Weak Digestion – Causes and Foods to Avoid

We all experience digestive problems at some point in life This is often due to overeating and indigestion which quickly passes after few hours or infection like the stomach flu which eases within  few days.  However, for some people digestion problems is a daily problem and can cause severe discomfort after eating. This is commonly termed as weak digestion but can refer to  host of digestive condition.

What does weak digestion mean?

Weak digestion is not a medical term but refers to maldigestion. This simply means that digestion is impaired in some way that hampers absorption of nutrients and can lead to symptoms like nausea, bloating, abdominal cramps, diarrhea, excessive flatulence and fatty stools. Due to the length of the gut and host of organs associated with digesting, weak digestion could refer to a problem anywhere in the digestive system.

Since digestion is related the breakdown of food, most of the symptoms due to weak digestion tend to start within a few minutes to several hours after eating a meal. The upper digestive tract, from the mouth to first part of the small intestine, are themain areas involved with digestion whereas the lower parts focus more on absorption. Therefore  weak digestion usually indicates a problem in the upper parts of the digestive tract.

Read more on digestive problems.

Where does digestion start?

Digestion starts in the mouth the moment food is eaten. There are two types of digestion – mechanical and chemical. Mechanical digestion involves crushing, grinding and mixing to physically break down food. Chemical digestion involves the action of digestive enzymes to chemically reduce complex substances into simpler ones which can be absorbed.

Mouth and Esophagus

The teeth and tongue are responsible for mechanical digestion while the enzymes in saliva start chemical digestion in the mouth. The teeth grinds, cuts and crushes food into a soft mass for easier swallowing. Food is then rolled into a ball (bolus) and the pushed into the throat and then into the esophagus. Minimal digestion occurs in the esophagus as food is quickly pushed down it from the throat to the stomach.


Once in the stomach, more ‘aggressive’ digestion commences. The strong muscles in the stomach wall contract and relax to mechanically digest the food. At the same time the glands in the stomach wall release strong gastric acid and powerful digestive enzymes to chemically digest the food. This can persist for several hours as foods is mixed broken down and mixed with water and mucus.


The semi-solid mixture known as gastric chyme is then passed out of the stomach into the duodenum (first part of the small intestine). Here bile from the gallbladder is released to emulsify fats in the food. The more fat, the more bile is secreted. The pancreas also releases digestive enzymes into the duodenum based on the food composition. Another major part of chemical digestion occurs in the duodenum.

Digestion and Absorption

Digestion then continues as chyme moves down the small intestine. Further enzymes are secreted from the wall of the small intestine. Strong contractions to push forward the chyme known as peristalsis also crushes and squeezes the food until it is fully digested. Absorption of nutrients can occur in the mouth onwards but most absorption occurs within the small intestine. If food is not properly digested, absorption is then impeded.

Causes of Weak Digestion

A host of conditions can lead to poor digestion. Some of these conditions may be acute meaning that it is intense but lasts for a short period of time until it is treated or resolves on its own. Others may be chronic conditions where it persists for long periods of time and treatment may only be able to manage but not resolve it. Some of the possible conditions that can lead to weak digestion include:

  • Mouth and Teeth
    – Parotitis (parotid gland inflammation)
    – Salivary gland stones
    – Sjogren syndrome
    – Salivary gland tumors including cancer.
    – Poorly fitting dentures.
    – Lack of teeth.
  • Stomach
    – Gastric atrophy
    – Gastroparesis
    – Gastric outlet obstruction
    – Gastroenteritis
    H.pylori infection
    – Menetrier disease
    – Stomach cancer
    – Surgery – gastric resection, gastric bypss surgery, gastric bands, vagotomy.
  • Gallbladder and Pancreas
    – Gallstones
    – Cholecystitis (gallbladder inflammation)
    – Cholangitis (bile duct inflammation)
    – Bile duct stricture
    – Pancreatitis
    – Pancreatic exocrine insufficiency
    – Cancer of the gallbladder, bile duct or pancreas.
    – Surgery – gallbladder removal (cholecystectomy).
    * Liver problems can also affect digestion if bile production and outflow is impaired.
  • Small Intestine
    – Enteritis (small intestine inflammation)
    – Celic disease
    – Lactose intolerance
    – Tropical sprue
    – Short bowel syndrome
    – Small intestine bacterial overgrowth (SIBO)
    – Cancer of the small intestine
    – Surgery – gastroduodenal bypass surgery

Conditions like Crohn’s disease (a type of inflammatory bowel disease) can affect any part of the gut where it causes inflammation and ulceration of the gut walls. Similarly people with irritable bowel syndrome (IBS) may also experience digestion problems when the food moves too rapidly through the gut. Any cause of diarrhea may also be responsible, such as viral gastroenteritis.

Foods To Avoid for Weak Digestion

Many people with a weak digestion can identify problem foods which elicits symptoms after eating that specific food. When the problem food cannot be identified, a food diary may prove helpful. An elimination diet is another technique that can be used to isolate trigger foods.

  • Fried, greasy and fatty foods can be a problem for people with gallbladder problems or where the gallbladder has been removed due to reduced bile secretion.
  • Milk and dairy products are not digested by people with lactose intolerance. These undigested nutrients can then irritate the digestive tract.
  • Fructose (fruit sugar) and sorbotil (artificial sweetener in certain chewing gum) can also be a problem in people who have problems digesting and absorbing these substances.
  • High fiber foods such as fruits and vegetables can irritate the gut of any person as it cannot be digested within the human body.
  • Spicy foods or foods laden with other irritants like acid may also trigger digestive symptoms in conditions where the gut lining is inflamed or injured.
  • Wheat and other foods with gluten may be a problem for people with conditions like celiac disease and tropical sprue.

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