Macro- and micronutrient losses and nutritional status resulting from 44 days of total fasting in a non-obese man

Analysis of physiological and biochemical changes and metabolic shifts during 21-Day fasting hypometabolism

This study aimed to evaluate the impact of prolonged fasting on the physiological and biochemical alterations and metabolic shifts in healthy adults and to provide experimental data and theoretical support for the hypometabolic state induced by prolonged fasting. Thirteen volunteers were selected through public recruitment to undergo a 21-day complete fasting experiment. The experimental period lasted 34 days, including a 3-day baseline, 21-day completing fasting, 5-day calorie restriction and 5-day full recovery diet. Physiological indicators such as body weight, blood pressure, blood glucose, blood ketones, and blood uric acid were evaluated along with resting metabolic rate, routine blood tests, liver function, and heart function indexes employing traditional approaches. During the 21-day complete fasting period, there was a significant decrease in body weight (average - 14.96 ± 1.55%), a reduction in blood glucose (average - 21.63 ± 0.058%), an increase in blood ketones (from baseline 0.1 ± 0.04 mmol/L to 6.61 ± 1.25 mmol/L) and blood uric acid (from baseline 385.38 ± 57.78 µmol/L to 866.31 ± 172.01 µmol/L), a continuous decline in resting energy expenditure (average - 20.3 ± 11.13%), and the respiratory quotient tending towards fat metabolism. Most of the items in the complete blood count and liver indicators remained stable and within the normal range. Heart function showed functional adaptive changes without structural damage. Prolonged fasting can reduce the body's resting energy expenditure and adapt to body weight loss through physiological regulatory mechanisms without adverse effects on basic physiological functions or the structure of important organs. Under medical supervision, healthy adults can safely engage in prolonged fasting for up to 21 days with metabolic adaption and no damage to pivotal organ, which could provide potential technical support for human health and survival strategies in extreme conditions such as food shortages during long-duration manned spaceflight.

Timing of Resistance Training During Ramadan Fasting and Its Effects on Muscle Strength and Hypertrophy

PURPOSE

During Ramadan month, Muslims often continue training to maintain their muscle performance. However, trainers should stress the importance of the time of day chosen for practicing resistance training (RT) during Ramadan fasting to avoid health and performance alteration. Thus, this study aimed to investigate the effects of the timing of RT during Ramadan intermittent fasting (RIF) on muscle strength and hypertrophy in healthy male adults.

METHODS

Forty men were randomly allocated to 2 matched groups: 20 practicing whole-body RT in the late afternoon in a fasted state and 20 training in the late evening in a fed state (FED). Both groups performed 4 days per week of whole-body RT (∼75%-85% 1-repetition maximum, 12 repetitions/3-4 sets) during RIF. Anthropometric measurements and 1-repetition-maximum test for the squats, deadlift, and bench press were measured. A cross-sectional area of the quadriceps and biceps brachii was examined using ultrasound scans. All measurements were taken at 4 time points: 24 hours before the start of Ramadan, on the 15th day of Ramadan, on the 29th day of Ramadan, and 21 days after Ramadan.

RESULTS

Post hoc tests indicated significant preimprovement to postimprovement in FED at the 29th day of Ramadan for the 1-repetition-maximum test for the squats (P = .02; effect size = 0.21) and deadlift (P = .03; effect size = 0.24) when compared to 24 hours before the start of Ramadan. No significant changes were observed in the fasted-state group or for cross-sectional area for both groups.

CONCLUSIONS

Practicing RT during RIF appears not to have adverse effects on muscle hypertrophy and strength no matter whether it is practiced in FED or fasted state. However, RT had greater effects on muscle strength when applied in FED. Our findings suggest that training sessions should be scheduled after breaking the fast during Ramadan.

