Nutritional deficiency is the term used when the reserves of nutrients stored in the body are insufficient to support healthy cellular function. A wound requires nutrients to be redirected from their normal functions to use in the various stages of the healing process. However, when the individual is malnourished, any trauma may prove disastrous as they lack the reserves to respond to the metabolic demands of the wound. It is worth noting that malnutrition refers to insufficient calories, protein, or other nutrients needed for tissue maintenance and repair. The World Health Organization has outlined different forms of malnutrition. This includes malnutrition related to undernutrition, wasting, and overweight and obesity (amongst others).
Wound Healing and Nutritional Support
The body requires macronutrients and micronutrients to support body functions and systems. Macronutrient refers to the energy yielding nutrients such as carbohydrates, proteins, and fats, whereas micronutrients refers to non-energy yielding nutrients such as vitamins and minerals. Micronutrients generally support the functions of macronutrients and as such, are vitally important to the wound healing process. Fluids/water serves as the solvent for vitamins, minerals, glucose and other nutrients. As such, fluids/water play an important role in wound healing. See below for the breakdown of the roles played by macro- and micronutrients in wound healing:
- Proteins: Vital to the healing process. Supports platelet function, fibroblast proliferation, and wound remodeling. Helps with formation of lymphocytes, collagen, and new vasculature.
- Carbohydrates: Provide energy for recovery. Glucose is vital to wound healing as it supports cell growth, fibroblasts, and leukocytes. It plays a vital role in cell communication as a part of the immune response. Energy needs must be met in order to spare protein for wound repair and healing.
- Fats: Helps meet the increased caloric demand that results from post-trauma hypermetabolism. Influences the localized metabolism of the wound. Helps modulate inflammation and the immune response.
- B Vitamins: Moderates local wound metabolism and tissue synthesis. Participates in collagen synthesis.
- Vitamin C: Helps stabilize collagen, and support the tensile strength of the wound tissues. Modulates free radical metabolism.
- Vitamin D: Regulates growth and differentiation of cells, including lymphocytes, melanocytes, and fibroblasts.
- Vitamin K: Required for blood clotting.
- Zinc: Supports protein synthesis and immune functions. Vital for cell growth and proliferation, liberates vitamin A from the liver, interacts with platelets in flood clotting. Mega doses of zinc may inhibit healing and cause copper deficiency anemia.
- Iron: Delivers oxygen to tissues. Generation of energy from cells, transferrin, a blood protein, transfers iron to the tissues of the bed.
- Copper: Helps facilitate angiogenesis. Assists with cross linking of collagen fibers to rebuild tissue.
- Fluid serves as the solvent for minerals, vitamins, amino acids, and glucose, maintains fluid and electrolyte balance.
Nutritional Interventions in Wound Management
Screening tools that are quick, easy to use and have been validated should be used to identify individuals with wounds who are at risk for malnutrition. Once it has been determined that the individual is at risk, they should be referred to the registered dietitian/nutritionist who will complete an in-depth nutrition assessment and determine the appropriate calories, protein and other nutrients needed for healing. A variety of validated tools are available for the conduct of a nutritional screen. These include: the Malnutrition Screening Tool (MST), the Short Nutritional Assessment Questionnaire (SNAQ) and the Mini-Nutritional Assessment-Short Form (MNA-SF®).
The MST and the SNAQ were developed to help health care providers quickly screen nutritional status in acute care settings. The MST tool has three screening parameters: body mass index (BMI) with alternative measures noted if BMI is not appropriate, weight loss, and the acute disease effect score. The total of the three scores identifies low, medium or high risk nutritional status and includes appropriate interventions linked to each level of risk.
The MNA-SF ® is validated in both the community and healthcare setting specifically for adults over 65. The questions on the MNA-SF® address appetite, weight loss in the past three months, mobility, psychological stress or acute disease, neuropsychological problems, and BMI. Additional tools are the Subjective Global Assessment (SGA) and the Nutrition Risk screening (NRS-2002).
Weight loss, low BMI, and reduced appetite, which are predictors for the risk of malnutrition, are common characteristics of these validated tools.
Once a nutrition assessment is completed, and the gap between the nutrients needed and the nutrients consumed is identified, efforts to meet the nutrient gap should be part of the plan of care. Oral nutritional supplements (ONS), enhanced and fortified foods can be used to prevent or manage unintended weight loss and malnutrition in individuals who are unable to consume their estimated nutritional requirements consuming a regular diet.
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