Which equation best predicts energy expenditure in amyotrophic lateral sclerosis?

Nutritional and Microbiota-Based Approaches in Amyotrophic Lateral Sclerosis: From Prevention to Treatment

Metabolic alterations, including hypermetabolism, lipid imbalances, and glucose dysregulation, are pivotal contributors to the onset and progression of Amyotrophic Lateral Sclerosis (ALS). These changes exacerbate systemic energy deficits, heighten oxidative stress, and fuel neuroinflammation. Simultaneously, gastrointestinal dysfunction and gut microbiota (GM) dysbiosis intensify disease pathology by driving immune dysregulation, compromising the intestinal barrier, and altering gut-brain axis (GBA) signaling, and lastly advancing neurodegeneration. Therapeutic and preventive strategies focused on nutrition offer promising opportunities to address these interconnected pathophysiological mechanisms. Diets enriched with antioxidants, omega-3 fatty acids, and anti-inflammatory compounds-such as the Mediterranean diet-have shown potential in reducing oxidative stress and systemic inflammation. Additionally, microbiota-targeted approaches, including probiotics, prebiotics, postbiotics, and fecal microbiota transplantation, are emerging as innovative tools to restore microbial balance, strengthen gut integrity, and optimize GBA function. This review highlights the critical need for personalized strategies integrating immunonutrition and microbiota modulation to slow ALS progression, improve quality of life, and develop preventive measures for neurodegenerative and neuroinflammatory diseases. Future research should prioritize comprehensive dietary and microbiota-based interventions to uncover their therapeutic potential and establish evidence-based guidelines for managing ALS and related disorders.

Mapping the Evidence for Measuring Energy Expenditure and Indicating Hypermetabolism in Motor Neuron Disease: A Scoping Review

OBJECTIVE

To map the international methods used to measure energy expenditure of adults living with motor neuron disease (MND) and to highlight discrepancies when indicating hypermetabolism in the MND literature.

BACKGROUND

A decline in the nutritional status of patients is associated with exacerbated weight loss and shortened survival. Assessments of energy expenditure, using a variety of methods, are important to ensure an adequate energy intake to prevent malnutrition-associated weight loss. Assessments of energy expenditure are also commonly used to indicate hypermetabolism in MND, although these approaches may not be optimal.

METHODS

A protocol based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews Guidelines was developed. Three electronic databases (Medline [Ovid], CINAHL [EBSCO], and Web of Science) were exhaustively searched. Identified publications were systematically screened according to predefined PICOS eligibility criteria. The primary outcome was the identification of methods used to measure energy expenditure in MND. The secondary outcome was the identification of applications of energy expenditure assessments to indicate hypermetabolism in MND.

RESULTS

Thirty-two observational primary research publications were identified. Thirteen (40.6%) were longitudinal in design, with data on repeated measurements of energy expenditure presented in 3 (9.4%). Thirteen (40.6%) were case-control studies, of which 11 use a matched control group. Pulmonary function was used to assess eligibility in 10 publications. Energy expenditure was measured using indirect calorimetry (IC) in 31 studies. Discrepancies in the durations of fasted, measurement, and washout periods were observed. Of all included publications, 50% used assessments of resting energy expenditure to identify hypermetabolism. Bioelectrical impedance analysis was used to assess body composition alongside energy expenditure in 93.8% of publications.

CONCLUSIONS

Resting energy expenditure is most frequently measured using an open-circuit IC system. However, there is a lack of a standardized, validated protocol for the conduct and reporting of IC and metabolic status in patients with MND.

