Nutrition and Wound Healing
Nutrition plays an essential role in wound healing and care, and nutritional support needs to be considered a fundamental part of wound management. Poor nutrition before or during the healing process can delay healing and impair wound strength, making the wound more prone to breakdown. There is a significant body of evidence supporting the essential role of nutrition in wound healing.
Wound healing is a complex process – put simply, it is the process of replacing injured tissue with new tissue produced by the body which demands an increased consumption of energy and particular nutrients, including protein and kilojoules. When the body sustains a wound, the body releases stress hormones and metabolism changes in order to supply the injured area with the nutrients it needs to heal – this is known as the catabolic phase. If the catabolic phase is prolonged and/or the body is not provided with adequate nutrients, then the body can enter a protein energy malnutrition (PEM) state.
Protein-energy malnutrition (PEM) is when there is an inadequate or impaired absorption of both protein and energy. PEM causes the body to break down protein to use for energy, reducing the supply of amino acids needed to maintain body proteins and healing; this causes loss of lean body mass. PEM may be directly linked to wounds that aren’t healing. It can be defined as low Body Mass Index (BMI) or significant unintentional weight loss (of 5% or more) in conjunction with loss of subcutaneous fat and/or muscle wasting.
As an individual loses more lean body mass (LBM), wound healing is more likely to be delayed. With a 20% or greater loss of LBM, wounds start to compete with muscles for nutrients.
The Nutrition Facts
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 maintenance and repair of body tissue. Low protein levels will cause a decrease in collagen development, slowing the wound healing process. Adequate protein levels will help achieve optimal wound healing rates. Overall energy intake is also important, because if energy needs aren’t met the body will use protein for energy rather than for wound healing.
Sources of protein include red and white meats, fish, eggs, liver, dairy products (milk, cheese, and yoghurt), soy beans, legumes, nuts and seeds.
Energy
The main sources of energy for the human body – and for wound healing – are carbohydrates and fats. The main demand for energy from a wound is produced by collagen synthesis. Energy needs for healing increase according to increasing size and complexity of the wound. “High Energy” foods can be valuable for residents with wounds.
Fats
Fats, including mono- and polyunsaturated fats, provide vital fuel for wound healing. Fats are a safe and concentrated source of energy. Adequate fats are needed to prevent the body using protein for energy. Fatty acids are a major component of cell membranes, and demands for essential fatty acids increase after injury.
Good sources of fats to promote wound healing include meat, full-fat dairy products such as milk, cheese, butter, cream, yoghurt, ice-cream, and oils and fats used in cooking or as spreads
It is important to aim for weight maintenance during wound healing. If a person is overweight they should not try to lose weight until their wound has completely healed. A person who is underweight should try to put on enough weight to bring them into the normal range.
L-Arginine
L-Arginine is an amino acid that has properties that enhances some of the pathways involved in wound healing, such as its role in structural protein synthesis. As the body needs more protein during wound healing the demand for normally nonessential amino acids, such as l-arginine, becomes conditionally essential. Dietary supplementation with arginine has been shown to enhance protein metabolism, helping to reduce muscle loss, and collagen synthesis, which then helps to increase the strength of the wound. This is why arginine-containing nutritional supplements, such as Arginaid, may be useful.
Vitamin C
Vitamin C plays an important role in collagen synthesis and subsequent cross-linking, as well as the formation of new blood vessels (angiogenesis). Adequate Vitamin C levels will help strengthen the healing wound. Vitamin C deficiency has been found to impair wound healing and has also been associated with an increased risk of wound infection. Research has shown vitamin C supplementation helps promote pressure ulcer healing.
Vitamin C is found mostly in fruit and vegetables, especially oranges, grapefruit, tomatoes, and leafy vegetables. Fruit juices with added vitamin C are also a good source, although often they contain only small amounts of vitamin C.
Vitamin A
Vitamin A increases the inflammatory response in wounds, stimulating collagen synthesis. Low vitamin A levels can result in delayed wound healing and susceptibility to infection. Serious stress or injury can cause an increase in vitamin A requirements. While the mechanisms of vitamin A in wound healing are still not well understood, it is clear that it plays an important role. Supplementation with vitamin A requires caution, as there is a risk of toxicity.
Vitamin A is found in milk, cheese, eggs, fish, dark green vegetables, oranges, red fruits and vegetables
Zinc
Zinc is a trace element, found in small amounts in the body, which plays a role in wound healing.
Zinc is involved in protein and collagen synthesis, and in tissue growth and healing. Zinc deficiency has been associated with delayed wound healing, reduced skin cell production and reduced wound strength.
Dietary zinc sources include red meat, fish and shellfish, milk products, poultry and eggs.
Iron
Iron is a mineral that provides oxygen to the site of the wound; therefore iron (haemoglobin) deficiency can impair healing. Iron deficiency can also result in impaired collagen production and strength of the wound. The best sources of iron in the diet are red meat, offal, fish, eggs, wholemeal bread, dark green leafy vegetables, dried fruits, nuts and yeast extracts.
Other important factors
Hydration is important in wound healing, as dehydrated skin is less elastic, more fragile and more susceptible to breakdown. Dehydration will also reduce efficiency of blood circulation, which will impair the supply of oxygen and nutrients to the wound. One of the main risk factors for dehydration is poor oral intake.
Implementing nutrition strategies to promote wound healing
Optimising nutrition is important to best practice care in wound management. The overall goals should be to make sure the resident is acheiving optimum nutritional intake, to give wounds the best chance to heal. This can be achieved by providing the individual with adequate energy and nutrients, and preventing protein-energy malnutrition, to promote wound healing.
Any unintentional weight loss is of concern for all residents. It is important to note that overweight or obese individuals can still have protein and nutrient deficiencies that can often be missed. Unintentional weight loss in these individuals may be equally detrimental, as they will lose protein stores instead of fat, when suffering from a wound.
To help resident’s meet their nutritional needs to promote wound healing, it is helpful to identify and then address any barriers to intake. These can include confusion, poor appetite, dysphagia, lack of dexterity, cultural preferences, poor dentition, depression, pain etc.
High protein and energy foods should also be regularly offered, including:
High quality meats
Full cream milk, cheese, yoghurt, dairy desserts, butter
Bread, wholegrain cereals
Shakes, smoothies, fortified milks (e.g. with milk powder)
Here are some other strategies that can be used to promote good oral intake and meeting wound healing requirements:
Offer assistance and allow sufficient time for meals. Ensure the resident is positioned properly and is comfortable.
Provide encouragement, without forcing
Offer a variety of nutrient dense, high calorie and high protein meals
Encourage grazing – small frequent meals/snacks
Provide foods that patients like
Allow time for individuals to eat in a relaxed manner, with time to chew, feed themselves and finish their meal
Provide a pleasant mealtime environment
Explain that eating well, and eating the right foods, will aid recovery and healing
Provide assistance with the opening of containers, lids.
Some residents may find it difficult to meet high energy, protein and nutrient demands to promote adequate wound healing; in this situation nutrition supplementation may be suitable. If this is the case, refer to your facility Dietitian to assist with assessing the individual’s needs.