Exercise increases TCA intermediate concentrations during low-calorie diet independent of insulin resistance among women with obesity.

Tricarboxylic acid cycle intermediates (TCAi) have been proposed to act as myokines that influence energy metabolism. We determined if 2-weeks of low-calorie diet with interval exercise (LCD + INT) would increase TCAi more than a low-calorie diet (LCD). Twenty-three women were randomized to 2-weeks of LCD (n = 12, 48.4 ± 2.5 years, 37.8 ± 1.5 kg/m2, ~1200 kcal/d) or LCD + INT (n = 11, 47.6 ± 4.3 years, 37.9 ± 2.3 kg/m2; 60 min/d supervised INT of 3 min 90% & 50% HRpeak). TCAi and amino acids (AA) were measured at 0 min of a 75 g OGTT, while glucose, insulin, and FFA were obtained at 0, 30, 60, 90, 120, and 180 min to assess total area under the curve (tAUC180min) and insulin resistance (IR; tAUC180min of Glucose × Insulin). Fuel use (indirect calorimetry) was also collected at 0, 60, 120, and 180 min as was fitness (VO2peak) and body composition (BodPod). Treatments reduced weight (p < 0.001), fasting RER (p = 0.01), and IR (p = 0.03), although LCD + INT increased VO2peak (p = 0.02) and maintained RER tAUC180min (p = 0.05) versus LCD. Treatments increased FFA tAUC180min (p = 0.005), cis-aconitate, isocitrate, and succinate (p ≤ 0.02), as well as reduced phenylalanine and tryptophan, cysteine (p ≤ 0.005). However, LCD + INT increased malate, citrate, α-ketoglutarate, and alanine more than LCD (p ≤ 0.04). Thus, INT enhanced LCD effects on some TCAi in women with obesity independent of IR.

Brain-Derived Neurotrophic Factor as a Potential Mediator of the Beneficial Effects of Myo-Inositol Supplementation during Suckling in the Offspring of Gestational-Calorie-Restricted Rats.

This study aims to investigate the potential mechanisms underlying the protective effects of myo-inositol (MI) supplementation during suckling against the detrimental effects of fetal energy restriction described in animal studies, particularly focusing on the potential connections with BDNF signaling. Oral physiological doses of MI or the vehicle were given daily to the offspring of control (CON) and 25%-calorie-restricted (CR) pregnant rats during suckling. The animals were weaned and then fed a standard diet until 5 months of age, when the diet was switched to a Western diet until 7 months of age. At 25 days and 7 months of age, the plasma BDNF levels and mRNA expression were analyzed in the hypothalamus and three adipose tissue depots. MI supplementation, especially in the context of gestational calorie restriction, promoted BDNF secretion and signaling at a juvenile age and in adulthood, which was more evident in the male offspring of the CR dams than in females. Moreover, the CR animals supplemented with MI exhibited a stimulated anorexigenic signaling pathway in the hypothalamus, along with improved peripheral glucose management and enhanced browning capacity. These findings suggest a novel connection between MI supplementation during suckling, BDNF signaling, and metabolic programming, providing insights into the mechanisms underlying the beneficial effects of MI during lactation.

Sex-Dependent Metabolic Effects in Diet-Induced Obese Rats following Intermittent Fasting Compared with Continuous Food Restriction.

Recently, intermittent fasting has gained relevance as a strategy to lose weight and improve health as an alternative to continuous caloric restriction. However, the metabolic impact and the sex-related differences are not fully understood. The study aimed to compare the response to a continuous or intermittent caloric restriction in male and female rats following a previous induction of obesity through a cafeteria diet by assessing changes in body weight, energy intake, metabolic parameters, and gene expression in liver hepatic and adipose tissue. The continuous restriction reduced the energy available by 30% and the intermittent restriction consisted of a 75% energy reduction on two non-consecutive days per week. The interventions reduced body weight and body fat in both sexes, but the loss of WAT in females was more marked in both models of caloric restriction, continuous and intermittent. Both caloric restrictions improved insulin sensitivity, but more markedly in females, which showed a more pronounced decrease in HOMA-IR score and an upregulation of hepatic IRS2 and Sirt1 gene expression that was not observed in males. These findings suggest the fact that females are more sensitive than males to reduced caloric content in the diet.