A critical view of the use of predictive energy equations for the identification of hypermetabolism in motor neuron disease: A pilot study

BACKGROUND AND AIMS

People living with motor neuron disease (MND) frequently struggle to consume an optimal caloric intake. Often compounded by hypermetabolism, this can lead to dysregulated energy homeostasis, prompting the onset of malnutrition and associated weight loss. This is associated with a poorer prognosis and reduced survival. It is therefore important to establish appropriate nutritional goals to ensure adequate energy intake. This is best done by measuring resting energy expenditure (mREE) using indirect calorimetry. However, indirect calorimetry is not widely available in clinical practice, thus dietitians caring for people living with MND frequently use energy equations to predict resting energy expenditure (pREE) and estimate caloric requirements. Energy prediction equations have previously been shown to underestimate resting energy expenditure in over two-thirds of people living with MND. Hypermetabolism has previously been identified using the metabolic index. The metabolic index is a ratio of mREE to pREE, whereby an increase of mREE by ≥110% indicates hypermetabolism. We aim to critically reflect on the use of the Harris-Benedict (1919) and Henry (2005) energy prediction equations to inform a metabolic index to indicate hypermetabolism in people living with MND.

METHODS

mREE was derived using VO₂ and VCO₂ measurements from a GEMNutrition indirect calorimeter. pREE was estimated by Harris-Benedict (HB) (1919), Henry (2005) and kcal/kg/day predictive energy equations. The REE variation, described as the percentage difference between mREE and pREE, determined the accuracy of pREE ([pREE-mREE]/mREE) x 100), with accuracy defined as ≤ ± 10%. A metabolic index threshold of ≥110% was used to classify hypermetabolism. All resting energy expenditure data are presented as kcal/24hr.

RESULTS

Sixteen people living with MND were included in the analysis. The mean mREE was 1642 kcal/24hr ranging between 1110 and 2015 kcal/24hr. When REE variation was analysed for the entire cohort, the HB, Henry and kcal/kg/day equations all overestimated REE, but remained within the accuracy threshold (mean values were 2.81% for HB, 4.51% for Henry and 8.00% for kcal/kg/day). Conversely, inter-individual REE variation within the cohort revealed HB and Henry equations both inaccurately reflected mREE for 68.7% of participants, with kcal/kg/day inaccurately reflecting 41.7% of participants. Whilst the overall cohort was not classified as hypermetabolic (mean values were 101.04% for HB, 98.62% for Henry and 95.64% for kcal/kg/day), the metabolic index ranges within the cohort were 70.75%-141.58% for HB, 72.82%-127.69% for Henry and 66.09%-131.58% for kcal/kg/day, indicating both over- and under-estimation of REE by these equations. We have shown that pREE correlates with body weight (kg), whereby the lighter the individual, the greater the underprediction of REE. When applied to the metabolic index, this underprediction biases towards the classification of hypermetabolism in lighter individuals.

CONCLUSION

Whilst predicting resting energy expenditure using the HB, Henry or kcal/kg/day equations accurately reflects derived mREE at group level, these equations are not suitable for informing resting energy expenditure and classification of hypermetabolism when applied to individuals in clinical practice.

Malnutrition assessment by Global Leadership Initiative on Malnutrition criteria in patients with amyotrophic lateral sclerosis

Malnutrition can play an important prognostic role in terms of survival in patients with amyotrophic lateral sclerosis (ALS). In this clinical context, applying criteria defining malnutrition requires particular attention, especially in the initial stage of the disease. This article discusses the application of the most recent criteria used for the definition of malnutrition when applied to patients with ALS. Currently, the Global Leadership Initiative on Malnutrition (GLIM) criteria, which have received a worldwide consensus, are based on parameters such as unintentional weight loss, low body mass index (BMI), and reduced muscle mass (phenotypic criteria) in combination with reduced food intake and assimilation or inflammation and disease (etiologic criteria). However, as discussed in this review, the initial unintentional weight loss and the consequent BMI reduction could be attributed, at least in part, to muscle atrophy, which also alters the reliability of muscle mass assessment. Moreover, the condition of hypermetabolism, which is observed in up to 50% of these patients, may complicate the calculation of total energy requirements. Finally, it remains to be established if the presence of neuroinflammation can be considered a type of inflammatory process able to induce malnutrition in these patients. In conclusion, the monitoring of BMI, associated with body composition evaluation by bioimpedance measurement or specific formulas, could be a practicable approach to the diagnosis of malnutrition in patients with ALS. In addition, attention should be given to dietary intake (e.g., in patients with dysphagia) and excessive involuntary weight loss. On the other hand, as suggested by GLIM criteria, a single assessment of BMI resulting in <20 kg/m² or <22 kg/m² in patients aged <70 y and ≥70 y, respectively, should always be considered a sign of malnutrition.

