Objectives: This study aimed to correlate cognitive functions with fasting blood glucose through cognitive tests in young adults whose fasting blood glucose within the normal range. Materials and ...Methods: Study accomplished in Ankara University School of Medicine Department of Physiology, Neurophysiology laboratory in February-June 2018. Subjects who are hungry at least for 8 hours before cognitive testsand match the criteria involved in the study. Blood glucose values were measured before and after tests with One Touch blood glucose meter. Subjects’ reaction times and correct answer rates have collected. The outcomes have evaluated with SPSS 11.5 program. Results: The difference between blood glucose levels after and before the cognitive tests were correlated negatively with correct answer ratios in N-Back test (r=-0.238, p<0.05). However, this difference was also correlated positively with reaction time ratios in Ebbinghaus test (r=0.239, p<0.05). But this difference was not correlated with any ratios in Posner test. Subjects’ fasting hours, family history about diabetes, diet and sports routines, and their stress level in tests were not significantly correlated with fasting blood glucose levels or success ratios. Conclusion: Subjects whose blood glucose levels decreased after tests were significantly more successful in short-term memory tests. These findings could mean that successful usage of working memory and short time memory requires more glucose consumption. There is not enough study which investigates the relation between fasting blood glucose levels and cognition. In this point of view, our study is distinctive and open to further investigations.
Intermittent fasting is a broad term that encompasses a variety of programs that manipulate the timing of eating occasions by utilizing short-term fasts in order to improve body composition and ...overall health. This review examines studies conducted on intermittent fasting programs to determine if they are effective at improving body composition and clinical health markers associated with disease. Intermittent fasting protocols can be grouped into alternate-day fasting, whole-day fasting, and time-restricted feeding. Alternate-day fasting trials of 3 to 12 weeks in duration appear to be effective at reducing body weight (≈3%–7%), body fat (≈3–5.5 kg), total cholesterol (≈10%–21%), and triglycerides (≈14%–42%) in normal-weight, overweight, and obese humans. Whole-day fasting trials lasting 12 to 24 weeks also reduce body weight (≈3%–9%) and body fat, and favorably improve blood lipids (≈5%–20% reduction in total cholesterol and ≈17%–50% reduction in triglycerides). Research on time-restricted feeding is limited, and clear conclusions cannot be made at present. Future studies should examine long-term effects of intermittent fasting and the potential synergistic effects of combining intermittent fasting with exercise.
Background: Chronic protein restriction (PR) elicits an adaptive hunger for protein that is dependent on the liver-derived hormone fibroblast growth factor 21 (FGF21). This study investigated whether ...this PR-induced protein preference would be perturbed by a state of energy restriction (fasting). Methods: Wild-type (WT) and FGF21-KO mice were fed either a control (CON) or low-protein (LP) diet for 10 days before being placed into a metabolic chamber and offered the choice between 4% casein and 4% maltodextrin solutions along with their CON or LP diet. After a three-day baseline period, the mice underwent a 24-h fast, followed by an additional 24-h liquid-only phase in which they were offered only casein and maltodextrin (liquid-only). Results: CON or LP diet was then returned, and mice continued to choose between casein and maltodextrin for 5 days (follow-up). Compared to WT-CON mice, WT-LP mice exhibited a significant increase in casein consumption during the baseline period, and this increased casein intake was largely unchanged during the liquid-only (post-fasting) and follow-up phases. Contrastingly, WT-CON and WT-LP mice consumed similar amounts of malto during the baseline period, and both WT-CON and WT-LP mice markedly increased malto intake during the liquid-only phase (post-fasting), with this increase being larger in WT-LP. Thus absolute intake of casein was not changed post-fasting, but the preference for casein relative to malto was significantly reduced by fasting in both groups. In contrast to WT mice, FGF21-KO mice did not increase casein intake on the LP diet at any point during the study. However, they did markedly increase malto intake in the post-fasting, liquid-only phase. Conclusions: Taken together, these data indicate that WT mice independently balance the needs for protein vs energy, with protein restriction increasing casein intake and energy restriction increasing malto intake. Deletion of FGF21 blocks the adaptive response to protein restriction, but not to energy restriction.
Background: The role of glucose concentrations within the normal physiologic range in controlling energy intake is unclear. Prior evidence suggests that lower postprandial glucose concentrations ...relative to fasting concentrations, have a role in driving hunger and food intake. Thus, we hypothesized the change in fasting to 3 h plasma glucose after an oral glucose load would be positively associated with ad libitum energy intake. Methods: Healthy adults (n = 197; age 35 ± 11 years; 130 males, BMI 31 ± 8 kg/m2) with normal glucose regulation were included in the analysis. Using a 3 h 75 g OGTT, postload glucose change (fasting minus 3 h) was measured. Ad libitum energy intake was quantified using the day 1 calorie intake of a 3 d validated vending machine paradigm completed within 1 week after the OGTT. Body composition was assessed by DXA. Associations between changes in glucose and intake measures were assessed using partial Rs and general linear models adjusted for age, sex, race, fat-free mass index, and fat-mass index. Results: Mean glycemic change was 11.8 ± 18.3 mg/dL with range -42.5 to +48.0 mg/dL, where a positive value represents a 3 h value below fasting. A greater glucose drop at 3 h relative to fasting was associated with greater total intake (partial R = 0.16, β = 12.76 kcal/d per mg/dL, p = 0.04). This glucose drop was associated with greater fat intake (partial R = 0.17, β = 6.96 kcal/d per mg/dL, p = 0.02) but not with carbohydrate or protein intake (both p-values>0.09). Conclusions: Using objective measures of ad libitum food intake, this study confirms that relatively lower glucose concentrations relative to fasting following a glucose load is associated with higher energy intake. These results indicate that control of postprandial glycemia even within the physiologic range may be a target for interventions to prevent weight gain via personalized dietary prescriptions to minimize these drops in glucose.