Calorie Restriction Using High-Fat/Low-Carbohydrate Diet Suppresses Liver Fat Accumulation and Pancreatic Beta-Cell Dedifferentiation in Obese Diabetic Mice.

In diabetes, pancreatic ß-cells gradually lose their ability to secrete insulin with disease progression. ß-cell dysfunction is a contributing factor to diabetes severity. Recently, islet cell heterogeneity, exemplified by ß-cell dedifferentiation and identified in diabetic animals, has attracted attention as an underlying molecular mechanism of ß-cell dysfunction. Previously, we reported ß-cell dedifferentiation suppression by calorie restriction, not by reducing hyperglycemia using hypoglycemic agents (including sodium-glucose cotransporter inhibitors), in an obese diabetic mice model (db/db). Here, to explore further mechanisms of the effects of food intake on ß-cell function, db/db mice were fed either a high-carbohydrate/low-fat diet (db-HC) or a low-carbohydrate/high-fat diet (db-HF) using similar calorie restriction regimens. After one month of intervention, body weight reduced, and glucose intolerance improved to a similar extent in the db-HC and db-HF groups. However, ß-cell dedifferentiation did not improve in the db-HC group, and ß-cell mass compensatory increase occurred in this group. More prominent fat accumulation occurred in the db-HC group livers. The expression levels of genes related to lipid metabolism, mainly regulated by peroxisome proliferator-activated receptor α and γ, differed significantly between groups. In conclusion, the fat/carbohydrate ratio in food during calorie restriction in obese mice affected both liver lipid metabolism and ß-cell dedifferentiation.

Dietary restriction and life-history trade-offs: insights into mTOR pathway regulation and reproductive investment in Japanese quail.

Resources are needed for growth, reproduction and survival, and organisms must trade off limited resources among competing processes. Nutritional availability in organisms is sensed and monitored by nutrient-sensing pathways that can trigger physiological changes or alter gene expression. Previous studies have proposed that one such signalling pathway, the mechanistic target of rapamycin (mTOR), underpins a form of adaptive plasticity when individuals encounter constraints in their energy budget. Despite the fundamental importance of this process in evolutionary biology, how nutritional limitation is regulated through the expression of genes governing this pathway and its consequential effects on fitness remain understudied, particularly in birds. We used dietary restriction to simulate resource depletion and examined its effects on body mass, reproduction and gene expression in Japanese quails (Coturnix japonica). Quails were subjected to feeding at 20%, 30% and 40% restriction levels or ad libitum for 2 weeks. All restricted groups exhibited reduced body mass, whereas reductions in the number and mass of eggs were observed only under more severe restrictions. Additionally, dietary restriction led to decreased expression of mTOR and insulin-like growth factor 1 (IGF1), whereas the ribosomal protein S6 kinase 1 (RPS6K1) and autophagy-related genes (ATG9A and ATG5) were upregulated. The pattern in which mTOR responded to restriction was similar to that for body mass. Regardless of the treatment, proportionally higher reproductive investment was associated with individual variation in mTOR expression. These findings reveal the connection between dietary intake and the expression of mTOR and related genes in this pathway.

Fasting mimicking diet extends lifespan and improves intestinal and cognitive health.

Caloric restriction is an effective means of extending a healthy lifespan. Fasting mimicking diet (FMD) is a growing pattern of caloric restriction. We found that FMD significantly prolonged the lifespan of prematurely aging mice. In naturally aging mice, FMD improved cognitive and intestinal health. Through a series of behavioral experiments, we found that FMD relieved anxiety and enhanced cognition in aged mice. In the intestine, the FMD cycles enhanced the barrier function, reduced senescence markers, and maintained T cell naïve-memory balance in the lamina propria mucosa. To further explore the causes of immune alterations, we examined changes in the stool microbiota using 16S rRNA sequencing. We found that FMD remodeled gut bacterial composition and significantly expanded the abundance of Lactobacillus johnsonii. Our research revealed that FMD has in-depth investigative value as an anti-aging intervention for extending longevity and improving cognition, intestinal function, and gut microbiota composition.

