Nutrient Requirements offhe Elderly
December 1992: 447-448
Nutrient Requirements of the Elderly: An Overview Norimasa Hosoya, M.D., Ph.D.
Establishing the Allowances
Every country has its recommended dietary allowances, classified by gender, age, and activity level, which are used as guidelines for maintaining normal health and activity. Today in Japan persons aged 65 years and older account for more than 10% of the total population. Of these elderly, nearly 80% are receiving treatment for degenerative diseases, and about 10% are bedridden. Those living free of medical treatment are estimated at less than 10% of the elderly population. Thus, the elderly represent a large and relatively morbid group, and determining their nutrient requirements is both an important and difficult task. As part of our continuing battle against epidemic illness, infant death, perinatal death, and premature death, attention has focused on nutrition, particularly nutritional requirements for growth and development. As a consequence, nutrient requirements for adults and the elderly have been calculated as extensions of the needs for growth and development. However, using this model is inappropriate for the elderly and could result in overfeeding. Characteristics of the Elderly
In adulthood, various physical functions begin to deteriorate, and there is evidence of even greater deterioration with advancing age. Reserve and storage capacities decline, as do regulatory and recovery abilities, although these changes depend substantially on individual conditions. Normal nutritional status and the conditions required to maintain it also decline with aging. Insufficient dietary intake can deplete essential body components, leading to marginal or frank nutrient deficiencies. On the other hand, excessive intake of both macro- and micronutrients may lead to “borderline Dr. Hosoya is Emeritus Professor at the University of Tokyo; Vice President, Kokusai-Gakuin Saitama Junior College; and Chairman, Health Sciences Center in Ibaraki-prefecture, Japan. Nutrition Reviews, Vol. 50, No. 12
overnutrition” or “toxic status” (abnormal accumulation). Such nutrient imbalances pose additional problems during physiological stress and may precipitate infectious or degenerative diseases (Figure I ) , which, in turn, may be aggravated by altered nutritional status. Provision of Nutrients
Nutrition repletion and recovery from illness require a sufficient supply of nutrients. When digestive and absorptive function are compromised, or when a quick supply of nutrients is necessary, nutrients may be provided enterally or parenterally. The quantity to be administered at such a time is computed based on each individual’s metabolic requirements. These requirements are not always clear, however, due to age- and disease-associated changes in metabolic activity. Each person’s specific nutrient requirements for both immediate use and restoration of reserves are still a matter of conjecture. In addition to a decline in metabolic activity, the nutritional status of the elderly is also affected by changes in dentition. Accordingly, determination of the nutrient needs of the elderly requires consideration of both metabolic demands-based on internal utilization-and the bioavailability of nutrients, which is related to their digestion and absorption. The nutrient bioavailability of foods is affected by coexisting substances as well as by cooking and processing methods. Alterations in the gastrointesnormal (optimal)
n
marginal deficiency / /
deficiency tdisease factor- infectious / disease 2 death
borderline overnutrition
\
toxic status (abnormal accumulation) tdisease factor degenerative \ disease L death
-
Figure 1. The effects of under- and overnutrition on health. 447
tinal environment, such as achlorhydria, also influence nutrient bioavailability.
Conclusion The effects of a lifetime of individual physical and environmental conditions combine in the elderly to produce a widely diverse group. This individual
448
variability must be considered when designing a method to determine the nutrient requirements for the elderly. Although the requirements for nutrients delivered parenterally may be based solely on an individual’s demands for metabolism and recovery, requirements for nutrients delivered enterallyincluding regular meals as well as formulas-must also take into consideration nutrient bioavailability .
Nutrition Reviews, Vol. 50, No. 12
December 1992: 447-448
Nutrient Requirements of the Elderly: An Overview Norimasa Hosoya, M.D., Ph.D.
Establishing the Allowances
Every country has its recommended dietary allowances, classified by gender, age, and activity level, which are used as guidelines for maintaining normal health and activity. Today in Japan persons aged 65 years and older account for more than 10% of the total population. Of these elderly, nearly 80% are receiving treatment for degenerative diseases, and about 10% are bedridden. Those living free of medical treatment are estimated at less than 10% of the elderly population. Thus, the elderly represent a large and relatively morbid group, and determining their nutrient requirements is both an important and difficult task. As part of our continuing battle against epidemic illness, infant death, perinatal death, and premature death, attention has focused on nutrition, particularly nutritional requirements for growth and development. As a consequence, nutrient requirements for adults and the elderly have been calculated as extensions of the needs for growth and development. However, using this model is inappropriate for the elderly and could result in overfeeding. Characteristics of the Elderly
In adulthood, various physical functions begin to deteriorate, and there is evidence of even greater deterioration with advancing age. Reserve and storage capacities decline, as do regulatory and recovery abilities, although these changes depend substantially on individual conditions. Normal nutritional status and the conditions required to maintain it also decline with aging. Insufficient dietary intake can deplete essential body components, leading to marginal or frank nutrient deficiencies. On the other hand, excessive intake of both macro- and micronutrients may lead to “borderline Dr. Hosoya is Emeritus Professor at the University of Tokyo; Vice President, Kokusai-Gakuin Saitama Junior College; and Chairman, Health Sciences Center in Ibaraki-prefecture, Japan. Nutrition Reviews, Vol. 50, No. 12
overnutrition” or “toxic status” (abnormal accumulation). Such nutrient imbalances pose additional problems during physiological stress and may precipitate infectious or degenerative diseases (Figure I ) , which, in turn, may be aggravated by altered nutritional status. Provision of Nutrients
Nutrition repletion and recovery from illness require a sufficient supply of nutrients. When digestive and absorptive function are compromised, or when a quick supply of nutrients is necessary, nutrients may be provided enterally or parenterally. The quantity to be administered at such a time is computed based on each individual’s metabolic requirements. These requirements are not always clear, however, due to age- and disease-associated changes in metabolic activity. Each person’s specific nutrient requirements for both immediate use and restoration of reserves are still a matter of conjecture. In addition to a decline in metabolic activity, the nutritional status of the elderly is also affected by changes in dentition. Accordingly, determination of the nutrient needs of the elderly requires consideration of both metabolic demands-based on internal utilization-and the bioavailability of nutrients, which is related to their digestion and absorption. The nutrient bioavailability of foods is affected by coexisting substances as well as by cooking and processing methods. Alterations in the gastrointesnormal (optimal)
n
marginal deficiency / /
deficiency tdisease factor- infectious / disease 2 death
borderline overnutrition
\
toxic status (abnormal accumulation) tdisease factor degenerative \ disease L death
-
Figure 1. The effects of under- and overnutrition on health. 447
tinal environment, such as achlorhydria, also influence nutrient bioavailability.
Conclusion The effects of a lifetime of individual physical and environmental conditions combine in the elderly to produce a widely diverse group. This individual
448
variability must be considered when designing a method to determine the nutrient requirements for the elderly. Although the requirements for nutrients delivered parenterally may be based solely on an individual’s demands for metabolism and recovery, requirements for nutrients delivered enterallyincluding regular meals as well as formulas-must also take into consideration nutrient bioavailability .
Nutrition Reviews, Vol. 50, No. 12
