Nutrition
Nutrition has a vital role to play in the process of wound healing (Acton, 2013). Good nutrition facilitates healing, and malnutrition inhibits and complicates the process (Williams & Leaper, 2000).
Nutrients play vital roles in the constitution of a well-balanced diet, and any depletion in a person’s nutritional intake, especially proteins, can lead to malnutrition and protein energy malnutrition conditions, which are known to have an impact on health and well-being and on the wound healing process (Acton, 2013). Any deficiencies in the amount and quality of nutrients will prolong the healing process.
Risk factors for malnutrition include:
- Poor appetite
- Inability to feed oneself
- Requiring assistance to eat
- Impaired sense of taste and smell
- Inadequate or excessive intake of calories, protein, fluid or micronutrients
(Quain, 2015)
Nutritional deficiency may also be associated with other conditions, like those previously listed in the section titled Underlying Disorders.
It is a misconception that only underweight individuals can be malnourished. The imbalance between what is nutritionally required and what is consumed can include people eating too much food, particularly from certain food groups, such as fats and refined carbohydrates, as well as too little. (Bishop et al., 2018)
A holistic nutrition assessment is paramount to the early detection of nutritional deficiency. Furthermore, the use of recognised nutritional assessment tools, can significantly increase practitioners’ awareness in this area (Acton, 2013). The Malnutrition Universal Screening Tool (MUST) is an example of such. It is a five-step validated screening tool used to ascertain adults who are malnourished or at risk. It is widely used within the UK.
Most hospital and community/primary care trusts will have a nutritional risk assessment tool, which should be used to assess a patient’s nutritional risk when they commence care. The patient should then be weighed, and the assessment repeated regularly, usually once a week.
As a result of being deprived of one or more essential nutrients, some wounds may become ‘stuck‘ at a certain stage during the wound healing cascade (Acton, 2013).
The role certain nutrients play in wound healing will now be described in more detail:
Carbohydrates provide energy for the body. One of the main carbohydrates that is utilised is glucose. As wounds heal, new tissue has to be generated, which requires energy. Glucose is the primary source of energy for all cells and is required for leucocyte, macrophage and fibroblast function.
Carbohydrates are ‘protein sparing’, meaning that, in the absence of satisfactory energy, the body will then convert fat and protein to be used as sources of energy. If protein stores are not replaced, deficiency will occur, this can slow wound healing. A diet comprised of a sufficient amount of carbohydrates is vital to maximise wound healing. (Wound Educators, 2015)
Protein is a macronutrient with several key functions within wound healing. It is fundamental in the synthesis of enzymes and formation of collagen, connective tissue, capillaries and epithelial cells. Amino acids provide the building blocks of antibodies, macrophages and a healthy immune system (MacKay, 2019; Acton, 2013).
Inadequate intake of protein has been shown to significantly delay wound healing by prolonging the inflammatory phase (Acton, 2013). A protein deficiency may impair adequate collagen synthesis, leading to reduced tensile strength of a closed wound and increasing the risk of a wound becoming chronic (MacKay, 2019).
Adequate fat intake in the patient with an acute or chronic wound can supply additional energy to the wound healing process, as well as structural functions, including axonal myelination and lipid bilayers in cell and organelle membranes during tissue growth.
Dietary fats can produce adenosine triphosphate (ATP) via beta-oxidation, thereby addressing other energy-requiring processes to spare protein for wound healing. Fat intake is also important in the role of absorbing fat-soluble micronutrients, including vitamin A, omega-3 and omega-6 fatty acids.
Omega-6 fatty acids are an important precursor to production of prostaglandins, thromboxane and leukotrienes in the inflammatory response, resulting in platelet aggregation and inflammatory vasoconstriction. Omega-3 fatty acids, on the other hand, dampen inflammatory responses and result in vasodilation through cytokine release (Quain, 2015; Bishop et al., 2018).
Vitamin A is required for epithelial and bone tissue development, cellular differentiation and immune system function (Acton, 2013; MacKay & Miller, 2003). Early research suggests that Vitamin A benefits the wound by enhancing the early inflammatory phase, including increasing the number of monocytes and macrophages at the wound site, modulating collagenase activity, supporting epithelial cell migration, and improving localisation and stimulation of the immune response (Acton, 2013; Demetriou et al., 1984; Levenson et al., 1984).
Vitamin B complex is required for collagen linkage, protein synthesis, DNA synthesis and also for ensuring a healthy immune system (Acton, 2013; Kemp, 2001; West, 1990). Vitamin C is essential for collagen synthesis (Baranoski & Ayello, 2008). Vitamin E is an antioxidant and is responsible for normal fat metabolism and collagen synthesis (Baranoski & Ayello, 2008).
Vitamin D plays a role in maintaining homeostasis on a variety of the body's systems, for instance, accelerating wound healing, the immune system (by regulating the physiology of the immune response and decreasing any overregulation of the T-cells responses), and helps with bone formation. Vitamin D assists with structural integrity and transport functions of epithelial barriers, modulating the proliferation of keratinocytes. (Siregar & Hidayat, 2023. Quain &Khardori, 2015)
Copper is required for the synthesis of haemoglobin and collagen (Hess, 2005).
Iron is required for the creation of red blood cells and is an integral part of haemoglobin, which allows oxygen to be transported around the body. It is also involved in collagen synthesis (Todorovic, 2003).
Zinc is identified as a major trace element in the wound healing process because of its involvement in many different cellular processes (Gray, 2003; Collins, 2003). Zinc is required for DNA synthesis and replication and, therefore, essential for growth (Gray, 2003). Zinc is also necessary for antibody production and immune cell function (Collins, 2003). Throughout the proliferation and maturation phases, zinc is also required for collagen synthesis (Bradbury, 2006).
An adequate supply of nutrients is found in a normal, well-balanced diet. Patients should be referred to a dietician if the wound is not progressing to healing or if their diet appears not to contain the right nutrients and they are gaining or losing excessive amounts of weight.