View Product Catalogue

Search our database to view details of all our products.

More Details

View our Recipes

Click here to view our nutritional recipes

More Details

Latest news

CASE STUDY: Intensive Nutritional Intervention in a Frail, Elderly Patient

David Gray, Senior Specialist Dietitian at Guy’s and St Thomas’…

Case Study - Post-Pyloric feeding in gastroparesis: the role of high protein enteral feeds

Michelle Barry, Specialist Home Enteral Feeding Dietitian

There are several…

Available 1st March: 3 New Fortisip 2kcal Flavours

Help support your patients recovery with three tasty new flavours…

Nutricia Suggestion Engine - Conditions

Step 1

What information would you like to see?

Step 2

In order to show you information relevant to you, please select a condition of interest.

Step 3

Press the 'find' button below to find relevant articles,videos and podcasts.

You are viewing HCP Information

Wound healing

Working in Wound Care?


Wound healing, or wound repair, is a complex process in which the skin repairs itself after injury.

A wound is defined as a break in the continuity of the skin. Wounds can be broadly classified as acute or chronic. Acute wounds usually heal in an ordered, timely fashion and typically fall into one of two categories: traumatic wounds and surgical wounds. A chronic wound is a wound that does not heal in an orderly set of stages and in a predictable amount of time. Chronic wounds may never heal or may take years to do so. These wounds cause patients severe emotional and physical stress as well as creating a significant financial burden on patients and the whole healthcare system. Venous ulcers, arterial ulcers, diabetic foot ulcers, dehisced surgical wounds and pressure ulcers are examples of chronic wounds.

There is growing evidence that the burden of chronic wounds in Ireland is already high and likely to increase. It is estimated that 1-1.5% of the population are affected by a wound at any point in time. In the non-acute setting, a prevalence of 4% was identified in one study on the active caseload of community nurses (McDermott-Scales et al. 2009)

Phases of wound healing
Delayed wound healing
The role of nutrition

Return to the Top

Phases of wound healing

The wound healing response can be divided into four sequential but overlapping phases:

1 heamostasis
2 inflammatory
3 proliferation
4 maturation or remodeling

Haemostasis occurs immediately following injury. Haemostasis protects the body from excessive blood loss and increased exposure to bacterial contamination through:

- Vasoconstriction
- Migration of leukocytes and platelets
- Formation of fibrin

The inflammatory phase lasts from immediate post injury to 2-5 days. This phase prepares the wound bed for healing by removing necrotic and foreign material. Phagocytosis occurs whereby bacteria and debris are removed, and factors are released that cause the migration and division of cells involved in the proliferative phase.

The proliferative phase usually occurs on the fourth day after injury and is characterized by angiogenesis, epithelialization, granulation, tissue formation and collagen deposition. During this phase a matrix or latticework of cells forms. New blood vessels (capillaries) form which supply the rebuilding cells with oxygen and nutrients to support the production of proteins (primarily collagen). The collagen acts as the framework upon which the new tissues build. Collagen is the dominant substance in the final scar.

The maturation or remodeling phase normally begins a week after a wound is inflicted and may continue for one year or longer. During this phase, collagen is further deposited into the wound matrix and blood vessel density is reduced. The area increases in strength, eventually reaching 70-80% of the strength of uninjured skin.

However, this process is not only complex but fragile, and susceptible to interruption or failure leading to the formation of chronic non-healing wounds. Factors which may contribute to this include diabetes, venous or arterial disease, old age, and infection.

Delayed wound healing
The role of nutrition

Return to the Top

Delayed wound healing

The success of wound healing is known to depend on many intrinsic and extrinsic factors, e.g. underlying disease, age, nutrition and psychological well-being. In order to create a healing environment, all factors which adversely affect the health of the patient must be identified and, where possible, rectified. Table 1 highlights some of the most common factors which can delay healing.

Table of Key Factors adversely affecting the healing process

Treatment of wounds involves a multi-faceted approach, to include adequate wound bed preparation, appropriate use of dressings, management of the underlying disease, and correction of factors which impair wound healing. The role of nutrition in wound management includes the correction of malnutrition, and the use of specific nutrients which have been shown to promote wound healing.

Phases of wound healing
The role of nutrition

Return to the Top

The role of nutrition in wound healing

Optimal wound healing requires adequate nutrition. Nutritional deficiencies impede the normal processes that allow progression through the stages of wound healing. Poor nutritional status can also be a cause of wound development, for example, patients with poor dietary intake and low body weight have been shown to be at increased risk of pressure ulcer development.

Malnutrition and wound healing
Research shows that malnutrition negatively affects the wound healing process. Malnutrition prolongs the inflammatory phase by decreasing the proliferation of fibroblasts and formation of collagen as well as reducing tensile strength and angiogenesis. It can also place the patient at risk of infection by decreasing T-cell function, phagocyte activity and complement and antibody levels. A 2005 meta-analysis by Stratton et al showed that provision of oral nutrition supplements (250-500kcal per serving) given over 2 to 26 weeks was related to a significantly lower incidence of pressure ulcer development compared with standard care and that risk of developing pressure ulcers could be reduced by 25% with the provision of oral/enteral nutrition support to correct malnutrition.

