Which diets or supplements are most effective for preventing and treating pressure ulcers and do they cause unwanted effects?

Key messages

• Due to a lack of robust evidence, the benefits and unwanted effects of most diets and supplements for the prevention and treatment of pressure ulcers are unclear.

• Energy, protein and micronutrients; protein, arginine, zinc and antioxidants; arginine and micronutrients; and collagen supplements may be better than a standard diet alone for healing pressure ulcers.

• We need more and better studies with larger samples, and longer follow-up times, which examine the same outcomes, to determine the real effect of nutritional interventions for the prevention and treatment of pressure ulcers.

What are nutritional interventions?

Nutritional interventions are special meals or supplementary food in addition to a person's normal diet to help with general health or specific conditions. They may be extra calories, macronutrients (like proteins) or micronutrients (like vitamins or minerals). They can be given by mouth or through a tube (called tube feeding). They can also be given via an infusion or injection (parenteral nutrition).

Why is nutrition important for people with pressure ulcers or at risk of developing pressure ulcers?

Pressure ulcers are also known as pressure sores, bedsores and decubitus ulcers. They are an injury to the skin or underlying tissue, or both, caused by pressure, shear and friction. Pressure on the skin reduces circulation; shear is when layers of skin and tissue slide over one another, when the patient moves in bed, for example; and friction is when the skin rubs against bedsheets or clothing. Pressure ulcers usually form on bony parts of the body, such as the heels or tail bone. People who are immobilized, by a fall or surgery, for example, or who have conditions like diabetes or vascular disease are at risk of getting pressure ulcers. If they have poor nutrition, they may be at greater risk of getting pressure ulcers and these may be more severe.

What did we want to find out?

We wanted to know whether nutritional interventions help to prevent people developing pressure ulcers and to promote the healing of existing pressure ulcers.

We were interested in the effect of nutritional interventions on:

• the development or healing of pressure ulcers

• possible unwanted effects experienced by individuals

• individual quality of life

What did we do?

We searched for studies that investigated any form of nutritional intervention compared with a normal diet, placebo (dummy medicine) or another type of nutritional intervention. We compared and summarized the results of studies that examined similar nutritional interventions and assessed our confidence in the evidence based on factors such as study methods and sample sizes.

What did we find?

We found 33 studies that involved 7920 people. Eleven studies looked at the effects of nutritional interventions on preventing pressure ulcers and 24 studies evaluated nutritional interventions for treating pressure ulcers. Amongst those, two studies investigated the effects on both preventing and treating pressure ulcers.

Main results

Preventing pressure ulcers in people at risk of getting them

• Energy, protein and micronutrient supplements may make little to no difference to the development of a pressure ulcer (3 studies, 1634 people).

• A protein supplement may make little to no difference in pressure ulcer development (4 studies, 4264 people). It is unclear if the protein supplement causes any unwanted effects.

• it is unclear if other supplements have an effect on pressure ulcer development.

Treating people with pressure ulcers

• Energy, protein and micronutrient supplements may increase the number of people whose pressure ulcers healed, but we are very uncertain about this result (3 studies, 577 people). It is unclear if the energy, protein and micronutrient supplements cause any unwanted effects.

• Compared to a standard diet, we are uncertain whether protein, arginine, zinc and antioxidant supplements improve the healing of pressure ulcers, (2 studies, 71 people). We do not know if protein, arginine, zinc and antioxidant supplements cause any unwanted effects.

• Arginine and micronutrient supplements may not increase the number of pressure ulcers healed, but they may slightly increase pressure ulcer healing (2 studies, 231 people). It is unclear if the intervention has an effect on acceptability and unwanted effects.

• Collagen supplements probably increase pressure ulcer healing (1 study, 74 people). The intervention may increase unwanted effects, but we are very uncertain about this result.

• it is unclear if other supplements have an effect on the healing of pressure ulcers.

What are the limitations of the evidence?

We have little to very little confidence in our findings because many of the studies were small, of low quality, and did not provide data on everything we were interested in. About half of the studies were funded or supported by pharmaceutical companies, which might have influenced the results. We could not use data from studies about some types of nutritional interventions because the diet or supplement was only examined in one study.

How up to date is this review?

The review is up to date to May 2022.

Authors' conclusions: 

The benefits of nutritional interventions with various compositions for pressure ulcer prevention and treatment are uncertain. There may be little or no difference compared to standard nutrition or placebo. Nutritional supplements may not increase gastrointestinal side effects, but the evidence is very uncertain. Larger studies with similar nutrient compositions would reduce these uncertainties. No study investigated the effects of special diets (e.g. protein-enriched diet, vegetarian diet) on pressure ulcer incidence and healing.

