Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Healing rates
Systematic review	88 people with pressure ulcers in nursing homes or hospital, some of whom were receiving ultrasound treatment for their pressure ulcers Data from 1 RCT	Ulcer healing 84 days 17/43 (39%) with ascorbic acid 1000 mg daily 22/45 (49%) with ascorbic acid 20 mg daily	RR 0.81 95% CI 0.50 to 1.30		Not significant
Systematic review	20 people with pressure ulcers having surgery Data from 1 RCT	Ulcer healing 4 weeks with ascorbic acid 1000 mg daily with placebo Absolute results not reported	RR 2.00 95% CI 0.68 to 5.85		Not significant
Systematic review	12 institutionalised people being fed through a tube Data from 1 RCT	Ulcer healing 8 weeks with very high-protein diet with high-protein diet Absolute results not reported	RR 0.11 95% CI 0.01 to 1.70		Not significant
Systematic review	20 people with pressure ulcers having surgery Data from 1 RCT	Mean reduction in would surface 1 month 84% with ascorbic acid 1000 mg daily 43% with placebo	P <0.005	Effect size not calculated	ascorbic acid
RCT 3-armed trial	16 people with stage 2 or 3 pressure ulcers In review	Mean score Pressure Ulcer Scale for Healing (PUSH) 3 weeks 7 with diet A 6 with diet B 2.6 with diet C	Diet C v Diet A and B: P <0.05 This study randomised only 16 people between the 3 groups and did not report the proportion of participants with complete healing	Effect size not calculated	standard hospital diet plus 500 kcal, protein 21 g, vitamin C 500 mg, zinc 30 mg, and arginine 9 g
RCT	89 people resident in long-term care facilities with stage II, III, or IV pressure ulcers In review	PUSH 8 weeks 3.55 with concentrated, fortified, collagen protein hydrolysate supplement 3.22 with placebo	P <0.05 However, these results should be interpreted with caution, as groups were imbalanced at baseline (mean PUSH scores at baseline: 9.11 in people taking supplements v 6.07 in people taking placebo) and results were not based on an intention-to-treat analysis	Effect size not calculated	nutritional supplements
Systematic review	95 people (80 completed study), age range 22 to 102 years, acute care, grade I to IV ulcers, trial duration 1 week Data from 1 RCT	Adjusted mean change in ulcer size on wound surface area 2.70 with standard care plus standard diet 2.76 with consistent wound care 2.60 with controlled nutritional support 2.34 with consistent wound care plus controlled nutritional support	Reported as not significant for any comparison P value not reported		Not significant
RCT	30 people, aged 65 years or over, recent onset (<1-month history) grade II to IV ulcers, orally or tube fed	PUSH change from baseline 12 weeks 6.1 with disease-specific nutrition treatment 3.3 with standard diet	P <0.05 Analysis was not by intention to treat (2 people were excluded), only people with recent pressure ulcers were included in the trial, and people who were tube fed or fed orally were not analysed separately	Effect size not calculated	disease-specific nutrition treatment