Project description:Aims/hypothesis: Dietary restriction (DR) reduces adiposity and improves metabolism in patients with one or more symptoms of the metabolic syndrome. Nonetheless, it remains elusive whether the benefits of DR in humans are mediated by calorie or nutrient restriction. This study was conducted to identify whether isocaloric dietary protein restriction is sufficient to confer the beneficial effects of dietary restriction in patients with metabolic syndrome. Methods: We performed a prospective, randomized controlled dietary intervention under constant nutritional and medical supervision. A total of 21 individuals diagnosed with the metabolic syndrome was randomly assigned for caloric restriction (CR; n = 11, mean age 49 ± 8.5 years, female 63%; diet of 5,941 ± 686 KJ per day) or isocaloric dietary protein restriction (PR; n = 10, mean age 51.6 ± 8.9 years, female 50%; diet of 8,409 ± 2,360 KJ per day) and followed for 27 days. Results: Like CR, PR promoted weight loss (-6.6%, P= 0.0041) due to reduction in adiposity (-9.9%, P= 0.0007), associated with reductions in blood glucose (-52.7%, P= 0.0002), lipid levels (cholesterol, -35.4%, P= 0.0010; triglycerides, -39.5% P= 0.0022) and blood pressure (systolic, -37.7 P< 0.0001; diastolic, -73.2% P< 0.0001). PR resulted in enrichment of metabolic pathways related to the immune system such as B cell proliferation, lymphocyte proliferation and leukocyte proliferation in subcutaneous adipose tissue. Hence, a reduction in calorie intake or changes in the gut microbiome are not necessary to confer the metabolic benefits of DR. Instead, a reduction in protein intake with a mild increase in carbohydrate intake to maintain the isocaloric balance of the diet is sufficient to improve metabolic control. Conclusions/interpretation: Protein restriction is sufficient to confer almost the same clinical outcomes as calorie restriction without the need for a reduction in calorie intake. The isocaloric characteristic of the PR intervention makes this approach a more attractive and less drastic dietary strategy in clinical settings and has greater potential to be used as adjuvant therapy for people with the metabolic syndrome.

Project description:Caloric restriction (CR) can delay morbidity and mortality in a broad range of species, including mice and macaques. Mutations and chemical agents, such as resveratrol or rapamycin that partly mimic the CR effect, can similarly increase survival or extend lifespan. In humans, however, the effects of CR or other life-extending agents have not been investigated systematically. Humans already display lower mortality and greater maximal lifespan compared to closely related species, including chimpanzees and macaques. It is thus possible that humans, during their evolution, have acquired genetic mutations mimicking the CR effect. To address this question, we compared transcriptome differences between humans and other primates, with transcriptome changes observed in mice subjected to CR [see references below]. We show that the human transcriptome state examined in multiple tissues and across different ages resembles the transcriptome state of mice fed ad libitum, relative to CR mice or mice treated with resveratrol. Furthermore, transcriptome changes induced by CR were enriched among genes showing age-related changes among primates, concentrated in specific expression patterns, and could be linked with specific functional pathways, including insulin signalling, cancer, and immune response. These findings indicate that the evolution of human longevity was likely independent of CR-induced lifespan extension mechanisms. Consequently, application of CR or CR-mimicking agents may offer a promising direction in the extension of healthy human lifespan. References for the transcriptome changes observed in mice subjected to CR: 1) Barger JL, Kayo T, Vann JM, Arias EB, Wang J, Hacker TA, Wang Y, Raederstorff D, Morrow JD, Leeuwenburgh C, et al: A low dose of dietary resveratrol partially mimics caloric restriction and retards aging parameters in mice. PLoS One 2008, 3:e2264. 2) Tsuchiya T, Dhahbi JM, Cui X, Mote PL, Bartke A, Spindler SR: Additive regulation of hepatic gene expression by dwarfism and caloric restriction. Physiol Genomics 2004, 17:307-315. 3) Baur JA, Pearson KJ, Price NL, Jamieson HA, Lerin C, Kalra A, Prabhu VV, Allard JS, Lopez-Lluch G, Lewis K, et al: Resveratrol improves health and survival of mice on a high-calorie diet. Nature 2006, 444:337-342. We collected post-mortem brain, heart, and liver samples from 16 human, 16 chimpanzee and 4 rhesus macaque seperately. All these individuals are adults. RNA extracted from the dissected tissue was hybridized to AffymetrixM-BM-. Human Gene 1.0 ST arrays to quantify gene expression level. We collected prefrontal cortex tissues of mice with age ranging from postnatal 2 days to 2.5 years. The strain of the mice is C57BL/6. RNA extracted from the dissected tissue was hybridized to AffymetrixM-BM-. Mouse Gene 1.0 ST Arrays to quantify gene expression level.

Project description:Caloric restriction (CR) can delay morbidity and mortality in a broad range of species, including mice and macaques. Mutations and chemical agents, such as resveratrol or rapamycin that partly mimic the CR effect, can similarly increase survival or extend lifespan. In humans, however, the effects of CR or other life-extending agents have not been investigated systematically. Humans already display lower mortality and greater maximal lifespan compared to closely related species, including chimpanzees and macaques. It is thus possible that humans, during their evolution, have acquired genetic mutations mimicking the CR effect. To address this question, we compared transcriptome differences between humans and other primates, with transcriptome changes observed in mice subjected to CR [see references below]. We show that the human transcriptome state examined in multiple tissues and across different ages resembles the transcriptome state of mice fed ad libitum, relative to CR mice or mice treated with resveratrol. Furthermore, transcriptome changes induced by CR were enriched among genes showing age-related changes among primates, concentrated in specific expression patterns, and could be linked with specific functional pathways, including insulin signalling, cancer, and immune response. These findings indicate that the evolution of human longevity was likely independent of CR-induced lifespan extension mechanisms. Consequently, application of CR or CR-mimicking agents may offer a promising direction in the extension of healthy human lifespan. References for the transcriptome changes observed in mice subjected to CR: 1) Barger JL, Kayo T, Vann JM, Arias EB, Wang J, Hacker TA, Wang Y, Raederstorff D, Morrow JD, Leeuwenburgh C, et al: A low dose of dietary resveratrol partially mimics caloric restriction and retards aging parameters in mice. PLoS One 2008, 3:e2264. 2) Tsuchiya T, Dhahbi JM, Cui X, Mote PL, Bartke A, Spindler SR: Additive regulation of hepatic gene expression by dwarfism and caloric restriction. Physiol Genomics 2004, 17:307-315. 3) Baur JA, Pearson KJ, Price NL, Jamieson HA, Lerin C, Kalra A, Prabhu VV, Allard JS, Lopez-Lluch G, Lewis K, et al: Resveratrol improves health and survival of mice on a high-calorie diet. Nature 2006, 444:337-342.

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Potassium restriction phenocopies caloric restriction to extend chronological lifespan in yeast

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