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Caloric restriction and insulin sensitivity

caloric restriction and insulin sensitivity

DDRGK1 regulates NF-κB activity by modulating IκBα stability. Restrictkon Type diabetes medical alert sensitiviyy several within-class modules, such as for fecal metabolic features for Type diabetes medical alert Anti-aging skincare routine distinct cluster of nodes variables can be seen, sAT genes, or serum metabolic features, where several features corresponding to serum glucose clustered together. Top bar navigation. The increase in adiponectin following PR may be a compensatory response to protect against leptin-induced inflammation Wu, H. caloric restriction and insulin sensitivity

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Caloric restriction and insulin sensitivity -

The sooner these treatments arrive, the more lives will be saved. Find out how to help ». We know that calorie restriction CR greatly improves insulin sensitivity - which seems to be one of the ways in which it increases life span - just as eating too much and getting fat tends to lead to insulin resistance and the diabetes that follows.

Here, researchers are making slow inroads into understanding why CR does this: "Caloric restriction CR has been shown to retard aging processes, extend maximal life span, and consistently increase insulin action in experimental animals.

The mechanism by which CR enhances insulin action, specifically in higher species, is not precisely known. We sought to examine insulin receptor signaling and transcriptional alterations in skeletal muscle of nonhuman primates subjected to caloric restriction over a 4 year period.

CR increases insulin sensitivity on a whole body level and enhances insulin receptor signaling in this higher species. CR in cynomolgus monkeys may alter insulin signaling in vivo by modulating protein content of insulin receptor signaling proteins.

Post a comment; thoughtful, considered opinions are valued. New comments can be edited for a few minutes following submission. Whether increased FCS affects insulin sensitivity by increased spillover of triglyceride into visceral fat or into muscle, liver, or other nonadipose tissues is unclear.

Calorie restriction reduces fat mass, delays the development of age-associated diseases such as type 2 diabetes, and increases lifespan in rodents. In obese humans, it is well established that calorie restriction, weight loss, and exercise improve insulin sensitivity 6 — 11 , although the additional benefits of increased exercise on insulin sensitivity are debated.

Moreover, the extent that these interventions alter ectopic fat accumulation in muscle and liver has not been explored. Moderate weight loss, by diet alone or in combination with exercise, however, does not alter muscle lipid depots, despite significant improvements in insulin sensitivity 6 , 14 , Hepatic fat, on the other hand, was significantly lowered by moderate weight reduction in obese women and in type 2 diabetes 16 , To our knowledge no study has yet determined the effect of caloric restriction with or without exercise on ectopic fat in nonobese individuals.

The goal of this study was, therefore, to determine in healthy nonobese, glucose tolerant subjects 1 the relationships among total body fat, visceral fat, FCS, intramyocellular lipid IMCL , intrahepatic lipid IHL , and insulin sensitivity index S i and 2 the effects of a calorie-restricted diet alone or in conjunction with exercise on ectopic fat, visceral fat, FCS, insulin sensitivity, and β-cell function.

Details of this study are reported elsewhere The study was approved by the Pennington Biomedical Research Center Institutional Review Board and the CALERIE Data Safety Monitoring Board, and all subjects provided written informed consent.

To carefully determine individual energy requirements, total daily energy expenditure was measured by two day measures of doubly labeled water, once while participants followed their usual diet at home and once while they were being provided with a weight maintenance diet by the metabolic kitchen.

Patients were then admitted to the ward for 5 days of metabolic testing. Participants were provided with all food for the first 12 weeks and for weeks 22— For weeks 13—22, participants self-selected their diet based on their calorie targets.

CREX participants increased their energy expenditure by Participants were required to conduct three sessions per week under supervision. For unsupervised sessions, participants wore a portable heart rate monitor Polar S, Polar Beat, Port Washington, NY with heart rate and exercise duration recorded.

For support, all participants attended weekly group meetings that were led by clinical psychology professionals. All metabolic tests were performed during inpatient stays at baseline and month 6 following a h overnight fast and at least 48 h after the last bout of exercise.

