Published research on these nutrients

Weimann A, et al. ESPEN guideline on clinical nutrition in surgery, update 2025. Clin Nutr. 2025.

The 2025 update of the European clinical nutrition guideline for elective and non-elective surgery adds recommendations on frailty assessment, sarcopenia diagnosis, and prehabilitation.

Cross MB, et al. Evaluation of malnutrition in orthopaedic surgery. J Am Acad Orthop Surg. 2014.

This review reports that malnutrition is common in orthopaedic patients and is associated with wound complications and poorer surgical outcomes.

Ueyama H, et al. Perioperative essential amino acid supplementation facilitates quadriceps muscle strength and volume recovery after TKA: a double-blinded randomized controlled trial. J Bone Joint Surg Am. 2023.

Two years after knee replacement, patients who took essential amino acids around surgery had greater rectus femoris muscle area and quadriceps strength than the placebo group. Clinical outcome scores did not differ between the groups.

Ueyama H, et al. Perioperative essential amino acid supplementation suppresses rectus femoris muscle atrophy and accelerates early functional recovery following total knee arthroplasty. Bone Joint J. 2020.

In this randomized trial, which received the Knee Society Ranawat Award, investigators reported less rectus femoris atrophy and faster early functional recovery after knee replacement.

Khani Y, et al. Peri-operative protein or amino acid supplementation for total joint arthroplasty: a systematic review and meta-analysis. J Orthop Surg Res. 2025.

Pooling 19 studies of 903 hip and knee replacement patients, investigators reported that essential amino acid supplementation reduced quadriceps and hamstring muscle loss.

Dreyer HC, et al. Essential amino acid supplementation mitigates muscle atrophy after total knee arthroplasty: a randomized, double-blind, placebo-controlled trial. JB JS Open Access. 2018.

Essential amino acids taken for one week before and six weeks after knee replacement reduced the loss of quadriceps muscle volume compared with placebo.

Travica N, et al. The effects of surgery on plasma/serum vitamin C concentrations: a systematic review and meta-analysis. Br J Nutr. 2022.

Pooling 23 studies, investigators found that blood vitamin C levels fall by about 39 percent in the first week after surgery and remain about 21 percent lower two to three months later.

Behrend H, et al. Vitamin C demand is increased after total knee arthroplasty: a double-blind placebo-controlled-randomized study. Knee Surg Sports Traumatol Arthrosc. 2019.

In this randomized trial, vitamin C levels fell after knee replacement in the placebo group, and the investigators concluded that knee replacement depletes vitamin C.

Shaw G, et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017.

In healthy men, gelatin, a collagen protein, taken with vitamin C before activity doubled a blood marker of new collagen formation compared with placebo.

Hu YG, et al. The effects of beta-hydroxy-beta-methyl butyrate supplementation in surgical patients: a systematic review and meta-analysis of randomized controlled trials. Front Nutr. 2025.

Pooling 11 randomized trials of 575 surgical patients, investigators reported shorter hospital stays, fewer postoperative complications, and longer six-minute walking distances with HMB.

Ekinci O, et al. Effect of Calcium beta-Hydroxy-beta-Methylbutyrate (CaHMB), Vitamin D, and Protein Supplementation on Postoperative Immobilization in Malnourished Older Adult Patients With Hip Fracture: A Randomized Controlled Study. Nutr Clin Pract. 2016.

In older adults after hip fracture surgery, a supplement combining HMB, vitamin D, and protein led to faster wound healing, earlier mobilization, and greater muscle strength than standard care.

Malafarina V, et al. Effectiveness of nutritional supplementation on sarcopenia and recovery in hip fracture patients. A multi-centre randomized trial. Maturitas. 2017.

In hip fracture patients, an oral supplement enriched with HMB and vitamin D improved muscle mass, and the investigators reported better functional recovery.

Deutz NE, et al. Effect of beta-hydroxy-beta-methylbutyrate (HMB) on lean body mass during 10 days of bed rest in older adults. Clin Nutr. 2013.

In this randomized trial of older adults on bed rest, HMB preserved lean body mass, while the placebo group lost muscle.

Bogunovic L, et al. Hypovitaminosis D in patients scheduled to undergo orthopaedic surgery: a single-center analysis. J Bone Joint Surg Am. 2010.

Forty-three percent of patients scheduled for orthopaedic surgery had vitamin D levels below 32 ng/mL before their operation.

Hespel P, et al. Oral creatine supplementation facilitates the rehabilitation of disuse atrophy and alters the expression of muscle myogenic factors in humans. J Physiol. 2001.

In healthy young adults recovering from two weeks of leg immobilization, creatine taken during a ten-week rehabilitation program led to faster recovery of muscle size and strength than placebo.

Vosahlo J, et al. Oral enzyme combination with bromelain, trypsin and the flavonoid rutoside reduces systemic inflammation and pain when used pre- and post-operatively in elective total hip replacement: a randomized exploratory placebo-controlled trial. Ther Adv Musculoskelet Dis. 2023.

In this randomized trial in hip replacement, an enzyme combination containing bromelain, taken before surgery and for six weeks after, lowered C-reactive protein and patient-reported pain during the first postoperative week compared with placebo.

Liu S, et al. Oral Bromelain for the Control of Facial Swelling, Trismus, and Pain After Mandibular Third Molar Surgery: A Systematic Review and Meta-Analysis. J Oral Maxillofac Surg. 2019.

Pooling six randomized trials in oral surgery, investigators reported less postoperative swelling with bromelain and less pain at seven days.

Landi F, et al. Supplementation with Bromelain, Troxerutin, and Escin to Support Postoperative Recovery After Hip or Knee Arthroplasty in Older Adults: A Pilot Study. Nutrients. 2025.

In this pilot study of older adults in rehabilitation after hip or knee replacement, a supplement containing bromelain was associated with greater reductions in pain and swelling and faster functional recovery.

Rojano-Ortega D, et al. Quercetin supplementation promotes recovery after exercise-induced muscle damage: a systematic review and meta-analysis of randomized controlled trials. Biol Sport. 2023.

Pooling 13 randomized trials, investigators reported that quercetin, mostly at 1,000 mg per day, accelerated recovery of muscle function and reduced muscle soreness after intense exercise.