Starvation and Its Effects on the Gut

There is growing awareness that intestinal dysfunction determines the clinical outcomes of situations as diverse as undernourished children in urban tropical slums and undernourished surgical patients in intensive care units. As experimental starvation in humans has only rarely been studied, and largely not using current biomedical research tools, we must draw inference from disparate clinical and experimental observations as to the derangements present in the starved gut. There is good evidence of intestinal atrophy and achlorhydria in starvation and severe undernutrition. Historical reports from concentration camps and conflict settings consistently reported a noncontagious phenomenon called "hunger diarrhea," but in settings where starved individuals are isolated from others (prisoners on hunger strike, anorexia nervosa) diarrhea is not a feature. Changes in intestinal permeability and absorption have been infrequently studied in experimental starvation; available data suggest that short-term starvation reduces sugar absorption but not permeability. Severe acute malnutrition in children is associated with severe changes in the intestinal mucosa. Experimental animal models may help explain some observations in humans. Starved rats develop a hypersecretory state and intestinal barrier defects. Starved pigs demonstrate prolongation of rotavirus diarrhea and reproduce some of the absorptive and barrier defects observed in malnourished children. However, there remains much to be learned about the effects of starvation on the gut. Given the high prevalence of undernutrition in hospitals and disadvantaged communities, the lack of attention to the interaction between undernutrition and gastrointestinal damage is surprising and needs to be corrected. Current sophisticated cellular and molecular techniques now provide the opportunity to create fresh understanding of gastrointestinal changes in pure undernutrition, using volunteer studies and samples from anorexia nervosa.

Similar late effects of a 7-week orthodox religious fasting and a time restricted eating pattern on anthropometric and metabolic profiles of overweight adults

A hypocaloric diet, based on Orthodox fasting (OF) was followed by 29 overweight adults. A low-calorie, 16/8, time restricted eating (TRE) pattern was followed by 16 age- and weight-matched participants. Anthropometric, lipid, glycaemic and inflammation markers were assessed at baseline, at the end of the intervention (7 weeks from baseline) and 6 weeks after the cessation of diets (13 weeks from baseline). There was a trend of weight loss in both groups, which was evident at week 7 (TRE: -2.1 ± 1.0; OF: -2.0 ± 0.5 kg, p < 0.001 from baseline) and remained significant at week 13 (TRE: -2.9 ± 0.7; OF: -2.6 ± 0.3 kg, p < 0.001 from baseline). In the OF group, lipid concentrations declined at week 7 compared with baseline, increasing at week 13 compared with week 7. Our findings suggest that OF promotes a decrease in lipid concentrations, which however, is not evident 6 weeks after its end.

A Novel 7-Days Prolonged Dietary Deprivation Regimen Improves ALT and UA After 3-6 Months Refeeding, Indicating Therapeutic Potential

Objectives: The aim of this study was to evaluate a total fasting regimen assisted by a novel prebiotic, Flexible Abrosia (FA), in more than 7 days of continual dietary deprivation (7D-CDD). Our analysis included basic physical examinations, bioelectrical impedance analysis, and clinical lab and ELISA analysis in normal volunteers.

Methods: Seven healthy subjects with normal body weight participated in 7D-CDD with the assistance of a specially designed probiotic. Individuals were assigned to take FA (113.4 KJ/10 g) at each mealtime to avoid possible injuries to intestinal flora and smooth the hunger sensation. During 7D-CDD, the subjects were advised to avoid any food intake, especially carbohydrates, except for drinking plentiful amounts of water. The examination samples were collected before CDD as self-control, at 7 days fasting, and after 7~14 days of refeeding. Three subjects were also tested after 6-m refeeding.

Results: The FA-CDD regimen significantly decreased suffering from starvation, with tolerable hunger sensations during the treatment. With the addition of daily mineral electrolytes, the subjects not only passed through the entire 7D-CDD regimen but also succeed in 12~13 days total fasting in two subjects. There was a significant reduction in blood glucose, insulin, and high-density lipoprotein levels during fasting, and the blood concentrations of uric acid (UA), alanine aminotransferase (ALT), and creatine kinase (CK) were increased. However, after more than 2 months of refeeding, the disease markers ALT, GOT, and CK either remained stable or were slightly downregulated compared to their initial D0 control level.

Conclusion: Our experiment has supplied the first positive evidence that, with the assistance of a daily nutritional supply of around 100 kcal total calories to their intestinal flora, human subjects were able to tolerate hunger sensations. We have found that, although 7D-CDD induced increases in UA, CK, and transferases during fasting, refeeding led the markers to become either down-regulated or unchanged compared to their initial levels. This phenomenon was further confirmed in longer-term (6 m) recovery. Our results failed to support the hypothesis that fasting induced liver damage, since ALT, GOT, and CK remained low after longer-term refeeding. Our findings indicate that the 7D-CDD regimen might be practical and that it might be valuable to design larger clinical fasting trials for improvement of health strategy-targeting in metabolic disorders.

