CALERIE

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CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) is a trial currently underway in the U.S. to study the effects of prolonged calorie restriction on healthy human subjects.

Contents

The CALERIE study is being carried out at the Pennington Biomedical Research Center (Baton Rouge, Louisiana), the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University (Boston, Massachusetts) and the Washington University School of Medicine (St. Louis, Missouri). [1] It is hoped that caloric restriction reduces the incidence of cardiovascular disease and cancer and leads to a longer life, as has been demonstrated previously in numerous animal studies. [2] CALERIE is the first study to investigate prolonged calorie restriction in healthy humans. Study subjects are selected from people who are not obese (because calorie restriction on obese people is already known to lengthen life, but possibly for different reasons). [3]

A smaller predecessor study ended in 2006. Forty-eight subjects were randomly assigned to a control group and a treatment group; those in the treatment group were put on a 25% calorie reduction over a 6-month period. It was found that the treatment group had lower insulin resistance, lower levels of LDL cholesterol, lower body temperature and blood-insulin levels as well as less oxidative damage to their DNA. [3]

The second, larger, phase of CALERIE began in 2007. The participants are subjected to a 25% calorie restriction over a 2-year period, and several physiological variables are regularly monitored. Participants are paid $5,000 at Tufts and Pennington and $2,400 at Washington University. As of October 2009 the study had 132 participants and was still accepting new ones. [2]

Study subjects have to be highly motivated and organized enough to keep a detailed journal of all foods they eat. Their daily baseline calorie requirements are precisely determined before the trial: in a two-week laboratory test the rate of carbon dioxide production is measured, allowing to compute the number of burned calories. The subjects are then taught a diet of low-energy density foods, such as vegetables, fruits (especially apples), insoluble fiber and soups. Most subjects reported that they felt hungry for the first few weeks, after which they adjusted to the new diet. Complaints focused on the rigid bookkeeping scheme imposed on them. [2]

Results were posted to the Clinical Trial website in 2018 with a (paywalled) Lancet article [4] published in 2019. MSN published article [5] based on an interview with Dr Kraus.

Background

That calorie restriction (CR) might lengthen human lifespan was suggested by various studies on laboratory animals. However, when the studies were extended to long-lived primates (rhesus monkeys), while it was indeed found in a 2012 study by the US National Institute on Aging (NIA) that CR had benefits to immune function, motor coordination, and resistance to sarcopenia, a CR regimen implemented in rhesus monkeys of various ages did not improve survival outcomes.

The authors considered that the study suggested "a separation between health effects, morbidity and mortality", and that "study design, husbandry and diet composition may strongly affect the life-prolonging effect of CR in a long-lived non-human primate". [6]

Related Research Articles

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<span class="mw-page-title-main">Luigi Fontana (medical researcher)</span> Italian/Australian physician scientist, professor, environmentalist and author

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Rafael de Cabo is a Spanish scientist and Branch Chief of the Translational Gerontology Branch at the National Institute on Aging, a division of the U.S. National Institutes of Health. His research on calorie restriction in rhesus macaques suggested that calorie restriction in monkeys have no significant effects on their lifespan. In 2011, his research on obese mice suggested that resveratrol mimetic helps extend longevity and his research on male mice suggested that metformin have a longevity effect.

Leanne M. Redman is a physiologist. She is an LPFA Endowed Fellowship Professor at the Pennington Biomedical Research Center of the Louisiana State University System, where she studies childhood obesity. She was lead researcher on a study that found that low-calorie diets decreased the effects of aging. Redman received the 2018 NPA Garnett-Powers & Associates Mentor Award in recognition of support for post-doctorate mentee scholars in her reproductive endocrinology lab.

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References

  1. ↑ About CALERIE Archived 2010-02-12 at the Wayback Machine , retrieved 12 October 2009.
  2. 1 2 3 Gertner, Jon (2009-10-07). "The Calorie-Restriction Experiment". The New York Times Magazine.
  3. 1 2 Eat less, live more, The Economist, April 22, 2006
  4. ↑ Kraus, W. E.; Bhapkar, M.; Huffman, K. M.; Pieper, C. F.; Krupa Das, S.; Redman, L. M.; Villareal, D. T.; Rochon, J.; Roberts, S. B.; Ravussin, E.; Holloszy, J. O.; Fontana, L.; CALERIE Investigators (2019). "2 years of calorie restriction and cardiometabolic risk (CALERIE): exploratory outcomes of a multicentre, phase 2, randomised controlled trial". The Lancet. Diabetes & Endocrinology. 7 (9): 673–683. doi:10.1016/S2213-8587(19)30151-2. PMC   6707879 . PMID   31303390.
  5. ↑ "Cutting 300 Calories a Day Shows Health Benefits".{{cite journal}}: Cite journal requires |journal= (help)
  6. ↑ Mattison, Julie A.; Roth, George S.; Beasley, T. Mark; Tilmont, Edward M.; Handy, April M.; Herbert, Richard L.; Longo, Dan L.; Allison, David B.; Young, Jennifer E.; Bryant, Mark; Barnard, Dennis; Ward, Walter F.; Qi, Wenbo; Ingram, Donald K.; de Cabo, Rafael (2012). "Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study". Nature. 489 (7415): 318–321. Bibcode:2012Natur.489..318M. doi:10.1038/nature11432. ISSN   0028-0836. PMC   3832985 . PMID   22932268.
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