The survey is a phase IV, prospective randomized clinical trial to determine whether an immunomodulating nutrient-enriched diet compared to a standard diet can improve nutritional status and reduce postoperative infection and surgery-induced immune suppression in patients with gastric cancer or GIST undergoing major surgery in a single medical center.

Primary Objective:

1. The primary end points:

   To evaluate the effect of immunomodulating diets on the postoperative inflammatory response: including interleukin (IL)-6, C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α).

2. Secondary Objectives:

(1). Biochemistry parameters: glucose,blood urine nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, triglycerides, cholesterol, low-density lipoprotein, high-density lipoprotein, sodium, and leukocyte count.

(2). Nutritional status: albumin, prealbumin, BMI (3). Adverse events (4). Clinical outcomes: postoperative complications, time to first bowel action and length of hospital stay after surgery.

Number of Subjects: Eligible patients will be randomized in 2 arms in the ratio of 1:1, to reach 15 patients at least in each.

Plan of the Study:

1. This is a randomized, comparative, double blinded study in 2 arms.
2. Study Schedule Study date: the time getting approval letter issued by both regulatory authority and institutional review board (IRB). Duration of the study: 5 years.
3. Duration of Treatment: Treatment was administered before curative surgery for gastric adenocarcinoma or gastric GIST, and postoperative day 5-14 or to discharge whichever occurred first, or consent withdrawal during any time of the study, when the patient would be withdrawn.

Inclusion Criteria:

• Age between 20-85 years old
• Histologically proven primary gastric cancer or GIST.
• Patients was planning to receive elective curative gastric surgery, such as partial gastrectomy, subtotal gastrectomy, proximal gastrectomy, total gastrectomy, etc.
• Patient is able to understand the requirements of the study and written informed consent was obtained from each subject.

Exclusion Criteria:

• They were less than 20 years or over 85 years old
• Hepatic dysfunction or bile stasis (serum total bilirubin >2.5 mg/dL)
• Renal dysfunction (serum creatinine >1.5 mg/dL), or required hemodialysis
• Cardiac dysfunction (NYHA functional class >III, or stroke history)
• Severe hypoalbuminemia (albumin <2.5 g/dL)
• Karnofsky performance status less than 60
• Overweight (body mass index [BMI] >30 kg/m2)
• Exhibited drug abuse or chronic alcoholism
• Had life-threatening disease, or underwent emergent surgery
• With infection or bowel obstruction
• Pregnant or lactating
• Had received chemotherapy within 14 days of the initiation of the trial
• Had received immunosuppressive therapy or had immunological diseases recently
• Had already participated in another clinical study with an investigational drug or an investigational medical device within a month of the initiation or during the study
• Hypersensitive to casein, fish oil, soybean, or corn oil