Podcast Episode 47: Nutrition and Wounds

Hello, my name is James Duchatel and I am a clinical dietitian working predominantly within the hospital sector in Sydney, Australia but also working within my own private practice. I specialise in providing nutritional care for those recently discharged from hospital who require ongoing nutrition support at home, for example, people with wounds. In this recording, I am pleased to present facets of the science behind nutrition and its crucial role in wound healing. I will be covering the significance of nutrition and wound healing, outlining individuals with wounds and where they may be nutritionally compromised or where implications arise, including barriers to healing, how the dietician assessment and optimal nutrition can be utilised for the prevention of wounds, all the way through to the role of nutrition and specific strategies within the wound healing phase. I will also be making reference to specific statistics and pieces of evidence from multiple studies that are readily available on PubMed and Wiley online library. There are some fantastic papers that explore very deeply nutrition and its link with wound healing for those that want to learn more. When thinking of wounds, you would not refer someone for a dietetic assessment for a scratch. We are talking about those slow to heal wounds that are either breaking down or simply not healing. These wounds have often been present for weeks to months and really take their toll on an individual's skin integrity, infection risk and nutritional status. For example, ulcers, burns, pressure injuries and surgical wounds that won't heal weeks later. To begin, I thought I would provide a little background into who dietitians are and what is encompassed within our profession. As dietitians, we utilize scientific principles, methods and evidence-based best practice guidelines in the assessment of individuals. Specifically pertaining to my own practice, I frequently work with individuals in the treatment of multiple wound types within a broader multidisciplinary team providing guidance to the individual, members of family and other health professionals. A standard assessment would involve establishing a collateral history with the patient. Have they recently lost weight unintentionally? Have they been experiencing a reduced appetite? Are their biochemical parameters normal? Do they meet their baseline nutritional requirements, let alone elevated requirements for optimal healing? Do we need to consider micronutrient supplementation or oral nutrition support? Let's get into the specifics. Nutrition Nutrition plays an essential role in wound healing and wound care practices and nutritional screening and support must be considered a fundamental part of wound management. Studies show poor nutrition before or during the healing process may delay healing and impair wound strength, making the wound more prone to breakdown and infections. Neglecting the nutritional health of an individual with a wound can compromise the entire wound management process. Poor nutrition can often be referred to as malnutrition or undernutrition in which there any imbalance in a person's intake of energy, known as calories or kilojoules, and or nutrients. Malnutrition is far more common than one would think, with recent evidence suggesting that the prevalence of malnutrition in the acute hospital can be as high as 20% to 50% of patients, with the highest proportion of malnourishment found within nursing home populations, up to 85% of these individuals showing poor nutritional status. I've highlighted the elderly population here, as this group tends to have the highest risk of wounds and impair healing with a statistically higher prevalence of malnutrition also. However, other population groups are at very high risk of wounds and impaired healing with poor nutrition too, including individuals with single or several comorbidities which I will outline further on. In my own experience, patients with chronic wounds are often deficient in protein and chelogels, the two key components involved in wound healing. For other population groups, development of nutritional deficiencies may arise from medical, psychological, physiological, social and socio-economic difficulties. For example, leading causes of malnutrition within acute settings is decreased food intake associated with loss of appetite. This reduced food intake may be related to several commonalities including reduced energy expenditure or activity, particularly with age, pain which can be exacerbated with the presence of wounds, social isolation, certain comorbidities including depression, obesity, dementia, stroke or dysphagia and other oral dysfunctions, as well as deterioration of sense of taste and smell. So how do you get a dietitian involved? In the hospital setting or any long-term care facility, a malnutrition risk assessment should be completed regularly for every patient. This may be something like the malnutrition screening tool or MST or malnutrition universal screening tool known as MUST, which assesses an individual's malnutrition risk through questions on amount of weight loss and reduced intake and appetite. Patients should also be regularly checked for pressure injuries and their skin integrity checked for breakdown. In the community, it may be the GP or community nurse which refers on to a dietitian when wounds become chronic or start to break down. Following on from the use of these tools and referral to a dietitian, a complete nutritional assessment is conducted. This analyses anthropometrical data, commonly weight, BMI, waist and hip, analysis of biochemical nutrition markers with particular focus on electrolytes, protein, renal and liver markers and blood count, clinical symptoms such as appetite, potential GI symptoms, chewing and swallowing difficulties and presence of wounds and risk of pressure injury and pressure areas, and also a comprehensive diet history. This can involve gathering information on food and meals consumed on average during the day and week, which is used