Scientists don't know, for example, whether an herb that seems to raise the levels of antibodies in the blood is actually doing anything beneficial for overall immunity. There appears to be a connection between nutrition and immunity in the elderly. Older people tend to eat less and often have less variety in their diets. One important question is whether dietary supplements may help older people maintain a healthier immune system. But that doesn't mean the effects of lifestyle on the immune system aren't intriguing and shouldn't be studied.