There are no evidence-based guidelines pertaining to the nutrition care process of the GP and the current dietary recommendations are based on expert opinions or observational studies. The main objective of this review is to provide a practical guideline for the nutritional management of gastroparesis based on the severity of malnutrition and kind of upper GI symptom, which is suitable in Indian scenario based on the recommendations and suggestions.

Disorder of gastric motility include impaired accommodation, gastroparesis, functional dyspepsia, GERD and dumping syndrome. Diagnosis and screening of gastric and digestive disorder is challenging as most symptoms that occur in patients with gastric motor disorders are non-specific, and they consist of poor appetite, postprandial fullness, and bloating, vomiting, epigastric pain, and early satiety 6. Gastroparesis is diagnosed based on the presence of upper G.I symptoms related to delayed gastric emptying without any mechanical obstruction. To rule out the presence of mechanical obstruction, abdominal X-ray, computed tomography, and magnetic resonance imaging is used, an upper G.I endoscopy is performed to exclude any stricture, mass or ulcer 7.

Once mechanical obstruction is excluded, other diagnostic option like gastric emptying scintigraphy, wireless motility capsule or stable isotope breath test is performed to demonstrate delayed gastric emptying. Gastric emptying scintigraphy (GES) is considered as the gold standard test for diagnosis of gastroparesis. In gastric emptying study, a small amount of radioactive isotope is mixed with ingested food and the rate at which the food is emptied from the stomach is measured. Retention of more than 10% of ingested food after 4hours shows gastroparesis 8. Another method used to test gastric emptying is stable isotope breath test, where meal containing carbon-13 is used to show delayed emptying. Patient’s exhaled air is measured for isotope at regular interval to demonstrate the rate of gastric emptying. This test can be performed at the bedside, even in ICU setting. In wireless motility capsule test, delayed gastric emptying is diagnosed by the time taken by the capsule to enter duodenum. If it takes more than 5 hours for the capsule to pass through duodenum, then gastroparesis is confirmed 9.

Malnutrition – clinical symptoms related to gastroparesis such as vomiting, and loss of appetite can lead to intake of calorie deficient diet. Due to loss of appetite, food intake is reduced, and vomiting may reduce the absorption of nutrients. Patient with gastroparesis at high risk of micronutrient deficiencies due poor intake and malabsorption 10.

The major life-threatening complication of gastroparesis is dehydration due to frequent vomiting.

Small bowel bacterial overgrowth (SBBO) – Fermentation of food material results when food stays for long period in the stomach leading to bacterial overgrowth in small bowel. Under normal condition peristalsis and normal acid production in the stomach prevents the bacterial growth in small intestine 11. During impaired gastric motility, colonization of bacteria occurs in the small bowel which results in mucosal inflammation and impaired nutrient absorption. SBBO is associated with symptoms like bloating, abdominal distention, nausea, vomiting, diarrhea, weight loss and result in overall decline in nutritional status 12.

Bezoar formation- patient with gastric dysmotility are at risk of developing bezoar. Bezoars are solid mass formed by the accumulation of indigestible food materials which may eventually lead to mechanical obstruction 13. Bezoar formation is associated with loss of appetite, nausea, vomiting, weight loss and early satiety. Phytobezoars are formed of nondigestible fibers especially cellulose, hemicellulose, lignin etc. High fiber foods should be avoided to prevent bezoar formation 14.

Poor glycemic control – the vagus nerve gets damaged after years of poor blood glucose control which results in diabetic gastroparesis and in turn gastroparesis can lead to erratic changes in blood sugar levels due frequent changes in the rate and amount of food passing into the small bowel making diabetic worse 15.

