Irish hospitals must become vegan friendly and cater for patients who are following the plant-based diet which shuns meat and dairy.
Wide-ranging new guidelines issued by the HSE to hospitals on food and nutrition point out that many principles of a vegan and vegetarian diet follow national goals for healthy eating and include higher intakes of complex carbohydrates, fibre, pulses, fruit and vegetables.
However, vegetarian dietary practices can vary in terms of the food individuals eat and exclude.
It can be difficult to meet the nutrition standards for energy and protein, the guidelines warn.
The patient needs to decide which foods they do not want to eat but the hospital also has to take into account clinical requirements when they are unwell.
Hospitals need to have a vegetarian option available once daily on the regular and healthy eating menu offering variety and choice of meals.
The report - 'Nutritional Care for Adult Patients in Acute Hospitals' - said a hospital stay can cause malnutrition in a patient due to their illness and change in food intake.
Older patients, people with cancer, those undergoing surgery and sufferers of gastrointestinal disease are particularly vulnerable.
"It is well established that the nutritional status of patients can deteriorate the longer their stay in hospitals and approximately two-thirds lose weight during their hospital stay," it said.
When a patient is admitted they should be screened for food, nutrition and hydration needs and risk of malnutrition.
This needs to be done weekly along with a record taken of basics, such as weight.
When patients have an extended stay in hospital they may develop "menu fatigue".
In this case they should have a supplementary a la carte menu to the regular fare to whet their appetite.
"When planning hospital menus, limiting fat, sugar and salt intake will not be appropriate for a large number of patients in times of acute illness when appetite may be reduced and when priority is to ensure adequate energy," it added.
The guidelines also highlight how "water is essential to health but is often overlooked". Patients should have access to chilled water 24 hours a day.