Body fat was measured by dual-energy X-ray absorptiometry QDA A; Hologics, Bedford, MA and multislice computed tomography scanning of the abdominal region GE High Speed Plus; General Electric, Fairfield, CT was performed to quantify abdominal fat compartments Muscle and liver lipid stores were determined by proton magnetic resonance spectroscopy using point-resolved spectroscopy Subcutaneous abdominal needle biopsies were performed, and FCS was determined by the Multisizer-3 counter Beckman Coulter, Fullerton, CA as previously described Insulin sensitivity was determined by the insulin-modified frequently sampled intravenous glucose tolerance test 22 , At 20 min, a bolus injection of insulin 0.

The S i and acute insulin response to glucose AIR g were calculated by the minimal model Because of illness or problems with intravenous lines, four tests could not be analyzed at month 6.

Glucose was analyzed using a Synchron CX7 Beckman-Coulter, Brea, CA and insulin was analyzed via immunoassay on the DPC Diagnostic Product Corporation, Los Angeles, CA. SAS version 9. Pearson or Spearman rank order correlations were used where appropriate, and general linear regression was used to identify any interactions of the changes with sex.

To assess the effect of the intervention among the four groups, the change from baseline to month 6 was computed, and an ANCOVA was performed with baseline values included in the model as covariates and adjusted with respect to Tukey-Kramer.

Two subjects withdrew during the study; one was a control subject who withdrew for personal reasons and the other subject, who was following the LCD diet, was lost to follow-up.

Data are therefore presented on 46 subjects. Characteristics of the subjects at baseline are reported in Table 1.

Subjects were generally in good health with fasting glucose, insulin, and blood pressure within recommended ranges; 30 Caucasians, 15 African Americans, and 1 Asian were examined.

IMCL in the soleus was not correlated with FCS, VAT, or IHL. All of the above correlations were also statistically significant at month 6 data not shown. The impact of the intervention can be seen in Table 1 by comparing results at month 6 versus baseline.

The changes in body composition and abdominal fat were not dependent on whether the caloric deficit was achieved by exercise and diet CREX or diet alone CR and LCD. The improvement in S i was not different among the three intervention groups.

The changes in IMCL, IHL, FCS, and the other abdominal fat depots were not additional independent determinants. These correlation analyses were repeated with the control group removed. The significance of the relationship between the changes in FCS and VAT and the changes in IHL and percent fat was lost, but no other relationships were affected.

In this study we examined the relationships between S i and various indexes of body fat in overweight, glucose-tolerant subjects before and after calorie restriction. At baseline, we found that 1 fat deposition in liver was related to the accumulation of fat in the abdominal visceral area and to enlarged subcutaneous abdominal adipocytes and 2 increased FCS but not ectopic fat deposition in muscle and liver was independently associated with reduced insulin sensitivity.

In response to 6 months of calorie restriction, we found that 1 weight, visceral fat, and FCS are reduced with improvements in S i and reduced AIR g and 2 fat deposition in liver but not muscle was reduced by the intervention, but the changes were not associated with improvements in S i.

Several studies have suggested that ectopic fat accumulation is independent of whole-body adiposity 16 , 24 — However, other studies have noted that lipid accumulation in both muscle 27 , 31 — 33 and liver 34 — 37 increases as a function of obesity, providing that subjects with a wide range of adiposity are studied.

In this study, we observed that lipid deposition in liver but not muscle was related to both total and abdominal adiposity. Specifically, our findings indicate that ectopic fat in the liver may be related to visceral fat stores.

This relationship between liver lipid and visceral adiposity has been noted in some 34 , 38 but not all 29 , 30 studies. Most interestingly, we observed that liver lipid infiltration tended to be greater in overweight individuals who had enlarged adipocytes and increased visceral abdominal adiposity.

Furthermore, visceral fat was related to FCS. These findings support the hypothesis that inadequate subcutaneous adipose stores result in lipid overflow into visceral fat and other nonadipose tissues In this regard, visceral fat could be considered as a marker of ectopic fat.

