Coeliac disease symptoms
A person with coeliac disease has a bad reaction to gluten that can cause symptoms including indigestion, stomach pain, bloating, diarrhoea, and constipation and loss of appetite.
Coeliac disease can cause malnutrition as nutrients from food aren't absorbed properly, leading to unexpected weight loss and conditions such as anaemia.
Symptoms differ from person to person and can be mild to severe.
Signs and symptoms of malabsorption
The three major categories of dietary nutrients are carbohydrates, proteins and fat. Absorption of all of these nutrients can be reduced in coeliac disease; however, fat is the most commonly and severely affected nutrient. Most of the gastrointestinal symptoms and signs of coeliac disease are due to the inadequate absorption of fat (fat malabsorption). Gastrointestinal symptoms of fat malabsorption include diarrhoea, malodorous flatulence (foul-smelling wind), abdominal bloating and increased amounts of fat in the stool (steatorrhea). The unabsorbed fat is broken down by intestinal bacteria into fatty acids, and these fatty acids promote secretion of water into the intestine, resulting in diarrhoea. Fatty stools typically are large in volume, malodorous (foul smelling), greasy, light tan or light grey in colour, and tend to float in the toilet bowl. Oil droplets (undigested fat) also may be seen floating on top of the water.
Loss of intestinal villi also causes malabsorption of carbohydrates, particularly the sugar lactose. Lactose is the primary sugar in milk. Lactose is made up of two smaller sugars, glucose and galactose. In order for lactose to be absorbed from the intestine and into the body, it must first be split into glucose and galactose. The glucose and galactose then can be absorbed by the cells lining the small intestine. The enzyme that splits lactose into glucose and galactose is called lactase, and it is located on the surface of the small intestinal villi. In coeliac disease the intestinal villi along with the lactase enzymes on their surface are destroyed, leading to malabsorption of lactose.
Signs and symptoms of malabsorption of lactose are particularly prominent in individuals with coeliac disease who have underlying lactose intolerance, a genetically determined reduction in the activity of lactase. Symptoms of lactose malabsorption (diarrhoea, excessive flatulence (passing wind), abdominal pain and abdominal bloating or distension) occur because unabsorbed lactose passes through the small intestine and into the colon. In the colon, there is a normal bacterium that contains lactase and is able to split the lactose, using the resulting glucose and galactose for its own purposes. Unfortunately, when they split the lactose into glucose and galactose, the bacteria also release gas (hydrogen and /or methane). A proportion of the gas is expelled and is responsible for the increased flatus (passing wind) that may occur in coeliac disease. Increased gas mixed in the stool is responsible for stool floating in the toilet bowl.
Not all of the lactose that reaches the colon is split and used by colonic bacteria. The unsplit lactose that reaches the colon causes water to be drawn into the colon (by osmosis). This promotes diarrhoea.