Security Hunger-Strike Prisoners in the Emergency Department: Physiological and Laboratory Findings

BACKGROUND

Medical treatment of hunger-strike patients, especially those in incarceration facilities, may pose clinical and treatment challenges for the treating physicians.

OBJECTIVE

The aim of our study is to describe the epidemiology and clinical and laboratory characteristics of hunger-strike prisoners presenting to the emergency department (ED) and to describe etiologies of hospitalization and complications among this group.

METHOD

We retrospectively examined clinical and laboratory manifestations of 50 hunger-strike prisoners who were referred for evaluation to the ED after a longstanding fast.

RESULTS

After a mean of 38 (28-44) days of a hunger strike, the most common complaints were chest pain and abdominal pain (14/60 [23.3%], 13/60 [21.6%], respectively). Mean weight loss percentage was 18.5%, and most patients were bradycardic (25/40 [62.5%]), and some hypothermic (16/50, [32%]). We describe several laboratory disturbances observed in these patients; leukopenia was the most common hematologic manifestation (31/50 [62%]), and a prolonged international normalized ratio was observed in 12/29 (41.3%) patients. We hospitalized 12% of the patients; the most common hospitalization cause was bradycardia (3/6 [50%]).

CONCLUSIONS

Our study found that the most common clinical symptom was chest pain, which has not been previously reported among hunger strikers. We observed a substantial number of laboratory disturbances due to muscle wasting and protein loss and due to presumed vitamin and micronutrient deficiencies. We suggest monitoring electrocardiograms for heart rate, blood count, chemistry, coagulation tests, and vitamin levels.

Sexual dimorphism in skeletal muscle protein turnover

Skeletal muscle is the major constituent of lean body mass and essential for the body's locomotor function. Women have less muscle mass (and more body fat) than men and are therefore not able to exert the same absolute maximal force as men. The difference in body composition between the sexes is evident from infancy but becomes most marked after puberty (when boys experience an accelerated growth spurt) and persists into old age. During early adulthood until approximately the fourth decade of life, muscle mass is relatively stable, both in men and women, but then begins to decline, and the rate of loss is slower in women than in men. In this review we discuss the underlying mechanisms responsible for the age-associated sexual dimorphism in muscle mass (as far as they have been elucidated to date) and highlight areas that require more research to advance our understanding of the control of muscle mass throughout life.

Serum Albumin and Prealbumin in Calorically Restricted, Nondiseased Individuals: A Systematic Review

PURPOSE

Undernutrition is often suspected in patients when serum albumin or prealbumin levels are low. We asked whether these measures are indeed low in undernourished people if no inflammatory illness is present.

METHODS

We did a systematic review to identify otherwise healthy subjects who were severely nutrient-deprived due to poor access to food or unwillingness to eat. We excluded children and pregnant women. We tabulated available measures of nutrient intake, anthropometry, serum albumin and prealbumin, and, when available, changes in these measures during nutritional intervention.

RESULTS

In otherwise healthy subjects, serum albumin and prealbumin levels remained normal despite marked nutrient deprivation until the extremes of starvation, that is, body mass index <12 or more than 6 weeks of starvation.

CONCLUSIONS

In these otherwise healthy subjects, serum albumin and prealbumin levels are not "markers of nutritional status." The "markers" failed to identify subjects with severe protein-calorie malnutrition until extreme starvation. That is, they failed to identify healthy individuals who would benefit from nutrition support, becoming abnormal only when starvation was already obvious. In contrast, serum albumin and prealbumin levels are known to fall promptly with injury or illness regardless of nutrient intake. They are negative acute-phase reactants. When these measures are low in sick patients, this cannot be assumed to reflect nutritional deprivation. Decisions about nutrition support should be based on evidence of meaningful benefit from this treatment rather than on assessment of "nutritional markers."

Episodes of voluntary total fasting (hunger strike) in Spanish prisons: A descriptive analysis

OBJECTIVE

To provide a description of the frequency and main features of the episodes of voluntary total fasting (VTF) taking place in Spanish prisons.

