Can pitaya and apples be eaten together?
Generally speaking, dragon fruit and apples can be eaten together, as detailed below:

Dragon fruit is rich in dietary fiber, vitamin C, B vitamins, and various minerals such as calcium, magnesium, and phosphorus. Apples are also high in dietary fiber, vitamin C, vitamin K, and minerals like potassium and magnesium. There is no nutritional conflict between the two; rather, they complement each other and provide more comprehensive nutrition. Both contain antioxidants that help combat free radicals and protect the body from oxidative stress.
For individuals with a sensitive digestive system, consuming large amounts of different fruits simultaneously may cause gastrointestinal discomfort, such as bloating or diarrhea. For people with diabetes, consideration should be given to the impact of dragon fruit and apples on blood sugar levels. Although these fruits contain relatively low levels of sugar, excessive intake at one time may still cause fluctuations in blood glucose levels for those with poor glycemic control.
In daily diets, it is recommended to diversify food sources and maintain balanced nutrient intake, while also paying attention to individual responses to different foods in order to maintain good digestive health.