Dysregulation of miRNA-mRNA expression in fetal growth restriction in a caloric restricted mouse model.

Fetal growth restriction (FGR) is associated with aberrant placentation and accounts for a significant proportion of perinatal deaths. microRNAs have been shown to be dysregulated in FGR. The purpose of this study was to determine microRNA-regulated molecular pathways altered using a caloric restricted mouse model of FGR. Pregnant mice were subjected to a 50% caloric restricted diet beginning at E9. At E18.5, RNA sequencing of placental tissue was performed to identify differences in gene expression between caloric restricted and control placentas. Significant differences in gene expression between caloric restricted and control placentas were observed in 228 of the 1546 (14.7%) microRNAs. Functional analysis of microRNA-mRNA interactions demonstrated enrichment of several biological pathways with oxidative stress, apoptosis, and autophagy pathways upregulated and angiogenesis and signal transduction pathways downregulated. Ingenuity pathway analysis also suggested that ID1 signaling, a pathway integral for trophoblast differentiation, is also dysregulated in caloric restricted placentas. Thus, a maternal caloric restriction mouse model of FGR results in aberrant microRNA-regulated molecular pathways associated with angiogenesis, oxidative stress, signal transduction, apoptosis, and cell differentiation. As several of these pathways are dysregulated in human FGR, our findings suggest that this model may provide an excellent means to study placental microRNA derangements seen in FGR.

[Regulation of Aging Processes: A Perspective of Dietary Restriction Models].

The moderate restriction of dietary energy intake (dietary restriction: DR) extends the lifespan and health span of various laboratory animals, suggesting that it delays the aging process inherent in many animal species. Attenuated growth hormone and insulin-like growth factor-1 (IGF-1) signaling caused by mutations also increases the lifespan of mice, even those allowed to feed freely. In nematodes, the Daf16, mammalian Forkhead box O (FoxO) transcription factor, was shown to be required for lifespan extension in response to reduced IGF-1 signaling. Because DR also decreases the plasma concentration of IGF-1 in mammals, the IGF-1-FoxO axis may play a central role in the lifespan extension effect of DR and, thus, retardation of aging. Studies using knockout mice under DR conditions revealed the importance of FoxO1 and nuclear factor erythroid-derived 2-like 2 (Nrf2) in tumor suppression, and FoxO3 in lifespan extension. Human genomic studies also identified a strong association between a FOXO3 single nucleotide polymorphism and longevity. The aging mechanism is the most important risk factor for disease and frailty in aging humans. Therefore, further research on the application of DR to humans, the development of compounds and drugs that mimic the effects of DR, and mechanisms underlying FOXO3 polymorphisms for longevity is highly relevant to extending the human health span.

BLMP-1 is a critical temporal regulator of dietary-restriction-induced response in Caenorhabditis elegans.

The extrinsic diet and the intrinsic developmental programs are intertwined. Although extensive research has been conducted on how nutrition regulates development, whether and how developmental programs control the timing of nutritional responses remain barely known. Here, we report that a developmental timing regulator, BLMP-1/BLIMP1, governs the temporal response to dietary restriction (DR). At the end of larval development, BLMP-1 is induced and interacts with DR-activated PHA-4/FOXA, a key transcription factor responding to the reduced nutrition. By integrating temporal and nutritional signaling, the DR response regulates many development-related genes, including gska-3/GSK3ß, through BLMP-1-PHA-4 at the onset of adulthood. Upon DR, a precocious activation of BLMP-1 in early larval stages impairs neuronal development through gska-3, whereas the increase of gska-3 by BLMP-1-PHA-4 at the last larval stage suppresses WNT signaling in adulthood for DR-induced longevity. Our findings reveal a temporal checkpoint of the DR response that protects larval development and promotes adult health.

Perspective: The Impact of Fasting and Caloric Restriction on Neurodegenerative Diseases in Humans.

