{"type":"trials","record":{"id":21847,"source_id":"clinicaltrials-gov","external_id":"NCT01508091","title":"Calorie Restriction Retards the Aging Process","brief_summary":"Calorie restriction is the only experimental manipulation that prolongs longevity in experimental animals. The life prolonging effects of calorie restriction are related to a lower incidence of tumors and less inflammation, but more importantly, a lower generation of reactive oxygen species (ROS). This effect is related to the overexpression of two groups of enzymes. One is a group of (NAD+)-dependent deacetylases called sirtuins whose main actions are to increase free fatty acid flow from adipose tissue, improve insulin secretion and promote mitochondrial biogenesis in muscle. The other group corresponds to uncoupling proteins (UCP), specially UCP 3 that reduces the mitochondrial production of ROS. On the other hand, an effect of calorie restriction that is always reported, is a decrease in resting energy expenditure. A reduction in the activity of UCP1 in brown adipose tissue could be a mechanisms to explain this effect. However sirtuins apparently increase the expression of UCP1.Recently PET CT scans have emerged as a non invasive methodology to recognize brown adipose tissue activity and indirectly, UCP1 activity. Also measurement of telomere length in peripheral blood mononuclear cells has consolidated as a good marker of aging. Two possible models of calorie restriction can be studied in humans. One is a retrospective model in which adults are separated in those that have maintained a stable weight during adulthood in a manner analogous to the weight clamp model of calorie restriction in non human primates. This model is only reliable if there are objective records of the weight that the studied subjects had 20 or more years ago. In the retrospective part of this project the investigators propose to study adults whose weight was recorded previously. The investigators pretend to compare telomere length and expression of SIRT1 and 6 in PBMC, plasma 8 isoprostanes and carotid intima media thickness between weight maintainers and weight gainers. The investigators hypothesis is that weight maintainers will have a better aging profile than weight gainers. In the prospective part of the project the investigators will study a human model of calorie restriction prescribing a 25% reduction in calorie intake during 3 months and comparing groups according to weight loss. At baseline and the end of the study period, UCP3 and SIRT1 expression in muscle biopsies, SIRT1 and 6 expression in PBMC and brown adipose activity, assessed by 18fluorodeoxyglucose uptake using PET/CT will measured. The investigators hypothesis is that individuals subjected to calorie restriction will experience an increase in the expression of UCP3, SIRT1 and SIRT6 and a reduction in brown adipose tissue activity. Simultaneously, these subjects will experience a reduction in oxidative stress markers in muscle and plasma.","overall_status":"Unknown","phases":[],"study_type":"INTERVENTIONAL","sponsor":"University of Chile","enrollment":48,"countries":["Chile"],"start_date":"2012-05-01","completion_date":"2013-06-01","last_update_date":"2012-10-23","source_url":"https://clinicaltrials.gov/study/NCT01508091","editorial_summary":"A registered study indexed because it matched monitored longevity research terms. Registry status: Unknown. Registration does not establish safety or effectiveness.","first_seen_at":"2026-09-24T01:17:10.897288+00:00","last_seen_at":"2026-09-25T06:25:45.678+00:00","metadata":{"sex":"FEMALE","acronym":null,"age_range":"25 Years to 40 Years","comparator":null,"organization":"University of Chile","interventions":["energy restricted mediterranean-type diet","25 % calorie restriction"],"registry_source":"ClinicalTrials.gov","outcome_measures":["UCP3 mRNA expression in vastus lateralis after energy restriction — 3 months","Brown adipose tissue (BAT) activity, indicating UCP1 expression after calorie restriction — 3 months"],"design_description":"NA · SINGLE GROUP · BASIC SCIENCE · NONE","source_has_results":false},"controlled_terms":["Obesity","energy restricted mediterranean-type diet","25 % calorie restriction"],"relevance_confidence":100,"source_quality_score":100,"freshness_score":35,"publication_state":"published","match_explanation":"Title contains controlled term: calorie restriction.","quality_checked_at":"2026-09-25T06:25:48.368501+00:00","duplicate_cluster_key":"id:nct01508091","duplicate_of_id":null,"evidence_snapshot":{"status":"structured","version":1,"duration":"2012-05-01 to 2013-06-01","comparator":null,"confidence":"structured-source","population":"FEMALE · 25 Years to 40 Years","provenance":{"duration":"start_date and completion_date","comparator":"registry arm fields","population":"registry eligibility fields","intervention":"registry intervention fields","participants":"enrollment","study_design":"study_type and registry design fields","evidence_stage":"phases","reported_outcome":"not available","outcomes_measured":"registry outcome-measure fields"},"generated_at":"2026-09-25T06:25:45.738Z","intervention":["energy restricted mediterranean-type diet","25 % calorie restriction"],"participants":48,"study_design":"NA · SINGLE GROUP · BASIC SCIENCE · NONE","subject_scope":"Human clinical study registration","evidence_stage":"Phase not reported","safety_context":"Eligibility, adverse-event details, and clinical decisions must be checked in the official registry and with qualified clinicians.","source_support":"Structured registry protocol metadata; no finding-level conclusion is generated.","main_limitation":"This is a study registration. No reusable structured result is available here, so it cannot show whether the intervention worked or was safe.","reported_outcome":null,"outcomes_measured":["UCP3 mRNA expression in vastus lateralis after energy restriction — 3 months","Brown adipose tissue (BAT) activity, indicating UCP1 expression after calorie restriction — 3 months"],"regulatory_context":"Trial registration is not regulatory approval and does not establish that an intervention is available."},"clinical_trial_topics":[{"topic_slug":"caloric-restriction","is_published":true,"match_reasons":["Title contains controlled term: calorie restriction.","Abstract contains controlled term: calorie restriction.","Source terminology contains: calorie restriction.","Title supplies longevity context: aging.","Study type is explicitly identified as INTERVENTIONAL."],"matched_fields":["title","abstract","controlled terminology","title context","study type"],"relevance_score":100,"intelligence_topics":{"name":"Caloric restriction","slug":"caloric-restriction"}}],"content_sources":{"name":"ClinicalTrials.gov","homepage_url":"https://clinicaltrials.gov/"}},"canonical_url":"https://www.immortal.life/trials/21847","automation_disclosure":"Generated automatically from cited source metadata. No scientist, clinician, researcher, editor, or human reviewer evaluates this publication before release."}