Urine dipsticks are not accurate for detecting mild ketosis during a severely energy restricted diet

Perioperative urinary ketosis and metabolic acidosis in patients fasted for undergoing gynecologic surgery

BACKGROUND

Our bodies have adaptive mechanisms to fasting, in which glycogen stored in the liver and muscle protein are broken down, but also lipid mobilisation is triggered. As a result, glycerol and fatty acids are released into the bloodstream, increasing the production of ketone bodies in liver. However, there are limited studies on the incidence of perioperative urinary ketosis, the intraoperative blood glucose changes and metabolic acidosis after fasting for surgery in non-diabetic adult patients.

METHODS

We conducted a retrospective cohort study involving 1831 patients undergoing gynecologic surgery under general anesthesia from January to December 2022. Ketosis was assessed using a postoperative urine test, while blood glucose levels and acid-base status were collected from intraoperative arterial blood gas analyses.

RESULTS

Of 1535 patients who underwent postoperative urinalysis, 912 (59.4%) patients had ketonuria. Patients with ketonuria were younger, had lower body mass index, and had fewer comorbidities than those without ketonuria. After adjustments, younger age, higher body mass index and surgery starting late afternoon were significant risk factors for postoperative ketonuria. Of the 929 patients assessed with intraoperative arterial blood gas analyses, 29.0% showed metabolic acidosis. Multivariable logistic regression revealed that perioperative ketonuria and prolonged surgery significantly increased the risk for moderate-to-severe metabolic acidosis.

CONCLUSION

Perioperative urinary ketosis and intraoperative metabolic acidosis are common in patients undergoing gynecologic surgery, even with short-term preoperative fasting. The risks are notably higher in younger patients with lower body mass index. Optimization of preoperative fasting strategies including implementation of oral carbohydrate loading should be considered for reducing perioperative metabolic derangement due to ketosis.

Ketogenic therapy towards precision medicine for brain diseases

Precision nutrition and nutrigenomics are emerging in the development of therapies for multiple diseases. The ketogenic diet (KD) is the most widely used clinical diet, providing high fat, low carbohydrate, and adequate protein. KD produces ketones and alters the metabolism of patients. Growing evidence suggests that KD has therapeutic effects in a wide range of neuronal diseases including epilepsy, neurodegeneration, cancer, and metabolic disorders. Although KD is considered to be a low-side-effect diet treatment, its therapeutic mechanism has not yet been fully elucidated. Also, its induced keto-response among different populations has not been elucidated. Understanding the ketone metabolism in health and disease is critical for the development of KD-associated therapeutics and synergistic therapy under any physiological background. Here, we review the current advances and known heterogeneity of the KD response and discuss the prospects for KD therapy from a precision nutrition perspective.

Very low-calorie ketogenic diet in the treatment of adaptive thermogenesis: A case report

OBJECTIVES

The management of the phenomenon of adaptive thermogenesis poses a challenge to the successful treatment of overweight/obesity with a nutritional intervention that minimizes the loss of muscle mass, with little cognitive restraint use and disorganization of eating behavior. On the other hand, it creates a significant calorie deficit for the reduction of body fat. The aim of this case report was to discuss the effects of a very low-calorie ketogenic diet in a woman with obesity and low resting metabolic rate.

CASE DESCRIPTION

A 36-y-old white woman with a history of obesity and bulimia nervosa who has had difficulty losing and maintaining weight despite numerous dietary and pharmacologic treatments.

RESULTS

There was a loss of 12 kg in 115 d, reaching 13.4 kg, with 11.4 kg of fat mass (FM). The resting metabolic rate showed an increase of 79% in relation to the initial rate, reaching normal levels for the predictive equations and maintaining this level in the first-year follow-up. Additionally, improvement of metabolic laboratory parameters and eating behavior traits were described.

CONCLUSIONS

In this specific case of bulimia nervosa resulting in hypometabolism (low resting metabolic rate/fat-free mass) and obesity, the very low-calorie ketogenic diet intervention has demonstrated a possibility of weight loss with little cognitive restraint use, thereby increasing resting metabolic rate in the short and medium terms, ultimately promoting a negative energy balance. In relation to the numeric results, it seems positive; however, more research is necessary to evaluate the effects on the overall relationship with food and its long-term repercussions.

Defining Physiological Ketosis Following Very-Low-Calorie Diets

INTRODUCTION

Very low-calorie diets (VLCDs) are used preoperatively in bariatric-metabolic surgery; however, this can lead to physiological ketosis. Euglycemic ketoacidosis is an increasingly recognized complication in diabetic patients on sodium-glucose-cotransporter-2 inhibitors (SGLT2i) undergoing surgery and requires assessment of ketones for diagnosis and monitoring. VLCD induced ketosis may confound monitoring in this group. We aimed to evaluate the influence of VLCD, compared to standard fasting, on perioperative ketone levels and acid-base balance.