to analyse nutritional adequacy through the breakdown of key nutrients. Before discussing dietary interventions of wound healing, following on from the nutritional assessment, I believe it is important to acknowledge the prevention of the development or breakdown of wounds. There's certainly risk factors associated with diet and nutrition that may lead to chronic wounds including malnutrition and undernourishment, diabetes which can be exacerbated with poor control including hyperglycemia, renal impairment or disease with early and end-stage kidney disease manifesting to losses of protein, electrolyte disturbances and edema, as well as weight. Underweight individuals often with an increased risk of pressure injury and pressure area development, for example, and overweight and obesity impacting total nutritional requirements and decreased vascularity of adipose tissue. Therefore, the early identification and management of risk factors is of the utmost importance in the prevention of wounds. The European Pressure Ulcer Advisory Panel is one body that echoes this sentiment and in fact recommends the screening and assessment of the nutritional status of every individual at risk of pressure ulcers in the healthcare settings. An example of screening tools used in Australian hospitals may be the Waterlow scale or the Norton scale. Screening should be repeated weekly for inpatients and when there is clinical concern for outpatients and care home residents to ensure that the patient's nutritional intake is adequate to meet the metabolic demands of wound healing. Having run through the how and why of nutrition we can now look into the key nutrients and dietary considerations and how they play a direct role in the wound healing and intervention phase. During the wound healing phase the human body demands an increased consumption of energy and protein as well as particular nutrients. The body undergoes a catabolic phase when it sustains wound. Essentially the body releases stress hormones as well as metabolism changes to supply the injured area with nutrients to heal. If this phase is prolonged or the body doesn't have adequate nutrients, the body can enter what's known as a protein energy malnutrition or PEM state. Put simply, PEM is when there is insufficient intake or absorption of protein, energy and micronutrients to meet metabolic demand. PEM causes the body to break down protein to use for energy when insufficient, reducing the supply of amino acids needed to maintain body proteins and healings. This causes loss of lean body mass. To give an idea on the metabolic demand, the presence of a chronic wound can increase protein requirements by 120 to 200 percent and calorie requirements by approximately 50 percent in order to maintain and appropriate lean body mass. This is key as the significance of the losses of 10% lean body mass are associated with impaired immunity and risk of infection. Losses of 20% resulting in a decreased rate of wound closure and cause the skin to thin with wounds competing with muscles for nutrients. Losses of 30% halting the healing with the body postponing the healing process to address lean body mass and also predispose the individual to new wound formation. And finally, losses of 40% plus, often resulting in death. This really highlights the need to meet energy and protein requirements specifically to reduce the risk of losses of weight and muscle in wound management. To summarise the link between energy and protein, energy needs for healing increase according to the size and complexity of the wound, with the main demand for energy for collagen synthesis for the wound. Our main sources of energy are carbohydrates, fats and proteins. As mentioned, if energy is insufficient then additional protein will be broken down, resulting in reduction of muscle and overall body mass. Common recommendations in acute and community settings involve choosing energy-dense foods such as full cream dairy products, low GI carbohydrates such as whole grain breads, cereals, rice, pasta and potatoes, healthy fats such as avocado, nuts, plant-based spreads and oils, as well as enriching and fortifying meals. In the hospital I work at we use a skin milk powder that isn't dissolvable enriching milks, soups and sauces. Now protein, this is essential for the maintenance and repair of body tissue. When depleted, protein will cause a decrease in collagen development, slowing the wound healing process. Adequate protein levels will help achieve optimal wound healing rates. For example, slow to heal and chronic wounds can require 1.5 grams of protein per kilo of body weight for most individuals, comparative to an average recommended intake of 0.75 to 1 grams per kilo of body weight. For example, a person weighing 80 kilograms would require approximately 120 grams of protein daily. Protein requirements should be calculated on an individual basis and needs to happen along with calories because if energy needs aren't met the body will use protein for energy rather than for wound healing. Good sources of protein in our diet include meat, fish, chicken, eggs, dairy products including milk, yogurt and cheese, beans, legumes, nuts, seeds and grains, as well as meat alternatives such as tofu. To put the protein content of food versus requirements into perspective, 100 grams of chicken breast contains approximately 25 to 30 grams of protein. So when we refer back to the example of person weighing 80 kilos, that provides up to a quarter of their requirements. This proposes difficulties for individuals to meet the requirements who may be nutritionally compromised due to poorer intake as mentioned earlier, or with higher daily nutritional targets, highlighting the need for a specific tailored dietary plan. Moving on to a specific type of protein or amino acid L-Arginine. L-Arginine is an amino acid that has several properties that enhances a number of the pathways involved in wound healing such as its role in structural protein synthesis. Dietary supplementation with arginine has been shown to enhance protein metabolism, helping