Read the full abstract...
Background: 

Pressure ulcers are localized injuries to the skin or the underlying tissue, or both, and are common in older and immobile people, people with diabetes, vascular disease, or malnutrition, as well as those who require intensive or palliative care. People with pressure ulcers often suffer from severe pain and exhibit social avoidance behaviours. The prevention and treatment of pressure ulcers involves strategies to optimize hydration, circulation, and nutrition. Adequate nutrient intake can reduce the risk factor of malnutrition and promote wound healing in existing pressure ulcers. However, it is unclear which nutrients help prevent and treat pressure ulcers. This is an update of an earlier Cochrane Review.

Objectives: 

To evaluate the benefits and harms of nutritional interventions (special diets, supplements) for preventing and treating pressure ulcers in people with or without existing pressure ulcers compared to standard diet or other nutritional interventions.

Search strategy: 

We used extensive Cochrane search methods. The latest search was in May 2022.

Selection criteria: 

We included randomized controlled trials (RCTs) in people with or without existing pressure ulcers, that compared nutritional interventions aimed at preventing or treating pressure ulcers with standard diet or other types of nutritional interventions.

Data collection and analysis: 

We used standard Cochrane methods. Our primary outcome for prevention studies was the proportion of participants who developed new (incident) pressure ulcers. For treatment studies, our primary outcomes were time to complete pressure ulcer healing, number of people with healed pressure ulcers, size and depth of pressure ulcers, and rate of pressure ulcer healing. Secondary outcomes were side effects, costs, health-related quality of life and acceptability. We used GRADE to assess certainty of evidence for each outcome.

Main results: 

We included 33 RCTs with 7920 participants. Data for meta-analysis were available from 6993 participants.

Pressure ulcer prevention

Eleven studies (with 12 arms) compared six types of nutritional interventions for the prevention of pressure ulcers.

Compared to standard diet, energy, protein and micronutrient supplements may result in little to no difference in the proportion of participants developing a pressure ulcer (energy, protein and micronutrient supplements 248 per 1000, standard diet 269 per 1000; RR 0.92, 95% CI 0.71 to 1.19; 3 studies, 1634 participants; low-certainty evidence).

Compared to standard diet, protein supplements may result in little to no difference in pressure ulcer incidence (protein 21 per 1000, standard diet 28 per 1000; RR 0.75, 95% CI 0.49 to 1.14; 4 studies, 4264 participants; low-certainty evidence). The evidence is very uncertain about the gastrointestinal side effects of these supplements (protein 109 per 1000, standard diet 155 per 1000; RR 0.70, 95% CI 0.06 to 7.96; 2 studies, 140 participants, very low-certainty evidence).

The evidence is very uncertain about the effects of protein, arginine, zinc and antioxidants; L-carnitine, L-leucine, calcium, magnesium and vitamin D; EPA, GLA and antioxidants; disease-specific supplements on pressure ulcer incidence when compared to standard diet (1 study each; very low-certainty evidence for all comparisons).

Pressure ulcer treatment

Twenty-four studies (with 27 arms) compared 10 types of nutritional interventions or supplements for treatment of pressure ulcers.

Compared to standard diet, energy, protein and micronutrient supplements may slightly increase the number of healed pressure ulcers (energy, protein and micronutrients 366 per 1000, standard diet 253 per 1000; RR 1.45, 95% CI 1.14 to 1.85; 3 studies, 577 participants, low-certainty evidence). The evidence is very uncertain about the effect of these supplements on gastrointestinal side effects.

Compared to standard diet, the evidence is very uncertain about the effect of protein, arginine, zinc and antioxidant supplements on pressure ulcer healing (pressure ulcer area: mean difference (MD) 2 cm² smaller, 95% CI 4.54 smaller to 0.53 larger; 2 studies, 71 participants, very low-certainty evidence). The evidence on side effects of these supplements is very uncertain.

Compared to standard diet, supplements with arginine and micronutrients may not increase the number of healed pressure ulcers, but the evidence suggests a slight reduction in pressure ulcer area (MD 15.8% lower, 95% CI 25.11 lower to 6.48 lower; 2 studies, 231 participants, low-certainty evidence). The evidence is very uncertain about changes in pressure ulcer scores, acceptability, and side effects of these supplements.

Compared to placebo, collagen supplements probably improve the mean change in pressure ulcer area (MD 1.81 cm² smaller, 95% CI 3.36 smaller to 0.26 smaller; 1 study, 74 participants, moderate-certainty evidence). The evidence is very uncertain about the effect of these supplements on side effects.

The evidence is very uncertain about the effects of vitamin C, different doses of arginine; EPA, GLA (special dietary fatty acids) and antioxidants; protein; a specialized amino acid mixture; ornithine alpha-ketoglutarate and zinc supplements on pressure ulcer healing (1 or 2 studies each; very low-certainty evidence).