100% Whey Protein Based Diet In Enhancing Pressure Ulcer Healing.

A pressure ulcer is defined as an area of localized damage to the skin and underlying tissues caused by pressure, shear, friction, and/or a combination of these. The most common sites for pressure ulcers are the sacrum, heels, ischial tuberosities, greater trochanters, and lateral malleoli.

In Singapore, the prevalence of pressure ulcers was 18.1%, while the incidence was 8.1% in a tertiary hospital in Singapore in 2002. With a rapidly ageing population in Singapore, the prevalence of pressure ulcers is expected to increase further.

Pressure ulcers are associated with serious medical complications, prolonged hospital stay and frequent re-admissions. Patients with pressure ulcers generally have significantly poorer physical function, are less able to perform self-care, and are less mobile. A new pressure ulcer is estimated to increase a patient's hospital stay by nearly a factor of five. Furthermore, pressure ulcers are also correlated with more than two fold rates of increased mortality independent of the source of the ulcer. Pressure ulcers are one of the patient safety indicators reflecting quality of life according to the Agency for Healthcare Research and Quality. Besides affecting the quality of life of patients, pressure ulcers are also associated with the increased utilisation of healthcare resources resulting in a high cost burden to healthcare systems worldwide.

Pressure ulcers occur in individuals with limited mobility due to pressure, or pressure in combination with shear, which decreases circulation and causes tissue damage. Elderly patients and patients with specific predisposing conditions such as hip fractures are particularly at risk. In addition, patients whom are malnourished are not only at risk of pressure ulcers but also have impaired wound healing. Patients with pressure ulcers tend to have negative energy balance and current guidelines recommend the assessment of nutritional status when progress for pressure ulcers closure does not occur and the use of oral nutritional supplements when an oral diet is not sufficient to meet requirements. In particular, nutritional care in wound healing should be directed at ensuring adequate supply of proteins and calories. Major guidelines currently recommend a minimum calorie intake of 30-35 kilocalories per kg per day and protein intake of 1.25-1.5g per kg per day for adults with a pressure ulcer who are assessed as being at risk of malnutrition.

Currently, there is paucity of studies demonstrating the effect whey protein has on wound healing in humans. The effect of whey protein on wound healing has only been studied in diabetic rats which has shown to accelerate closure and the healing process of their wounds. It was postulated that the healing property of whey was due to its ability to limit prolonged inflammation (reduction in IL-6, TNF-alpha, IL-1b and IL-10) and elevating the antioxidant defence system (by up-regulating glutathione and superoxide dismutase).

Whey protein comprises of 20% of the protein content in cow's milk as compared to casein which makes up the remainder of 80%. Whey is made up of immunoglobulins, lactoalbumins, lactoferrin, cysteine and other minor proteins. Compared to casein, whey has rapid gut clearance as it is readily absorbed, has higher nutritional value, maintains and increases lean body mass and has shown to have greater muscle protein accrual in the elderly. Moreover, whey has positive immuno-modulatory effects and is able to maintain better glycaemic control in diabetics due to its lower post-prandial glycaemia, greater stimulation of incretin production and direct insulinotropic effect.

At present, Peptamen® is the only product available in Singapore that contains 100% hydrolysed whey protein. It is a commercially available peptide-based diet (classified under "medical foods" by the US Food and Drug Administration) that provides complete nutrition. It is hypoallergenic (lactose- and gluten-free), appropriate for those with gastrointestinal maldigestion and/or malabsorption and can be used for total nutrition support via oral or tube feeding. We hypothesize that a 100% whey protein based diet (Peptamen®) enhances pressure ulcer healing.