Loss of vision is one of the most feared consequences of aging. Adults with poor vision are at a significantly higher risk for many social and health problems including depression, social withdrawal, accidents, and self-administered medication errors. Common causes of blindness in adults include macular degeneration, cataracts, glaucoma, and diabetic retinopathy.

Age, stress, and poor nutrition can sap our immune system of its effectiveness. Influenza provides one example; during young adulthood, when the body can mount a robust immune response to this common virus, influenza is rarely fatal. Among the elderly, however, the virus is associated with significant rates of death and hospitalization.