MATERIAL AND METHODS

Information on the episodes of VTF reported between 04/01/2013 and 03/31/2014 was gathered. Once the appropriate informed consent was given, other data on social, demographic, penitentiary and clinical aspects were collected. A descriptive study of such variables together with a bivariate analysis was then carried out by means of standard statistical techniques and binary logistic regression models. IBM SPSS Statistics v.20 software was used for this purpose. This study was approved by an accredited Clinical Research Ethics Committee.

RESULTS

354 episodes of VTF took place among an average population of 29,762 prisoners. Therefore, the incidence rate was 11.9 VTF episodes per ‰ inmates-year. Informed consent (IC) was given in 180 cases (50.8%). 114 were of Spanish nationality and the average age was 38.7 years old (95% CI 37.2-40.1). The median duration of the episodes was 3 days (IQR 1-10), ranged between 1 and 71 days. The main reason was a disagreement on the decisions of treatment groups (57 cases, 31.7%). The average weight loss was 1.3 kg (70.8 vs. 69.5; p < 0.0001) and 0.7 of the BMI (24.5 vs. 23.8; p < 0.0001). 60 prisoners (33.3%) lost no weight at all and only 8 (4.4%) lost over 12% of the basal weight (8.5 kg). Ketone smell was identified in 61 cases (33.9%) and ketonuria in 63 (35%).

CONCLUSIONS

Only one third of those who go on hunger strike in prison actually fast. Revindicative episodes of voluntary total fasting are somewhat common in Spanish prisons, but rarely are they carried out rigorously and entail a risk for those who fast.

A mathematical model of weight loss under total starvation: evidence against the thrifty-gene hypothesis

The thrifty-gene hypothesis (TGH) posits that the modern genetic predisposition to obesity stems from a historical past where famine selected for genes that promote efficient fat deposition. It has been previously argued that such a scenario is unfeasible because under such strong selection any gene favouring fat deposition would rapidly move to fixation. Hence, we should all be predisposed to obesity: which we are not. The genetic architecture of obesity that has been revealed by genome-wide association studies (GWAS), however, calls into question such an argument. Obesity is caused by mutations in many hundreds (maybe thousands) of genes, each with a very minor, independent and additive impact. Selection on such genes would probably be very weak because the individual advantages they would confer would be very small. Hence, the genetic architecture of the epidemic may indeed be compatible with, and hence support, the TGH. To evaluate whether this is correct, it is necessary to know the likely effects of the identified GWAS alleles on survival during starvation. This would allow definition of their advantage in famine conditions, and hence the likely selection pressure for such alleles to have spread over the time course of human evolution. We constructed a mathematical model of weight loss under total starvation using the established principles of energy balance. Using the model, we found that fatter individuals would indeed survive longer and, at a given body weight, females would survive longer than males, when totally starved. An allele causing deposition of an extra 80 g of fat would result in an extension of life under total starvation by about 1.1-1.6% in an individual with 10 kg of fat and by 0.25-0.27% in an individual carrying 32 kg of fat. A mutation causing a per allele effect of 0.25% would become completely fixed in a population with an effective size of 5 million individuals in 6000 selection events. Because there have probably been about 24,000 famine events since the evolution of hominins 4 million years ago, there has been ample time even for genes with only very minor impacts on adiposity to move to fixation. The observed polymorphic variation in the genes causing the predisposition to obesity is incompatible with the TGH, unless all these single nucleotide polymorphisms (SNPs) arose in the last 900,000 years, a requirement we know is incorrect. The TGH is further weakened by the observation of no link between the effect size of these SNPs and their prevalence, which would be anticipated under the TGH model of selection if all the SNPs had arisen in the last 900,000 years.

Low blood thiamine concentrations in children upon admission to the intensive care unit: risk factors and prognostic significance

BACKGROUND

Thiamine deficiency has been associated with poorer clinical outcomes. Early recognition of thiamine deficiency is difficult in critically ill patients because clinical signs are nonspecific.

OBJECTIVE

We determined the prevalence of and identified risk factors associated with low blood thiamine concentrations upon admission of children to a pediatric intensive care unit and evaluated this condition as a predictor of clinical outcomes.