The hypometabolic state: a good predictor of a better prognosis in amyotrophic lateral sclerosis

BACKGROUND

Malnutrition and weight loss are negative prognostic factors for survival in patients with amyotrophic lateral sclerosis (ALS). However, energy expenditure at rest (REE) is still not included in clinical practice, and no data are available concerning hypometabolic state in ALS.

OBJECTIVE

To evaluate in a referral cohort of patients with ALS the prevalence of hypometabolic state as compared with normometabolic and hypermetabolic states, and to correlate it with clinical phenotype, rate of progression and survival.

DESIGN

We conducted a retrospective study examining REE measured by indirect calorimetry in patients with ALS referred to Milan, Limoges and Tours referral centres between January 2011 and December 2017. Hypometabolism and hypermetabolism states were defined when REE difference between measured and predictive values was ≤-10% and ≥10%, respectively. We evaluated the relationship between these metabolic alterations and measures of body composition, clinical characteristics and survival.

RESULTS

Eight hundred forty-seven patients with ALS were recruited. The median age at onset was 63.79 years (IQR 55.00-71.17). The male/female ratio was 1.26 (M/F: 472/375). Ten per cent of patients with ALS were hypometabolic whereas 40% were hypermetabolic. Hypometabolism was significantly associated with later need for gastrostomy, non-invasive ventilation and tracheostomy placement. Furthermore, hypometabolic patients with ALS significantly outlived normometabolic (HR=1.901 (95% CI 1.080 to 3.345), p=0.0259) and hypermetabolic (HR=2.138 (95% CI 1.154 to 3.958), p=0.0157) patients.

CONCLUSION

Hypometabolism in ALS is not uncommon and is associated with slower disease progression and better survival than normometabolic and hypermetabolic subjects. Indirect calorimetry should be performed at least at time of diagnosis because alterations in metabolism are correlated with prognosis.

Dysregulation of energy homeostasis in amyotrophic lateral sclerosis

PURPOSE OF REVIEW

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease targeting upper and lower motor neurons, inexorably leading to an early death. Defects in energy metabolism have been associated with ALS, including weight loss, increased energy expenditure, decreased body fat mass and increased use of lipid nutrients at the expense of carbohydrates. We review here recent findings on impaired energy metabolism in ALS, and its clinical importance.

RECENT FINDINGS

Hypothalamic atrophy, as well as alterations in hypothalamic peptides controlling energy metabolism, have been associated with metabolic derangements. Recent studies showed that mutations causing familial ALS impact various metabolic pathways, in particular mitochondrial function, and lipid and carbohydrate metabolism, which could underlie these metabolic defects in patients. Importantly, slowing weight loss, through high caloric diets, is a promising therapeutic strategy, and early clinical trials indicated that it might improve survival in at least a subset of patients. More research is needed to improve these therapeutic strategies, define pharmacological options, and refine the population of ALS patients that would benefit from these approaches.

SUMMARY

Dysfunctional energy homeostasis is a major feature of ALS clinical picture and emerges as a potential therapeutic target.

Hypermetabolism associated with worse prognosis of amyotrophic lateral sclerosis

BACKGROUND AND OBJECTIVE

Exploration of hypermetabolism in amyotrophic lateral sclerosis (ALS) with different ethnicities is needed to understand its metabolic implications for clinical management. We aimed to evaluate the features of hypermetabolism and investigate its association with clinical characteristics and prognosis of ALS in a prospective Chinese cohort.

METHODS

This prospective study was conducted at Peking University Third Hospital, China from 2017 to 2020. 343 participants were enrolled initially. After strict screening, 147 matched health controls and 93 patients with ALS were eligible and underwent detailed clinical assessments. Disease severity and progression were evaluated using recognized scales. Metabolic assessments included body composition and metabolic index (MI) [hypermetabolism if MI ≥ 120.0%]. Patients were followed up every 6 months for survival analysis.

