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Changes in Physiology of the Aging Elderly Adults – Research Guider

The paper 'Changes in Physiology of the Aging Elderly Adults' is a worthy example of a research paper on psychology.
Aging is a syndrome of changes that are deleterious, progressive, universal and (thus far) irreversible. Over the next several decades, the practice of medicine will be greatly influenced by the health care needs of the growing elderly population. The number of individuals over the age of 65 years in the United States could triple over the next 30 years and strategies to improve nutritional health in older individuals require a unique approach and sensitivity to the individual's needs (Morley and Thomas, 2007). According to estimates, as many as 85 percents of adults in long-term care facilities and more than half of all seniors cared for at home suffer from under-nutrition and malnutrition. The health-care personnel must be aware of the decline in physiologic reserve associated with aging and provide systematic nutritional care to them to prevent as well treat the disorders associated with aging, such as weakness, depression, incontinence, and frequent fractures. The physiological and biochemical effects of aging and the importance of nutrition to counter these effects are summarized in the following text.

Energy Requirement and Nutrition – The energy requirement of the elderly people is much less than the young ones because the metabolic rate becomes slower and they are physically less active. "Adults over the age of 70 have unique dietary needs," says first author Alice H. Lichtenstein, D.Sc., director of the Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts (USDA HNRCA). "Their bodies still require the same or higher levels of nutrients for optimal health outcomes.” Tufts university has adapted the food pyramid for the elderly to advise specific requirements of the elderly (Lichtenstein et al, 2008, p. 78).  The elderly should avoid empty energy food like alcohol or other beverages since their total food intake as well as digestion is much reduced and they have to receive their calories from the reduced intake only. The university recommends dietary supplements to fulfill the requirements of the other nutrients.    

Generalized weakness and arthritis - Decline of body weight and muscle mass; decrease in the lean body mass and weakening of the joints due to diminished chondroitin sulfate and hyaluronic acid in the cartilage tissues are responsible for the generalized weakness seen in the elderly. These changes may contribute to the development of osteoarthritis (Resnick and Dosa, 2005, P. 49).  Rheumatoid arthritis, on the other hand, is caused by the generation of autoantibodies against the cartilage proteoglycans leading to the autoimmune destruction of the joints. To build up or at least maintain the muscle mass, there should be adequate proteins in the diet (RDA: 0.8-1.0 g/kg).

Age-related decreased secretion of growth hormone (GH) has been implicated in the progressive weakness of the muscles during aging. Due to low GH, there is a decrease in muscle proteins in most tissues of the body accompanied by an increased fat deposition. This, in turn, decreases the total oxygen consumption and blood flow needs of the muscles, resulting in decreases in skeletal muscle blood flow and cardiac output. The administration of growth hormone shows a reversal of the effect of aging on the muscles

Skin changes - changes in the extracellular matrix proteins causes progressive wrinkling of the skin. Atrophy of perivascular connective tissue of hands and arms leads to senile purpura — loosening of the skin tissue and tear of the small blood vessels giving dark purple, irregularly shaped hemorrhagic areas. The protective subcutaneous fat layer is lost and skin becomes prone to injury and abrasions. Dehydration increases this risk of skin injury; therefore, a lot of fluid intake along with good nutrition (a couple of snacks per day) can help.

Kidney function and Blood Pressure - There is a gradual decrease in nephron number due to nephrosclerosis and glomerulosclerosis with the advancing age. The reduced number of nephrons (although benign) is reflected by a progressive decrease in both renal blood flow and glomerular flow rate (GFR). The deteriorating renal function is also, at least partly, responsible for increased systolic blood pressure with age because the renin-angiotensin system also becomes less efficient. A slight increase in systolic pressure usually occurs beyond the age of 60 years. This might results from the hardening of the arteries due to atherosclerosis that is triggered by the LDL-cholesterol in blood. The elderly, therefore, need to be particularly cautious about high cholesterol food. Although all the elderly do not respond to low sodium diets, the total daily intake of sodium should be restricted to 2.3 gm. People with hypertension should need less than 1.5 gm sodium per day.

Compromised renal function also delays the biological clearance of the administered drugs in the elderly, therefore, the doses of the medicine also need to be adjusted.

