Introduction

Could metallic micronutrients be the missing link for your patient with a chronic wound? When we consider the nutrition required to optimize wound healing, protein supplementation is usually the star of the show. However, there are micronutrients involved in wound healing on a cellular level. Although the daily requirements may be small, they are mighty—and if deficient, they may be the missing step in healing a chronic wound.

Iron

Iron is most notably associated with hemoglobin formation. Therefore, it isn’t often considered unless the patient is believed to be anemic. However, iron has a vital role in the production of collagen. Thus, iron deficiency is associated with skin-related conditions such as pallor, pruritus, brittle hair and fingernails, and a higher association with bacterial and fungal skin infections.¹ Iron deficiency can be very common in specific populations, including individuals experiencing heavy bleeding (including heavy menstruation) and those whose diets do not permit animal products.² Iron deficiency is detrimental, but there is also concern with having too much of a good thing. Excess iron stored in the skin is the culprit in chronic lower extremity skin changes such as hemosiderin staining and lipodermatosclerosis.¹ In addition to these skin changes, a surplus of cutaneous iron can affect the response of macrophages and causing unrestrained proinflammatory activation.¹

Chronic wound exudate contains higher levels of iron as compared with acute wounds, and this seems to suggest a correlation with a prolonged inflammatory state and delayed healing.¹ Iron chelation therapies and dressings are being studied because they may have a role in promoting vascular endothelial growth factor to stimulate granulation tissue formation and angiogenesis.¹ Iron is naturally occurring in animal proteins (meat, seafood, poultry), fortified cereals and breads, and white or kidney beans and lentils.² If supplementing with oral iron, consider that calcium may interfere with the absorption of iron; direct patients to take calcium and iron supplements at different times of the day.

Zinc

Zinc is a cofactor in the function of hundreds of different proteins, and it is involved in DNA repair, apoptosis, regulation of the extracellular matrix, defense against antioxidants, scar formation, and more.³ Zinc is a work horse, having an important role during each phase of wound healing. The skin’s epidermis stores an estimated 5% of the zinc present in the body. Zinc deficiency, a problem associated with malnutrition globally, is associated with rough skin, delayed wound healing, dermatitis, and a higher risk of skin lesions. Foods that contain zinc include animal proteins (red meat, poultry), beans, chickpeas, and nuts.⁴ Fortified breakfast cereals and whole-grains may also be zinc-containing food options, especially for those who do not eat animal products.⁴

Copper

Copper is an important micronutrient associated with vascular endothelial growth factor expression, causing angiogenesis and remodeling of the extracellular matrix.⁵ It is shown to be present in higher concentrations in a wound during the first few days of wound healing, after which it decreases during the proliferative phase.⁶ Topical application of copper sulfate was shown to accelerate wound closure and thicken granulation and epithelial tissue, as well as provide some antibacterial effects.⁵ Copper is found in foods such as beef, organ meats, potatoes, mushrooms, seeds, nuts, and even chocolate.⁷ Copper deficiency is considered rare in humans, but it may be seen in people with celiac disease, people taking high doses of zinc supplements, and people with a genetic condition resulting in malabsorption of copper.⁷

Conclusion

A thorough nutritional assessment is an important step in a comprehensive examination. Encourage patients to report their dietary habits and any personal, cultural, or religious practices related to their diet to gain a more complete picture of which nutrients may be lacking or excessive. Many patients don’t report the over-the-counter medications they are taking, so be sure to inquire about any vitamins or supplement use. Consider evaluating patients for deficiencies in these important micronutrients, and utilize the help from our professional colleagues in nutrition and dietetics as a part of our interdisciplinary approach to provide comprehensive and effective care.

References

1. Wright JA, Richards T, Srai SK. The role of iron in the skin and cutaneous wound healing. Front Pharmacol. 2014;5:156. doi:10.3389/fphar.2014.00156.
2. National Institutes of Health. Iron fact sheet for health professionals. NIH Office of Dietary Supplements. 2020. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/. Accessed December 13, 2020.
3. Lin PH, Sermersheim M, Li H, Lee PHU, Steinberg SM, Ma J. Zinc in wound healing modulation. Nutrients. 2017;10(1):16. doi:10.3390/nu10010016.
4. National Institutes of Health. Zinc fact sheet. NIH Office of Dietary Supplements. 2020. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/. Accessed December 13, 2020.
5. Borkow G, Gabbay J, Zatcoff R. Could chronic wounds not heal due to too low local copper levels? Med Hypotheses. 2008;70:610-613.. doi: 10.1016/j.mehy.2007.06.006.
6. Coger V, Million N, Rehbock C, et al. Tissue concentrations of zinc, iron, copper, and magnesium during the phases of full thickness wound healing in a rodent model. Biol Trace Elem Res. 2019;191,167-176. doi.org/10.1007/s12011-018-1600-y.
7. National Institutes of Health. Copper fact sheet. NIH Office of Dietary Supplements. 2020. https://ods.od.nih.gov/factsheets/Copper-HealthProfessional/. Accessed December 13, 2020.

About the Author

Lauren graduated with a BSN from the University of Buffalo in Western New York, where she was born and raised. She has held various nursing jobs, but continued to work towards a goal of a career in wound care nursing after she was one of only two students who signed up for a wound care clinical during nursing school. She currently works at the Advanced Wound Healing Center in Orchard Park, NY where she once had her nursing clinicals. She became credentialed in Wound, Ostomy, and Continence Nursing in 2019 and is incorporating her knowledge and skills into her busy clinic practice. When not at work, Lauren enjoys indoor spinning, playing guitar, video games, and rooting for the Buffalo Bills NFL team.