I'm surprised that no one here had a doctor who mentioned the water issue. That was the first "line of defense" so-to-speak that my husband's doctor came up with. Two quarts, minimum a day. I've heard of the vinegar thing, and I'm glad it works for your dad. But Doc said that you need to get that uric acid out of your system, and water, water, water is the only way. I didn't mean to brush off dietary stuff, it's just that when it is so bad, you need something more, and the water, water, water is the way to go. As far as other dietary things go, go to arthritis sites. Gout is related to arthritis (related? If I remember right, it's been a couple of years since I did the research, I believe it is a form of arthritis). Cherries is one of the touted helps. Unfortunately right at the time diabetes reared its ugly head as well as arthritis/gout. So flooding his system with cherry juice wasn't an option.
My husband was in his late 50s when it happened. Me being a great "talk to everyone about it" kind of person discovered many people I know have it. A great artist I know gets it in his fingers. My father's been on allopurinol for years (love him dearly, but Daddy wouldn't drink a glass of water unless he was dying of thirst in the Mojave. Oh, excuse me, we spent lots of time in the Mojave, and I don't remember him ever drinking a glass of water). It is more common in men than women, and the toes are the start of it. Hubby thought he'd stubbed or jammed his toes, a natural thought since we were travelers at the time and we were always running into things in the trailer at night. But it got worser and worser (bad grammar on purpose!). At its worse, the food swelled so badly I was honestly concerned that his skin would split. That's when he gave up on any cure but the meds.
Even with the Rx, though, he did learn that two quarts is important to his health. Since this is the health line, I will add something that others might take into consideration. His "old man" (i.e. he is 61) drip drip rather than healthy stream has gone back to a "young man" healthy pee, so it has to be good for the prostate as well.