Neurodegenerative diseases (NDs) are characterized by the progressive functional and structural denaturation of neurons in the central and peripheral nervous systems. Despite the wide range of genetic predispositions, the increased emergence of these disorders has been associated with a variety of modifiable risk factors, including lifestyle factors. Diet has been shown to influence cognitive alterations in the elderly population with age-related brain pathologies, and specific dietary interventions might, therefore, confer preservatory protection to neural structures. Although Mediterranean and ketogenic diets have been studied, no clear guidelines have been implemented for the prevention or treatment of ND in clinical practice. Murine models have shown that intermittent fasting and caloric restriction (CR) can counteract disease processes in various age-related disorders, including NDs. The objective of this perspective is to provide a comprehensive, comparative overview of the available primary intervention studies on fasting and CR in humans with ND and to elucidate possible links between the mechanisms underlying the effects of fasting, CR, and the neuropathology of ND. We also included all currently available studies in older adults (with and without mild cognitive impairment) in which the primary endpoint was cognitive function to provide further insights into the feasibility and outcomes of such interventions. Overall, we conclude that nutritional intervention trials focusing on fasting and CR in humans with ND have been neglected, and more high-quality studies, including longitudinal clinical intervention trials, are urgently needed to elucidate the underlying immune-metabolic mechanisms in diet and ND.

Caloric Restriction Improves Spatial Learning Deficits in Tau Mice.

Background: Caloric restriction (CR) has been recognized for its benefits in delaying age-related diseases and extending lifespan. While its effects on amyloid pathology in Alzheimer's disease (AD) mouse models are well-documented, its effects on tauopathy, another hallmark of AD, are less explored. Objective: To assess the impact of a short-term 30% CR regimen on age-dependent spatial learning deficits and pathological features in a tauopathy mouse model. Methods: We subjected male PS19 tau P301S (hereafter PS19) and age-matched wildtype mice from two age cohorts (4.5 and 7.5 months old) to a 6-week 30% CR regimen. Spatial learning performance was assessed using the Barnes Maze test. Tau pathology, neuroinflammation, hippocampal cell proliferation, and neurogenesis were evaluated in the older cohort by immunohistochemical staining and RT-qPCR. Results: CR mitigated age-dependent spatial learning deficits in PS19 mice but exhibited limited effects on tau pathology and the associated neuroinflammation. Additionally, we found a decrease in hippocampal cell proliferation, predominantly of Iba1+ cells. Conclusions: Our findings reinforce the cognitive benefits conferred by CR despite its limited modulation of disease pathology. Given the pivotal role of microglia in tau-driven pathology, the observed reduction in Iba1+ cells under CR suggests potential therapeutic implications, particularly if CR would be introduced early in disease progression.

Caloric restriction, Sirtuins, and cardiovascular diseases.

ABSTRACT: Caloric restriction (CR) is a well-established dietary intervention known to extend healthy lifespan and exert positive effects on aging-related diseases, including cardiovascular conditions. Sirtuins, a family of nicotinamide adenine dinucleotide (NAD + )-dependent histone deacetylases, have emerged as key regulators of cellular metabolism, stress responses, and the aging process, serving as energy status sensors in response to CR. However, the mechanism through which CR regulates Sirtuin function to ameliorate cardiovascular disease remains unclear. This review not only provided an overview of recent research investigating the interplay between Sirtuins and CR, specifically focusing on their potential implications for cardiovascular health, but also provided a comprehensive summary of the benefits of CR for the cardiovascular system mediated directly via Sirtuins. CR has also been shown to have considerable impact on specific metabolic organs, leading to the production of small molecules that enter systemic circulation and subsequently regulate Sirtuin activity within the cardiovascular system. The direct and indirect effects of CR offer a potential mechanism for Sirtuin modulation and subsequent cardiovascular protection. Understanding the interplay between CR and Sirtuins will provide new insights for the development of interventions to prevent and treat cardiovascular diseases.

[Dietary Management of Obesity].

