Appendix 1. Search strategy

1. exp Preoperative Period/ or exp Preoperative Care/ or preoperative.mp.

2. exp Perioperative Nursing/ or exp Perioperative Care/ or perioperative.mp.

3. 1 or 2

4. exp Food, Formulated/ or exp Nutritional Status/ or exp Dietary Supplements/ or    

    exp Malnutrition/ or exp Enteral Nutrition/ or sip feeds.mp. or exp Nutritional Requirements/

5. Oral supplements.mp.

6. parenteral nutrition.mp. or exp Parenteral Nutrition/

7. exp Parenteral Nutrition/ or exp Enteral Nutrition/ or enteral.mp.

8. jejunostomy.mp. or exp Jejunostomy/

9. exp Enteral Nutrition/ or nasogastric.mp.

10. gastrostomy.mp. or exp Gastrostomy/

11. 4 or 5 or 6 or 7 or 8 or 9 or 10

12. exp Glutamine/ or exp Food, Formulated/ or exp Arginine/ or exp Fatty Acids,   

     Omega‐3/ or immunonutrition.mp.

13.  Novel substrates.mp.

14. exp Carbohydrates/ or carbohydrate.mp.

15. glucose.mp. or exp Glucose/

16. protein.mp. or exp Proteins/

17. Amino acids.mp. or exp Amino Acids/

18. 12 or 13 or 14 or 15 or 16 or 17

19. exp Esophagectomy/ or gastrointestinal surgery.mp. or exp Gastrectomy/

20. colorectal surgery.mp. or Colorectal Surgery/

21. exp Gastrectomy/ or gastric cancer surgery.mp.

22. exp Esophagectomy/ or oesophageal cancer surgery.mp.

23. pancreatic cancer surgery.mp. or exp Digestive System Surgical Procedures/ or        

      exp Pancreatectomy/ or exp Pancreaticoduodenectomy/

24. 19 or 20 or 21 or 22 or 23

25. 4 or 5 or 6 or 7 or 8 or 9 or 10 or 12 or 13 or 14 or 15 or 16 or 17

26. 3 and 11 and 18 and 24