MATERIALS AND METHODS

Twenty-seven patients were prospectively recruited to the intervention group and 26 to the control group from two tertiary referral centres in Melbourne, Australia. Intervention group patients were severely obese (body mass index) (BMI) (≥35), undergoing bariatric-metabolic surgery, and prescribed 2 wk of VLCD preoperatively. Control group patients underwent general surgical procedures and prescribed standard procedural fasting only. Patients were excluded if diabetic or prescribed SGLT2i. Ketone and acid-base measurements were taken at regular intervals. Univariate and multivariate regression was utilised with significance defined as P < 0.005.

CLINICALTRIALS

gov ID: NCT05442918.

RESULTS

Patients on VLCD, compared to standard fasting, had an increased median preoperative (0.60 versus 0.21 mmol/L), immediate postoperative (0.99 versus 0.34 mmol/L) and day 1 postoperative (0.69 versus 0.21 mmol/L) ketone level (P < 0.001). Preoperative acid-base balance was normal in both groups, however VLCD patients were found to have a metabolic acidosis immediately postoperatively (pH 7.29 versus pH 7.35) (P = 0.019). Acid-base balance had normalized in VLCD patients on postoperative day 1.

CONCLUSIONS

Preoperative VLCD resulted in increased pre- and postoperative ketone levels with immediate postoperative values consistent with metabolic ketoacidosis. This should be considered particularly when monitoring diabetic patients prescribed SGLT2i.

Feasibility of ketogenic diet therapy variants for refractory epilepsy in neonates to infants under 2 years old

BACKGROUND

Ketogenic diet Therapy (KDT) has been reported as a possible beneficial management strategy for controlling seizures in infants aged <2 years, but the safety and efficacy of this therapy remain to be investigated. We investigated the achievability, tolerability, efficacy, and safety of KDT for patients under 2 years old.

MATERIALS AND METHODS

Infants younger than 2 years old with pharmacoresistant epilepsy were enrolled in this prospective study. We divided cases into three age groups: I) neonates; II) infants aged 1-12 months; III) infants aged 12-24 months. KDT initiation protocol were administration through parenteral route, enteral route or oral feeding. Seizure reduction rate, physical growth, and adverse effects were assessed at monthly visit.

RESULTS

Thirteen patients who completed 6 months of KDT were recruited. There was one neonate in group I, 9 infants in group II, and 3 infants in group III. Eleven of them (11/13, 84.6%) were responders to KDT. All infants with underlying genetic etiology were seizure free after treating with KDT. The starting keto ratio was 1.1 mmol/L in group I, 2.3 mmol/L in group II, and 2.8 mmol/L in group III, which gradually approached 3:1-4:1 over 5-7 days. There were no symptomatic adverse effects or growth retardation in any of the study subjects.

CONCLUSIONS

KDT is a promising alternative therapy with high feasibility, safety, and efficacy for pharmacoresistant epilepsy in infants under 2 years old, especially for those with genetic etiology. The starting keto ratio should be lower, and the keto ratio titration period should be longer than for children older than 2 years.

Factor Analysis of the Brazilian Questionnaire on Adherence to Ketogenic Dietary Therapy: Keto-Check

BACKGROUND

several strategies are used to assess adherence to ketogenic dietary therapies (KDTs), the most commonly used being ketonemia or ketonuria, despite their limitations. The purpose of this article is to carry out an exploratory and confirmatory factor analysis on the proposed Keto-check (adherence's KDT Brazilian questionnaire).

METHODS

there was a methodological study of a quantitative nature, complementary to the analysis realized previously, with a complimentary sample. The factorial analysis was performed with Factor software for parallel exploratory analysis, replicability, and confirmatory factor analysis. Graphical representation was created according to the number of factors resulting from the analysis.

RESULTS

116 questionnaires were reached by complementary data collection (n = 69 actual data, complementing n = 47 previous data) through online forms. A polychoric correlation matrix suitability analysis resulted in a significant Bartlett statistic (p = 0.0001) and a Kaiser-Meyer-Olkin (KMO) test of 0.56. The parallel factorial analysis resulted in two factors, graphically represented as "efficacy" and "adherence". A confirmatory factor analysis, considered fair, indicated an RMSEA of 0.063, NNFI resulted in 0.872, CFI in 0.926, and GFI in 0.897.

CONCLUSION

this study confirms the validity of Keto-check through a more detailed analysis. Adherence is the key to improving the effectiveness of KDTs; therefore, improving knowledge about it can lead to a better healthcare approach.

Efficacy of low carbohydrate and ketogenic diets in treating mood and anxiety disorders: systematic review and implications for clinical practice

BACKGROUND

There is mounting interest in the potential efficacy of low carbohydrate and very low carbohydrate ketogenic diets in various neurological and psychiatric disorders.

