (n = 309). Interventions: Intensive lifestyle change with goals of weight reduction and 150 min/wk of moderate intensity exercise or metformin administered 850 mg twice a day or placebo. Main Outcome Measures: Associations between changes in VAT, SAT, and sex hormone changes over 1 year. Results: Among men, reductions in VAT and SAT were both independently associated with significant increases in total testosterone and SHBG in fully adjusted models. Among women, reductions in VAT and SAT were both independently associated with increases in SHBG and associations with estrone differed by menopausal status. Associations were similar by race/ethnicity and by randomization arm. No significant associations were observed between change in fat depot with change in estradiol or DHEAS. Conclusions: Among overweight adults with impaired glucose intolerance, reductions in either VAT and SAT were associated with increased total testosterone in men and higher SHBG in men and women. Weight loss may affect sex hormone profiles via reductions in visceral and subcutaneous fat.
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A pooled analysis of post-diagnosis lifestyle factors in association with late estrogen-receptor-positive breast cancer prognosis.
Nechuta, S, Chen, WY, Cai, H, Poole, EM, Kwan, ML, Flatt, SW, Patterson, RE, Pierce, JP, Caan, BJ, Ou Shu, X
International journal of cancer. 2016;138(9):2088-97
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Literature shows that women with oestrogen-receptor-positive (ER+) [cells that have a receptor protein that binds the hormone oestrogen] breast cancer have a better prognosis in the first several years after diagnosis but may have higher risk of recurrence in later years after diagnosis. The aim of this study was to evaluate the associations of postdiagnosis lifestyle factors in association with breast cancer prognosis overall with ER+ late breast cancer outcomes among breast cancer survivors. This study is a prospective study based on ‘The After Breast Cancer Pooling Project’ which includes data from several long-term (>10 years), prospective cohorts of breast cancer survivors. This study included breast cancer survivors from the U.S. cohorts only i.e. a pooled analysis of over 6,500 ER+ breast cancer survivors. Results indicate that: • large post-diagnosis weight gain, obesity, and daily alcohol consumption (≥ 1 drink/day) increased the risk of late recurrence (≥5 years after diagnosis); • physical activity reduced the risk of all-cause mortality, but not the risk of late recurrence; and • current and heavy former smoking was associated with increased risk of late recurrence and all-cause mortality. Authors conclude that modifiable lifestyle factors were important predictors of late recurrence and mortality among long-term ER+ breast cancer survivors.
Abstract
Lifestyle factors have been well studied in relation to breast cancer prognosis overall; however, associations of lifestyle and late outcomes (>5 years after diagnosis) have been much less studied, and no studies have focused on estrogen receptor-positive (ER+) breast cancer survivors, who may have high risk of late recurrence and mortality. We utilized a large prospective pooling study to evaluate the associations of lifestyle factors with late recurrence and all-cause mortality among 6,295 5-year ER+ Stage I-III breast cancer survivors. Pooled and harmonized data were available on clinical factors and lifestyle factors (pre- to post-diagnosis weight change, body mass index (BMI) (kg/m(2)), recreational physical activity, alcohol intake and smoking history), measured on average 2.1 years after diagnosis. Updated information for weight only was available. Study heterogeneity was evaluated by the Q-statistic. Multivariable Cox regression models were stratified by study. Adjusting for clinical factors and potential confounders, ≥ 10% weight gain and obesity (BMI, 30-34.99 and ≥ 35) were associated with increased risk of late recurrence (hazard ratios (95% confidence intervals): 1.24 (1.00-1.53), 1.40 (1.05-1.86) and 1.41 (1.02-1.93), respectively). Daily alcohol intake was associated with late recurrence, 1.28 (1.01-1.62). Physical activity was inversely associated with late all-cause mortality (0.81 (0.71-0.93) and 0.71 (0.61-0.82) for 4.9 to <17.4 and ≥ 17.4 metabolic equivalent-hr/week). A U-shaped association was observed for late all-cause mortality and BMI using updated weight (1.42 (1.15-1.74) and 1.40 (1.09-1.81), <21.5 and ≥ 35, respectively). Smoking was associated with increased risk of late outcomes. In this large prospective pooling project, modifiable lifestyle factors were associated with late outcomes among long-term ER+ breast cancer survivors.
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Effect of Two-Year Caloric Restriction on Bone Metabolism and Bone Mineral Density in Non-Obese Younger Adults: A Randomized Clinical Trial.
