Food Protection Trends - September/October 2020 - 376

to the microvascular (small blood vessels) and macrovascular
(larger blood vessels) systems (8, 58).
People with diabetes are at increased risk of foodborne
infection (20, 38, 40, 51, 52). During a Salmonella Enteritidis
outbreak in a hospital setting, a case-control study revealed
that patients with diabetes who required medication to control
their blood glucose levels (insulin or oral hypoglycemia
medication) were more likely to develop salmonellosis (52).
Neal and Slack (40) studied notified cases of Campylobacter
gastroenteritis in adults over a 14-month period in the United
Kingdom and found that diabetes mellitus increases the
risk of campylobacteriosis, similar to the scenario seen with
salmonellosis. Risk of listeriosis also may be elevated among
people with diabetes (51). Mook et al. (38) reported that
diabetes increased the risk for serious infection from Listeria
monocytogenes; patients with diabetes had an 11-fold increased
risk of developing listeriosis. Even greater risk of infection with
listeriosis was suggested by Goulet and Marchetti (20), who
stated that patients with insulin-dependent diabetes were 25
times more likely to develop listeriosis than were healthy, nondiabetic individuals.
Aside from the increased risk of contracting foodborne
infections for people with diabetes, the symptoms associated
with foodborne illness could trigger life-threatening diabetes complications in this vulnerable group. Excessive
vomiting can lead to hypoglycemia (low blood glucose
concentration), which can be abrupt and if left untreated
can lead to blurred vision, slurred speech, confusion, and
even loss of consciousness (10). Diabetic ketoacidosis is
another potentially dangerous condition that may develop in
people with diabetes as a result of foodborne infection (37).
Diabetic ketoacidosis is most commonly associated with type
1 diabetes and occurs when the body has insufficient insulin
to allow enough glucose to enter cells, causing the body to
burn fatty acids and produce acidic ketone bodies (11). A
high concentration of ketone bodies in the blood can cause
particularly severe illness, including coma or death, when not
treated quickly (1).
WHY ARE PEOPLE WITH DIABETES AT AN
INCREASED RISK OF FOODBORNE INFECTION?
The increased risk of foodborne infection among people
with diabetes is likely due to autonomic neuropathy, in which
elevated blood glucose causes damage to nerves that control
involuntary bodily functions, including digestion (53).
Within the digestive system, autonomic neuropathy may
result in gastroparesis, a condition in which reduced smooth
muscle control slows or stops the movement of food from the
stomach to the small intestine (25). The resultant prolonged
gastrointestinal transit time can give harmful bacteria time
to multiply (30). Gastroparesis probably affects 20 to 50%
of the individuals with diabetes and is especially common in
those with type 1 diabetes or those with long-standing (>10
years) type 2 diabetes (3). Production of gastric acid, which

376

Food Protection Trends September/October

is responsible for the breakdown of food and beverages in
the stomach, may also be reduced. Because hydrochloric acid
functions as a barrier to ingested bacteria, reductions in this
acid would limit the bactericidal activity in the stomach (17).
Poor glycemic control (inability to maintain appropriate
blood glucose concentrations) seems to be an important risk
factor in the increased susceptibility of infection for people
with diabetes and is powerfully associated with serious
infections (9). A review of epidemiological studies revealed
clinically important (ca. 1.5 to 3.5 times higher) infection
risks associated with poor glycemic control (45). Poor
glycemic control also is associated with impaired neutrophils
(27), white blood cells that are important in the early stages
of the immune response to foodborne infection (13).
Therefore, how well an individual manages her or his diabetes
and maintains blood glucose concentrations may impact the
risk of foodborne infection. In particular, those individuals
with type 1 diabetes are less likely to have good glycemic
control (9) and thus may be at approximately double the
risk of foodborne infection compared with individuals with
type 2 diabetes (5). Poor glycemic control among individuals
with type 1 diabetes also has been associated with low
socioeconomic status and depression and is more likely to
occur in young adults (22, 31).
HOW TO REDUCE THE RISK OF FOODBORNE
INFECTION AMONG PEOPLE WITH DIABETES?
Considering the number of people with diabetes
worldwide, the increased risk of foodborne infection, and
the potentially life-threatening diabetic complications
associated with foodborne infection; individuals with
diabetes are an important group to target in the context of
food safety education. Engagement with this vulnerable
group and promotion of food safety education is of particular
importance. People with diabetes often are unaware that they
are at increased risk of foodborne infection (15). Optimistic
bias and feelings of personal invulnerability are common,
whereby any risk is perceived to be greater to others than
to themselves (14). Consequently, food safety education
initiatives may be overlooked because they are perceived to
be aimed at those individuals at greater risk (44).
Given the importance of attitudes in relation to behavior
change (42), targeted interventions must address an
individual's perceptions of risk, control, and responsibility
for foodborne infection (14). Interventions must be clear
concerning 'why' these individuals are more susceptible
to foodborne infection, highlight 'what' practices should
be followed, and demonstrate 'how' engagement with
the recommended practices will be beneficial in reducing
the associated risks. Individuals with diabetes should be
encouraged to assess risk and determine whether they
are going to adopt risk-reducing behaviors. Constructs of
the Health Belief Model (18) should be considered in the
development of targeted interventions. For example, when

Food Protection Trends - September/October 2020

Table of Contents for the Digital Edition of Food Protection Trends - September/October 2020