Diet for gastro: the low FODMAP diet during the recovery phase after gastroenteritis

DIET for GASTRO: The low FODMAP diet during the recovery phase after an episode of gastroenteritis

Dr Jane Muir, Dr Marina Iacovou, Dr CK Yao and Dr Judy Moore - Research Dietitian, 29 May 2016

    If you have recently experienced the following tummy symptoms after a recent overseas trip or after a bout of ‘food poisoning’, it is likely that you had an episode of acute gastroenteritis.


  •  Abdominal pain, bloating
  •  Nausea 
  •  Vomiting with frequent, watery bowel actions
  •  Lethargy or fatigue
  •  Lack of appetite
  •  Malaise (general feelings of discomfort, illness)

These symptoms are often short-term and can last between a few days to a week. However, research is showing that a small proportion of people can then go on to develop symptoms of irritable bowel syndrome (IBS). In a Nottingham survey1 of people reporting an episode of bacterial gastroenteritis (food poisoning) over a 6 month period,  

  • 25% had symptoms persisting up to 6 months.

  • 1 in 14 then went on to develop IBS (or what is termed ‘post-infectious IBS’)

  • Women or those with a longer duration of the gastroenteritis were at greater risk of developing post-infectious IBS

Unfortunately there is limited scientific evidence to guide our recommendations for dietary management for gastroenteritis. Below we have provided some practical suggestions which may be helpful for your recovery.

Days 1-2:  Acute phase

During the first 24-48 hours the main priority to manage gastroenteritis is hydration and fluid replacement. During this period, the body loses a large amount of water and electrolytes and therefore there is a significant risk of dehydration. Ensure you are still getting more than 2-3 L of fluids per day. Incorporating oral rehydration solutions every few hours are an achievable way of replenishing electrolytes whilst promoting water re-absorption along the gastrointestinal tract.  Keep sipping fluids as much as you can.  There are oral rehydration solutions available from pharmacies.   Sucking ice blocks and sipping dry ginger ale can help.  If necessary, limit food intake.   You need plenty of rest.

Following the first 1-2 days you may start to feel hungry (a good sign). Take it slowly- a bland diet is best so avoid rich fatty foods, spicy foods, caffeine and dairy products.  Try flat lemonade, dry ginger ale, plain rice, dry toast *, dry biscuits*, clear soup* or broth *.   Have small frequent snacks as your appetite allows.

(*low FODMAP foods may be better tolerated – see below)

Days 3-5- Recovery Phase:

The Low FODMAP diet may be a useful dietary approach during the recovery phase after a bout of gastroenteritis once you are over the first acute 24-48 hr, and have started to re-introduce foods.  As fructose, sorbitol, and mannitol can also increase water delivery into the small and large intestine, temporary restriction of these FODMAPs may also alleviate symptoms. Changing over to lactose-free alternatives may also be beneficial as temporary lactase deficiency is common. You can always start by restricting intake of HIGH FODMAP foods and focusing predominantly on LOW FODMAP foods until symptom control is achieved.

You do not need to follow a low FODMAP diet once symptoms of gastroenteritis are resolved. Instead, use your symptoms as a guide as to when you can reintroduce high FODMAP foods and return to your usual diet.

If concerned, see your doctor

  • Of particular concern is if you can’t keep any fluids down for 24 hours, (and are showing signs of dehydration, dry skin, dry and sunken eyes, small amounts of very dark urine or no urine over 12 hours), you have a very high temperature (e.g. over 39 degrees), you are vomiting blood or have bloody diarrhoea- then go see your doctor. 
  • If your symptoms persist for more than a week, a visit to your doctor is worthwhile to exclude any other more sinister gastrointestinal causes. 
  • If you are pregnant or breastfeeding see your doctor immediately. You may need intravenous fluids.  
  • If you are at all concerned for any reason do not hesitate to call your doctor or the practice nurse.

It is important to ensure EXCELLENT HANDWASHING while you are unwell as gastroenteritis can be highly contagious.

Gastroenteritis in infants and children

Gastroenteritis in infants and young children is usually caused by a virus. It is highly infectious and typically spread when in contact with another person who has the illness. For this reason, infants and children are abstained from school, day-care or kindergarten while they are unwell. It is also very important in infants and children to see your doctor, especially if you have an infant less than 6 months of age or weights less than 8 kg.

Symptoms may include vomiting, diarrhoea, fever and tummy pains. As in adults, the main treatment is ‘fluids’, to prevent dehydration.

  • In breast-fed infants, it is important to continue breastfeeding, though they many need more frequent breast-feeds. Oral rehydration solutions or water maybe offered to infants. Instructions on preparing oral rehydration solutions, need to be strictly followed as described on packets. For infants under 6 months old, water must be boiled.

  • Oral rehydration solutions are available at pharmacies. They can be purchased in the form of powders (made up to a fluid solution) and icy-poles. The powdered option can be chilled and made up into ice blocks.

  • In formula-fed infants, their usual formula should be made up to normal strength (not diluted). Oral rehydration solutions may also be needed.

  • In young children who are able to drink out of a cup (or sippy-cup), offer oral rehydration fluids, water, or diluted juice. Avoid giving undiluted juices and high sugar drinks and foods, such as: jams, jelly, sweets and cordial. These contain too much sugar and may worsen diarrhoeal symptoms. Also avoid high sugar foods such as, jams, jelly and sweets.

  • Food intake is likely to reduce because of poor appetite. There is no reason to restrict intake or specific foods (besides high sugar products) during illness or once appetite returns.

  • Lactose intolerance may occur in some infants and children following an episode of gastroenteritis. See a doctor if this is suspected. In these cases, lactose-free products may be required for a few days/weeks until the gut recovers. In breast-fed infants, changes to the maternal diet are not recommended or necessary.     

For more information on managing gastroenteritis in infants and children please refer here

1Neal KR, Hebden J, Spiller R. Prevalence of gastrointestinal symptoms six months after bacterial gastroenteritis and risk factors for development of the irritable bowel syndrome: postal survey of patients. British Medical Journal. 1997; vol. 314: pages 779.

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