Abstract
Adequate nutrition is required for optimal wound healing. The normal processes that allow the progress of wound healing are disrupted due to nutritional deficiencies. Increased infection rates and decreased wound tensile strength are associated with malnutrition. Chronic on-healing wounds are formed in malnourished patients or individuals. Such patients can develop infections, pressure ulcers, and delayed wound healing. Morbidity and mortality among malnourished patients with chronic wounds constitute a serious clinical concern. Wound healing is considered as a complex process. It is the process of replacing injured tissue with new tissue (produced by the body). Production of new tissue is associated with the consumption of nutrients and energy (mainly proteins). The paper provides evidence on the importance of nutrients in wound healing.
Introduction
Adequate nutrition is required for optimal wound healing. The normal processes that allow the progress of wound healing are disrupted due to nutritional deficiencies. Increased infection rates and decreased wound tensile strength are associated with malnutrition. Chronic on-healing wounds are formed in malnourished patients or individuals. Such patients can develop infections, pressure ulcers, and delayed wound healing. Morbidity and mortality among malnourished patients with chronic wounds constitute a serious clinical concern. Most nutrition therapies are aimed at correcting the nutritional deficiencies to enhance the wound healing process. It is although more important since most patients with chronic skin ulcers suffer from malnutrition and micronutrient status to some degree. (Stechmiller JK. 2010)
The improper absorption and distribution or essential nutrients is termed as malnutrition. The most serious type of malnutrition is termed as protein-energy malnutrition (PEM). PEM can be defined as the impaired or inadequate absorption of both energy and protein. PEM can worsen when combined with malabsorption of fat, increased stress, impaired carbohydrate utilization, and illness. There is a direct correlation between the indication of PEM and wounds that are non-healing. The reversal of PEM combined with good wound management is associated with wound prevention and healing. An increase in energy consumption id associated with wound healing (the replacing of injured tissue and new tissue production).
The process of wound healing
The process of wound healing is often associated with the consumption of nutrients, especially, calories and proteins. It is important to have these nutritional needs in order to achieve fast wound healing. The entire process of wound healing is highly dependent on angiogenesis. (This is turn, may be suppressed if the needs are not met). (Wild T, et al. 2010)
The fibroblast exudes products composed of only peptides or proteins (collagen matrix, proteoglycans and glycosaminoglycans, cytokines and growth stimulants). It is considered as the most important cell in the proliferative stage of wound healing. The products exuded by the fibroblast are essential in the wound healing process. A hyper-metabolic/catabolic state that further increases nutritional demands is caused by the exudation of these vital nutrients in wound healing. In most cases, it is often the wound that instigates, detrimental and serious malnutrition in patients. An intact immune system and breakdown of protein from muscle is required for all wound-healing functions. An increase in nutritional demand is observed in patients infected with a pressure ulcer. Pressure ulcer is often increases tissue damage, causes further strain, and a deeper ulcer in turn increases the nutritional demands.
The principles of nutrition and wound care
The principles of nutrition and wound care are based on the different foods consumed and their role in wound healing. One of the important principle of wound healing is calorie value. Calories play an important role in nutrition. Calorie needs increase with injury or stress. Most foods contain calories. Common healthy supplements of for wound healing are smoothies and nutritional shakes. The next important aspect of wound healing is protein. Proteins play an important role in muscle mass and immune response. Common sources of food include meat, milk, legumes, and seeds. Nutritional supplements of proteins include milkshakes and smoothies. An individual consuming a healthy portion of proteins on a daily basis would have a high rate of wound healing. Fast wound healing is associated with hydration. It is important to keep the body well-hydrated in order to ensure a fast recovery from wounds. Common hydrating sources include water, juice, milk, and yogurt. If a patient is unable to consume fluids directly, intravenous fluid supplementation is important to ensure hydration and fast wound healing.
The E’s of nutrition
Often, initial and repetitive encouragement at mealtime is needed to increase nutrition in the elderly. Tips to increase nutrition are mentioned here below:
- Encourage food likes, and eliminate food dislikes.
- Encourage full portion consumption of all protein foods
- Encourage a sitting or upright position for eating.
- Encourage time for chewing, self-feeding (e.g., finger foods) and meal completion.
- Encourage frequent drinking of fluids.
- Ensure resident has dentures and/or mouth care as required for meals.
(Adapted from: Hurd A. T. Nutrition and Wound-care Management/Prevention)
During the process of wound healing, many researchers have proven the role of nutrition. Moreover, there is a large body of evidence demonstrating the essential role of nutrition in wound healing. Healing may be prolonged or impaired without inadequate nutrition. Accelerated wound healing is observed in patients with nutritional supplements. Thus, improved nutritional status enables the body to heal wounds at a fast pace.
