High rate of deficiency in the amino acids tryptophan and histidine in people with wounds: implication for nutrient targeting in wound management--a pilot study.

Background: Malnutrition resulting from inadequate protein, energy, or micronutrient intake has been identified as an independent risk factor for the development of pressure ulcers in older adult patients and is associated with increased morbidity and death.

Objective: To assess the relationship between albumin, the standard biochemical marker of nutritional adequacy, and amino acid status in people with wounds.

Methods: The authors performed tests for serum albumin, prealbumin, and amino acid profiles on 18 consecutive hospital patients with wounds and 7 patients without wounds.

Results: A low level of the essential amino acids tryptophan and histidine was a common finding in older people with wounds. Of the 18 consecutive wound cases, 16 (88.9%) were found to be deficient in tryptophan, histidine, or both. Moreover, levels were generally found to be lower than those in the group without wounds. The levels of all other amino acids were essentially normal for all patients. Finally, although serum albumin is often used as a surrogate marker of amino acid adequacy or nutritional status, clinically abnormal albumin had poor specificity (63.2%), poor sensitivity (60.7%), and low positive predictive value (70.8%) for the identification of a low tryptophan or histidine level.

Conclusions: People with wounds are a relatively at-risk group and are likely to be overlooked in terms of micronutrient deficiencies, and these findings have important implications in terms of potential specific targeting of nutrient supplementation.