It’s possible but unlikely. Some nutrients, especially in vegetables, are heat sensitive. If the motor heats up too much, it can kill some of the nutrients. Use quick pulses, and don’t leave the blender on for too long, or make a lot of back-to-back healthy items. Furthermore, the quality of the motor and how easily it turns the blades will also play into how much heat it throws. Less heat, more power in every sip of whatever you’re making.\r