Nutritional Screening of all patients at risk of chronic wounds is recommended in order to prevent complications of malnutrition (HSE 2009). The MUST tool is a universally accepted screening tool which can be used in all care settings, and it has been recommended by the National Best Practice and Evidence Based Guidelines for Wound Management published by the HSE (HSE 2009).

The role of specific nutrients in wound healing
Wound nutrition is essentially whole body nutrition and the goal is to maintain body mass, limit weight loss and provide adequate nutrients to promote healing. Nutritional intake should be varied and balanced to provide all the essential nutrients.

A significant number of studies have investigated the potential value of specific nutrients in regulating wound healing as follows:

Energy (kilocalories)
Provision of adequate energy is the primary concern in facilitating wound healing. Excess energy may lead to obesity, itself a complicating factor for wound healing, whilst insufficient energy from fat and carbohydrate may result in protein being used as an energy source.

The American Society for Parenteral and Enteral Nutrition and the Wound Healing Society, provide a recommended guideline of 30-35kcal/kg body weight/day as a caloric requirement for wound healing in non-obese individuals. The European Pressure Ulcer Advisory Panel recommends a minimum of 30-35kcals /kg body weight/day as a general guideline for patients with pressure ulcers. Obese, geriatric and underweight patients will require a more individualised approach to determining energy needs.

Protein is necessary for the synthesis of enzymes involved in wound healing, proliferation of cells and collagen, and formation of connective tissue. An inadequate protein intake, often in conjunction with excessive losses of protein via heavily exudating wounds, will lead to a deficiency which can prolong the inflammatory response and result in oedema secondary to hypoalbuminaemia, thereby delaying the healing process. The recommended intake of protein associated with wound healing is between 1-1.5g/kg body weight/day. If the patient is severely catabolic, with more than one wound, or with a stage III or IV pressure ulcer, they may require 1.5-2g/kg body weight/day (monitoring of hydration status and renal function recommended).

Arginine is a semi-essential amino acid that enhances wound collagen deposition and protein synthesis. Arginine supplementation has been shown to increase production of nitric oxide which is bactericidal and enhances immune function. It also stimulates insulin and growth hormone secretion, two products known to be closely related to wound healing.

Vitamin C
Vitamin C, also known as ascorbic acid, functions in the synthesis of collagen. Vitamin C deficiency results in very little collagen deposition and markedly retarded gain in tensile strength. Vitamin C also functions as an antioxidant. It has been shown that older individuals, particularly those living is residential care, tend to have low plasma Vitamin C concentrations as do smokers and patients with liver disease and cancer. The Vitamin C status of hospitalised patients deteriorates during hospital stay. Intake to prevent deficiency is clearly indicated.

Vitamin A
Vitamin A increases the inflammatory response in wounds, stimulating collagen synthesis. Low vitamin A levels can result in delayed wound healing and susceptibility to infection. It has also been shown that vitamin A can restore wound healing impaired by longterm steroid therapy or by diabetes. Serious stress or injury can cause an increase in vitamin A requirements. While the mechanisms of vitamin A in wound healing are still not well understood, it is clear that it plays an important role.

Zinc is a trace element, present in small amounts in the body. Zinc plays a key role in protein and collagen synthesis, and in tissue growth and healing. Zinc deficiency has been associated with delayed wound healing, reduced skin cell production and reduced wound strength. The potential role of zinc supplementation in wound healing has been investigated; healing appears to be accelerated only in patients with low serum zinc levels. Hospitalised patients are potentially at risk of zinc deficiency due to decreased food intake and increased losses due to diarrhoea, fistulae and malabsorption. Insufficient dietary intake of zinc can be further exacerbated by zinc loss from excess wound drainage. Assessing zinc deficiency can be difficult as serum/ plasma levels may not be a true indication of zinc levels at the wound itself.

Iron is vital in collagen metabolism and for oxygen transport. Deficiency due to poor intake and blood loss may result in iron deficiency anaemia which, unless corrected, will delay wound healing.

Fluid intake should be given important consideration as dehydrated skin becomes inelastic, fragile and more susceptible to breakdown.

Other nutrients which have important functions in association with wound healing include vitamin E, vitamin K, vitamin B complex, copper, manganese, chromium and essential fatty acids. Poor nutrition leading to nutrient deficiencies will interfere with wound healing, mostly by delaying the healing response. Evaluation of a patient’s nutritional status through assessment and the provision of a nutritionally appropriate diet is one of the first principles to healing.

Phases of wound healing
Delayed wound healing

Return to the Top

HCP Information for Wound healing

The content provided by Nutricia is for information purposes only and is in no way intended to be a substitute for medical consultation with your doctor, dietitian or healthcare professional. The information, opinions, and recommendations presented in these pages are not intended to replace the care of your own doctor, dietitian or healthcare professional. Before you make any changes in the management of your diet / treatment or any other persons diet /treatment you should always consult your doctor, dietitian or healthcare professional. Although we carefully review our content, Nutricia cannot guarantee or take responsibility for the medical accuracy of documents we publish, nor can Nutricia assume any liability for the content of any web site linked to our site. © 2016 Nutricia. All rights reserved.