RESULTS

Compared with controls, hypermetabolism was significantly more prevalent in ALS (p = 0.009). MI was consistently higher in ALS than controls (p = 0.009). Further correlation analysis showed that MI significantly decreased with disease progression, as graded by King's College staging system (p < 0.001). MI was significantly correlated with fat-free mass and fat mass (p = 0.005 and 0.007). Survival analysis showed that hypermetabolism independently indicated a worse prognosis for ALS (HR = 1.020, CI = 1.004-1.036, p = 0.013).

CONCLUSION

A significant increase in the prevalence and degree of hypermetabolism was identified in ALS compared with strictly matched controls. Metabolic index, which is significantly associated with disease progression and body composition, is an independent prognostic indicator for a worse survival of ALS.

Metabolic Abnormalities, Dietary Risk Factors and Nutritional Management in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a devastating progressive neurodegenerative disease that affects motor neurons, leading to a relentless paralysis of skeletal muscles and eventual respiratory failure. Although a small percentage of patients may have a longer survival time (up to 10 years), in most cases, the median survival time is from 20 to 48 months. The pathogenesis and risk factors for ALS are still unclear: among the various aspects taken into consideration, metabolic abnormalities and nutritional factors have been the focus of recent interests. Although there are no consistent findings regarding prior type-2 diabetes, hypercholesterolemia and ALS incidence, abnormalities in lipid and glucose metabolism may be linked to disease progression, leading to a relatively longer survival (probably as a result of counteract malnutrition and cachexia in the advanced stages of the disease). Among potential dietary risk factors, a higher risk of ALS has been associated with an increased intake of glutamate, while the consumption of antioxidant and anti-inflammatory compounds, such as vitamin E, n-3 polyunsaturated fatty acids, and carotenoids, has been related to lower incidence. Poor nutritional status and weight loss in ALS resulting from poor oral intake, progressive muscle atrophy, and the potential hypermetabolic state have been associated with rapid disease progression. It seems important to routinely perform a nutritional assessment of ALS patients at the earliest referral: weight maintenance (if adequate) or gain (if underweight) is suggested from the scientific literature; evidence of improved diet quality (in terms of nutrients and limits for pro-inflammatory dietary factors) and glucose and lipid control is yet to be confirmed, but it is advised. Further research is warranted to better understand the role of nutrition and the underlying metabolic abnormalities in ALS, and their contribution to the pathogenic mechanisms leading to ALS initiation and progression.

Hypermetabolism is a reality in amyotrophic lateral sclerosis compared to healthy subjects

RATIONALE

Hypermetabolism (HM) in Amyotrophic lateral sclerosis (ALS) is the reflection of a high energy metabolic level, but this alteration seems controversial. The main objective of the study was to confirm the existence of HM during ALS compared to healthy subjects.

METHODS

A cohort of ALS patients was compared to a control group without metabolic disorder. The assessment included anthropometric criteria measurements, body composition by bioelectric impedance analysis and resting energy expenditure (REE) by indirect calorimetry. HM was defined as a variation > +10% between measured and calculated REE. Statistical analysis used Mann-Withney and Chi2 tests. Multivariate analysis included logistic regression.

RESULTS

287 patients and 75 controls were included. The metabolic level was higher in ALS patients (1500 kcal/24 h [1290-1693] vs. 1230 kcal/24 h [1000-1455], p < 0.0001) as well as the REE/fat free mass ratio (33.5 kcal/kg/24 h [30.4-37.8] vs. 28.3 kcal/kg/24 h [26.1-33.6], p < 0.0001). 55.0% of ALS patients had HM vs. 13.3% of controls (p < 0.0001). HM was strongly and positively associated with ALS (OR = 9.50 [4.49-20.10], p < 0.0001).

CONCLUSIONS

HM in ALS is a reality, which affects more than half of the patients and is associated with ALS. This work confirms a very frequent metabolic deterioration during ALS. The identification of HM can allow a better adaptation of the patients' nutritional intake.

Hypermetabolism in ALS is associated with greater functional decline and shorter survival

OBJECTIVE

To determine the prevalence of hypermetabolism, relative to body composition, in amyotrophic lateral sclerosis (ALS) and its relationship with clinical features of disease and survival.