DESIGN

A prospective cohort study was conducted in 202 children who had whole-blood thiamin concentrations assessed by HPLC upon admission to the intensive care unit. The following independent variables for thiamine deficiency were analyzed: age, sex, nutritional status, clinical severity scores upon admission (ie, the revised Pediatric Index of Mortality and Pediatric Logistic Organ Dysfunction score), systemic inflammatory response measured by C-reactive protein serum concentrations, severe sepsis or septic shock, heart failure, and cardiac surgery. The dependent variables in the outcome analyses were mortality, length of stay, and time on mechanical ventilation.

RESULTS

Low blood thiamine concentrations upon admission were detected in 57 patients (28.2%) and were shown to be independently associated with C-reactive protein concentrations >20 mg/dL (odds ratio: 2.17; 95% CI: 1.13, 4.17; P = 0.02) but not with malnutrition. No significant association was shown between low blood thiamine concentrations upon admission and outcome variables.

CONCLUSIONS

The incidence of low blood thiamine concentrations upon admission was high. Of the risk factors examined, only the magnitude of the systemic inflammatory response showed an independent association with this event. The association between thiamine deficiency upon admission and prognosis requires further investigation.

Restoration of body energy reserves during refeeding in rats is dependent on both the intensity of energy restriction and the metabolic status at the onset of refeeding [corrected]

During starvation, after a short dynamic period of adaptation (phase I), a metabolic steady state is reached in which proteins are spared and lipids provide most of the energy expended [phase II (P2)]. However, protein breakdown increases dramatically once a lower threshold of body lipids is reached [phase III (P3)]. Body composition, energy intake, energy expenditure, and energy efficiency were determined in 8 groups of rats (fed, food-deprived up to P2 or P3 of starvation and refed for 3 d, 7 d, or until body mass restoration) to determine whether the kinetics of lipid and/or protein reserve recovery may be slowed down when refeeding occurs after the lipid threshold has been reached. Despite larger losses, P3 refed rats restored their body reserves as efficiently as those refed in P2. Whatever the nutritional status at the onset of refeeding, rehydration occurred first and hyperphagia played a more important role than hypometabolism in the restoration of the lost reserves. However, the pattern of body component gains was different during early refeeding. In P3 refed rats, body lipids were restored preferentially by significant contribution from endogenous lipid production. Thus, the extent of lipid depletion has important consequences for the restoration pattern of the body reserves. It depends not only on the intensity of the energy restriction (partial or total) as already demonstrated but also on the metabolic status at the onset of refeeding. These results may have significant implications on the way refeeding should be conducted after severe energy depletion.

Metabolic and hormonal changes during the refeeding period of prolonged fasting

OBJECTIVE

The discovery of leptin, a hormone primarily involved in adaptation to fasting, led to an increased interest in appetite regulation and appetite-modulating hormones. Here, we present unique data from a case of extreme starvation and refeeding, showing changes in plasma concentrations of appetite-modulating and metabolic hormones as well as biochemical changes, and draw attention to the dangers of the refeeding syndrome.

PATIENTS AND METHODS

We studied the refeeding period of a 44-day voluntary fast uncomplicated by underlying disease. Biochemical and hormonal variables were compared with 16 matched subjects such that the BMI range of the controls covered the entire spectrum for the index subject's recovering BMI.

RESULTS

Lack of calorie intake with free access to water resulted in 25% loss of body weight. Haemoconcentration was observed and feeding was started with a low sodium, hypocaloric liquid formulation. During early refeeding, marked hypophosphataemia, haemodilution and slight oedema developed. Vitamins B1, B12 and B6 were depleted while serum free fatty acids, ketone bodies and zinc levels were abnormally high; abnormal liver function developed over the first week. The hormonal profile showed low IGF-I and insulin levels, and elevated IGF-binding protein-1 concentrations. Appetite-regulating hormones were either very low (leptin and ghrelin) or showed no marked difference from the control group (peptide YY, agouti-related peptide, alpha-melanocyte-stimulating hormone, neuropeptide Y and pro-opiomelanocortin). Appetite was low at the beginning of refeeding and a transient increase in orexin and resistin was observed coincidently with an increase in subjective hunger.

CONCLUSIONS

Our study illustrates the potential dangers of refeeding and provides a comprehensive insight into the endocrinology of prolonged fasting and the refeeding process.