Villareal, DT, Fontana, L, Das, SK, Redman, L, Smith, SR, Saltzman, E, Bales, C, Rochon, J, Pieper, C, Huang, M, et al
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2016;31(1):40-51
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While there is increasing evidence that caloric restriction (CR) can extend a healthy lifespan in humans, it is not known whether weight loss is linked to reductions in bone mineral density (BMD) in younger adults. The aim of this trial was to assess the effect of prolonged caloric restriction on bone mass density and bone metabolism in 218 healthy adults aged 21 to 40. Participants were randomised to either a 25% caloric restriction or ad libitum diet for two years. The findings of this study showed that the CR group had a larger increase in markers of bone turnover and caused a modest but significant decline in bone mineral density. Based on these findings, the authors suggest that further research is needed to determine whether bone loss increases fracture risk, and whether interventions can prevent bone loss that occurs with CR-induced weight loss.
Abstract
Although caloric restriction (CR) could delay biologic aging in humans, it is unclear if this would occur at the cost of significant bone loss. We evaluated the effect of prolonged CR on bone metabolism and bone mineral density (BMD) in healthy younger adults. Two-hundred eighteen non-obese (body mass index [BMI] 25.1 ± 1.7 kg/m(2) ), younger (age 37.9 ± 7.2 years) adults were randomly assigned to 25% CR (CR group, n = 143) or ad libitum (AL group, n = 75) for 2 years. Main outcomes were BMD and markers of bone turnover. Other outcomes included body composition, bone-active hormones, nutrient intake, and physical activity. Body weight (-7.5 ± 0.4 versus 0.1 ± 0.5 kg), fat mass (-5.3 ± 0.3 versus 0.4 ± 0.4 kg), and fat-free mass (-2.2 ± 0.2 versus -0.2 ± 0.2 kg) decreased in the CR group compared with AL (all between group p < 0.001). Compared with AL, the CR group had greater changes in BMD at 24 months: lumbar spine (-0.013 ± 0.003 versus 0.007 ± 0.004 g/cm(2) ; p < 0.001), total hip (-0.017 ± 0.002 versus 0.001 ± 0.003 g/cm(2) ; p < 0.001), and femoral neck (-0.015 ± 0.003 versus -0.005 ± 0.004 g/cm(2) ; p = 0.03). Changes in bone markers were greater at 12 months for C-telopeptide (0.098 ± 0.012 versus 0.025 ± 0.015 μg/L; p < 0.001), tartrate-resistant acid phosphatase (0.4 ± 0.1 versus 0.2 ± 0.1 U/L; p = 0.004), and bone-specific alkaline phosphatase (BSAP) (-1.4 ± 0.4 versus -0.3 ± 0.5 U/L; p = 0.047) but not procollagen type 1 N-propeptide; at 24 months, only BSAP differed between groups (-1.5 ± 0.4 versus 0.9 ± 0.6 U/L; p = 0.001). The CR group had larger increases in 25-hydroxyvitamin D, cortisol, and adiponectin and decreases in leptin and insulin compared with AL. However, parathyroid hormone and IGF-1 levels did not differ between groups. The CR group also had lower levels of physical activity. Multiple regression analyses revealed that body composition, hormones, nutrients, and physical activity changes explained ∼31% of the variance in BMD and bone marker changes in the CR group. Therefore, bone loss at clinically important sites of osteoporotic fractures represents a potential limitation of prolonged CR for extending life span. Further long-term studies are needed to determine if CR-induced bone loss in healthy adults contributes to fracture risk and if bone loss can be prevented with exercise.
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Glycemic index, glycemic load, and risk of type 2 diabetes: results from 3 large US cohorts and an updated meta-analysis.
Bhupathiraju, SN, Tobias, DK, Malik, VS, Pan, A, Hruby, A, Manson, JE, Willett, WC, Hu, FB
The American journal of clinical nutrition. 2014;100(1):218-32
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Carbohydrates are the principle dietary components that effect blood glucose concentrations. The association between Type 2 diabetes (T2D) and diets with different levels of sugars and carbohydrates has been controversial in the prevention of T2D. Foods can be measured for their impact on blood glucose concentration using the Glycaemic Index (GI) and the Glycaemic Load (GL). The objective of this meta-analysis was to update previous studies and evaluate the association between the GI and GL of dietary intake and the risk of T2D. The authors found a significant association between the GI and GL of food intake and T2D risk and conclude that high GI and GL foods increase the risk of T2D. However, GI is more strongly associated to T2D than GL.