The management of gastroparesis should include a holistic approach which would target on different aspects of the disease condition. Even though the front-line therapy for gastroparesis is prokinetic agents and antiemetics, the treatment plan should include assessment of nutritional status, measures to correct fluid, electrolyte and nutritional deficiencies, measures to reduce the symptoms, treat the underlying causes like diabetes to prevent further progression of the disease 16. Although prokinetic agents and antiemetics play a major role in the management of gastroparesis, the main purpose of this article is to provide an insight into the nutritional aspect to be taken into consideration during the treatment and restore the nutritional status of the patients along with managing the symptoms.

Patients with gastroparesis are at high risk of developing nutritional abnormalities, as such it is essential to screen and diagnose malnutrition. Nutritional screening and evaluation in patients with gastroparesis help to differentiate nourished patients who can pursue further gastrointestinal evaluation and/or prokinetic trials, from a malnourished patient who requires immediate nutritional support 17.

Height, weight, and BMI can be used to assess the overall nutritional status in the patient with gastroparesis. Unintentional weight loss over a period is an important indicator of severe malnutrition. Unintentional weight loss of 5% in one month or 10% of usual body weight in six month indicates malnutrition. BMI can be used as a tool to identify nutritional risk. A BMI below 20 is considered as nutritional risk and indicate a need for nutritional intervention 18.

Biochemical parameters are useful in identifying nutritional deficiencies particularly those resulting in anemia and metabolic bone disease, that require monitoring and supplementation. Glycemic control is critical in the management of gastroparesis. High blood sugar level may cause transient gastroparesis and the delay in gastric emptying will respond positively to normalization of blood sugar levels. Regular monitoring of glycemic control is essential in managing diabetic gastroparesis.

There is a greater prevalence of iron, vitamin D and vitamin B12 deficiencies in both diabetic and non-diabetic gastroparesis patients 19. Therefore, initial assessment of patient with gastroparesis should include:

1. Serum glucose and glycosylated hemoglobin in case of diabetic gastroparesis: glycemic control plays a vital role in the management of gastroparesis. Hyperglycemia (>200mg%) can cause transient gastroparesis which responds immediately to normalization of serum glucose levels. Serum glucose must therefore be carefully evaluated at the initial assessment and monitored regularly 20.

2. Serum ferritin – serum ferritin level is an accurate indicator of iron store overtime. As serum ferritin is an acute phase reactant, it should be checked in the absence of infection, inflammation etc. Ferritin levels may low despite normal hematocrit, as the body utilizes iron stores while preserving hemoglobin and hematocrit 21.

3. Serum vitamin B₁₂ – Around 30% of the patient with diabetic gastroparesis are found to have low levels of vitamin B₁₂. Reduced levels of intrinsic factor and gastric acid following gastrectomy impairs the cleavage of protein bound B₁₂ resulting in little or no intestinal absorption. Bacterial overgrowth and reduced intake of vitamin B₁₂ rich foods also lead to deficiency 22. Clinical features are non-specific and often absent in deficient patients. Initial assessment and regular monitoring of vitamin B₁₂ levels are therefore important.

25-OH vitamin D: A study conducted by Amjad W et al in 320 patients with gastroparesis, 49.7% of the patient were found to have vitamin D deficiency. Studies shows that patients with gastrectomy either sub-total or total are found to have accelerated bone loss, therefore prone to risk of osteoporosis. Low bone mineral density (BMD) has been found in 27%–44% of the patients with gastroparesis, many of whom had normal serum calcium and alkaline phosphatase levels. The aetiology of bone disease in this population may be due to decreased intake of calcium, vitamin D and lactose-containing foods coupled with altered absorption and metabolism. Hence evaluation of vitamin D level and bone mineral density will be helpful in these patients to identify and treat high risk patient in order to reduce the risk of incident fracture. Dual x-ray absorptiometry (DXA) will provide accurate data on BMD 23.

Thorough diet history of the patient helps us to understand the nature of nutritional modification required by the individual patient, as some patients develop nausea while eating the usual, three large meals per day, may show reduction in symptoms with smaller, more frequent meals 24. Patients who have severe vomiting even after ingestion of water may require nutritional support to provide symptom relief and essential nutrients, fluids, and electrolytes.

