Nutritional status and wound healing

Nutrition Research Newsletter, Sept, 2008

Veins function to return blood back into the heart. The veins present in the legs have one-way valves that permit blood to flow from the legs toward the body and eventually to the heart. When the valves function well, they prevent pooling of blood in the legs. The diseases of the veins include blood clots, varicose veins, swelling of legs, and sores on the legs. Nutritional status and good nutrition plays a crucial role in promoting wound healing. During the wound healing process, the basic essential nutrients such as calories, proteins, vitamins especially A, C, and minerals especially zinc is vital. Venous disease is more common in overweight and obese individuals. In this study, a team of researchers from the University of Washington demonstrates the association between nutritional status and severity of nonhealing venous leg ulcerations in overweight and obese individuals.

Jeniffer Tobon, one of the authors of the study says, "Little is known about the relationship between specific macro- and micro-nutrients and wound healing outcomes in this population. Thus, the broader goal of this study was to explore the relationships among nutritional characteristics of obese individuals with venous disease and contribute to the very limited knowledge that is presently available about this clinical problem." In this cross-sectional observational design study, a total of eight patients were recruited from an outpatient wound care clinic aged above 50 years and with a BMI of greater than or equal to 25. The nutritional status of the subjects was evaluated using anthropometric measurements, nutrient analysis of dietary intake, serum albumin, vitamins A and C, and zinc levels. Severity of venous ulceration was assessed at the time of data collection, using the leg ulcer measurement tool (LUMT).

All patients received a topical ulcer treatment to promote moist wound healing and all but one patient received appropriate levels of compression using elastic tubular support bandages or multilayer compression bandage systems. Dietary nutrient intake of the subjects when compared with recommended daily intake (RDI) levels were suboptimal for protein, vitamin C or zinc in five patients, while serum levels of at least one of these nutrients were below normal in six patients. Vitamin A dietary intake met or exceeded the RDI for all patients and two patients had elevated serum levels for this nutrient. A positive correlation was found between serum albumin, average daily intake and percent RDI of protein. No significant correlations were observed for other nutrients in relation to daily intake. An inverse relationship was found among LUMT score and serum vitamin A levels, and a positive correlation was observed between LUMT score and serum vitamin C. No clear relationships were shown between serum zinc, albumin, and LUMT scores.

Wound healing is a complex process that increases the body's metabolic demands. Although many essential nutrients are involved in wound healing, among the best studied and most relevant are protein, vitamins A and C, and zinc. Protein, present in the skin primarily in the form of collagen, is critical throughout the wound repair cascade. Vitamin A deficiency leads to altered collagen synthesis, limited cross-linking of fibers, and diminished epithelialization. Low levels of this antioxidant may also limit the cellular immune response. Vitamin C, when deficient, results in decreased wound tensile strength related to a poorly laid collagen framework. A lack of the water-soluble vitamin C also diminishes angiogenesis due to the increased formation of weakened capillaries. Deficiencies of the trace mineral zinc can affect a wound's susceptibility to various pathogens and impair overall wound integrity by lowering rates of fibroblast proliferation, collagen synthesis, and epithelialization.

Tobon says, "Obesity has been implicated in problems with wound healing in general, which may be linked to nutritional status. Fat tissue is poorly vascularized, which results in decreased blood flow and delivery of nutrients to wound sites. A common misunderstanding about obese individuals, often based on their appearance, is that they cannot be undernourished. As a result, injured obese patients are rarely screened for nutritional deficits and little is known about their nutritional status. Our findings suggest that optimizing protein and nutrient-dense caloric intake will help promote timely wound healing."

Details: Jeniffer Tobon, The Everett Clinic, Geriatric Extended Care Team, 3901 Hoyt Avenue, Everett, WA 98201. Voicemail: 425-259-1177, Ext. 4086. Cell: 425-238-4457. Fax: 425-259-1172. E-mail: jentobon@gmail.com.