Chapter 9: Peripheral Neuropathy Associated With Nutritional Deficiency

Objectives

On completion of this chapter, the student/practitioner will be able to:

• List the common presenting signs and symptoms of nutrition-related peripheral nerve injury.

• Describe the etiologies of alcohol-related neuropathy.

• Discuss the role of “balanced” nutrients in homeostasis.

• List and describe diagnostic neuropathic patterns related to common nutritional deficiencies.

• Explain the complex roles of vitamins and nutrients in peripheral nerve health.

Key Terms

• Macronutrient

• Mineral

• Neuropathies

• Nutrient

• Nutritional deficiency

• Vitamin

Introduction

Localization of lesions in neurology is paramount to identification and management of disease. In clinical practice, the primary site and cause of a peripheral neuropathy may not be easy to determine. Peripheral nerve disorders may reflect damage to a neuronal cell body, its axon, the myelin sheath, supporting tissue, and the vascular supply. Nerve conduction studies and specific neurological physical examinations can be useful. Otherwise, the clinical presentation and past medical history provide the etiological clues. The influence of nutritional deficiency always needs to be considered.

The cells of the peripheral nervous system (PNS) and central nervous system (CNs) require a steady supply of nutrients to maintain optimal function. Similarly, other tissues within the body require an assortment of nutrients for maintaining metabolic processes at the cellular and molecular levels. Manifestations of nutrient deficits throughout the body continue to be characterized; the focus in this chapter is on currently recognized signs and symptoms associated with the nervous system, their clinical cause, and their pathological description.

Nutrients, Nutritional Status, and the Nervous System

Nutrients and Nutritional Status

Human metabolism requires substrate materials that cannot be synthesized by the body or are detected in quantities insufficient to meet the body's needs. These essential substrates are the nutrients that are consumed daily through a healthy diet. The nutrients have been reasonably well classified as either macronutrients or micronutrients.

Macronutrients are required in gram quantities daily, whereas micronutrients are generally required in milligram or microgram quantities. Macronutrients include proteins, carbohydrates, fats, and water. The three carbon-based nutrients flow through common routes of intermediary metabolism and contribute to the energy needs of the body, with most reactions occurring in environments containing water. Besides roles in energy metabolism, macronutrients play important structural and transport roles within the body. The fundamental units of any protein are amino acids, which are obtained daily via nutrient consumption. Proteins serve a structural role in all cells of the body and function as enzymes, hormones, and membrane transporters. Individual amino acids and fatty acids have specific physiological roles at cellular targets.¹

Although micronutrients do not provide calories toward energy needs, this group of nutrients, which includes vitamins and minerals, is ...