Give Your Dog a Daily Vitamin

"I believe taking daily vitamins improves health, and lessens the chances of disease," Messonnier says. "We live in a toxic world, and over time this damages people and dogs. Anti-oxidants provide at least some protection."

Dogs can get stressed out, too. What stresses out your dog? It's not likely to be a bad day at the office. But maybe it's been a rainy week and you haven't gone for your regular walks. Or perhaps loud Aunt Gertrude, who steps on dogs' tails, is visiting. Left unchecked, stress can prompt illness or exacerbate an existing problem. Vitamins help build immune response.

You might think only old dogs need vitamins. However, Messonnier says it's actually a good idea to begin with puppies. Still, it's never too late.

He says that essentially dogs require the same vitamins people do. You could share your multi-vitamin with your best friend. However, Messonnier says that rather than use a manufactured product meant for people, you'll be far better off if you use food sources, such as fish oil (for Omega-3 fatty acids) or alfalfa (which has vitamin K and properties that may thwart cancer) for many of the vitamins. Messonnier also suggests a multi-vitamin made for dogs.