Wound care providers know that a patient’s nutritional status can have a profound effect on wound healing. Unfortunately, research has provided few definite answers as to exactly which nutritional interventions are most effective. Nutrition assessment, diagnosis, intervention, monitoring, and evaluation are commonplace for patients within hospitals and long-term care (LTC) facilities. Unfortunately, most outpatient wound clinics don’t have protocols in place for evaluating a patient’s nutritional status and implementing timely nutritional interventions. This can be a cause for concern in instances when patients are being seen conjunctively by an outpatient wound clinic and an LTC facility. Wound care clinicians may be unfamiliar with the criteria used to determine whether nutritional status is compromised and may be unsure of which interventions are most useful if ongoing communication with LTC staff is not occurring. Additionally, many wound clinics don’t have access to a registered dietitian (RD) whose expertise is needed in evaluating and treating patients living with chronic wounds. Each patient that presents to the wound clinic will have unique nutritional needs, so clinical judgment is critical when making nutritional recommendations for all patients living with chronic wounds — particularly older adults. Comprehensive nutritional assessment can identify those needs, and regular monitoring and evaluation of weight and food intake can help determine if changes in the nutritional plan of care are needed to help facilitate wound healing. This article will discuss how to evaluate nutritional status, review nutritional needs for wound healing, and provide practical information on how to maximize nutritional status in older adults who are living with chronic wounds.
Evaluating Nutritional StatusImproving a patient’s nutritional status begins with the identification of underlying problems such as malnutrition. Pressure ulcers are frequently connected to malnutrition, but its diagnosis is not as simple as requesting an albumin and prealbumin level. Evidence now shows that serum hepatic proteins are not the “gold standard” nutritional assessment tool.1,2 Rather, low serum albumin and prealbumin are indicators of underlying inflammation related to acute or chronic illness.1 Although this information has been in the literature for at least 10 years, it has been slow to trickle down to clinicians, who often still request serum hepatic proteins and identify a patient as malnourished on these lab results. So how is malnutrition identified? In May 2013 the Academy of Nutrition and Dietetics and the American Society for Parenteral and Enteral Nutrition published a consensus statement on the subject. The paper suggests malnutrition be diagnosed using a set of criteria that includes energy (caloric) intake, weight loss, loss of muscle mass, loss of subcutaneous fat, localized or generalized fluid accumulation that might mask weight loss, and diminished functional status as measured by hand-grip strength.1 The consensus statement emphasizes that comprehensive assessment is needed to evaluate malnutrition. Changing the paradigm in healthcare facilities to use the suggested criteria is a dynamic work in progress that will take time to incorporate into facility protocols. RDs in LTC facilities and hospitals typically use weight history and meal intake to help identify compromised nutritional status. That information can be difficult to obtain in an outpatient setting, but can still serve as a basis for identifying nutritional problems. Patients should be weighed at each clinic visit and weight history should be collected from medical records. Significant weight loss (defined as > 5% of body weight in 30 days or 10% in 180 days) and slow losses over time can both be indicators of changes in food intake and/or underlying medical problems. It is also important to learn about patients’ food and fluid intake by asking simple questions about what they eat. The US Department of Agriculture (USDA; reference www.choosemyplate.gov; see Figure 1) recommends consuming a minimum of 5-6 oz of sources of protein, 2-3 servings of dairy, 2 c of fruits, at least 6 servings of grain products, and 2.5 c of vegetables daily. Specific meal patterns for various calorie levels are also available (http://choosemyplate.gov/supertracker-tools/daily-food-plans.html). It is important to understand that a patient’s intake can be suboptimal for many reasons. In the aging population, difficulty with driving, shopping, or food preparation can play a major role in the quality of the diet. Evaluating a patient’s weight over time and gathering information about his/her normal food intake can provide clues as to whether nutritional status is compromised. Knowledge of a patient’s normal intake and barriers to eating a nutritious diet can help wound care providers develop appropriate care plans.
