600 likes | 1.31k Views
Caloric Restriction and Longevity. Lisa Cui, Tin Wing ( Faneu ) Liu, Ayumi Tsurushita November 8, 2011. Outline. Introduction Mouse studies of caloric restriction Human studies of caloric restriction Cautions of caloric restriction Conclusion. Introduction.
E N D
Caloric Restriction and Longevity Lisa Cui, Tin Wing (Faneu) Liu, Ayumi Tsurushita November 8, 2011
Outline • Introduction • Mouse studies of caloric restriction • Human studies of caloric restriction • Cautions of caloric restriction • Conclusion
Introduction • Caloric restriction (CR)– generally defined as 20-40 % of ad libitum consumption with adequate nutrients • First study on mice was done in the 1930s by McCay et al • Showed an increase in mean and maximal lifespan • Other proposed benefits: • Decreased CVD risk, later onset of chronic disease, decreased oxidative damage
Hypothesis of the Mechanism of CR • Decreased energy expenditure • Decreased body weight • Decreased oxidative stress/free radicals • Hormesis - low levels of stress have positive, potentially life- extending effects
Rodents Study by Sohal et al. • Oxidative Damage during aging and in response to food restriction in the mouse • Oxidative Damage: • Inherent inadequacy of antioxidant defenses • Oxidative stress: imbalance between oxidant fluxes and antioxidant defenses • Aim: to test the relevance and validity of oxidative stress hypothesis of aging in life span extension by CR
Rodent Study by Sohal et al. • Study Design • 59 mice aged 9, 16 or 23 months • Ad libitum (AL) fed mice and CR (40% lower in calories) fed mice • Obtaining data of reduced protein oxidation, O2- and H2O2 production in the brain, heart, and kidney.
Rodent Study by Sohal et al. • Results: • CR rats exhibited a 43% extension in average life span • Mitochondrial oxidants production increases with age = biomarkers of aging • Protein Oxidative Damage is associated with aging process • CR lessens the damage
Rodents Study by Masoro et al. • Effect of CR on Age-associated Diseases • Male ad lib. Rats and CR rats (60% intake) • Common problem with increasing age in male mice: Chronic Nephropathy • Ad lib. –fed rats had more kidney lesions • DR rats were much older at the time of death than the ad. lib-rats • Decrease the contribution of pituitary adenoma to death
Rodents Studies by Masoro et al. • The reduction of dietary energy intake but NOT a specific dietary component is responsible for the anti-ageing action of CR.
Summary of results of rodent studies • Increase in mean and maximal lifespan • Decrease in oxidative damage • Later onset of kidney disease Photo Credit rats image by Olga Barbakadze from Fotolia.com
Human Studies PubMed • Biosphere 2 • CALERIE studies • Epidemiological Study of population in Okinawa
Biosphere 2 • Completely closed, self-sustaining ecological system • Subjects: Four women and four men from the ages 27 to 42 years, and one aged 67 years Biosphere 2 in Oracle, Arizona
Biosphere 2 • Study design: • Diet: • low-calorie (1750–2100 kcal/d) • vegetables, fruits, nuts, grains, and legumes, with small amounts of dairy, eggs, and meat • 12% calories from protein, 11% from fat, and 77% from complex carbohydrates • daily vitamin and multivitamin supplements. • Blood samples were drawn from the eight crew members to monitor biological markers.
Biosphere 2 • Results: • Decrease in BMI of the men decreased by 19%, and the BMI of the women by 13%. • Decrease in fasting blood sugar decreased by 21% • Decrease in fasting insulin by 42% • Decrease in cholesterol by 30%. • Decline in LDL:HDL rati
Biosphere 2 • Strength of the study: • Length (2 years) • Subjects were human • Calorie closely monitored, and caloric restriction maintained • Weakness of the study: • Small sample size • No control group • Other confounding variables such as the daily physical exercise
CALERIE Study 1 • Effect of 6-Month Calorie Restriction on Biomarkers of Longevity, Metabolic Adaptation, and Oxidative Stress in Overweight Individuals • 6 months of calorie restriction • Randomized controlled trial of healthy, sedentary men and women (N=48)
CALERIE Study • Result: • reduced weight, fat mass, fasting serum insulin levels, and core body temperature in caloric restriction groups • calorie restriction results in a decline in DNA damage • No strong evidence for reduced oxidative damage
CALERIE Study • Calorie restriction or exercise: effects on coronaryheart disease risk factors. A randomized, controlledtrial • Length: 1-yr • Randomized, controlled trial in middle- aged lean and overweight men and women • Group 1: 20% increase in energy expenditure alone • Group 2: 20% decrease in energy intake alone on metabolic risk factor
Result: • improves CHD risk profile • loss of 10% of body weight. • reduced triacylglycerol • reduced LDL-C • favorable changes in blood pressure
CALERIE study • Improvements in glucose tolerance and insulin action induced by increasing energy expenditure or decreasing energy intake: a randomized controlled trial • Sedentary men and women aged 50 – 60 y with a body mass index (kg/m2 ) of 23.5–29.9 were randomly assigned to 1 of 2 weight- loss interventions [12 mo of exercise training (EX group; n = 18) or calorie restriction (CR group; n =18)] or to a healthy lifestyle (HL) control group (n =10). • decrease calorie intake by 16% during the first 3 mo and by 20% during the remaining 9 mo. • improves glucose tolerance and insulin action