Obesity is defined as a condition characterized by the abnormal accumulation of fat cells, which results in increased body weight. Worldwide, obesity is progressively on the rise, leading to an increased prevalence of chronic conditions such as cardiovascular disease, type 2 diabetes, and hyperlipidemia. Obesity is a result of the interplay between genetic, metabolic, social, behavioral, and cultural factors, necessitating an interdisciplinary and multimodal management approach. Diet therapy, which includes dietary modifications and nutritional interventions, is a fundamental component of the multifaceted approach to managing obesity. The principle of diet therapy is based on achieving weight loss through a negative energy balance and maintaining weight through an equilibrium of energy intake and expenditure. Strategies for weight loss and control rely on caloric restriction, macronutrient distribution, and dietary patterns such as the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets. Recently, studies have been conducted on weight control using information and communication technology-based interventions, as well as interventions based on intestinal microorganisms which consider inter-individual variability and long-term adherence. In conclusion, diet therapy stands as a pivotal element in the management of obesity, providing a personalized and comprehensive approach to weight control. By combining evidence-based dietary strategies with behavioral modifications and consistent support, healthcare professionals can enable individuals to attain and sustain a healthier weight, thereby reducing related health risks.

Liver-derived plasminogen mediates muscle stem cell expansion during caloric restriction through the plasminogen receptor Plg-RKT.

An intriguing effect of short-term caloric restriction (CR) is the expansion of certain stem cell populations, including muscle stem cells (satellite cells), which facilitate an accelerated regenerative program after injury. Here, we utilized the MetRSL274G (MetRS) transgenic mouse to identify liver-secreted plasminogen as a candidate for regulating satellite cell expansion during short-term CR. Knockdown of circulating plasminogen prevents satellite cell expansion during short-term CR. Furthermore, loss of the plasminogen receptor KT (Plg-RKT) is also sufficient to prevent CR-related satellite cell expansion, consistent with direct signaling of plasminogen through the plasminogen receptor Plg-RKT/ERK kinase to promote proliferation of satellite cells. Importantly, we are able to replicate many of these findings in human participants from the CALERIE trial. Our results demonstrate that CR enhances liver protein secretion of plasminogen, which signals directly to the muscle satellite cell through Plg-RKT to promote proliferation and subsequent muscle resilience during CR.

Caloric restriction reduces proteinuria in male rats with established nephropathy.

Reducing proteinuria is a crucial approach in preventing kidney function loss. Previous preclinical studies indicated that caloric restriction (CR) imposed at a young age protects against age-related proteinuria. However, these studies have not explored CR in established renal disease. Therefore, this study aimed to investigate the impact of CR on established proteinuria. Rats, aged 12 ± 2 weeks, were administered 2.1 mg/kg of Adriamycin. Six weeks after injection, protein excretion was measured, and a [13 N]ammonia positron emission tomography (PET) scan was conducted to assess kidney perfusion. After 7 weeks rats were divided into four groups: ad libitum (AL) and CR groups fed either a 12% or a 20% protein diet. All groups were treated for 12 weeks. Blood pressure was measured and a second PET scan was acquired at the end of the study. The animals subjected to CR exhibited a 20.3% decrease in protein excretion (p = 0.003) compared to those in the AL groups. Additionally, blood pressure in the CR group was 21.2% lower (p < 0.001) than in the AL groups. While kidney function declined over time in all groups, the 20% CR group demonstrated the smallest decline. Thus CR effectively reduces urinary protein excretion and lowers blood pressure in rats with established proteinuria.

Effects of dietary intervention on human diseases: molecular mechanisms and therapeutic potential.

Diet, serving as a vital source of nutrients, exerts a profound influence on human health and disease progression. Recently, dietary interventions have emerged as promising adjunctive treatment strategies not only for cancer but also for neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions have demonstrated substantial potential in modulating metabolism, disease trajectory, and therapeutic responses. Metabolic reprogramming is a hallmark of malignant progression, and a deeper understanding of this phenomenon in tumors and its effects on immune regulation is a significant challenge that impedes cancer eradication. Dietary intake, as a key environmental factor, can influence tumor metabolism. Emerging evidence indicates that dietary interventions might affect the nutrient availability in tumors, thereby increasing the efficacy of cancer treatments. However, the intricate interplay between dietary interventions and the pathogenesis of cancer and other diseases is complex. Despite encouraging results, the mechanisms underlying diet-based therapeutic strategies remain largely unexplored, often resulting in underutilization in disease management. In this review, we aim to illuminate the potential effects of various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet, on cancer and the aforementioned diseases. We explore the multifaceted impacts of these dietary interventions, encompassing their immunomodulatory effects, other biological impacts, and underlying molecular mechanisms. This review offers valuable insights into the potential application of these dietary interventions as adjunctive therapies in disease management.

