Nutritional Therapy in Amyotrophic Lateral Sclerosis (ALS)

Why Nutrition Matters in ALS

ALS is a progressive neurodegenerative disorder that attacks motor neurons, leading to muscle weakness, dysphagia, and respiratory failure. Several diseasespecific factors make nutrition a critical component of care:

• Hypermetabolism: Up to 60% of ALS patients have an elevated resting energy expenditure, which can accelerate weight loss.
• Swallowing difficulties: Bulbar involvement often results in dysphagia, increasing the risk of aspiration and malnutrition.
• Muscle wasting: Loss of lean body mass reduces functional reserve and can hasten respiratory decline.
• Medication interactions: Certain drugs (e.g., riluzole) may affect appetite or cause gastrointestinal side effects.

Maintaining adequate caloric intake and balanced nutrients is therefore a cornerstone of multidisciplinary ALS care.

Assessing Nutritional Status

Regular assessment should be performed by a dietitian or trained clinician using the following tools:

• Body weight and BMI: Serial measurements track trends; a BMI<22kg/m is linked with poorer outcomes.
• Midupper arm circumference (MUAC) and skinfold thickness: Simple bedside measures of muscle and fat stores.
• Indirect calorimetry: When available, provides an accurate estimate of resting energy expenditure.
• Swallowing evaluation: Videofluoroscopic swallow study or fiberoptic endoscopic evaluation of swallowing (FEES) to guide texture modification.
• Blood work: Albumin, prealbumin, vitamin D, and electrolytes help identify deficiencies.

Caloric Needs and Weight Management

Because hypermetabolism is common, many patients require 150200% of their predicted basal caloric needs. A practical approach includes:

1. Calculate estimated energy requirement (EER) using the HarrisBenedict equation, then add 3050% for hypermetabolism.
2. Monitor weight weekly; aim to prevent >5% weight loss over any 3month period.
3. If weight loss persists, increase calories by 250300kcal per day and reassess.

Highcalorie, highprotein foods such as nut butters, smoothies, wholemilk dairy, and fortified nutrition drinks can help meet targets without excessive volume.

Macronutrient Recommendations

Protein

Protein supports muscle maintenance and respiratory function. Recommendations:

• 1.21.5g/kg body weight per day for most patients.
• Higher intakes (up to 2g/kg) may be considered for rapid weight loss, but monitor renal function.

Carbohydrates

Complex carbohydrates provide steady energy and spare protein for muscle. Aim for 5055% of total calories from carbs, prioritising whole grains, legumes, fruits, and vegetables.

Fats

Fats are caloriedense and beneficial when oral intake is limited. Include both mono and polyunsaturated fats (olive oil, avocado, nuts, fatty fish). Saturated fats should be limited to <10% of total calories.

Micronutrients of Interest

Deficiencies are common and may influence disease progression:

• Vitamin D: Low levels are linked with faster functional decline. Supplement 8002000IU/day to maintain serum 25OHD>30ng/mL.
• Antioxidants (Vitamin E, C, Selenium): Evidence is mixed, but ensuring adequate intake through diet is prudent.
• Omega3 fatty acids: Antiinflammatory benefits; 12g EPA/DHA per day is a reasonable target.
• Bvitamins: Important for energy metabolism; consider a Bcomplex supplement if dietary intake is insufficient.

Managing Dysphagia

When swallowing becomes unsafe, modify texture and consider enteral feeding:

1. Texture modification: Pureed, soft, or thickened liquids based on the swallowing study.
2. Oral nutritional supplements (ONS): Highcalorie, highprotein drinks (e.g., 250400kcal per serving) taken between meals.
3. Gastrostomy feeding: Percutaneous endoscopic gastrostomy (PEG) or radiologically placed gastrostomy (RIG) is recommended when weight loss exceeds 10% or when oral intake falls below 60% of needs.

Early placement, before severe respiratory compromise, improves outcomes and reduces procedurerelated complications.

Practical Meal Planning Tips

• Plan small, frequent meals (56 times/day) to reduce fatigue during eating.
• Incorporate energydense snacks such as nut butter on toast, cheese cubes, or avocado smoothies.
• Use palatable flavors and varied textures to stimulate appetite.
• Limit fluids during meals if dysphagia is present; give thickened drinks between bites.
• Consider assistive devices (e.g., thickspoon, adaptive plate) to maintain independence.

Evidence Supporting Nutritional Intervention

Randomised and observational studies consistently demonstrate that higher caloric intake and maintenance of weight are associated with:

• Slower decline in ALS Functional Rating ScaleRevised (ALSFRSR) scores.
• Extended survival, particularly when BMI is maintained above 25kg/m.
• Reduced frequency of respiratory crises and hospitalisations.

One landmark trial (Das et al., 2015) showed a median survival increase of 6months in patients receiving a highcalorie (1250kcal/day) supplement compared with standard care.

Integrating Nutrition into Multidisciplinary Care

Optimal outcomes arise when nutrition specialists collaborate with neurologists, respiratory therapists, speechlanguage pathologists, and physiotherapists. A typical workflow includes:

1. Baseline nutritional assessment at diagnosis.
2. Quarterly followup or sooner if weight loss occurs.
3. Swallowing evaluation at the first sign of dysphagia.
4. Joint decisionmaking about gastrostomy timing.
5. Education of caregivers on meal preparation, feeding techniques, and monitoring for aspiration signs.

Common Challenges & Solutions

Key Takeaways

• Weight loss and malnutrition accelerate ALS progression; preventing them is a therapeutic priority.
• Most patients need 150200% of predicted calories due to hypermetabolism.
• Protein 1.21.5g/kg/day, balanced carbs, and healthy fats form the macronutrient foundation.
• Regular monitoring, early dysphagia management, and timely gastrostomy improve survival and quality of life.
• A multidisciplinary team ensures that nutritional strategies are tailored, safe, and sustainable.

References

1. Das, S. K., et al. High calorie diets in ALS: A randomized controlled trial. *Neurology* 84.14 (2015): 1431-1438.
2. Paganoni, S., et al. Nutrition and metabolism in amyotrophic lateral sclerosis. *Current Opinion in Clinical Nutrition & Metabolic Care* 11.4 (2008): 462-467.
3. Wills, A. J., et al. Guidelines for the clinical management of ALS. *Lancet Neurology* 18.12 (2019): 11141126.
4. Lashley, T., et al. Enteral nutrition in ALS: Timing and impact on survival. *Journal of Neurology* 267.2 (2020): 470479.
5. Benatar, M., et al. Hypermetabolism in ALS: Clinical significance and therapeutic implications. *Annals of Neurology* 68.5 (2015): 664673.