Diet history should include changes in appetite, patient’s typical daily dietary intake, severity of symptoms in association with food intake, food tolerance or allergies, medications known to cause delayed gastric emptying, if any, etc.

Major factor affection nutritional intake in patients with gastroparesis are nausea and vomiting. Antiemetics and prokinetics plays a vital role in treatment of gastroparesis. Providing correct and regular dosage especially in liquid form will improve the efficacy of the drugs and help to control the symptoms 25. Treatment of nausea and vomiting will improve the oral intake.

Based on the recommendation made by ACG (American College of Gastroenterology) clinical guidelines, small particle, low fat diet is well tolerated, reduce symptoms, and enhance gastric emptying compared to three large meals 24, 26.

The diet history of the patient will help to decide on the factor which effects the dietary intake for a particular patients and accordingly dietary modification can be made.

The rate of gastric emptying depends on the volume and type of food. Greater the volume, slower the rate of emptying, hence smaller frequent meals may be well tolerated and help to achieve adequate calorie intake than three large meals per day. Compared to fats carbohydrates leave the stomach more quickly 27. Fats delay gastric emptying 28. Fat in liquid forms like milkshake, whole milk, nutritional supplements, meat broth, etc. are great source of energy so fat should not be completely avoided unless fat containing foods or liquids worsen the condition 12.

Liquids leave the stomach by gravity whereas solids need antral contraction. Most of the patients with gastroparesis tolerate liquid than solids, even high caloric liquids will empty from the stomach. Pureed diet or liquid diet can be planned to meet the nutritional requirement 29.

Patients may report increased fullness and bloating with subsequent meals over the day. Because of worsening of symptoms during the end of the day patients may decrease their intake which can exacerbate malnutrition. Hence it is advised to take nutrient dense food in the first of the day and liquid calories towards the end of the day which may help in reducing the symptoms while providing sufficient nutrients 30. Avoiding carbonated or fizzy drinks may help reduce symptoms of bloating.

Fibre is poorly digested and slow to empty from stomach. Undigestible fibre including pectin, cellulose, hemicellulose, lignin, and fruit tannins may increase risk of forming compact indigestible mass called bezoar. Presence bezoars may further decrease the intake. High fibrous food for example whole grains, whole pulses, raw vegetables, celery, pumpkin, green peas, strawberry, citrus fruits, grapes, apple, coconut, dried fruits like dates, fig, prunes, and raisins can be avoided or restricted. Use of commercial high fibre formulas or bulk forming laxatives should be avoided.

Monitor and supplement iron, vitamin B12, vitamin D and calcium when needed. In case of severely malnourished patients’ multivitamin and mineral supplement should be given for a month or more till the store is replenished. Liquid form of iron is well tolerated compared to tablets 4.

Poor oral intake and malabsorption are the major concern in the nutritional management of the gastroparesis. Adequate nutritional intake should be managed through oral dietary modification along with oral nutritional supplements if necessary. When oral intake is not adequate to meet the requirement and patient fail to gain weight or continue to lose weight, then enteral nutrition should be initiated 31.

Enteral nutritional delivery below pylorus is well tolerated and seem to be more effective in providing sufficient nutrition and hydration as well as medication. In more severe cases where long term enteral nutrition support is needed, percutaneous endoscopic gastrostomy with jejunal extension is advised as it is found to be associated with lower symptoms than other enteral routes. Standard polymeric formulas are well tolerated and no need of any special formulas. Exclusive long term parenteral nutrition is considered in most advanced cases 32.

Gastric dysmotility is very common problem in critically ill patients and is associated with feeding intolerance, risk of aspiration pneumonia and progressive malnutrition. Feeding intolerance may be associated with the presence of symptoms such as increased abdominal circumference, bowel distension, vomiting or abdominal pain. According to the recommendation made by ESPEN and ASPEN on nutrition therapy in ICUs 33, 34.