AIMS

To conduct a systematic review and narrative synthesis of low carbohydrate and ketogenic diets (LC/KD) in adults with mood and anxiety disorders.

METHOD

MEDLINE, Embase, PsycINFO and Cochrane databases were systematically searched for articles from inception to 6 September 2022. Studies that included adults with any mood or anxiety disorder treated with a low carbohydrate or ketogenic intervention, reporting effects on mood or anxiety symptoms were eligible for inclusion. PROSPERO registration CRD42019116367.

RESULTS

The search yielded 1377 articles, of which 48 were assessed for full-text eligibility. Twelve heterogeneous studies (stated as ketogenic interventions, albeit with incomplete carbohydrate reporting and measurements of ketosis; diet duration: 2 weeks to 3 years; n = 389; age range 19 to 75 years) were included in the final analysis. This included nine case reports, two cohort studies and one observational study. Data quality was variable, with no high-quality evidence identified. Efficacy, adverse effects and discontinuation rates were not systematically reported. There was some evidence for efficacy of ketogenic diets in those with bipolar disorder, schizoaffective disorder and possibly unipolar depression/anxiety. Relapse after discontinuation of the diet was reported in some individuals.

CONCLUSIONS

Although there is no high-quality evidence of LC/KD efficacy in mood or anxiety disorders, several uncontrolled studies suggest possible beneficial effects. Robust studies are now needed to demonstrate efficacy, to identify clinical groups who may benefit and whether a ketogenic diet (beyond low carbohydrate) is required and to characterise adverse effects and the risk of relapse after diet discontinuation.

Important Functions and Molecular Mechanisms of Mitochondrial Redox Signaling in Pulmonary Hypertension

Mitochondria are important organelles that act as a primary site to produce reactive oxygen species (ROS). Additionally, mitochondria play a pivotal role in the regulation of Ca²⁺ signaling, fatty acid oxidation, and ketone synthesis. Dysfunction of these signaling molecules leads to the development of pulmonary hypertension (PH), atherosclerosis, and other vascular diseases. Features of PH include vasoconstriction and pulmonary artery (PA) remodeling, which can result from abnormal proliferation, apoptosis, and migration of PA smooth muscle cells (PASMCs). These responses are mediated by increased Rieske iron–sulfur protein (RISP)-dependent mitochondrial ROS production and increased mitochondrial Ca²⁺ levels. Mitochondrial ROS and Ca²⁺ can both synergistically activate nuclear factor κB (NF-κB) to trigger inflammatory responses leading to PH, right ventricular failure, and death. Evidence suggests that increased mitochondrial ROS and Ca²⁺ signaling leads to abnormal synthesis of ketones, which play a critical role in the development of PH. In this review, we discuss some of the recent findings on the important interactive role and molecular mechanisms of mitochondrial ROS and Ca²⁺ in the development and progression of PH. We also address the contributions of NF-κB-dependent inflammatory responses and ketone-mediated oxidative stress due to abnormal regulation of mitochondrial ROS and Ca²⁺ signaling in PH.

Effects of an low carbohydrate/healthy fat/ketogenic diet on biomarkers of health and symptoms, anxiety and depression in Parkinson's disease: a pilot study

Aim: To evaluate a low carbohydrate/healthy fat/ketogenic diet (LCHF/KD) on symptoms, depression, anxiety and biomarkers in adults with Parkinson's disease (PD). Patients & methods: 16 adults ages 36-80 with PD participated in the intervention for 12 weeks. The study provided pre-post-study comparisons of biomarkers, weight, waist measurement, united Parkinson's Disease Rating Scale (UPDRS), Parkinson's Anxiety Scale (PAS) and Center for Epidemiologic Studies Depression Scale Revised-20 (CESD-R-20) Depression Scale. Results: Although LCHF/KD improves blood glucose in diabetes and seizure control in epilepsy, research gaps exist in this dietary intervention in PD. Statistically, significant improvements occurred in several measurements, PAS scores and Part I of the UPDRS. Conclusion: The LCHF/KD shows positive trends with improvements in biomarkers and anxiety symptoms. Further research is needed to evaluate dietary interventions for PD.

Effect of severe compared with moderate energy restriction on physical activity among postmenopausal female adults with obesity: a prespecified secondary analysis of the Type of Energy Manipulation for Promoting optimum metabolic health and body composition in Obesity (TEMPO) Diet randomized controlled Trial

BACKGROUND

An under-explored strategy for increasing physical activity is the dietary treatment of obesity, but empirical evidence is lacking.

OBJECTIVES

We aimed to compare the effects of weight loss via severe as opposed to moderate energy restriction on physical activity over 36 mo.

