Throughout life, nutrition is an important determinant of health, physical and cognitive function, vitality, overall quality of life, and longevity. The quantity and variety of available foods, as well as the meaningfulness of the social interactions provided by meals, are important to psychological well-being. The composition of the diet and the amount that is consumed are strongly linked to physiological function. When a well-balanced diet is not maintained, malnutrition may develop with consequent detrimental effects on health and well-being.


Malnutrition can have many manifestations. As outlined in Chapter 40, a diet that is deficient in one or more required nutrients (e.g., calories, protein, minerals, fiber, or vitamins) can lead to a state of nutritional deficiency. The greater the magnitude and duration of the nutritional deprivation and the more fragile the individual, the more likely nutritional deficits will produce noticeable body compositional changes, functional impairments, or overt disease. Even borderline dietary deficiencies can have important health consequences such as producing subtle organ system impairments, diminished vitality, or increasing the individual's susceptibility to disease. Protein and protein-energy undernutrition are two of the most common, frequently unrecognized, and potentially serious forms of nutritional deficiency. The prevalence of these conditions is particularly high among chronically ill older individuals and those in hospitals, nursing homes, and other institutional settings. Although there is a complex interrelationship between nutrition, disease, and clinical outcomes, protein and protein-energy undernutrition appear to be significant contributors to disease-related morbidity and mortality in these populations. At the other end of the spectrum, the persistent consumption of excess quantities of one or more nutrients can have similar untoward consequences. Forms of malnutrition that result from excess consumption include hypercholesterolemia, hypervitaminosis, and obesity. Studies indicate that obesity is the most common nutritional disorder of advanced age in western societies with a high prevalence among the noninstitutionalized free-living elderly. Many obese older individuals have other nutritional disorders. Among chronically ill or functionally debilitated obese older individuals, protein undernutrition is a common, serious, and frequently unrecognized problem that can develop for many reasons including an imbalanced diet, disease, and inactivity.


Recognizing and maintaining an optimally balanced diet is an important challenge, particularly as individuals age. The challenge is particularly great for older people who already are malnourished, especially if they have nutritional disorders that developed earlier in life, such as obesity, osteoporosis, or protein undernutrition. Even healthy individuals often fail to maintain an optimal diet owing to lack of knowledge, resources, or willpower. The process of aging can introduce other factors including acute and chronic disease, physical disabilities, social isolation, use of multiple medications, depression, impaired cognitive ability, and disregulation of appetite control that may contribute further to poor eating habits and the development or exacerbation of nutritional disorders. In turn, inappropriate dietary intake and poor nutritional status can impact the progression of many acute and chronic diseases such as coronary heart disease, cancer, stroke, diabetes, and osteoporosis, which are among the 10 leading causes of ...

Want access to your institution's subscription?

Sign in to your MyAccess Account while you are actively authenticated on this website via your institution (you will be able to tell by looking in the top right corner of any page – if you see your institution’s name, you are authenticated). You will then be able to access your institute’s content/subscription for 90 days from any location, after which you must repeat this process for continued access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess account, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessMedicine Full Site: One-Year Subscription

Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessMedicine

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.