METHODS

Fifty-eight patients with clinically definite or probable ALS as defined by El Escorial criteria, and 58 age and sex-matched control participants underwent assessment of energy expenditure. Our primary outcome was the prevalence of hypermetabolism in cases and controls. Longitudinal changes in clinical parameters between hypermetabolic and normometabolic patients with ALS were determined for up to 12 months following metabolic assessment. Survival was monitored over a 30-month period following metabolic assessment.

RESULTS

Hypermetabolism was more prevalent in patients with ALS than controls (41% vs 12%, adjusted OR=5.4; p<0.01). Change in body weight, body mass index and fat mass (%) was similar between normometabolic and hypermetabolic patients with ALS. Mean lower motor neuron score (SD) was greater in hypermetabolic patients when compared with normometabolic patients (4 (0.3) vs 3 (0.7); p=0.04). In the 12 months following metabolic assessment, there was a greater change in Revised ALS Functional Rating Scale score in hypermetabolic patients when compared with normometabolic patients (-0.68 points/month vs -0.39 points/month; p=0.01). Hypermetabolism was inversely associated with survival. Overall, hypermetabolism increased the risk of death during follow-up to 220% (HR 3.2, 95% CI 1.1 to 9.4, p=0.03).

CONCLUSIONS AND RELEVANCE

Hypermetabolic patients with ALS have a greater level of lower motor neuron involvement, faster rate of functional decline and shorter survival. The metabolic index could be important for informing prognosis in ALS.

Nutrition management methods effective in increasing weight, survival time and functional status in ALS patients: a systematic review

Poor prognosis and decreased survival time correlate with the nutritional status of patients with amyotrophic lateral sclerosis (ALS). Various studies were reviewed which assessed weight, body mass index (BMI), survival time and ALS functional rating scale revised (ALSFRS-R) in order to determine the best nutrition management methods for this patient population. A systematic review was conducted using CINAHL, Medline, and PubMed, and various search terms in order to determine the most recent clinical trials and observational studies that have been conducted concerning nutrition and ALS. Four articles met criteria to be included in the review. Data were extracted from these articles and were inputted into the Data Extraction Tool (DET) provided by the Academy of Nutrition and Dietetics (AND). Results showed that nutrition supplementation does promote weight stabilisation or weight gain in individuals with ALS. Given the low risk and low cost associated with intervention, early and aggressive nutrition intervention is recommended. This systematic review shows that there is a lack of high quality evidence regarding the efficacy of any dietary interventions for promoting survival in ALS or slowing disease progression; therefore more research is necessary related to effects of nutrition interventions.

Altered Metabolic Homeostasis in Amyotrophic Lateral Sclerosis: Mechanisms of Energy Imbalance and Contribution to Disease Progression

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the death of motor neurones, which leads to paralysis and death in an average of 3 years following diagnosis. The cause of ALS is unknown, but there is substantial evidence that metabolic factors, including nutritional state and body weight, affect disease progression and survival. This review provides an overview of the characteristics of metabolic dysregulation in ALS focusing on mechanisms that lead to disrupted energy supply (at a whole-body and cellular level) and altered energy expenditure. We discuss how a decrease in energy supply occurs in parallel with an increase in energy demand and leads to a state of chronic energy deficit which has a negative impact on disease outcome in ALS. We conclude by presenting potential and tested strategies to compensate for, or correct this energy imbalance, and speculate on promising areas for further research.