METHODS

A total of 101 postmenopausal female adults (45-65 y, BMI 30-40 kg/m2, <180 min/wk of structured exercise) were randomly assigned to either 12 mo of moderate energy restriction (25%-35% of energy requirement) with a food-based diet, or a severe intervention involving 4 mo of severe energy restriction (65%-75% of energy requirement) with a total meal replacement diet, followed by 8 mo of moderate energy restriction. Physical activity was encouraged, but no tailored or supervised exercise prescription was provided. Physical activity was assessed with an accelerometer worn for 7 d before baseline (0 mo) and 0.25, 1, 4, 6, 12, 24, and 36 mo after intervention commencement.

RESULTS

Compared with the moderate group, the severe group exhibited greater mean: total volume of physical activity; duration of moderate-to-vigorous-intensity physical activity (MVPA); duration of light-intensity physical activity; step counts, as well as lower mean duration of sedentary time. All these differences (except step counts) were apparent at 6 mo [e.g., 1006 metabolic equivalent of task (MET)-min/wk; 95% CI: 564, 1449 MET-min/wk for total volume of physical activity], and some were also apparent at 4 and/or 12 mo. There were no differences between groups in the 2 other outcomes investigated (self-efficacy to regulate exercise; and proportion of participants meeting the WHO's 2020 Physical Activity Guidelines for MVPA). When the analyses were adjusted for weight at each time point, the differences between groups were either attenuated or abolished.

CONCLUSIONS

Among female adults with obesity, including a dietary component to reduce excess body weight-notably one involving severe energy restriction-could potentially enhance the effectiveness of physical activity interventions.This trial was registered at www.anzctr.org.au as ACTRN12612000651886.

Feasibility of an MI-CBT ketogenic adherence program for older adults with mild cognitive impairment

BACKGROUND

The National Institutes of Health Obesity-Related Behavioral Intervention Trials model for intervention development was used to establish the feasibility and proof of concept of a motivational ketogenic nutrition adherence program for older adults with mild cognitive impairment.

METHODS

This was a single-arm, single-center feasibility trial. A comprehensive assessment protocol, including a clinical interview, neuropsychological testing, and genetic sequencing was used as an initial screening. Nine participants (aged 64-75) with possible amnestic mild cognitive impairment were consented for the intervention. Participants completed pre- and post-intervention neuropsychological assessments using the updated Repeatable Battery for Assessment of Neuropsychological Status. Participants tracked their macronutrient consumption using food diaries and ketone levels using urinalysis test strips daily. Mood and other psychosocial variables were collected through surveys, and qualitative exit interviews were completed.

RESULTS

100% of participants who began the trial completed the 6-week ketogenic nutrition adherence program, including completion of the pre- and post-assessments. Eight participants achieved measurable levels of ketones during the program. The average self-rated adherence across the program was 8.7 out of 10. A Wilcoxon Signed-Rank test demonstrated significant improvement in cognitive performance from baseline (median = 88) to follow up (median = 96, Z = - 2.26, p = .024). The average difference in cognitive performance from baseline to follow-up was - 7.33 (95% CI - 12.85, - 1.82).

CONCLUSIONS

Results supported the feasibility for moving to the next phase and demonstrated proof of concept for the intervention. The next step is a randomized pilot trial to test clinical signals of effect compared to a control condition.

TRIAL REGISTRATION

This trial was retrospectively registered with clinicaltrials.gov on July 13, 2021. The trial number is NCT04968041.

Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future

The ketone bodies acetoacetate (AcAc) and β-hydroxybutyrate (βHB) have pleiotropic effects in multiple organs including brain, heart, and skeletal muscle by serving as an alternative substrate for energy provision, and by modulating inflammation, oxidative stress, catabolic processes, and gene expression. Of particular relevance to athletes are the metabolic actions of ketone bodies to alter substrate utilisation through attenuating glucose utilisation in peripheral tissues, anti-lipolytic effects on adipose tissue, and attenuation of proteolysis in skeletal muscle. There has been long-standing interest in the development of ingestible forms of ketone bodies that has recently resulted in the commercial availability of exogenous ketone supplements (EKS). These supplements in the form of ketone salts and ketone esters, in addition to ketogenic compounds such as 1,3-butanediol and medium chain triglycerides, facilitate an acute transient increase in circulating AcAc and βHB concentrations, which has been termed 'acute nutritional ketosis' or 'intermittent exogenous ketosis'. Some studies have suggested beneficial effects of EKS to endurance performance, recovery, and overreaching, although many studies have failed to observe benefits of acute nutritional ketosis on performance or recovery. The present review explores the rationale and historical development of EKS, the mechanistic basis for their proposed effects, both positive and negative, and evidence to date for their effects on exercise performance and recovery outcomes before concluding with a discussion of methodological considerations and future directions in this field.