Nutritional Needs for Wound HealingEnergy, Protein, & Fluid The process of wound healing often results in a hypermetabolic state, meaning it requires energy above and beyond what is needed for daily activities.3 There are several ways to estimate calorie needs, but the National Pressure Ulcer Advisory Panel (NPUAP) clinical practice guidelines recommend 30-35 calories per kg of body weight per day for individuals under stress with a pressure ulcer.2 Caloric requirements should be individualized and may vary depending on a patient’s medical condition, ability to ambulate, and age. A patient with a pressure ulcer or chronic wound needs to eat enough protein to maintain positive nitrogen balance. When protein intake is not adequate, the body can break down lean body mass (LBM) to help meet its calorie needs. Preventing this process is critical because loss of LBM will impede wound healing.3 Research on protein needs for wound care patients is limited, but NPUAP recommends 1.25-1.5 g of protein per kg of body weight per day.2 To meet those needs, some patients will need more protein foods than is recommended by USDA. Renal status may change protein recommendations; those with chronic kidney disease may need less protein to prevent a decline in kidney function. Fluid intake is particularly important for older adults, who may not feel thirsty and as a result not drink enough to meet their needs. Dietitians have several ways to estimate fluid needs, but 30 mL of fluid per kg of body weight per day is a quick and easy estimation. More fluid may be needed if a wound has significant drainage or the patient uses an air-fluidized mattress. Less may be needed for those with conditions such as heart or renal failure. Vitamins & Minerals In the past, multivitamins and supplements such as vitamin C and zinc (nutrients thought to be important to wound healing) have been routinely ordered for wound healing. Some facility protocols still recommend these nutrients in amounts above the upper limits of the Dietary Reference Intakes established by the USDA. NPUAP guidelines suggest vitamin and/or mineral supplements should be offered to a patient with a pressure ulcer only when dietary intake is poor or a deficiency is confirmed or suspected.2 If a patient is taking a multivitamin, the addition of supplemental zinc could contribute to mineral overload. Most nutrition experts agree that eating a variety of nutrient-rich foods as recommended by USDA is generally the best strategy for meeting nutrient needs, with supplements added only if they appear necessary.
Strategies to Promote Wound HealingNutritious food is the first intervention for a patient with a healthy appetite. Patients should strive to eat a diet that provides enough protein, calories, vitamins, and minerals to meet their unique nutritional needs using USDA recommendations as a general guideline. Because both calorie and protein needs are elevated in wound care patients, it often makes sense to suggest high-calorie, high-protein meals and snacks such as meats, eggs, milk, cheese, yogurt, dried beans, and nuts and seeds (including peanut butter). Recommendations should take into account a patient’s cultural background, food preferences, lifestyle, and economic limitations. Those who are on restrictive therapeutic diets might benefit from individualizing the diet and discontinuing restrictions, especially if the change increases nutrient intake and prevents unintended weight loss.2 If a patient tires easily when preparing food, wants a quick snack, or has a poor appetite at meal times, oral nutrition supplements (ONS) are convenient sources of calories and protein. Research supports the use of ONS for wound healing if needed because of poor intake.2 Various types of supplements are available, including milkshake-type beverages, clear beverages, bars, and puddings. Finding the form of supplement that a patient will consume is one key to the success of a nutritional intervention.
Targeted Nutrition TherapyArginine and glutamine are two amino acids that are considered conditionally essential, meaning they may be needed during periods of stress, such as during wound healing. -hydroxy--methyl buterate (HMB), a metabolite of the amino acid leucine, is thought to promote tissue-building and to help maintain muscle mass. Oral nutrition supplements containing arginine, glutamine, and/or HMB are available as adjuncts to other ONS for tissue-building and wound healing. Research on these products is ongoing and evidence-based recommendations are not available.2 However, they are frequently used to treat pressure ulcers and chronic wounds with anecdotal success reported.
