All physiological systems experience age-associated decrements in function that can be described as "primary aging." There is mounting evidence that many of these changes can be delayed or even prevented by long-term caloric restriction (CR). In humans, the first experiments on the effect of energy restriction were performed by Keys et.al in the 1950s. In these classic experiments, lean volunteers consumed 50% of their habitual caloric intake. There was a decrease in basic metabolic rate when adjusted for body surface area, body weight, and cell mass. However, there were also indications of malnutrition with deficiencies in many micronutrients. Beyond this experiment, most information comes from animal models, and significant CR benefits have been observed. In 2001 and 2002, the National Institute on Aging (NIA) issued Requests for Application to perform detailed clinical studies into the effects of CR in humans. The stated purpose was,"... to gain knowledge about the effects in humans of sustained CR on physiology, metabolism, body composition, risk factors for age-related pathologies ... and its potential adverse effects." Phase 1 of the program has been completed, and following a detailed and comprehensive developmental process, the Phase 2 study has begun. Power calculations indicate that to address the primary study outcomes, as well as important secondary and exploratory outcomes, 250 participants should be enrolled. By March 2009, however, we anticipate randomizing only 170 participants. The present application therefore requests funding to complete the Phase 2 study with the full complement of 250 participants.
The Specific Aims are: (1) maintain statistical power for the two primary outcomes at the originally planned levels;(2) increase statistical power for important secondary and exploratory outcomes to more acceptable levels relative to a study with only 150 enrolled;(3) complete enrollment of volunteers into the Phase 2 study in an expeditious manner and minimize participant drop-out;(4) undertake detailed procedures to safeguard the fidelity of the intervention and maintain quality control over the outcome determinations;(5) store biological samples in a central repository, and provide opportunities for mechanistic studies by the greater scientific community;and, (6) perform detailed statistical analyses.

Public Health Relevance

CALERIE is the first comprehensive study to determine whether the salutary effects of caloric restriction observed in animal studies extend to human beings. Ultimately, CALERIE will further our knowledge of the basic biology of the human aging process. It may also contribute to development of practical strategies for retardation of aging and age-related diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project--Cooperative Agreements (U01)
Project #
3U01AG022132-10S2
Application #
8710649
Study Section
Special Emphasis Panel (ZAG1-ZIJ-7 (O2))
Program Officer
Romashkan, Sergei
Project Start
2002-09-30
Project End
2014-06-30
Budget Start
2013-08-15
Budget End
2014-06-30
Support Year
10
Fiscal Year
2013
Total Cost
$765,749
Indirect Cost
$235,469
Name
Duke University
Department
Biostatistics & Other Math Sci
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Redman, Leanne M; Kraus, William E; Bhapkar, Manju et al. (2014) Energy requirements in nonobese men and women: results from CALERIE. Am J Clin Nutr 99:71-8
Lam, Yan Y; Redman, Leanne M; Smith, Steven R et al. (2014) Determinants of sedentary 24-h energy expenditure: equations for energy prescription and adjustment in a respiratory chamber. Am J Clin Nutr 99:834-42
Roberts, Susan B; Speakman, John (2013) Update on human calorie restriction research. Adv Nutr 4:563-4
Stewart, T M; Bhapkar, M; Das, S et al. (2013) Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE Phase 2) screening and recruitment: methods and results. Contemp Clin Trials 34:10-20
Bales, Connie W; Kraus, William E (2013) Caloric restriction: implications for human cardiometabolic health. J Cardiopulm Rehabil Prev 33:201-8
Racette, Susan B; Das, Sai Krupa; Bhapkar, Manjushri et al. (2012) Approaches for quantifying energy intake and %calorie restriction during calorie restriction interventions in humans: the multicenter CALERIE study. Am J Physiol Endocrinol Metab 302:E441-8
Rochon, James; Bales, Connie W; Ravussin, Eric et al. (2011) Design and conduct of the CALERIE study: comprehensive assessment of the long-term effects of reducing intake of energy. J Gerontol A Biol Sci Med Sci 66:97-108
Martin, Corby K; Das, Sai Krupa; Lindblad, Lauren et al. (2011) Effect of calorie restriction on the free-living physical activity levels of nonobese humans: results of three randomized trials. J Appl Physiol 110:956-63
Rickman, Amy D; Williamson, Donald A; Martin, Corby K et al. (2011) The CALERIE Study: design and methods of an innovative 25% caloric restriction intervention. Contemp Clin Trials 32:874-81