Strawberry Shortcake SPIRU-TEIN Shake Rich in flavor and nutrition--that’s SPIRU-TEIN! One of life’s true pleasures is enjoying a delicious treat you know is good for you in every way. Nature’s Plus is especially proud of its entire line of SPIRU-TEIN products. With zero fat, SPIRU-TEIN delivers a healthy infusion of plant-based protein, along with other essential nutrients.