Even if you have a healthy diet, you should consider supplementing it with vitamins, minerals, and herbs to promote optimal daily wellness and to boost your immune system. While there is some debate about the value of taking supplements, almost everyone would allow that taking a daily multivitamin can help prevent deficits. If you aren't doing this now, start. Many manufacturers offer such multi-caps in formulas specially designed for seniors, and you may want to opt for one of those.
Beyond this minimum, many people use supplements to support their immune systems and to improve their mental sharpness, circulation, bone-density, libido, weight-loss, or breathing. The claims and counter-claims in such areas can be complex and inconclusive. If you're wiling to investigate and inquire, however, you're bound to find supplements that can benefit you.
Buy a bottle of daily multi-caps, not at the local supermarket, but preferably at your local food co-op or health food store, or even at a place like GNC. As you shop, talk to the clerk about the various manufacturers and their products. Discuss your overall health and see what recommendations the clerk makes. Don't buy any more that the original multi-caps you came in for, but when you get home research some of the other products on the Web.