The gastrointestinal tract starts from the mouth and ends at the anus, plays very important role in digesting the food, absorbing the nutrients and throwing out the unwanted portions as feces. The different segments of the gastrointestinal tract undertake different functions.
Gastrointestinal disease is the second most common indication for hospital admission of elderly patients, second only to heart disease. Elderly suffer from digestive system ailments four times as commonly as do the younger adults.
Aging is not associated with a difference in either the desire to eat or the hunger response before a meal intake. But the postprandial hunger response and the desire to keep eating gets reduced. The person feels satiated too soon and therefore doesn’t eat in accordance to the hunger felt before the meal.
About 40% of elderly complain of a dry mouth. Chewing is difficult due to loss of lubrication, decreased muscle bulk of the muscles of mastication (chewing), reduced taste and smell perception and due to falling out of teeth.
Esophagus and Stomach
Esophageal function remains more or less preserved in old age except in extreme old age. Some minor movement inadequacy has been reported in some elderly in their 8th and 9th decades which has led to slower movement of food from the mouth into the stomach. Acid re flux is a noted problem in the old age with the tendency of re flux increasing four folds in old age compared to that in young adults.
The prevalence of atrophic gastritis in old age is significant. It is a condition in which the stomach tissue becomes paler, and less functional. The acid secretion decreases and therefore the digestion of protein that begins in the stomach by pepsin fails to get started. The absorption of iron and vitamin B12 is also dependant on the function of stomach mucosa. These are essential for blood cell production and since their absorption suffers, the result is nutritional anaemia.
The protective mechanisms of the stomach, like mucous, bicarbonate and prostaglandin secretions also start wearing off in old age, resulting in gastric ulcers. Statistically, aches and pains are pretty common in old age and elderly tend to be under some kind of pain killers, most common being the non-steroidal anti inflammatory drugs (NSAIDs). NSAIDs further impair the prostaglandin secretion in the stomach causing ulcers or worsening the existing ones. Stomach emptying is also variably impaired for both solids and liquids and hence they tend to not feel hungry.
The blood supply to the gut in general (called the splanchnic circulation) gets reduced and the part that suffers the most is the small intestine since this is the segment of maximum digestion and absorption as the food stays here for a pretty long time. The absorption of various nutrients remains fairly balanced. In fact, the absorption of fat soluble vitamins, especially vitamin A is increased. However, the absorption of zinc and calcium decreases with age.
Colon may appear to be significantly involved in old age from the very common complain of constipation in the elderly, but, the colon seems to be minimally affected in the elderly. The constipation is more closely associated with immobilisation and dietary factors.
The ano-rectal changes are significant more so in the elderly female. The tone of the lower anal sphincter is markedly reduced. This is partially because of loss of muscle mass and the withdrawal of hormones in post menopausal females. The rectal wall elasticity also decreases leading to both frequent urge and incontinence.
Pancreas shows significant aging changes. The tissue shrinks and the ducts dilate. There are some cases of duct stenosis (narrowing) leading to blockage of flow. The enzyme secretion reduces significantly, especially the bicarbonates.
The liver shows decrease in weight, as well as reduction in the number of liver cells. There are significant changes in alcoholics like scarring, fibrosis and cirrhosis. The enzymatic reactions of the liver mainly the detoxification reactions all get slowed down.
However, there are no age specific changes seen in conventional liver function tests.
As the bile secretion is reduced in elderlies, the gallbladder tends to respond slow to intestinal stimulation. The proportion of cholesterol and phospholipids increase in the bile leading to increased tendency of stone formation.
Physiological and structural changes due to aging, leading to alterations in diet:
Gastrointestinal Disease Specific in Elderly
- Zenker’s diverticulum
- Atrophic gastritis
- Gastric ulcers especially with H. pylori association
- Bowel diverticulosis
- Mesenteric infarcts
- Colon polyps and colonic cancer (cancer more prevalent in males)
- Biliary tract obstruction leading to jaundice
- Constipation and diarrhoea alternating in inflammatory bowel disease
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