Adding Vitamin C to the Wound Management Mix

Advances in Skin & Wound Care,  Apr 2004  by Collins, Nancy

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Mrs P, a 73-year-old woman with diabetes, has been in deteriorating health for the past 2 years. Six months before admission to a wound center from her long-term-care residence, Mrs P suffered a small right intracerebral hemorrhage resulting in temporary left hcmiparesis.

Clinical assessment reveals a cachectic woman with a Stage III pressure ulcer measuring 2.5 × 3 cm on her left buttock. She also has skin tears on both arms.

Consistent with best practices, an interdisciplinary approach was used to develop a management program to promote the healing of Mrs P's pressure ulcer and prevent further skin breakdown. Local wound care consisted of debridement and a dressing to absorb exudates while maintaining adequate moisture to promote healing.

In addition, the nutrition protocol prescribed by the dietitian included a routine vitamin C supplement, based on the physiologic role of vitamin C in collagen formation, the AHCPR guideline, and reports in the literature.l'7 This article takes a closer look at the possible role of vitamin C in wound healing.

Vitamin C and Pressure Ulcers

Vitamin C is essential for wound healing because of its role in collagen formation. Adequate levels of vitamin C are needed to form a cosubstratc in the hydroxylation of proline to hydroxyproline and lysine to hydroxylysine. Hydroxyproline and hydroxylysine are essential for stabilizing the triple helix structure of collagen with strong hydrogen bonding and crosslinks. Without this stabilization, the structure disintegrates rapidly.8

Vitamin C also provides tensile strength to newly built collagen, which allows new tissue to stretch without tearing. Tensile strength is an important factor in wound care because healed pressure ulcers are susceptible to future skin breakdown.

Vitamin C may be best known for its antiscorbutic and antioxidant properties. In cells and body fluids, vitamin C helps prevent damage to tissues, which may be important in preventing certain diseases. In the intestines, vitamin C protects iron from oxidation, enhancing iron absorption.9 Vitamin C also gives strength to capillary walls in vascular tissue.

Unfortunately, there is little data on the role of vitamin C in the treatment of pressure ulcers. Goode et al1 showed that vitamin C depletion was associated with the development of pressure ulcers in patients with a fractured femur.

Taylor et al2 reported the results from a prospective doubleblind placebo-controlled trial in 20 surgical patients. In the group treated with ascorbic acid, there was a mean reduction in pressure ulcer area of 84% after 1 month, compared with 42.7% in the placebo group.

Ringsdorf and Chcraskin3 administered daily vitamin C doses of 500 mg to 3000 mg to subjects recovering from surgery, other injuries, pressure ulcers, and leg ulcers induced by hcmolytic anemia. Four grams of scorbic acid given daily produced a significant improvement in the quality of newly synthesized collagen, but it did not alter collagen formed before vitamin C supplementation. Other studies of vitamin C supplementation in patients with pressure ulcers who were not severely deficient have had variable results.10

Daily Requirements

Most clinicians refer to the National Academy of SciencesNational Research Council (NAS-NRC) Recommended Dietary Allowances (RDAs) for specific recommendations on vitamin C intake." Table 1 summarizes the RDAs and upper limits (LJLs) of daily intake for vitamin C. The RDA, however, is for healthy individuals and does not address illness or infirmity.

The RDA for vitamin C is 75 mg for healthy women and 90 mg for healthy men. ' ' Women require a lower amount of vitamin C because they have a smaller lean body mass. People who smoke require an additional 35 mg/day because smoking increases oxidative stress and metabolic turnover of vitamin C."

According to the clinical practice guideline on pressure ulcer treatment from the Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare, Research and Quality), vitamin and mineral deficiencies have been reported in the majority of nursing home studies.4 The guideline recommends a daily high-potency vitamin and mineral supplement for all patients with suspected vitamin deficiency. Although this recommendation has a strength of evidence rating of C-meaning there is a clinical opinion, but no collection of rigorous, controlled studies to back it up-it seems practical to provide additional vitamin C to patients who are suspected of having a deficiency.4

Indeed, most of the wound healing literature includes recommendations to provide adequate amounts of vitamin C for healing based on its function in the hydroxylation of proline to hydroxyproline rather than on the results of specific placebocontrolled trials.

Sources of Vitamin C

Vitamin C is water soluble, which means it is not stored in the body and must be replenished daily. Vitamin C is the most unstable of all water-soluble vitamins, with cooking, handling, and processing affecting its content in food. The vitamin reacts with the metallic ions of iron and copper and is easily destroyed by oxygen, alkalies, and high temperature.