When a patient develops a pressure ulcer, many facilities implement protocols that include supplementation with vitamin C and/or zinc to enhance wound healing. Is this practice safe? Is it effective? Should dietetic practitioners recommend these nutrients for patients with pressure ulcers?
Use of Vitamin C and Zinc for Healing of Pressure Ulcers
While it is clear that nutrition assessment and intervention is considered an integral part of pressure ulcer treatment, use of vitamins and mineral supplements is controversial. Most clinical dietitians are comfortable making recommendations for protein, calories, and fluid needs for a high-risk or pressure-ulcer patient, but may be in unfamiliar territory when it comes to supplement recommendations.
Both vitamin C and zinc play a number of essential roles in the body, including involvement in collagen synthesis. Both nutrients are fairly safe at large doses. Vitamin C has been widely touted for every purpose from the “cure for the common cold” to heart disease prevention to wound healing. Medline Plus’s on-line description of vitamin C can be accessed at http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-vitaminc.html. The tolerable upper intake level for vitamin C in adults is 2000 mg/day. Toxicity may result in kidney stones, severe diarrhea, nausea, and gastritis. Occasionally, flushing, faintness, dizziness, and fatigue have been noted with excessive Vitamin C intake. Large doses may cause hemolysis (red blood cell destruction) in patients with glucose 6-phosphate dehydrogenase deficiency. High doses of vitamin C should be avoided in people with conditions aggravated by acid loading, such as cirrhosis, gout, renal tubular acidosis, or paroxysmal nocturnal hemoglobinuria.
Zinc has been used since ancient times for wound healing, although the clinical evidence to support its use is limited. Visit http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-zinc.html for Medline Plus’s on-line description of zinc supplements. As established by the Dietary Reference Intakes, the tolerable upper intake level for zinc is 40 mg/day. Higher doses may cause vomiting, diarrhea, headaches, and a metallic taste in the mouth. Large doses of zinc may affect absorption of calcium and copper and may interfere with many common medications, including hormone replacement therapy, antibiotics, and NSAIDS (Collins).
Based on the limited volume of evidence that currently exists, vitamin C and zinc may both be indicated in patients with pressure ulcers who are deficient in those nutrients. Assessing a deficiency is difficult (Thompson and Furhman). Routine treatment with vitamin C and zinc to promote wound healing is not supported by scientific evidence. While routine supplementation with vitamin C will probably not hurt a patient, it is unlikely that vitamin C supplementation will accelerate wound healing in non-deficient individuals (Thompson and Furhman). No evidence exists to support the routine use of supplemental zinc to promote healing of pressure ulcers (Thompson and Furhman). Supplemental zinc can have consequences related to interactions with medications and nutrient absorption (Collins).
Both vitamin C and zinc continue to be ordered routinely used for pressure ulcer treatment. If supplementation is ordered due to suspected deficiency or poor intake, the patient should be monitored and the dose discontinued when the wound heals or if they do not appear to be making a difference in the wound healing process.
Vitamin C and zinc are found in the diet, in multivitamins (which are often routinely prescribed for older adults and/or hospitalized patients), and in liquid protein supplements such as Ensure or med pass programs that are used as an additional source of protein for patients with pressure ulcers. It is likely that a patient that is eating fairly well and/or receiving other forms of supplements is obtaining the RDA for both vitamin C and zinc.
Implications for dietetic practitioners
Therapeutic doses of vitamin C and zinc do not appear to improve wound healing, unless a patient is deficient in those nutrients. Routine supplementation with these nutrients may not enhance wound healing. However, each patient should be assessed individually because those who are deficient may benefit from supplementation.
Registered dietitians should include assessment of vitamin C and zinc consumed by patients as part of routine nutrition assessment for pressure ulcer patients. This assessment should include a patient’s intake of foods containing vitamin C and zinc, clinical signs of vitamin C or zinc deficiency, side effects of large doses, and interference of the nutrients with other prescribed medications. In some cases supplements may be beneficial, especially if a patient is not eating well. Pharmacists can assist in recommending appropriate nutrient prescriptions and in discontinuing supplements when appropriate.
Health care facilities should review their existing protocols for routine supplementation with vitamin C and zinc for patients with pressure ulcers. Registered dietitians can play a critical role in establishing protocols for supplementation and assessment of individual residents for nutrient deficiencies.
Collins N. Adding Vitamin C to the Would Management Mix. Advances in Skin and Wound Care: 17(3):109-112, April 2004.
Collins N. Zinc Supplementation: Yea or Nay? Advances in Skin and Wound Care 16 (5):186-188, 2002.
Mandal A. Do Malnutrition and nutritional supplementation have an effect on the wound healing process? J Wound Care 15 (6): 254-7, June, 2006.
Thompson C and Fuhrman MP. Nutrients and Wound Healing: Still Searching for the Magic Bullet. Nutrition in Clinical Practice 20:331-347, June 2005.
Thompson, CW. Nutrition and Adult Wound Healing. Nutrition Week, January 18, 2003.