The Natural Swallowing Process
The swallowing diagram illustrates the natural swallowing process. After the food is chewed, it travels to the back area of the mouth, as indicated in picture 1.
In picture 2, the airway closes off preventing any food from entering the passage to the nose. The area of the esophagus opens to allow the food to pass down the throat.
The airway is then able to reopen and breathing can resume normally, as illustrated in picture 3.
What Happens When Dysphagia Occurs
Dysphagia can result when this sequence is disrupted at any point. Weak tongue or cheek muscles may make it hard to move food around in the mouth for chewing. Food pieces that are too large for swallowing may enter the throat and block the passage of air.
Other problems include not being able to start the swallowing reflex (a stimulus that allows food and liquids to move safely through the pharynx) because of a stroke or other nervous system disorder. People with these kinds of problems are unable to begin the muscle movements that allow food to move from the mouth to the stomach. Another difficulty can occur when weak throat muscles cannot move all of the food toward the stomach. Bits of food can fall or be pulled into the windpipe (trachea), which may result in lung infection. (Ayers, Keller, Lee, 2003)
Some causes of dysphagia include:
- Muscle disorders (dermatomyositis, myotonic dystrophy)
- Nervous system problems
- Obstructive lesions in the throat or esophagus, such as tumors
- Central nervous system infections
- Vitamin B12 deficiency
- Head injury
- Cerebral Palsy
- Parkinson’s Disease
- Huntington’s Disease
- Myasthenia Gravis
- Amyotrophic Lateral Sclerosis
- Multiple Sclerosis
- Infection with herpes simplex virus or yeast
- Narrowing of the esophagus after infection or irritation
- Injury to the swallowing muscles from chemotherapy and radiation for cancer
- Birth defects (such as Oral-Facial Clefts)
- Head and neck cancers
- Scarring after radiation treatment for cancer
- Type 2 Diabetes
- Alcohol Abuse and Alcoholism
- Alzheimer’s Disease
- Post-polio Syndrome
- Thyroid disorders
- An estimated 25 million people in the United States have the current diagnosis of dysphagia.
- Approximately one million people annually receive a new diagnosis of dysphagia.
- Nearly 60,000 people die each year from complications associated with swallowing disorders.
Once dysphagia has been diagnosed, food texture needs to be modified. Pudding-like consistency is often prescribed for patients who have dysphagia.
Unfortunately texture-modified food can be unappealing – especially where the constituent parts of a meal are not identifiable. This may be alarming or confusing to consumers, especially those with a degree of cognitive impairment. Texture-modified food may also be low in nutrient density if liquidized with water. These factors are problematic if eating is tiring or stressful for the patient or if they are also experiencing a range of physical, psychological and social problems affecting their appetite and nutritional status. Food surveys of individuals on texture-modified diets have frequently found lower intakes of energy and protein than those consuming a normal diet. (Wright, Cotter, Hickson, 2005)
- Ayers Tiffany, Keller Lauren, Lee Tyler, “About Dysphagia” (2003): (Western Kentucky University Department of Communication Disorders).
- Wright L, Cotter D, Hickson M, “Comparison of Energy and Protein Intakes of Older People Consuming a Texture-modified Diet with a Normal Hospital Diet,” Journal of Human Nutrition and Dietetics 18 (2005): 212-220.