Pilot Study to Explore the Accuracy of Current Prediction Equations in Assessing Energy Needs of Patients with Newly Diagnosed Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is rare, yet it is the most common brain malignancy and has a poor prognosis. In regard to GBM, there is a dearth of research on resting energy expenditure (REE) and the accuracy of extant prediction equations. The aim of this cross-sectional study was to compare measured REE (mREE) to commonly used prediction equations in newly diagnosed GBM patients. REE was collected by indirect calorimetry in 20 GBM patients. Calculated REE was derived from Harris-Benedict (again with weight adjusted for obesity), Mifflin-St Jeor, and the 20 kcal/kg body weight ratio method. Paired t-tests and Bland-Altman analyses were used to compare group means, evaluate the bias, and find the limits of agreement. Clinical accuracy was assessed by determining the percentage of patients with predicted REE within ±10% of mREE. Subjects were evenly distributed with regard to gender, primarily Caucasian, and largely overweight or obese and had a mean age of 57 years. All equations overestimated mREE. Mifflin-St Jeor and adjusted Harris-Benedict had the narrowest limits of agreement and accurately predicted 60% and 65% of subjects, respectively. Clinicians should be aware of the discrepancy between commonly used prediction equations and REE. More research is needed to verify these findings and decipher the cause and significance in the GBM population.

Noninvasive ventilation reduces energy expenditure in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) leads to chronic respiratory failure. Diaphragmatic dysfunction, a major driver of dyspnea and mortality, is associated with a shift of the burden of ventilation to extradiaphragmatic inspiratory muscles, including neck muscles. Besides, energy expenditure is often abnormally high in ALS, and this is associated with a negative prognostic value. We hypothesized that noninvasive ventilation (NIV) would relieve inspiratory neck muscles and reduce resting energy expenditure (REE).

METHODS

Using indirect calorimetry, we measured REE during spontaneous breathing (REESB) and NIV (REENIV) in 16 ALS patients with diaphragmatic dysfunction, during the first 3 months of NIV. Measured values were compared with predicted REE (REEpred)(Harris-Benedict equation).

RESULTS

NIV abolished inspiratory neck muscle activity. Even though our patients were not hypermetabolic, on the contrary, with a REESB that was lower than REEpred (average 11%), NIV did reduce energy expenditure. Indeed, median REENIV, in this population with a mean body mass index of 21.4 kg.m-2, was 1149 kcal/24 h [interquartile 970-1309], lower than REESB (1197 kcal/24 h, 1054-1402; mean difference 7%; p = 0.03, Wilcoxon). REESB and REENIV were correlated with forced vital capacity and maximal inspiratory pressure.

CONCLUSIONS

NIV can reduce energy expenditure in ALS patients probably by alleviating the ventilatory burden imposed on inspiratory neck muscles to compensate diaphragm weakness. It remains to be elucidated whether or not, in which population, and to what extent, NIV can be beneficial in ALS through the corresponding reduction in energy expenditure.

Nutrition assessment and management in amyotrophic lateral sclerosis

In recent years nutrition assessment and management in amyotrophic lateral sclerosis (ALS) have drawn increased attention. Frequent evaluation of nutrition status is warranted in ALS, given the common occurrence of dysphagia and hypermetabolism and varying disease progression rates. Nutrition management includes dietary and swallow strategies, possible gastrostomy tube placement, and recommendations for vitamin and mineral supplementation. Strategies to assess and optimize nutrition status and prolong survival in ALS patients are reviewed with recommendations based on current research.

Nutrition management of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease with high risk of malnutrition. Symptoms of dysphagia, depression, cognitive impairment, difficulty with self-feeding and meal preparation, hypermetabolism, anxiety, respiratory insufficiency, and fatigue with meals increase the risk of malnutrition. Malnutrition negatively affects prognosis and quality of life, making early and frequent nutrition assessment and intervention essential. Implementation of an adequate calorie diet, dietary texture modification, use of adaptive eating utensils, and placement of a feeding tube aid in preventing malnutrition. When nutrition status is compromised by dysphagia and weight loss (5%-10% of usual body weight) or body mass index <20 kg/m(2) without weight loss and when forced vital capacity is >50%, a percutaneous endoscopic gastrostomy placement is indicated. When forced vital capacity is <50%, a radiologically inserted gastrostomy is the preferred means of enteral placement due to lessened aspiration and respiratory risk. Parenteral nutrition (PN) is indicated only when enteral nutrition (EN) is contraindicated or impossible. This article reviews the background of ALS, nutrition implications and risk of malnutrition, treatment strategies to prevent malnutrition, the role of EN and PN, and feeding tube placement methods according to disease stage.