Tehillim 19:14 says:
גם מזדים, חשוך עבדך-- אל-ימשלו-בי אז איתם
Also from zeidis keep your servant away, let them not rule over me
Who were these grandfathers who wanted to rule over King David, and as King of Israel with an army at his disposal, why was he so afraid of a group of presumably old men?
Ruth 4:22 indicates that David's grandfather was a worker. David, as king, was trying to make sure the workers didn't have any control over him. That is, he was anti-union.
"Zeidi's" is the name of a traditional Jewish food, consisting of chicken nuggets in a spicy sauce whose recipe is as closely guarded as that of the ketoret. In our generation, the keepers of this recipe have a shop near Yeshiva University in New York City. Not being subject to the restriction on honey like the ketoret, "Zeidis" is irresistible, but can lead to heartburn. David is praying for relief from this heartburn.
Even from Zeidis spare your servant, that it may not control me, then I will be healthy
He was most probably scared of Eglon Melech Moav his ancestor.
Dovid Hamelech was lactose intolorent. Yes.
That explains why he wanted to stay away from Zitis, not Zeidis.