Conditions That Affect Nutritional RecommendationsObesity Obese patients (those with a BMI >30) and morbidly obese patients (BMI > 40) living with wounds present a challenge to clinicians. Dietitians use the Mifflin St. Jeor formula to estimate the resting metabolic rate of obese patients, (see Table 1) using patients’ actual body weight, even if it is well above their ideal body weight for their height.4 This formula usually results in different calorie estimates from the formula that is recommended by the NPUAP. Assessment of protein and fluid needs is complicated in obese patients; some clinicians use patients’ actual body weight and others use an adjusted body weight. Research is not clear as to which method is most accurate. What is clear is that adding protein to the diet will also add calories, which could contribute to unwanted weight gain in an already obese patient. If a patient’s wound is healing, weight is stable, and there are no signs or symptoms of dehydration, his/her protein, calorie, and fluid needs are most likely being met. Although it might seem counterintuitive, drastic cuts in calories are not usually recommended in obese wound care patients. Reducing calories to promote weight loss could compromise wound healing by breaking down lean body mass and/or result in a diet that is compromised in nutrients. For that reason, in most cases, wound healing should take precedence over weight loss. Diabetes Blood sugar control is important to all patients living with diabetes, but especially those with wounds. High blood glucose can lead to defective white blood cell function and make a diabetic wound susceptible to infection. In the aging population, however, blood glucose goals may be relaxed based on expected life span and comorbidities.5 Food choices, including the timing and carbohydrate content of meals and snacks, can have an impact on glycemic control and any form of carbohydrate can affect blood sugars eaten in excess. For that reason, portion control of all carbohydrates is important. Choosing whole-grain breads and cereals over refined grains will provide added fiber, vitamins, and minerals. Patients should be taught to choose appropriate carbohydrate portions and balance food with oral medication and insulin to help optimize glycemic control. Patients living with diabetes should be counseled on the relationship between high blood sugars and wound healing and be encouraged to make healthy choices, but some patients will resist adhering to nutritional recommendations. Providers who work with the elderly know and respect the fact that for many older adults, quality of life takes precedence over blood sugar control. Rather than provide a restrictive diet, one key to managing blood sugars in many older adults with limited life spans is to adjust timing and/or doses of medication to match meal consumption.5
Tube Feeding & Wound HealingPatients with a poor intake and/or unintended weight loss may be candidates for tube feeding if it is consistent with the patient’s wishes. Studies have not supported improved outcomes for pressure ulcers in those receiving enteral support.2 The decision to place a tube ultimately lies with a patient and/or responsible party after the healthcare professional has presented the risks and benefits. Tube-fed patients with new wounds may need their feeding adjusted to meet elevated protein and calorie needs. This can usually be achieved by increasing the volume or duration of the current feeding. Specialized formulas high in protein or designed to enhance immune function may benefit wound healing. Physicians should consult the RD to select the most appropriate tube feeding formula and determine the total volume, infusion rate, and additional water flushes to meet the patient’s needs. Tube feeding should be assessed periodically to assure the feeding is being delivered correctly and that it meets the patient’s protein, calorie, and fluid needs. Nancy Collins is a registered dietitian and founder and executive director of Nutrition411.com. Correspondence may be sent to NCtheRD@aol.com. Liz Friedrich is associate director of Nutrition411.com and president of Friedrich Nutrition Consulting, Salisbury, NC.
References1. White JV, Guenter P, Jensen G, Malone A, Schofield M. Consensus Statement of the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition: Characteristics recommended for the identification and documentation of adult malnutrition (undernutrition). J Acad Nut Diet. 2012;112: 730-738. 2. National Pressure Ulcer Advisory Panel and European Pressure Ulcer Advisory Panel. Prevention and treatment of pressure ulcers: Clinical practice guidelines. Washington, DC. National Pressure Ulcer Advisory Panel, 2009. 3. Demling R. Nutrition, anabolism, and the wound healing process: An overview. Eplasty. 2009; 9: e9. 2009 Feb 3. Accessed online: www.ncbi.nlm.nih.gov/pmc/articles/PMC2642618/ 4. Academy of Nutrition and Dietetics Evidence Analysis Library. Adult weight management (AWM): Determination of resting metabolic rate. Accessed online: http://andevidencelibrary.com/template.cfm?template=guide_summary&key=621. 5. American Medical Directors Association. Diabetes management in the long-term care setting clinical practice guideline. Columbia, MD: AMDA 2008, revised 2010;13,3.