At baseline and at month 6, large fat cells were also the strongest determinant of insulin resistance in these nondiabetic subjects. This finding prompts speculation that impaired adipogenesis may be the primary defect in insulin resistance, and the hypothesis is supported by findings that humans with partial or complete loss of adipose tissue are extremely insulin resistant 40 , that surgical replacement of adipose stores in the fatless mouse restores insulin sensitivity 41 , and that expression of Wnt signaling genes and adipogenic transcription factors are reduced in nondiabetic subjects with a family history of type 2 diabetes Large fat cells have also been shown to have a different pattern of adipocytokine secretion than smaller fat cells 43 , which may contribute to the strong association between large FCS and insulin sensitivity.

In contrast to previous studies 24 , 26 — 28 , 31 , 44 , 45 , we observed that IMCL was not related to insulin sensitivity. Furthermore, IMCL was not related to adipocyte size.

Our results are consistent with the hypothesis that IMCL stores alone are not sufficient to account for impaired insulin action 46 — Liver lipid, on the other hand, was inversely related to insulin sensitivity.

Liver lipid content has previously been reported to correlate with measures of whole-body insulin sensitivity in individuals with and without diabetes 30 , 34 , 35 , 38 , 49 , but this relationship is difficult to explain mechanistically because most ingested or infused glucose is taken up by muscle.

Theoretically, IHL is expected to correlate with reduced hepatic insulin sensitivity impaired insulin suppression of glucose rate of appearance and not necessarily with whole-body insulin action. However, the accumulation of hepatic triglyceride has been hypothesized to reduce insulin clearance and lead to peripheral insulin resistance via a downregulation of insulin receptors 34 , Clearly, prospective human studies that define whether lipid accumulation in liver precedes insulin resistance would be of interest.

Contrary to some previous studies 51 , 52 , we observed that diet alone or with exercise produced identical reductions in weight, fat mass, and abdominal fat mass. These conflicting results may be due to inaccurate calculations of the energy costs of the prescribed activity in those studies, which would lead to differences in energy deficits among groups.

We also observed that FCS was reduced in response to an energy deficit, but we could not detect an additional effect of exercise. Our study was underpowered to detect differences in FCS among groups and our results contrast with the reports of You et al.

The current study is also the first to simultaneously measure ectopic fat stores in both muscle and liver in response to a calorie restriction intervention. We found that the calorie restriction alone or with exercise did not affect IMCL in the soleus. These results are consistent with previous studies 6 , 14 , 15 and together with the findings that IMCL was not independently related to S i suggest that IMCL accumulation alone is not likely to be a causal factor leading to acquired insulin-signaling defects in muscle.

Many other factors, including lipid droplet size, location of lipid droplets relative to mitochondria, and muscle oxidative capacity, are all potential determinants of insulin resistance 15 , 48 , An alternate hypothesis is that the capacity for lipid metabolism is an important mediator in the association between IMCL and insulin resistance.

Caution must be exercised when interpreting these results because the study may have been underpowered to detect small differences in IHL among groups.

The reduction in liver lipid levels is consistent with results of Tiikkainen et al. In addition, we also observed parallel reductions in IHL and abdominal visceral fat. In summary, calorie restriction by diet alone or in conjunction with exercise leads to similar improvements in insulin sensitivity and reductions in β-cell sensitivity in overweight, glucose-tolerant subjects.

The study also provides support for the hypothesis that the underlying pathologic cause of insulin resistance is related to abnormal partitioning of fat among adipose, hepatic, muscle, and pancreatic tissues, probably as a result of an inability to make new fat cells.

However, the finding that IMCL was not responsive to weight loss despite improvements in insulin sensitivity suggests that intracellular fat accumulation is not a causal factor in insulin resistance in muscle. Overall, this study provides new evidence to suggest that impaired adipogenesis and increased liver lipid infiltration occur early in the pathogenesis of insulin resistance.

In healthy overweight men and women at baseline, there was a strong positive correlation between abdominal subcutaneous FCS and VAT A and abdominal subcutaneous FCS and IHL B. Groups were pooled for analysis. The improvement in insulin sensitivity with 6 months of calorie restriction was significantly associated with the loss of fat mass A and abdominal VAT depots B but not to the change in subcutaneous abdominal FCS C and IHL D.

