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Diabetes a Risk Factor for Foodborne Illness
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Fall 2005
Diabetes is on the rise. Today, 1 in 16 persons in the U.S. (6.3%) has diabetes, one fourth of whom don't know they have the disease. Another 15% have pre-diabetes, a condition in which a person's blood glucose levels are higher than normal, but not high enough to be diagnosed with diabetes. In total, the Centers for Disease Control and Prevention (CDC) estimate that one in three of us will be diagnosed with diabetes at some point in our lifetime. Diabetes is an autoimmune disease that results from either a loss of insulin production (type 1) or decreased ability to use insulin effectively (type 2). Insulin is a hormone needed to convert sugar, starches and other food into energy needed for daily life.
Immune Function
Both type 1 and type 2 diabetes disrupt the normal metabolism of macronutrients. Hyperglycemia occurs when glucose is not properly cleared from circulation. This excess glucose binds to cellular proteins in a process called glycosylation, impairing the normal functioning of cells throughout the body. These glycosylated end products are thought to cause persistent activation of immune cells as the immune system reacts to rid the body of these foreign substances. Over time the immune cells become desensitized and less responsive to stimulus by foreign pathogens. As the weakened immune cells become less effective, risk of infection increases.
Endocrine/Nervous Systems
Glycosylated end products are also harmful to the endocrine and nervous systems. The hormone-releasing cells of the gut's inner mucosal layer and the enteric system nerves of the gut wall control the functions of gastric acid secretion, gastric motility and emptying, immune defenses, and circulation. Glycosylation disrupts the normal functioning of these endocrine cells, thereby decreasing gastrointestinal motility and slowing the transit time of food through the gut. Additionally, in advanced stages of diabetes, glycosylation causes degeneration of nervous tissue, which further impairs gastric functioning. The end result of these abnormalities is that the body is more susceptible to invasion by possible foodborne pathogens. Decreased gastric acid production prevents the body from ridding itself of harmful microorganisms, while decreased digestive motility allows pathogenic microorganisms to remain in the digestive tract for extended periods of time, thereby increasing susceptibility to foodborne illness.
Pathogens of Concern
According to Calvert and Yoshikawa (2001), campylobacteriosis is four times more common and salmonellosis three times more common in persons with diabetes than in the general population. Also, persons with diabetes are 25 times more likely to have listeriosis (Goulet and Marchetti, 1996).
Campylobacter jejuni, which causes campylobacteriosis, is the most common cause of bacterial foodborne diarrhea in the United States. The organism is not usually spread by person-to-person contact, but instead is transmitted mainly through food and water sources. It can be present in unpasteurized milk, undercooked meats and poultry, and contaminated water. Because Campylobacter jejuni causes illness by invading the mucus membrane of the small intestine, the gastrointestinal abnormalities associated with diabetes compromise the effectiveness of the immune system in fighting the infection. In addition, the organism is able to remain in the body longer and perhaps cause more severe illness due to decreased gastrointestinal motility.
Salmonellosis is caused by Salmonella species, bacteria that are common in poultry and often passed to humans through raw or undercooked eggs. Salmonella species can penetrate the stomach and epithelial cells of the small intestine causing inflammation of the intestinal lining. Again, the decreased gastrointestinal motility associated with diabetes makes it harder for the body to get rid of pathogens, increasing the risk of a more systemic illness.
Listeria monocytogenes is an opportunistic pathogen. Those who have a condition that interferes with T-cell mediated immunity (extreme ages, pregnancy, cancer, AIDS, diabetes) are predisposed to listeriosis, which is a severe disease with a high fatality rate. Deli meats, frankfurters (not reheated), paté and meat spreads, unpasteurized milk, and smoked seafood are high-risk foods for listeriosis. The pathogen is easily destroyed by cooking or reheating.
Precautions
There are several important precautions persons with diabetes can take to avoid illnesses caused by foodborne infections and to strengthen their ability to fight infections if they occur. These include:
- Maintain good control of blood glucose levels with proper diet and exercise.
- Wash hands, knives, cutting boards and food preparation areas with warm, soapy water after touching raw poultry, meat and seafood.
- Cook poultry, meats and eggs adequately. Avoid raw or lightly cooked eggs.
- Avoid unpasteurized milk, cheese and juice products.
- Thoroughly rinse fresh fruits and vegetables under running water before eating.
- Observe all expiration dates for perishable foods that are precooked or ready-to-eat.
Sources:
- Centers for Disease Control and Prevention.www.cdc.gov/nccdphp/aag/pdf/aag_ddt2005.pdf.
- Calvet H, Yoshikawa T. Infections in diabetes. Infectious Disease Clinics of N America, 2001; 14:407-421.
- Soory M. Hormone mediation of immune responses in the progression of diabetes, rheumatoid arthritis and periodontal diseases. Immune, Endocrine & Metabolic Disorders, 2002; 2:13-25.
- El-Salhy M. The possible role of the gut neuroendocrine system in diabetes gastroenteropathy. Histology and Histopathology, 2002; 17:1153-61.
- Prescott L, Harley J, Klein D. Microbiology, Fifth Edition. McGraw Hill, 2002.
- "Bad Bug Book," www.cfsan.fda.gov.
- Telzak E, Greenberg M, Budnick L, Singh T, Blum S. Diabetes Mellitus: a newly described risk factor for infection from Salmonella enteritidis. J Infectious Diseases, 1991; 164:538-41.
- Goulet V and Marchetti P. Listeriosis in 225 non-pregnant patients in 1992: clinical aspects and outcome in relation to predisposing conditions. Scand J Infect Dis. 1996; 28:367-74.
