Aging in Today's Environment (1987) / Chapter Skim
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5 Characteristics of the Environment, Aging, and the Aged
5 Characteristics of the Environment, Aging, and the Aged
Pages 72-108
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From page 72... ...
NTEHS, 1977, 1984~. Although a person might live in a general environment that seems constant, even over a long period, exposure to potentially toxic agents varies widely, that is, the toxic environment changes.
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From page 73... ...
The term food, as opposed to diet, applies to the intake in foodstuffs of possibly toxic substances that can alter life span, as distinct from quantitative intake of putatively nontoxic normal foodstuffs. Food consists mainly of complex mixtures and is not well defined from a toxicologic perspective.
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From page 74... ...
Second, exposures in this category are known or suspected to increase disease prevalence that might shorten life or mimic aging processes, or both. Thus, this category of environmental exposure must be considered avoidable toxic stress that is relevant for only some populations.
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From page 75... ...
An interesting topic that is excluded from the present discussion is the recently suggested importance of some environmental agents in the induction of parkinsonism, a disease considered characteristic of age. The suggestion was based on the development of a mode!
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From page 76... ...
Because chronic disease often has a long latency, it can be especially susceptible to the influence of nutrition. Nutrition is important in the pathogenesis of coronary heart disease, gallstones, appendicitis, varicose veins, obesity, hiatus hernia, and cancer (Burkitt, 1982~.
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From page 77... ...
Because the amount and type of food eaten might profoundly influence both aging processes and toxicity of environmental agents, failure to address this issue reduces the value of a study. The micronutrients, that is, minerals and vitamins, are difficult to study in the context of toxicity and aging partly because there are so many substances in each class of nutrients.
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From page 78... ...
Lower dietary protein content is generally associated with lower incidences of tumors (NRC, 1982) , such as 3-methy~cholanthrene-induced mammary adenocarcinoma in rats fed high-protein diets (Stray et al., 1964)
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From page 79... ...
ENVIRONMENT, AGING, AND THE AGED 79 incidence of cancer at several sites (NRC, 1982~. For example, increasing dietary fat from To to 20~o usually increases the incidence of mammary tumors both spontaneous tumors and, depending on the carcinogen used, induced tumors.
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From page 80... ...
Furthermore, some nutritional regimens and dietary components appear to promote aging processes, or at least the occurrence of ageassociated deterioration (Guigoz and Munro, 1985~. A substantial
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From page 81... ...
The increase is probably not a result of factors influencing basic aging processes, but rather results primarily from protecting the population from premature death due to specific infectious diseases and injuries. A change in the life span of a species is a better criterion than life expectancy.
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From page 82... ...
(1935) suggested that food restriction delayed the aging processes by slowing growth and development.
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From page 83... ...
Thus, the lower fat mass of food-restricted rats does not appear to be involved in the life-prolonging action. On the basis of data from a study in which the duration of food restriction and the part of the life span involved were varied, Stuchlikov et al.
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From page 84... ...
The proposal by Sacher (1977) that food restriction reduces the metabolic rate and by so doing retards the aging processes has been widely embraced.
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From page 85... ...
They found that food restriction that markedly increased life span and retarded a spectrum of aging processes did not decrease metabolic rate per unit of lean body mass or "metabolic mass." Thus, the hypothesis that food restriction slows the aging processes by lowering the metabolic rate should be discarded, because its effects on aging can occur without a decrease in metabolic rate. Masoro et al.
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From page 86... ...
Food restriction markedly retards the aging processes in rodents. It does not do so by reducing the input of a nutrient per unit of body weight.
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From page 87... ...
Replacing the casein in the diet with soy protein, without reducing dietary protein content or changing caloric intake, also increased life expectancy and life span of male Fischer 344 rats (Twasaki et al., 1986~. The major reason for the increase in longevity was thought to be retardation in the age-related progression in severity of chronic nephropathy.
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From page 88... ...
The life expectancy of Wistar rats was not influenced by the source of carbohydrate, but the life expectancy of BHE rats was reduced when sucrose was the source. Life span was not reported.
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From page 89... ...
Antioxidants, including vitamins, have often been found to increase life expectancy, but not life span, in roclents (Herman, 1978~. Moreover, the role of food intake in increasing life expectancy has usually not been adequately addressed.
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From page 90... ...
Special Dietary Requirements of the Aged Are the nutritional requirements of the American elderly met by the diets they consume? To answer this question, it is necessary to have a reference, or standard, that defines the nutritional needs of the elderly.
