General Medical Information

Nutrition

David J. Terris

Although adequate nutrition is important for normal wound healing, the body has apparently given wound repair such a high priority that compromise of the normal processes are only seen with severe nutritional deficiencies. For instance, although low serum albumin concentrations are associated with an increased risk of wound infection and dehiscence, protein depletion generally retards healing only when weight loss exceeds 20% of original body weight.

Most nutritional elements essential to wound repair have been identified because of the consequences of their deficiency. There are several specific vitamin deficiencies, for example, which can lead to diminished healing. Vitamin C deficiency (also called scurvy) prevents the hydroxylation of proline and lysine, for which it is a necessary cofactor. Production of collagen is therefore significantly reduced, whereas collagen lysis continues. Not only do new wounds heal poorly, but old healed scars become fragile and can break down.

Vitamin A deficiency (probably the most common vitamin deficiency in the Western world) causes impaired collagen synthesis and epithelialization, resulting in reduced tensile strength and increased susceptibility to infection. Supplementation not only prevents these effects but may also mitigate the deleterious effects associated with radiation, steroid therapy, and diabetes mellitus.

Zinc deficiency may lead to retarded wound healing by preventing cell proliferation, which particularly effects fibroplasia. Although zinc replacement (220 mg three times a day) is corrective, care should be taken not to provide zinc in the nondeficient state, because excessive levels may hamper macrophage migration and phagocytosis and therefore impair wound healing.

In summary, severe malnourishment may lead to compromised wound healing. Under that circumstance, appropriate nutritional supplementation will restore the normal wound repair mechanisms. However, most patients will derive no benefit from enhancement of their baseline nutritional status.