News Archive

E-News Exclusive

Nutritional Effects on Wound Healing

By Robert A. Norman, DO, MPH, MBA, and Trupal Patel

Nutrition is a critical component in all wound-healing processes for both younger and elder patients. The body falls into a hypermetabolic and catabolic state when it is healing1, and nutritional needs are increased as a result of any significant wound. Protein energy malnutrition (PEM) can lead to a loss of lean body mass (LBM) and depleted protein stores that can prevent proper healing.

PEM is most commonly seen in the chronic wound population, especially older adults, the disabled, or the chronically ill, hospitalized, or nursing home populations where chronic wounds tend to develop. Aging can also cause decreased endogenous anabolic activity.

Nutritional assessment and support should be well orchestrated and precise for these patients. The use of anabolic agents can significantly increase overall lean mass synthesis and directly or indirectly improve healing by increasing protein synthesis. The purpose of this review is to inform readers about various nutritional supplementations required in wound healing.

Skin and Wound Types

The skin is the body’s largest organ and is very susceptible to failures, as any other organ system. Wounds are disruptions of normal anatomic structure and function, often endangering the skin’s epithelial integrity.

Wounds are commonly classified based on their duration and depth. Acute wounds usually heal within three weeks, and chronic wounds can last more than three months. Abrasions, lacerations, incisions, and minor burns are considered to impact the superficial layers of the dermis, while deeper, thicker wounds penetrate the epidermis, the dermis, and the underlying tissue layer.

The outermost layer of skin, the stratum corneum, is the most important barrier, resisting moisture loss and impeding the penetration of outside toxins. Burns and trauma can open this layer, causing infections and dehydration. This protective layer is constantly shed and replaced. In diseases such as seborrheic dermatitis, the turnover time is shortened, while in psoriasis, it is rapid and causes improper skin cell functioning.

Among hospital inpatients, the prevalence of pressure ulcers may be as high as 14.8%, and the costs involved with the care of pressure ulcers is more than $1.3 billion in the United States.2,3 An estimated 10% to 25% of nursing home residents have experienced pressure ulcers.4 Proper wound care management and nutrition can significantly reduce pain, time, and costs for patients and providers.

Healing

Healing typically occurs in three phases: inflammation, proliferation, and remodeling. The goals of wound care include pain relief, odor elimination, infection prevention, functional maintenance and, where possible, healing.

When someone suffers a wound, available nutrients in the body, especially amino acids, are needed for healing, potentially leading to the loss of LBM so the body can obtain the necessary amino acids required for protein synthesis to achieve healing.1 The body also experiences additional calorie and energy demands. The normal process of healing cannot be dissociated from nutritional status because its biology is altered by chronic wounds, the stress response is activated by any wound, and any existing PEM accentuates the healing process.1

Nutrition

Wound healing goals should be to control the catabolic state, meet macronutrient needs, increase energy intake by 50% above daily needs, increase protein intake to twice the daily allowance to 1.5 g/kg/d, increase anabolic stimulation (with or without exogenous anabolic hormones), avoid replacement of LBM loss with fat gain, and utilize exercise to increase the body’s anabolic drive.1 Stressed and elder patients may also require an anabolic agent to override the catabolic stimulus. Aging increases protein requirements to avoid sarcopenia.

Before administering any nutritional instructions or supplements, the provider should assess the optimal substrate flow needed for healing a wound. Energy, protein, and micronutrient requirements should be made according to daily allowances, which have been defined in the past few decades of nutritional research. Malnourished patients, who already have a nutritional deficit and have lost weight, require a 50% increase over calculated maintenance calories (energy).1  Energy demands increase as little as 20% during recovery from elective surgery and as much as 100% for severe burns. In a national study by Bergstrom et al, nutritional support increased wound healing in stage 3 and 4 ulcers, whereas other studies have not shown a strong relationship between healing and nutrition.5

Caloric intake is essential for providing the energy needed to support proper wound healing. Skin cells are dependent on glucose as an energy source. Carbohydrates serve as structural lubricants, transportation, immunologic agents, hormones, and enzymes. Approximately 55% to 60% of total calories should be delivered as complex carbohydrates rather than as simple sugars.1 Carbohydrates also have been discovered to be a key factor in the activity of the enzymes hexokinase and citrate synthase used for wound repair reactions.1 Lactate, a metabolic by-product of glucose, has been shown to stimulate collagen synthesis via fibroblasts, provide energy, and activate many healing pathways. Patients with diabetes should be closely monitored with adequate insulin.

