The global demographic transition to an older population effects developing
as well as developed countries. By 2050, the world population over 60 years
of age is expected to reach two billion.
Mitochondria contain the only extra-nuclear source of DNA. Under evolutionary
pressure mitochondrial DNA (mtDNA) has adapted from genomes
containing over 1,000 kb containing significant quantities of non-coding DNA
to the highly compact mammalian mtDNA.
Caloric restriction (CR) retards the aging process in laboratory rodents
as characterized by a delayed occurrence or complete prevention of a broad
spectrum of age-associated pathophysiological changes and a 30–50% increase
in maximum lifespan .
It is becoming increasingly apparent that the early environment both before
birth and in infancy has profound effects on aging and long-term health. This
is due to environmental programming whereby influences acting at critical
periods of growth and development can permanently change structure and
function with lifelong consequences.
Aging is associated with predictable alterations in body fat that are thought
to have an important impact on health. From early adult life through middle
age there is a substantial increase in body fat [1, 2], while after 65–70
years of age body fat typically decreases, even in healthy individuals [1, 2].
We study body composition by dividing body mass into compartments
either by their function (bone, skeletal muscle, adipose tissue, extra-cellular
fluid, etc.) or by their chemical composition (water, protein, triglycerides, bone
mineral, glycogen, etc.).
The term insulin resistance (IR) defines an inappropriately low or absent
response of specific target tissues (skeletal muscle, adipose tissue, liver) to
the action of the hormone insulin.
Aging is associated with a higher risk for nutritional deficiencies which
cause adverse functional consequences. Functional and anatomic changes in
the gastrointestinal system could explain part of the nutritional alterations
observed in the elderly.
As a modifiable factor of bone health, unlike genetic factors, nutrition
deserves major interest, especially in the prevention of osteoporosis. Research
in this field first concentrated on the nutritional components of bone, such
as calcium, proteins, and vitamin D known for its direct impact on bone
metabolism, then on nutrients which influence bone metabolism
The concept that ‘we are what we eat’ is by no means a new one and
appears to be particularly true when one examines the effect of food intake on
Nutritional surveys in elderly populations have pointed to low energy and
nutrient intake. This is of particular concern among the homebound or frail
population groups [1–5] as reflected by considerable involuntary weight loss,
including net protein loss [6, 7] leading to muscle wasting .
Sarcopenia is the decline in muscle mass that occurs with normal aging.
Sarcopenia is a major cause of frailty, disability, and loss of independence
in the elderly .
It is clear that oxidative stress is associated with compromises to the lens.
Recent literature indicates that antioxidants may ameliorate that risk and may
actually decrease the risk for cataract.
Normal aging is often described as a continuous process characterized
by a decrease in lean body mass, an increase in fat, and a decrease in
total body water.
This work was supported by Federal funds from the US Department of
Agriculture, Agriculture Research Service under contract No. 58-1950-9-001,
and a National Institute on Aging grant AG 09140-07.
Aging is a continuum from birth to death but we age at various speeds
facing different aspects of aging. Chronological age is not a correct measure of
physical or intellectual age, because it might be considered only as one of the
facets of the aging process.
The fields of psychiatry and nutrition have been allied since Wernicke
and Korsakoff described the effects of thiamin deficiency in alcoholics, and
Meyer described the pathology of pellagra calling it central neuritis.