Grains also cause acid reflux for many people. Singers should also have only very small amounts of dairy because it increases mucus. Of course smoking is bad also.
It's true that there can be a bit of swelling of the vocal folds around the time of menstruation. While it may not be necessary to stop singing completely, my teachers always recommended to be careful and get a little more rest around this time. It is common for some people to get a little more vocally tired during their cycle.