Caloric restriction and intermittent fasting are known to prolong life- and healthspan in model organisms, while their effects on humans are less well studied. In a randomized controlled trial study ...(ClinicalTrials.gov identifier: NCT02673515), we show that 4 weeks of strict alternate day fasting (ADF) improved markers of general health in healthy, middle-aged humans while causing a 37% calorie reduction on average. No adverse effects occurred even after >6 months. ADF improved cardiovascular markers, reduced fat mass (particularly the trunk fat), improving the fat-to-lean ratio, and increased β-hydroxybutyrate, even on non-fasting days. On fasting days, the pro-aging amino-acid methionine, among others, was periodically depleted, while polyunsaturated fatty acids were elevated. We found reduced levels sICAM-1 (an age-associated inflammatory marker), low-density lipoprotein, and the metabolic regulator triiodothyronine after long-term ADF. These results shed light on the physiological impact of ADF and supports its safety. ADF could eventually become a clinically relevant intervention.
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•For healthy, non-obese adults, ADF is safe to practice for several months•4-week ADF decreases the body weight by 4.5% and improves the fat-to-lean ratio•Cardiovascular parameters and the CVD risk are improved upon ADF•ADF reduces T3 and periodically depletes amino acids, while increasing PUFAs
Stekovic et al. show in the clinic that alternate day fasting (ADF) is a simple alternative to calorie restriction and provokes similar improvements on cardiovascular parameters and body composition. ADF was shown to be safe and beneficial in healthy, non-obese humans, not impairing immune function or bone health.
Dietary interventions are potentially effective therapies for inflammatory bowel diseases (IBDs). We tested the effect of 4-day fasting-mimicking diet (FMD) cycles on a chronic dextran sodium sulfate ...(DSS)-induced murine model resulting in symptoms and pathology associated with IBD. These FMD cycles reduced intestinal inflammation, increased stem cell number, stimulated protective gut microbiota, and reversed intestinal pathology caused by DSS, whereas water-only fasting increased regenerative and reduced inflammatory markers without reversing pathology. Transplants of Lactobacillus or fecal microbiota from DSS- and FMD-treated mice reversed DSS-induced colon shortening, reduced inflammation, and increased colonic stem cells. In a clinical trial, three FMD cycles reduced markers associated with systemic inflammation. The effect of FMD cycles on microbiota composition, immune cell profile, intestinal stem cell levels and the reversal of pathology associated with IBD in mice, and the anti-inflammatory effects demonstrated in a clinical trial show promise for FMD cycles to ameliorate IBD-associated inflammation in humans.
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•FMD cycles partially reverse IBD-related pathology compared to water-only fasting•FMD cycles reduce intestinal inflammatory and immune and increase regenerative markers•FMD cycles promote the expansion of Lactobacillaceae and Bifidobacteriaceae•FMD cycles can reduce systemic inflammation and consequent leukocytosis in humans
Rangan et al. show that cycles of a fasting-mimicking diet (FMD) ameliorate intestinal inflammation, promote intestinal regeneration, and stimulate the growth of protective gut microbial populations in a mouse model displaying symptoms and pathology associated with IBD. They also show that a similar FMD is safe, feasible, and effective in reducing systemic inflammation and the consequent high levels of immune cells in humans.
In recent years a revival of interest has emerged in the health benefits of intermittent fasting and long-term fasting, as well as of other related nutritional strategies. In addition to meal size ...and composition a new focus on time and frequency of meals has gained attention. The present review will investigate the effects of the main forms of fasting, activating the metabolic switch from glucose to fat and ketones (G-to-K), starting 12-16 h after cessation or strong reduction of food intake. During fasting the deactivation of mTOR regulated nutrient signalling pathways and activation of the AMP protein kinase trigger cell repair and inhibit anabolic processes. Clinical and animal studies have clearly indicated that modulating diet and meal frequency, as well as application of fasting patterns, e.g. intermittent fasting, periodic fasting, or long-term fasting are part of a new lifestyle approach leading to increased life and health span, enhanced intrinsic defences against oxidative and metabolic stresses, improved cognition, as well as a decrease in cardiovascular risk in both obese and non-obese subjects. Finally, in order to better understand the mechanisms beyond fasting-related changes, human studies as well as non-human models closer to human physiology may offer useful clues.
KEY-MESSAGES
Biochemical changes during fasting are characterised by a glucose to ketone switch, leading to a rise of ketones, advantageously used for brain energy, with consequent improved cognition.
Ketones reduce appetite and help maintain effective fasting.
Application of fasting patterns increases healthy life span and defences against oxidative and metabolic stresses.
Today's strategies for the use of therapeutic fasting are based on different protocols, generally relying on intermittent fasting, of different duration and calorie intake.
Long-term fasting, with durations between 5 and 21 days can be successfully repeated in the course of a year.
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