Wound healing is considered as a complex process. It is the process of replacing injured tissue with new tissue (produced by the body). Production of new tissue is associated with the consumption of nutrients and energy (mainly proteins). Changes in healing process, energy, fats, carbohydrate, and protein metabolism are associated with wound and the process of wound healing. Stress hormones are released in a fight-or-flight reaction when the body sustains a wound, and the metabolism alters in order to supply the injured area with the nutrients it needs to heal– known as the catabolic phase. The body experiences an increase cellular and collagen turnover followed by an increased metabolic rate and loss of total body water. Similar effects are observed in a small wound. (Arnold M, et al. 2006)
Protein energy malnutrition (PEM) and wound healing
The body can enter a protein energy malnutrition (PEM) state if the catabolic phase is prolonged and/or the body is not provided with adequate nutrient supplies. Severity of the wound and the pre- existing nutritional status of the individual are factors that cause prolonged catabolism. Unintentional weight loss (of 5% or more) with loss of subcutaneous fat and/or muscle wasting or low Body Mass Index (BMI) is defined as PEM.
Wound healing is more likely to be delayed as an individual loses more lean body mass (LBM). Wounds compete with muscles for nutrients with a 20% or greater loss of LBM. The body will often prioritize the rebuilding of body over wound healing with available protein if LBM loss reaches 30% or more. Thus, it can be concluded that poor nutrition can have negative impacts on wound healing. Older people suffer from malnutrition, even though in today’s society we are fortunate to have access to a large number of nutritional foods. Up to 60% of older patients in hospitals are at risk of malnutrition or are completely malnourished. Between 40 and 85% have malnutrition in nursing homes while 20 to 60% of house care patients are malnourished.
Individuals or patients who need nutritional assessment (For wound care/healing)
Indicators of the need for nutritional assessment include
- Weight loss >5% or more
- Meals eaten less than 50%/two meals a day/refusal to eat a meal/refusal to eat for more than three days
- Poor appetite, consuming 1/2 or less at two or more meals/day for three days
- Nausea or vomiting for more than three days
- Poor fluid intake of less than 1,500 ml fluid/24 hours over past seven days
- Chronic infections (respiratory, urinary tract, etc.)
(Adapted from: Hurd A. T. Nutrition and Wound-care Management/Prevention)
The nutritional evidence on wound healing
There are a number of nutrients that play an important role in wound healing. The following is a summary of these nutrients.
Protein: Protein is essential for the repair and maintenance of body tissue. A decrease in collagen development is associated with depleted protein levels that slows the wound healing process. Optimal wound healing rates are only possible if adequate protein levels are maintained.
Amino acids
L-Arginine: It is an amino acid that plays an important role in structural protein synthesis. It also has several properties that enhances a number of the pathways involved in wound healing. The demand for normally non- essential amino acids, such as l-arginine, becomes essential as the body needs more protein during wound healing. Enhanced protein metabolism helps to decrease muscle loss. Dietary supplementation with arginine increases collagen synthesis and increases the strength of the wound. (Wild T, et al. 2010)
Fats: Fuel for wound healing is provided by fats, including mono- and polyunsaturated fats. Fats are a concentrated and safe source of energy. For example, fat has more energy at 9cal/g than carbohydrate at 5cal/g. To prevent the body using protein for energy, adequate fats are needed. Demands for essential fatty acids increase after injury and fatty acids are a major component of cell membranes. As the body cannot synthesize enough for the needs of wounds essential unsaturated fatty acids must be supplied in the diet. There is some evidence that omega 3 fatty acid may reduce the wound strength. However, the benefit of omega 3 fatty acid supplementation in wound healing is still not clear. (Wild T, et al. 2010)
Carbohydrates: It is a major source of calories for use by the body. The availability of carbohydrates is essential to prevent other nutrients (e.g. protein) from being converted into energy. Increased carbohydrate intake provides energy that is essential for optimal healing but it is not clear how carbohydrate deficiency influences wound healing
Antioxidants
Vitamin C: Vitamin C plays an important role in the formation of blood vessels (angiogenesis), collagen synthesis and subsequent crosslinking. Adequate vitamin C levels help strengthen the healing wound.
Vitamin A: It increases the inflammatory response in wounds by stimulating collagen synthesis. Delayed wound healing and susceptibility to infection are associated with low vitamin A levels.
Vitamin E: It is possible that vitamin E can reduce injury to the wound by controlling excessive free radicals.
Minerals.
Zinc: It has a well-established role in wound healing. Zinc plays a key role in protein and collagen synthesis, and in tissue healing and growth.
Iron: Iron deficiency can also result in impaired collagen production and strength of the wound. Iron deficiency can impair healing since it is also part of the system that provides oxygen to the site of the wound. (Kavalukas SL, & Barbul A 2011). Thus, it can be concluded that nutrients play an important role in wound healing.
References
- Stechmiller JK. Understanding the role of nutrition and wound healing. Nutr Clin Pract. 2010 Feb;25(1):61-8.
- Hurd A. T. Nutrition and Wound-care Management/Prevention. Wound Care Canada. 2 (2). Pdf file. Available at: http://cawc.net/images/uploads/wcc/2-2-hurd.pdf
- Wild T, Rahbarnia A, Kellner M, et al. Nutrition. 2010 Sep;26(9):862-6.
- Arnold M, Barbul A. Nutrition and wound healing. Plast Reconstr Surg. 2006 Jun;117(7 Suppl):42S-58S.
- Kavalukas SL, Barbul A. Nutrition and wound healing: an update. Plast Reconstr Surg. 2011 Jan;127 Suppl 1:38S-43S