Calorie Restriction and Time-Restricted Feeding: Effective Interventions in Overweight or Obese Patients Undergoing Radiotherapy Treatment with Curative Intent for Cancer.

This study assesses the feasibility of calorie restriction (CR) and time-restricted feeding (TRF) in overweight and obese cancer patients who realized little to no physical activity undergoing curative radiotherapy, structured as a prospective, interventional, non-randomized open-label clinical trial. Of the 27 participants initially enrolled, 21 patients with breast cancer were selected for analysis. The participants self-selected into two dietary interventions: TRF, comprising a sugar and saturated fat-free diet calibrated to individual energy needs consumed within an 8 h eating window followed by a 16 h fast, or CR, involving a 25% reduction in total caloric intake from energy expenditure distributed across 4 meals and 1 snack with 55% carbohydrates, 15% protein, and 30% fats, excluding sugars and saturated fats. The primary goal was to evaluate the feasibility of these diets in the specific patient group. The results indicate that both interventions are effective and statistically significant for weight loss and reducing one's waist circumference, with TRF showing a potentially stronger impact and better adherence. Changes in the LDL, HDL, total cholesterol, triglycerides, glucose and insulin were not statistically significant.

Very low calorie diets and total diet replacement in type 2 diabetes: where are we now?

Management of type 2 diabetes has now been simplified by the understanding that the condition is caused by excess fat in the liver together with suppression of beta cell function by the associated excess liver export of fat. These factors can be reversed by substantial weight loss leading to remission in the early years after diagnosis, or at least major decrease in cardiovascular risks and improvement in glucose control for all. Weight loss by any means is successful, but it is most easily achieved by rapid action using a low or very low calorie diet of around 800 kcal/day followed by sustained modest restraint of dietary habits. Oral hypoglycaemic agents and one antihypertensive drug can be withdrawn on day 1 of the weight loss diet, raising the importance of appropriate deprescribing.

Does time-restricted eating add benefits to calorie restriction? A systematic review.

OBJECTIVE: A growing body of evidence has supported the health benefits of extended daily fasting, known as time-restricted eating (TRE); however, whether the addition of TRE enhances the known benefits of calorie restriction (CR) remains unclear. METHODS: PubMed, Scopus, the Cochrane Library, and Google Scholar were searched through April 2023. This systematic review includes randomized controlled trials (RCTs) that compared CR + TRE with CR alone in energy-matched conditions of at least 8 weeks in duration that assessed changes in body weight and cardiometabolic disease risk factors in adults with overweight and/or obesity. RESULTS: Seven studies were identified (n = 579). Two studies reported greater weight loss and reductions in diastolic blood pressure with CR + TRE compared with CR alone after 8 to 14 weeks, whereas one study reported greater improvements in triglycerides and glucose tolerance with CR + TRE (3 days/week) compared with CR alone following 26 weeks. One study reported significant increases in homeostatic model assessment of insulin resistance (HOMA-IR) levels with CR + TRE versus CR alone after 8 weeks. There were no statistically significant differences in any other outcome variable between the two interventions. CONCLUSIONS: The addition of TRE to CR regimens resulted in greater weight loss and improvements in cardiometabolic risk factors in some studies; however, the majority of studies did not find additional benefits.

Dietary restriction and hepatic cancer: Systematic review and meta-analysis of animal studies.

The effect of calorie restriction, fasting, and ketogenic diets on the treatment of liver cancer remains uncertain. Therefore, we conducted a systematic review to evaluate the effect of restrictive diets on the development and progression of liver cancer in animal models. We did a meta-analysis using the Cochrane Collaboration's Review Manager software, with the random effects model and the inverse variance technique. We examined 19 studies that were conducted between 1983 and 2020. Of these, 63.2% investigated calorie restriction, 21.0% experimented with a ketogenic diet, and 15.8% investigated the effects of fasting. The intervention lasted anything from 48 h to 221 weeks. Results showed that restrictive diets may reduce tumor incidence and progression, with a significant reduction in the risk of liver cancer development. Thereby, our results suggest that putting limits on what you eat may help treat liver cancer in more ways than one.