Best supportive/preventative supplements for senior cat

My cat will turn 10 in a few months. He's had a few UTI's but hasn't had one in years. He also has IBD so he's on a limited ingredient diet and gets a probiotic for digestive health everyday. At his last visit they did a senior panel and everything came back great. Basically, he's pretty healthy.

But now that he is aging I am becoming worried about kidney disease or cancers as I know they affect older cats and can lead to their death.

I'm wondering if a daily supplement would be beneficial, or even one specifically for renal or cancer prevention. I know there are no miracles but I would like to do all I can to extend the quality and length of his life.

Does anyone have any thoughts on whether or not this is a good idea and/or recommendations for supplements?

I personally don't think that adding a supplement to a complete food is necessary or even a good idea.  http://www.petmd.com/cat/centers/nutrition/evr_ct_cats-really-need-nutritional-supplements    Adding vitamins and minerals could create issues with the balance or cause issues with too much of something.  Cats basically eat the same complete food each day unlike many people.

The one exception could be glucosamine chondroitin to help with joint health.  With IBD there may be a point at which your kitty will need vitamin B12 shots, I  have an IBD kitty and it hasn't become an issue but it is a possibility.  That is due to absorption issues in the intestines.  Many elderly people also reach a point where they need B12 shots but again that is an absorption issue.  

That's a great article, thank you! I was unsure about overloading on certain things if I gave a supplement. Right now he eats Merrick limited ingredient diet Turkey formula. He also gets plain cooked pork as a treat. I don't think I want to risk doing more harm than good. Thank you again!