Whenever you eat a meal, the nutrients in your food must be broken down so they can be absorbed through the lining of your intestine. This is accomplished by chewing in your mouth, churning in your stomach and the activities of digestive enzymes, which chemically prepare nutrients for assimilation. A lack of digestive enzymes can lead to diarrhea, malabsorption and nutrient deficiencies.
Salivary
Digestion begins in your mouth, where chewing mixes food with saliva and introduces it to its first enzymatic degradation. Salivary lipase and amylase begin the digestion of fats and starches, respectively. Although their contribution to digestion is probably minimal in healthy humans, salivary enzymes may be important in people with cystic fibrosis or pancreatic failure, according to a May 2002 "Oral Diseases" review. Sjögren's syndrome, radiation therapy to the head and neck and medications are the most common causes of decreased saliva production.
Gastric
Your stomach produces its own digestive enzymes -- gastric lipase and pepsin -- which help to digest fats and proteins, respectively. In 1990, researchers at Georgetown University Medical Center reported that these enzymes are distinct from similar enzymes in pancreatic secretions. For example, gastric lipase penetrates certain fats, such as milk fat, to a greater degree than pancreatic lipase. Gastric enzymes are more effective in an acidic environment, so conditions that reduce acid secretion, such as acid-suppressing drugs, pernicious anemia or age-related atrophy of the gastric mucosa, can reduce the effectiveness of gastric digestive enzymes.
Pancreatic
Your pancreas serves two major functions that are important to your health. Exocrine activities include the production and secretion of digestive enzymes, such as amylases, proteases and lipases. Endocrine functions include the excretion of insulin, glucagon and other hormones. Pancreatic diseases can interfere with both exocrine and endocrine functions. A 2011 review in "Advances in Medicine" cites a variety of conditions that can impair the production or secretion of pancreatic digestive enzymes, including acute or chronic pancreatitis, cystic fibrosis, pancreatic cancer, Crohn's disease, celiac disease and surgical resection of the pancreas or intestine. In 1996, Italian scientists demonstrated that Sjögren's syndrome, an autoimmune disease, also interferes with pancreatic exocrine function.
Considerations
As soon as you place food in your mouth, digestive enzymes begin to break it down in preparation for absorption in your intestine. Several conditions affecting saliva production, gastric acid secretion or pancreatic exocrine function can lead to a lack of digestive enzymes. Pancreatic enzymes appear to be the most active in promoting optimal digestion, but salivary and gastric enzymes play important roles, too. If you have persistent problems with digestion, see your physician for an evaluation to determine if digestive enzyme supplementation might be helpful.
References
- "Oral Diseases"; Saliva and Gastrointestinal Functions of Taste, Mastication, Swallowing and Digestion; A.M. Pedersen, et al.; May 2002
- "Nutrition"; Lingual and Gastric Lipases; M. Hamosh; Nov-Dec 1990
- "Advances in Medical Sciences"; Pancreatic Enzyme Replacement Therapy for Pancreatic Exocrine Insufficiency: When Is It Indicated, What Is the Goal and How To Do It? J.E. Domínguez-Muñoz; March 2011
- "Scandinavian Journal of Rheumatology"; Pancreatic Exocrine Involvement in Primary Sjögren's Syndrome; P.A. Ostuni, et al.; 1996
