Nutritional yeast is high in purines. Specifically, purines like adenine and guanine convert to uric acid, which may increase levels in the blood over time. Other vegetarian foods high in purines include bee pollen, chlorella, and possibly spirulina. Beer and fructose may also increase uric acid production. Fructose also inhibits the excretion of uric acid from the body. Beer may also have this same effect. Hope this helps!