Result: • improves glucose tolerance • Insulin sensitivity
Summary of Human Studies • reduced weight, fat mass, fasting serum insulin levels, and core body temperature in caloric restriction groups • calorie restriction results in a decline in DNA damage • No strong evidence for reduced oxidative damage • improves CHD risk profile (TG, LDL-C, BP) • loss of 10% of body weight. • improves glucose tolerance • Insulin sensitivity
Epidemiological study of the Okinawa population • Life expectancy • 86.0 years for Okinawan women • 77.6 years for Okinawan men • Caloric restriction due to • traditional Okinawa diet is low in calories but nutritionally dense • a result of periodic crop failures and marginal food supply that occurred post WWII until the 1960s
Epidemiological study of the Okinawa population • Low incidence of • CHD • Lymphoma,prostate cancer, breast cancer, and colon cancer are remarkably low in age-matched Okinawans versus other Japanese and Americans • life-long low BMI • extended mean and maximum life span
Cautions Regarding Calorie Restriction • Bone Loss and Bone Fracture • Decreased Aerobic Capacity • Changes in immune function Menopause and low estrogen can cause bone loss…but usually it’s much slower and less severe
CR Induces Bone Loss and Bone Fracture? • Pennington Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) Research Team • Subject: young, overweight individuals • Duration: 6 month • Result: 2 of the 3 biomarkers for longevity—fasting insulin concentrations and core body temperature—were reduced with CR • Possible mechanism: significant reductions in fasting concentrations triiodothyronine and leptin
Reduction in Bone Mineral Density • Washington CALERIE Study • Subject: middle-aged, non-obese adults aged 50 through 60 • Duration: 12 months • Results: reduction in bone mineral density (BMD) (approximately 1.5% overall) at the lumbar spine, total hip, femoral neck, and intertrochater was correlated to weight loss in the CR group
Decreased Aerobic Capacity • Washington University School of Medicine CALERIE • Subject: Healthy 50 to 60 year old nonobese men and women • Duration: 12 months of CR • Results: significant reductions in absolute thigh muscle mass, knee flexor strength, and VO2max, whereasasimilar1-yr energy deficit induced by exercise completely preserves thigh muscle massand strengthandimprovesVO2max.
Don’t Like Bone Loss and Decreased Aerobic Capacity? • Changes in bone mass and/or turnover are less pronounced when the same energy deficit is achieved by combining CR with structured aerobic exercise • Aerobic classes (step dancing) • Treadmills • Exercise bicycles • Ski machines • Air gliders • Jogging
Conclusion • There are both benefits and cautions to prolonged caloric restriction • CR may be improved if combined with exercise • Long term studies are necessary to assess relationship between caloric restriction and aging
Reference • Heilbronn, L. K., de Jonge, L., Frisard, M. I., DeLany, J. P., Larson-Meyer, D. E., Rood, J., et al. (2006). Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: A randomized controlled trial. JAMA : The Journal of the American Medical Association, 295(13), 1539-1548. • Lefevre, M., Redman, L. M., Heilbronn, L. K., Smith, J. V., Martin, C. K., Rood, J. C., et al. (2009). Caloric restriction alone and with exercise improves CVD risk in healthy non-obese individuals. Atherosclerosis, 203(1), 206-213. • Masoro, E. J. (1995). McCay's hypothesis: Undernutrition and longevity. The Proceedings of the Nutrition Society, 54(3), 657-664. • Sohal, R. S.; Ku, H. H.; Agarwal, S.; Forster, M. J.; Lal, H. Oxidative damage, mitochondrial oxidant generation and anti- oxidant defense during aging and in response to food restriction in the mouse. Mech. Ageing Dev. 74:121-133; 1994.
Reference • Trepanowski, J. F., Canale, R. E., Marshall, K. E., Kabir, M. M., & Bloomer, R. J. (2011). Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: A summary of available findings. Nutrition Journal, 10, 107. • Villareal, D. T., Fontana, L., Weiss, E. P., Racette, S. B., Steger-May, K., Schechtman, K. B., et al. (2006). Bone mineral density response to caloric restriction-induced weight loss or exercise-induced weight loss: A randomized controlled trial. Archives of Internal Medicine, 166(22), 2502-2510. • Walford, R. L., Mock, D., Verdery, R., & MacCallum, T. (2002). Calorie restriction in biosphere 2: Alterations in physiologic, hematologic, hormonal, and biochemical parameters in humans restricted for a 2-year period. The Journals of Gerontology.Series A, Biological Sciences and Medical Sciences, 57(6), B211-24. • Weiss, E. P., Racette, S. B., Villareal, D. T., Fontana, L., Steger-May, K., Schechtman, K. B., et al. (2007). Lower extremity muscle size and strength and aerobic capacity decrease with caloric restriction but not with exercise-induced weight loss. Journal of Applied Physiology (Bethesda, Md.: 1985), 102(2), 634-640. • Willcox, B. J., Willcox, D. C., Todoriki, H., Fujiyoshi, A., Yano, K., He, Q., et al. (2007). Caloric restriction, the traditional okinawan diet, and healthy aging: The diet of the world's longest-lived people and its potential impact on morbidity and life span. Annals of the New York Academy of Sciences, 1114, 434-455.