Fresh cucumber and pickles can have very different nutritional profiles.
Pickles are commonly made with significant amounts of salt, and some varieties can contain substantial amounts of sodium. Cleveland Clinic notes that a large dill pickle can contain more than two-thirds of the ideal daily sodium amount for an adult.
For people who have been advised to reduce sodium — particularly those managing high blood pressure or certain cardiovascular conditions — regularly eating large amounts of salty pickles may not be a good choice.
This does not mean you have to avoid all cucumbers. Fresh cucumber, especially when eaten without a salty dressing or heavily salted seasoning, is a very different choice from a highly salted pickle.