Analyses are reported with and without the control group included. Physical characteristics of the subject groups at baseline and following 6 months of calorie restriction. Differences between treatment groups for the change scores using an ANCOVA with the absolute change as the dependent variable and the baseline score as a covariate.

This work was supported by grants U01 AG to E. and K01 DK to D. is supported by a Neil Hamilton-Fairley Training Fellowship awarded by the National Health and Medical Research Council of Australia ID The authors thank the remaining members of the Pennington CALERIE Research Team: James DeLany, Corby Martin, Julia Volaufova, Marlene Most, Lilian de Jonge, Tuong Nguyen, Frank Greenway, Emily York-Crow, Catherine Champagne, Brenda Dahmer, Andy Deutsch, Paula Geiselman, Jennifer Howard, Jana Ihrig, Michael Lefevre, Darlene Marquis, Connie Murla, Sabrina Yang, Robbie Durand, Sean Owens, Aimee Stewart, and Vanessa Tarver.

Our gratitude is extended to the excellent staffs of the Inpatient Clinic and Metabolic Kitchen. Our thanks also go to Health and Nutrition Technology Carmel, CA for providing us with all of the HealthOne formula used in the study and to Edward J.

Robarge for technical assistance with collection of the magnetic resonance spectroscopy data. Finally, our profound gratitude goes to all the volunteers who spent so much time participating in this very demanding research study.

is currently affiliated with the Department of Family and Consumer Sciences, University of Wyoming, Laramie, Wyoming. is currently affiliated with the Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.

A table elsewhere in this issue shows conventional and Système International SI units and conversion factors for many substances. The costs of publication of this article were defrayed in part by the payment of page charges.

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RESEARCH DESIGN AND METHODS. Article Information. Article Navigation. Effect of Calorie Restriction With or Without Exercise on Insulin Sensitivity, β-Cell Function, Fat Cell Size, and Ectopic Lipid in Overweight Subjects D.

Enette Larson-Meyer, PHD ; D. Enette Larson-Meyer, PHD. This Site. Google Scholar. Leonie K. Heilbronn, PHD ; Leonie K. Heilbronn, PHD. Leanne M. Redman, PHD ; Leanne M.

Redman, PHD. Bradley R. Newcomer, PHD ; Bradley R. Newcomer, PHD.

Background: The Gut-brain connection responsible for calorie restriction CR festriction improvement calloric insulin sensitivity Rstriction have calroic been fully elucidated. Greater insight can sensitivitu achieved through deep biological phenotyping of subjects restrictipn CR, and Type diabetes medical alert Glutathione pills big data. Materials Nutritional factors in injury rehabilitation Methods: Senxitivity Type diabetes medical alert approach was applied to investigate associations between sensitivjty in IS and factors Hydration strategies for strength athletes host, microbiota, and lifestyle restrictkon a 6-week CR period in 27 overweight or obese adults ClinicalTrials. gov : NCT Partial least squares regression was used to determine associations of change week 6 — baseline between IS markers and lifestyle factors diet and physical activitysubcutaneous adipose tissue sAT gene expression, metabolomics of serum, urine and feces, and gut microbiota composition. ScaleNet, a network learning approach based on spectral consensus strategy SCS, developed by us was used for reconstruction of biological networks. Results: A spectrum of variables from lifestyle factors 10 nutrientsgut microbiota 10 metagenomics speciesand host multi-omics metabolic features: 84 from serum, 73 from urine, and from feces; and sAT gene probes most associated with IS were identified. Do restrkction want to live a longer life in good health? Balanced body fat threshold Type diabetes medical alert can make some difference, inaulin as exercise sensitivigy calorie restriction. But over the long haul all that really matters is caloric restriction and insulin sensitivity in medicine: building new classes of therapy to repair and reverse the known root causes of aging. The sooner these treatments arrive, the more lives will be saved. Find out how to help ». We know that calorie restriction CR greatly improves insulin sensitivity - which seems to be one of the ways in which it increases life span - just as eating too much and getting fat tends to lead to insulin resistance and the diabetes that follows.

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