Too many to list. vitamin d deficiency alone can cause depression, poor bone formation, fatigue. Sever inadequate vitamin A intake can cause night blindness and visual problems. Patients who dont get enough iron, may feel tired and weak from anemia. The list goes on.... there are also examples of poor protein intake, or undercalorie intake as in anorexics- the best is moderation, variety and balance in what you eat.
Aging & Diseases. As it turns out,many diseases have been proven to be from a combination of factors, especially poor nutrition.-Poor nutrition & a low level of antioxidants are 2 of many major factors in many cancers, immune problems, & even blindness. We need 3-4 helpings of fruits & 3-4 helpings of vegetables everyday-Ask yourself-Did I eat 3-4 helpings of fruits and 3-4 helpings of vegetables today & everyday.
Too many to list in . The space available. Undernutrition and over-nurtition (obesity) are both diseases. For undernutrition see this site for information. http://www.ncbi.nlm.nih.gov/pubmedhealth/pmh0001441/.