to decrease muscle loss and collagen synthesis which helps to increase the strength of the wound. In addition, L-Arginine is essential for the stimulation of the nitric oxide pathway, which is in turn important for collagen deposition in wound healing. Due to the nitrogen load on the kidneys however, prescription of such a protein should occur under the guidance of a dietician. L-Arginine supplementation has also been shown to enhance the immune system and improve the secretion of growth hormone and insulin that are also involved in wound healing. A typical dietary intake provides approximately four grams of L-Arginine, whereas evidence suggests supplementing with 9g of L-Arginine promotes wound healing. Typically prescribed supplements such as Arginate are used to achieve this in conjunction with a higher protein diet. Following on from the main or macronutrients necessary in wound healing, let's break down the essential vitamins and nutrients that are also involved. Vitamin C. Vitamin C also plays an important role in collagen synthesis as well as the formation of new blood vessels. Adequate vitamin C levels will help strengthen the healing of the wound, with research showing vitamin C supplementation helps promote pressure ulcer healing, whereas vitamin C deficiency has been found to impair wound healing and has also been associated with an increased risk of wound infection. Excellent sources include fruit and vegetables, particularly oranges, tomatoes, grapefruit, capsicums and leafy veg. 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. It has also been shown that vitamin A can restore wound healing impaired by long-term steroid therapy or by diabetes. Serious stress or injury can cause an increase in vitamin A requirements highlighting the importance to include sources of these foods in the diet. Vitamin A is found in milk, cheese, eggs, fish, dark green veg such as spinach, broccoli and kale, oranges and red and orange fruit and veg such as carrots, sweet potato, apple and red capsicum. Zinc plays a key role in protein and in collagen synthesis and in tissue growth and healing. Zinc deficiency, like other nutrients, has also been associated with delayed wound healing, reduced skin cell production, and reduced wound strength. Insufficient dietary intake of zinc can be further exacerbated by zinc loss from excess wound drainage. Sources include red meat, fish, shellfish, milk products, poultry, and eggs. Iron is part of the system that provides oxygen to the site of the wound. Therefore, iron deficiency can impair wound healing. deficiency can also result in impaired collagen production and strength of the wound. Iron absorption from non-meat sources can be enhanced with vitamin C with the best sources of iron in the diet being red meat, offal, fish, eggs, wholemeal bread, dark green leafy veg, dried fruits, nuts and yeast extracts. Another key dietary factor in wound healing is hydration. 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. A general guide to providing fluids is 30 to 35 mils per kilograms of body weight per day, however fluid requirements should be calculated on an individual basis. Reverting to the example of an individual weighing 80 kilos they will require approximately 2400 milliliters to 2800 milliliters based on 30 to 35 mils per kilo. Sources of hydration include water, juice, milk, jelly, ice cream, yogurt and soup. So to summarise, optimising nutrition is an important part of best practice care and wound management. The overall goal for the healthcare team should be to make sure the individual is in the optimum nutritional state to give wounds the best chance to heal. This can be achieved by providing the individual with adequate calories and nutrients which can prevent protein energy malnutrition and promote wound healing. Holistic wound care must include nutritional risk assessment and both nutritional support and supplementation where necessary according to an individual's needs. A nutrient rich diet is fundamental but sometimes it is not possible to achieve adequate level of essential nutrients through normal consumption of food and liquids. In these cases, high protein, high energy milk or juice nutritional supplementation have been shown to promote wound healing. Extra care needs to be taken when addressing the nutritional needs of an individual with pre-existing comorbidities. As mentioned earlier, diabetes, we're focusing on wound healing with type glycemic control or kidney disease paying particular attention to fluid, protein and specific nutrient intake so as to not further compromise kidney function whilst also aiming to achieve wound control. So for those who work within the wound management sector or for those with wounds don't forget nutritional intervention should be reviewed as part of the overall care plan. Regular ongoing evaluation is necessary especially as the benefits of nutritional support may take time to appear in those who are malnourished and have chronic wounds. Early intervention is key. Screen your patients for nutritional risk factors and refer to a dietician for any wounds that have been present for three months or more or if the patient is thought to be at nutritional risk. Referring to a dietician is important to ensure that the nutritional intervention is appropriate, relevant and done in a timely manner. This will assist in maximising efficacy of the team interventions and optimise the healing of the individual's wound. You can find an accredited practicing dietitian or registered dietitian near you through your country's governing body such as Dietitians Australia or talk to a local GP or specialist. I hope you've all found this information as a summary informative. Nutrition is multifactorial with wounds and could be discussed at greater lengths particularly when we're looking into other comorbidities impact on wound healing. I'd certainly encourage those interested to look into the many papers published for a deeper exploration into the interaction of of diet and nutrition for wound healing. Thank you for listening.