Protein deficiency during wound healing can be detrimental to the process. Amino acids are essential for cell proliferation and protein synthesis for rebuilding tissue and muscle. Fibroblast production requires protein substrates as well. The hypermetabolic catabolic state caused by a severe wound must be countered with high protein intake to prevent malnutrition and prolonged healing. Severely burned adults can assimilate only 1.5 g/kg/day into LBM; additional protein will be used only as a fuel source.1 An increase in anabolic activity via insulin can control protein loss.

In a study by Demling and DeSanti, the anabolic steroid oxandrolone was shown to significantly and safely improve the outcome of burn healing in a geriatric population.1 Other steroids used included human growth hormone, insulinlike growth factor, insulin, testosterone, and testosterone analogues.

Adequate amino acid intake and protein synthesis will accelerate the healing process. The most essential amino acid in wound healing is glutamine. Severe glutamine deficiency can occur after an injury, depleting the primary fuel source for rapidly dividing epithelial cells during healing. A glutamine dose of 0.3 to 0.4 g/kg/day is commonly administered after a major burn.1

Fats serve as both an energy source and as hormonal signals. Cell membranes are composed of fatty acids and require sufficient lipids for proper functioning. A key regulator in wound inflammation and healing is white adipose tissue. Polyunsaturated fats are used for membrane structure, whereas saturated fats are used mostly for energy.

The by-products of fat metabolism can have positive and negative effects. Lipid peroxidation can alter wound healing and stimulate apoptosis. However, other by-products such as leptins can protect the cell.

Fats are essential for treating both acute and chronic wounds and have multiple functions in the body. Ideal dietary intake for wound healing comprised of high levels of monosaturated fatty acids and omega-3 polyunsaturated fatty acids and approximately 20% to 25% of calories should be provided by fat but not more than 2 g/kg/day.1

Other trace elements that benefit wound healing are zinc, copper, manganese, and selenium. Zinc and manganese serve as essential cofactors in various metabolic pathways, including DNA and protein synthesis. Manganese is also a cofactor for the antioxidant superoxide dismutase and for metalloproteinase activity in the wound.1 Selenium is required for the glutathione system and cell protection. The key vitamins for energy are vitamin B complex and vitamin C. Oxidants are a major source of cell toxicity with wound inflammation, and antioxidant activity is essential for the wound-healing process to continue.1

Critical Considerations

As the body’s largest organ, the skin serves as a protective layer against outside toxins and moisture loss and maintains homeostasis functions. Upon injury, stress response and loss of nutrients cause impediments to healthy wound healing.

Nutritional status is extremely important in wound patients, especially in the geriatric population. Lower protein levels and calorie deficiencies slow wound healing and place a patient at risk for death.

Catabolic control with anabolic agents has been shown to boost healing. Providers should strive to improve the nutritional status for all patients with pressure ulcers, burns, lacerations, and superficial and thick-tissue wounds to ensure an adequate foundation for healing and to potentially reduce mortality.

— Robert A. Norman, DO, MPH, MBA, is an associate professor at Nova Southeastern University College of Osteopathic Medicine in Fort Lauderdale-Davie, Fla. He is founder, owner, and CEO of Dermatology Healthcare, a national company providing dermatology consults in long term care facilities.

— Trupal Patel, who holds a bachelor of science degree in biology from the University of Florida, is a premedical student and research associate at Dr. Robert Norman Dermatology in Tampa, Fla. 

References

  1. Demling RH. Nutrition, anabolism, and the wound healing process: An overview. Eplasty. 2009;9:e9.
  2. Redelings MD, Lee NE, Sorvillo F. Pressure ulcers: More lethal than we thought? Adv Skin Wound Care. 2005;18(7):367-372.
  3. Gallagher SM. Outcomes in clinical practice: pressure ulcer prevalence and incidence studies. Ostomy Wound Manage. 1997;43(1):28-32, 34-35, 38.
  4. Rhoades JA, Krauss NA. Chartbook #3: Nursing home trends, 1987 and 1996. May 1999. Agency for Healthcare Research and Quality Medical Expenditure Panel Survey. Available at: http://www.meps.ahrq.gov/mepsweb/data_files/publications/cb3/cb3.shtml. Accessed April 20, 2011.
  5. Bergstrom N, Horn SD, Smout RJ, et al. The National Pressure Ulcer Long-Term Care Study: Outcomes of pressure ulcer treatments in long-term care. J Am Geriatr Soc. 2005;53(10):1721-1729.