Which of the following is a side effect of oral glucose?

Nausea is indeed a recognized side effect of oral glucose administration. When individuals consume glucose, particularly if taken rapidly or in higher doses than the body is accustomed to, it can lead to gastrointestinal discomfort, which may manifest as nausea. This reaction is generally due to the rapid increase in blood sugar levels and how the digestive system copes with the sudden influx of simple sugars.

While headache, diarrhea, and blurred vision can occur under various circumstances related to glucose levels or metabolic changes, they are not typically classified as direct side effects of oral glucose. Headaches might occur due to sugar fluctuations or dehydration, diarrhea could result from excessive consumption or intolerance, and blurred vision is more often related to uncontrolled blood sugar levels rather than the direct intake of glucose. Understanding the physiological responses to glucose intake helps in recognizing why nausea is a more immediate and direct side effect.