Which of the following is a common symptom of foodborne illness?

Nausea is a common symptom of foodborne illness, as it often occurs when the body reacts to harmful pathogens or toxins present in contaminated food. When an individual ingests contaminated food, the gastrointestinal system can be affected, leading to sensations of discomfort, queasiness, or the urge to vomit. This reaction is part of the body's defense mechanism to eliminate the harmful substances encountered.

Other options, such as hair loss, increased energy, and blurred vision, are not typical symptoms associated with foodborne illnesses. Instead, these symptoms may stem from other health conditions or factors that are unrelated to food safety, further emphasizing why nausea is recognized as a hallmark symptom in scenarios involving foodborne pathogens.