Your overall health depends on the healthy functioning of your digestive system, which not only pulls nutrients from food to nourish the body, but also plays a role in protecting it from disease.
The development of a disorder, disease or cancer associated with the gastrointestinal (GI) tract can have a devastating impact on quality of life, yet stigma surrounding the symptoms, no matter how common they are, can prevent people from seeking medical advice.
Even common digestive disorders such as Irritable Bowel Syndrome (IBS), chronic constipation and reflux can be very disruptive. IBS in young people can lead to time lost from school or college. In older people it can lead to absenteeism at work, or a decrease in productivity. For some people, these conditions can be as disabling as serious heart or lung conditions.
CAUSES, SIGNS AND SYMPTOMS
Many digestive disorders have shared symptoms, which can complicate diagnosis. Indigestion, fullness after meals, abdominal pain, constipation, diarrhoea, flatulence, nausea and vomiting can have a host of different causes.
“Red flag” symptoms are of particular concern. They include difficulty swallowing, persistent vomiting, unintentional weight loss, loss of appetite, vomiting blood, blood in the stool, or a sudden change in bowel pattern in a middle-aged to older person. They may have a benign explanation, but could be an indicator of something more sinister. Delaying seeking medical advice can exacerbate the problem, especially in the case of cancer.
See the list below for the causes, signs and symptoms associated with the most common digestive disorders.
PREVENTION AND TREATMENT
There has been a significant increase in digestive disorders in recent decades as diets have changed. As people have gotten heavier, the prevalence of oesophageal reflux, oesophageal cancer and colon cancer have all gone up.
Achieving and maintaining a healthy body weight is important in preventing and managing digestive disorders. Eating a healthy Mediterranean-type diet also makes a difference.
Alcohol intake has a variety of effects on the GI tract, and contributes to a number of GI cancers. Smoking is also a risk factor, and has a negative impact on Crohn’s Disease.
The gut microbiome, the population of microorganisms living in our digestive tract, is very important to digestive health. Changes in the microbiome may be significant in IBS and Inflammatory Bowel Disease (IBD), and perhaps even in GI cancers. Products which modify the microbiome, including antibiotics, probiotics or prebiotics, will have an increasing role to play in the management of GI disorders in the future.
The list below is by no means exhaustive, but a summary of the most common disorders diagnosed among Irish people.
Indigestion and heartburn
As average body weight has increased, Ireland, in line with the rest of the western world, has seen an increase in the prevalence of gastro-oesophageal reflux. The spectrum of this disease can range from occasional heartburn, to further complications including oesophageal cancer.
Dyspepsia, the medical term for indigestion, can include heartburn but also other symptoms coming from the stomach and the upper GI tract such as nausea and vomiting. The cause is often unknown. Dyspepsia overlaps a lot with IBS (see below).
Reflux can usually be managed using acid-suppressing drugs, but may occasionally require surgery.
Helicobacter pylori
While the spiral-shaped bacterium Helicobacter pylori is decreasing in prevalence in developed countries like Ireland, it is still common, especially in older people. Data from 2009 shows 9 per cent of children in Ireland were infected, though rates in older people could be as high as 60 per cent, in line with international studies.
Although most people don’t develop symptoms, the bacteria can penetrate the stomach lining, leading to gastritis (inflammation of the stomach), gastric ulcers, duodenal ulcers, and very rarely, gastric cancer. It is a water-borne bacteria, so good hygiene can prevent infection, and it can be eliminated by antibiotics.
Coeliac disease
One in every 100 Irish people has Coeliac disease, an autoimmune disorder where the ingestion of gluten (a protein found in wheat, rye and barley) causes the body to attack the lining of the small intestine, reducing the ability to absorb nutrients from food. Some experts believe Ireland has the highest incidence of Coeliac disease in the world, due to a combination of genetics and exposure to a high wheat diet.
Diarrhoea is the most common symptom, but often patients are only diagnosed after presenting with a deficiency in iron or folic acid. In the past, almost all patients had weight loss, but that is uncommon now.
A very accurate blood test can check for Coeliac disease, making diagnosis easy. The only treatment is a strict gluten-free diet.
Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome, or IBS, is prevalent in about 10 per cent of adults in Ireland. The classic symptoms are intermittent abdominal pain, constipation or diarrhoea, bloating and flatulence. The pain is usually associated with bowel action – so when the person gets pain, they feel the need to go to the toilet, or when they have pain and do go it makes them feel better or worse. Anxiety or depression can exacerbate symptoms.
There is no test for IBS, but this constellation of symptoms in the absence of any other explanation leads to a diagnosis. The exact causes are unknown. There is a familial factor, though a genetic link has not been established.
Many IBS patients only experience symptoms after they eat. Patients used to be advised to take a lot of fibre, but it appears now that fibre may actually be a problem rather than a solution for some sufferers.
There is interest also in a group of carbohydrates called FODMAPs – found in otherwise healthy foods such as wheat, apples, pears, onions, garlic and dairy produce – that some people have difficulty digesting. Undigested FODMAPs end up in the colon, where bacteria ferment them, leading to cramps and diarrhoea.
There is no treatment for IBS, but symptoms can be managed through a controlled diet. A low FODMAPs diet has been shown to be effective for at least 70 per cent of people with IBS. Probiotics are being increasingly prescribed for the management of the condition.
Inflammatory Bowel Disease
There has been a significant increase in the prevalence of Inflammatory Bowel Disease (IBD) in recent decades in Ireland, which includes ulcerative colitis and Crohn's Disease. An estimated 20,000 people are affected by IBD in Ireland, according to the Irish Society for Colitis and Crohn's Disease (iscc.ie).
The “hygiene hypothesis” argues that as society becomes cleaner and more sanitised, there is less exposure to bugs in early childhood, and our immune systems are less able to deal with these immunological diseases later in life.
Symptoms include diarrhoea, abdominal pain and fatigue, caused by inflammation in the digestive system, usually in the lower sections of the small intestine (ileum and colon). IBD can be managed using a variety of drugs (anti-inflammatories, steroids, immune modulators and biological medications) and may involve surgery, but management needs to be individualised and supervised by experts.
Gastrointestinal cancers
Of all the gastrointestinal cancers, colon (also called rectal or colorectal) cancer is the most common. About 2,000 people are diagnosed in Ireland each year, and it is the second-most common cause of cancer death, according to the Irish Cancer Society. The disease has a significant genetic component. People with a history of IBD, or who eat a high-fat, low-fibre diet are also at increased risk. Symptoms range from abdominal pain to blood in the stool or anaemia. A bowel screening programme has recently been introduced in Ireland, which should improve rates of early diagnosis.
There has been a change in the nature of oesophageal cancer in recent decades. It used to be more common in the middle and upper sections of the oesophagus, but now it is mostly in the lower-third. The cell type has also changed, from a Squamous cell carcinoma, which is more common in elderly men who smoked and drank a lot of alcohol, to an adenocarcinoma, which is linked to reflux. Patients are usually diagnosed after experiencing difficulty swallowing.
Pancreatic cancer is becoming much more common. It is usually diagnosed very late, and has a very poor prognosis. Symptoms include abdominal and lower-back pain, and sudden weight loss.
Diverticulitis
Diverticula are pouches which develop in the wall of the colon. They are very common in older people and are associated with not eating enough fibre. For most people they cause no problem, but if they start to bleed or become inflamed or infected, it is called diverticulitis, which can cause an abscess or perforation of the colon.
Diverticulitis symptoms are similar to appendicitis, but with acute pain on the left side rather than the right. Fever, diarrhoea, and tenderness down the right side are also indications of the condition. Most patients respond to antibiotics; in a minority with complications, surgery may be required.
Constipation
Constipation affects about one in ten people in Ireland. It is more common in older people, who are more likely to have a low-fibre diet. It is also commonly complicates neurological disorders such as Parkinson’s Disease, and can lead to associated problems such as haemorrhoids or piles.
USEFUL LINKS
Irish Cancer Society
Eamonn Quigley is chief of the Gastroenterology and Hepatology Division at Houston Methodist Hospital in Texas, and principal investigator at the Alimentary Pharmabiotic Centre at University College Cork.