There are many different fruits and vegetables, in fact, that cats and especially dogs will gladly eat that can help boost their immune systems, fight off infections, and even prevent the formation of chronic and debilitating illnesses like cancer.

Topping this list is 1) carrots, which both veterinarians and nutrition experts alike agree is highly beneficial for animals. Rich in beta carotene, carrots help promote healthy vision as well as scavenge damaging free radicals that cause oxidative damage in the body. Carrots also contain falcarinol, a bioactive compound that helps thwart the development of cancer.