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From page 91... ...
· · baSlC 310 Ogle lSSUe. What information do we have on the nutritional requirements and needs of elderly people who are free of disease and have adequate economic resources?
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From page 92... ...
Plasma alkaline phosphatase activity was inversely related to the plasma 25-hydroxyvitamin D concentration, which might mean that the elderly need moderate vitamin D supplementation and more sunlight. Further information of this type is needed to define more fully the nutritional status of these subjects and of other populations of healthy elderly people, with regard to the spectrum of nutrients.
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From page 93... ...
There is evidence that the pathogenesis of age-related involutional changes of the kidney can be modulated by diet (Brenner et al., 1982~. High dietary protein accelerates progression of the lesions, and low-protein diets retard the process.
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From page 94... ...
was based on the food-restriction data base for rodents coupled with an abundant intake of essential nutrients and other substances having some evidence of antiaging action. It should be underscored, however, that there is very little evidence that such diets influence the aging processes of humans.
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From page 95... ...
, elderly patients receive more drugs than younger patients. Ambulatory Populations In a study of an ambulatory community-dwelling population in Albany, New York, Chien et al.
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From page 96... ...
A study by the Boston Collaborative Drug Surveillance Program showed that American hospital inpatients received an average of 9.1 different preparations, compared with 7.1 for patients in Canada, 6.3 for Israel, 6.8 for New Zealand, and 4.6 for Scotland. A detailed comparison between Scotland and the United States showed that patients in the United States were treated
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From page 97... ...
The explanation undoubtedly lies in the approach to drug therapy taught in undergraduate and postgraduate medical institutions. Long-Term-Care Facilities Patients in chronic-care institutions commonly receive many drugs, tranquilizers and hypnotic-sedatives being very common (Institute of Medicine and National Research Council, 1985~.
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From page 98... ...
The three most commonly prescribed antipsychotic drugs were thioridazine, chlorpromazine, and haloperidol. The authors suggested that those drugs might be used to mold patients into the institutional routine.
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From page 99... ...
Additional research is needed to clarify the clinical importance of such noncompliance in older patients. Adverse Drllg Reactions Adverse drug reactions might be the inevitable price of improved drug therapy for disease (Barr, 1955; Jick, 1974~.
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From page 100... ...
In one of the studies that did not show an age effect, the results suggested that the elderly might be unable to distinguish drug side effects from symptoms of "old ages and unable to communicate adverse effects to their providers (Klein et al., 1984~. Limitations of the data on adverse drug reactions in the elderly have been enumerated (Klein et al., 1981; Nolan and O'Malley, 1987b; Vestal et al., 1985~.
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From page 101... ...
Some people are convinced of the merits of an exclusively or predominantly vegetarian diet; others use supplements that include pure preparations of vitamins, amino acids, minerals, and other compounds, as well as many complex chemical mixtures represented by "unusual" plant and other materials or extracts. Whether such materials have any effect on the aging processes, either adverse or beneficial, generally has not been tested.
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From page 102... ...
Atrophy of Disuse Life-style can inevitably affect aging processes and the aged
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From page 103... ...
They can also conceivably accelerate or delay physiologic and anatomic changes associated with the passage of years. Clear examples are the variety of age-related- diseases induced by toxic chern~cals in tobacco smoke and the decrease in risk of cardiovascular disease produced by regular exercise.
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From page 104... ...
, and microorganisms and allergens. There is little epidemiologic information on the health effects of chronic, low-level exposure to any of these pollutants except tobacco smoke (National Research Council, 1986~.
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From page 105... ...
However, it appears that both active smoking and passive smoking increase susceptibility to the effects of radon, because radon progeny adhere to respirable particulate matter in tobacco smoke.
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From page 106... ...
Combustion Products The two indoor combustion products that most often cause concern about health effects on those exposed are nitrogen dioxide (NO2) and carbon monoxide (CO)
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From page 107... ...
Environmental Tobacco Smoke Tobacco smoke is a major source of pollution in the indoor environment. Nonsmokers absorb measurable amounts of CO and nicotine and can absorb small amounts of other constituents from environmental tobacco smoke (ETS)
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From page 108... ...
Chronic exposure to tobacco smoke apparently can impair immune system function. Laboratory studies on mice have found that chronic tobacco-smoke exposure accelerated many of the immunologic changes associated with aging, including marked modifications of the responses associated with the T-lymphocyte arm of the immune system and of the systemic clearance mechanisms.
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