Abstract
BACKGROUND Epidemiologic evidence for the relation between carbohydrate quality and risk of type 2 diabetes (T2D) has been mixed. OBJECTIVE We prospectively examined the association of dietary glycemic index (GI) and glycemic load (GL) with T2D risk. DESIGN We prospectively followed 74,248 women from the Nurses' Health Study (1984-2008), 90,411 women from the Nurses' Health Study II (1991-2009), and 40,498 men from the Health Professionals Follow-Up Study (1986-2008) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by using a validated questionnaire and updated every 4 y. We also conducted an updated meta-analysis, including results from our 3 cohorts and other studies. RESULTS During 3,800,618 person-years of follow-up, we documented 15,027 cases of incident T2D. In pooled multivariable analyses, those in the highest quintile of energy-adjusted GI had a 33% higher risk (95% CI: 26%, 41%) of T2D than those in the lowest quintile. Participants in the highest quintile of energy-adjusted GL had a 10% higher risk (95% CI: 2%, 18%) of T2D. Participants who consumed a combination diet that was high in GI or GL and low in cereal fiber had an ~50% higher risk of T2D. In the updated meta-analysis, the summary RRs (95% CIs) comparing the highest with the lowest categories of GI and GL were 1.19 (1.14, 1.24) and 1.13 (1.08, 1.17), respectively. CONCLUSION The updated analyses from our 3 cohorts and meta-analyses provide further evidence that higher dietary GI and GL are associated with increased risk of T2D.
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Effect of weight loss, exercise, or both on cognition and quality of life in obese older adults.
Napoli, N, Shah, K, Waters, DL, Sinacore, DR, Qualls, C, Villareal, DT
The American journal of clinical nutrition. 2014;100(1):189-98
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Obese adults may be at increased risk of dementia. Lifestyle interventions and weight loss are recommended for obese individuals, however, this may not be applicable to older obese individuals as extra weight could be protective against health risks in the older generation. This randomised controlled trail aimed to evaluate the combined and independent effect of weight loss and exercise on cognition & mood in 107 obese older adults over a one year period. The study found that diet and exercise both independently had a statistically significant impact on mood and quality of life. Exercise had the most significant impact, with the combination of diet and exercise being equal to the impact of exercise alone.
Abstract
BACKGROUND Obesity impairs cognition and health-related quality of life (HRQOL) in older adults; however, the appropriate treatment of obese older adults remains controversial. OBJECTIVE The objective was to determine the independent and combined effects of weight loss and exercise on cognition, mood, and HRQOL in obese older adults. DESIGN One hundred seven frail, obese older adults were randomly assigned to a control, weight-management (diet), exercise, or weight-management-plus-exercise (diet-exercise) group for 1 y. In this secondary analysis, main outcomes were Modified Mini-Mental State Examination (3MS) and total Impact of Weight on Quality of Life-Lite (IWQOL) scores. Other outcomes included Word Fluency Test, Trail Making Test Parts A and B, and Geriatric Depression Scale (GDS) scores. RESULTS Scores on the 3MS improved more in the diet (mean ± SE: 1.7 ± 0.4), exercise (2.8 ± 0.4), and diet-exercise (2.9 ± 0.4) groups than in the control group (0.1 ± 0.4) (between-group P = 0.0001-0.04); scores in the diet-exercise group improved more than in the diet group but not more than in the exercise group. Scores on the Word Fluency Test improved more in the exercise (4.1 ± 0.8) and diet-exercise (4.2 ± 0.7) groups than in the control group (-0.8 ± 0.8; both P = 0.001). For the Trail Making Test Part A, scores in the diet-exercise group (-11.8 ± 1.9) improved more than in the control group (-0.8 ± 1.9) (P = 0.001); a similar finding was observed for the Trail Making Test Part B. Scores on the IWQOL improved more in the diet (7.6 ± 1.6), exercise (10.1 ± 1.6), and diet-exercise (14.0 ± 1.4) groups than in the control group (0.3 ± 1.6) (P = 0.0001-0.03); scores in the diet-exercise group improved more than in the diet group but not more than in the exercise group. In the diet-exercise group, peak oxygen consumption and strength changes were independent predictors of 3MS changes; weight and strength changes were independent predictors of IWQOL changes. GDS scores did not change. CONCLUSIONS Weight loss and exercise each improve cognition and HRQOL, but their combination may provide benefits similar to exercise alone. These findings could inform practice guidelines with regard to optimal treatment strategies for obese older adults. This trial was registered atclinicaltrials.govas NCT00146107.