This is true only for old or expensive crystal glasses.
Most common soda-lime glass has negligible amounts of undesirable impurities, while borosilicate glass, like I use for my food and drinks, is even more pure and it contains almost nothing besides oxides of silicon, boron, sodium and aluminum, and it is inert in contact with food.
Most common soda-lime glass has negligible amounts of undesirable impurities, while borosilicate glass, like I use for my food and drinks, is even more pure and it contains almost nothing besides oxides of silicon, boron, sodium and aluminum, and it is inert in contact with food.