Brain Function, insomnia, and Alzheimer’s disease – The aging brain shows features of slowing of the metabolism. The brain fats become more unsaturated and synthesis of neurotransmitters like dopamine acetylcholine, norepinephrine, GABA and serotonin decreases. The effect is manifested as dementia and depression, sleep becomes more and more shallow and deep (stage IV) sleep is rare. Although deterioration in the mental faculty varies from individual to individual, some disease conditions appear to accelerate it. Depression is associated with nutritional deterioration in older persons and is highly prevalent among people of low socioeconomic status (German et al, 2010, P. In Press). Regular and adequate intake of foods rich in vitamin E and unsaturated fatty acids (PUFA) is essential for elderly individuals.

The connection between the physical or psychological stresses and aging is provided by glucocorticoid hormones. Cortisol is released under conditions of stress that lead to brain aging by a) reduced uptake of glucose in the neurons and b) reducing cellular superoxide dismutase and glutathione peroxidase activity in all brain areas. Estrogen prevents or even reverses cortisol-induced brain damage but the level of estrogens is known to diminish with advancing age.

Immune system and susceptibility to infection – Aging also induces immunosenescence and chronic inflammation due to a compromised ability to distinguish between self and foreign antigens. The prevalence of autoimmune disorders like rheumatoid arthritis and psoriasis is much higher in the elderly due to this immune-incompetence.  Aging also correlates with a progressive increase in the levels of proinflammatory cytokines, e.g., TNF-α, IL-1, and IL-6.

Malnutrition weakens the immune system putting the elderly people under increased risk of infections like pneumonia.

Hormones and Aging - A "neuro-hormonal clock" in the brain of mammals has been suggested to influence aging through altering gene expression throughout the body. The levels of dehydroepiandrosterone, melatonin, thyroid, and growth hormone decline with age, whereas that of catecholamines (epinephrine and norepinephrine) and glucocorticoids might increase.  Dehydroepiandrosterone protects against the harmful effects of cortisol and promotes lean body mass, reduces depression and improves immune function.

Osteoporotic Bones -  Elderly people are highly prone to spontaneous fractures because, over the priod of time, the bones lose calcium and become osteoporotic. Vitamin D insufficiency is common in elderly adults and leads to secondary hyperparathyroidism, bone loss, muscle weakness, and osteoporotic fractures (Mastaglia et al, 2010, P. In Press). Osteoporosis is also accelerated in post-menopausal women due to decreased estrogen levels.  Vitamin D (25-OH-D3) levels ≥20ng/ml must be maintained for good muscle function and strength and the elderly must be assessed for vitamin D nutritional status to avoid hypovitaminosis D and improve muscle function and strength.

General Considerations - Exercise is very important for the elderly (Tanaka and Seals, 2003, P. 2153) because of its effects on improving blood pressure and myocardial function, glucose homeostasis, bone density, insomnia, and even longevity. A high fiber diet is another consideration for the elderly. The GIT peristalsis gets slower with age and due to lesser physical activity. Food rich in fiber, e.g. consumption of whole grain products and whole fruit is recommended rather than the refined processed forms and canned juices.


Resnick Neil M. and Dosa David (2005) Geriatric Medicine. In Harrisons’ Principals of internal medicine (16th Ed. pp. 43-52). The USA. McGraw-Hill Companies, Inc.

Tanaka H. and Seals D.R. (2003). Dynamic exercise performance in Masters athletes: insight into the effects of primary human aging on physiological functional capacity. J Appl. Physiol, 95, 2152-2154.

Lichtenstein A.H., Rasmussen H., Yu W.W., Epstein S.R., Russell R.M. (2008). Modified MyPyramid for Older Adults. J Nutr., 138, 78-82.

German L., Kahana C., Rosenfeld V., Zebrowsky K., Wiezer Z., Frazer D. and Shahar D. R. (2010). Depressive symptoms are associated with food insufficiency and nutritional deficiencies in poor community-dwelling elderly people. The Journal of Nutrition, Health & Aging.,14, (In Press)

Mastaglia S.R., Seijo M., Muzio D., Somoza J., Nuñez M. and Oliveri B. (2010). Effect of vitamin D nutritional status on muscle function and strength in healthy women aged over sixty-five years. The Journal of Nutrition, Health & Aging., 14, (in Press)

Morley J.E. and Thomas D.R. (2007). Geriatric Nutrition, USA, CRC Press. Eds.

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