You can have just one symptom or a combination of symptoms. Your IBS may be severe or it may just flare up occasionally.
"The first thing you need to do is be formally diagnosed by your GP as a lot of other medical conditions are similar, for example endometriosis or colitis and these need to be discounted," according to dietitian and British Dietetic Association spokesperson, Sioned Quirke.
The symptoms of IBS often occur after eating, so food is often blamed as the cause but experts say the link between food and mood shouldn't be underestimated.
There's no definitive cause of IBS. Some doctors believe IBS is largely down to your state of mind. Even though its symptoms are very real and are often painful and embarrassing.
"IBS is the visceral expression of what's happening in a person's life," according to Dr Nick Read, gastroenterologist and medical adviser to the IBS network.
He says there seems to be a real connection between our brains and our guts, "So many people come to see me with IBS and there's nearly always something going on, they are pushing themselves or there's been a change, trauma or worry in their lives."
He says: "Food does have an influence because if a person is anxious or upset it makes their guts sensitive and that makes them more anxious and it becomes a vicious circle."
IBS and diet
Even taking on board the fact the IBS may have a psychological basis, what we eat and drink can have a dramatic effect on symptoms.
The general guidance from NICE, the National Institute for Health and Care Excellence, for people with IBS in England and Wales is:
Eat regular meals
Drink at least eight cups of fluid a day
Restrict coffee and tea to three cups a day
Reduce alcohol and fizzy drinks
"Take time to eat your food and chew it properly," says Sioned, "you need to give your gut as much help as you can."
Dump the junk
NICE also recommends reducing your intake of what's called resistant starch, often found in processed or pre-cooked foods.
The British Dietetic Association (BDA) suggests cutting down on rich and fatty foods like pies, fast foods and pizzas, as well as snacks like crisps, chocolates and cakes.
"Some people with IBS have a problem digesting fat, it can lead to loose bowel movements," says Sioned. "So avoid manufactured food and prepare fresh if you can."
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