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Geriatr Gerontol Int 2014; 14 (Suppl. 2): 17–22
REVIEW ARTICLE
Nutritional management of older adults with cognitive decline and dementia Sumito Ogawa Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
Age-related cognitive decline is a main predictor of disability among elderly people, and with the continued expansion of the aging population and the increase in life expectancy, the prevalence of mild cognitive impairment and dementia represented by Alzheimer’s disease (AD), which is a multifactorial neurodegenerative disorder of older adults, have increased. Recent epidemiological and observational studies suggest a relationship exists between lifestyle factors, including nutrition and diet, and cognitive function in aging adults. It is also suggested that malnutrition and nutrient deficiencies are associated with cognitive decline in patients with dementia. There are a variety of nutritional factors, including nutritional status and dietary patterns, that might be associated with cognitive function, and specific micronutrients and dietary components have been suggested to have an association with cognitive function as well. Based on these findings and evidence, evaluation of nutritional state, as well as nutritional intervention, might be able to play a role in the management and prevention of dementia. Geriatr Gerontol Int 2014; 14 (Suppl. 2): 17–22. Keywords: Alzheimer’s disease, dementia, nutrition.
Introduction Cognitive impairment and dementia are the major risk factors for disability among older adults, and optimizing mental health, as well as physical and social health, is important for maintaining independence and a good quality of life.1 With the increase in global life expectancy and the continual proportion of the aging population, the prevalence of mild cognitive decline and advanced forms of cognitive disorders represented by Alzheimer’s disease (AD) has also increased.2 Several epidemiological and observational studies suggest that nutritional status, as well as health behaviors, frailty, disability, functionality status and chronic diseases (e.g. hypertension, cardiovascular disease, diabetes mellitus and metabolic syndrome), is associated with cognitive impairment and dementia.1–6 Recent evidence has also shown that there is a relationship between lifestyle factors, including nutritional status, dietary patterns and cognitive function, in older adults.2,4,7–10 Advances in research into the mediators implicated in the pathogenic cascade of AD have suggested that specific nutrients and their combination might play Accepted for publication 19 December 2013. Correspondence: Dr Sumito Ogawa MD PhD, Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Email; [email protected]
© 2014 Japan Geriatrics Society
a role in modulating the potential mediators involved in the pathology of AD. An association between nutritional status, including the intake of certain dietary nutrients, and the development of AD has been also shown by epidemiological studies. In practice, malnutrition and nutrient deficiencies, associated with cognitive decline, are often observed in patients with dementia, and recent epidemiological studies have suggested that an increased intake of certain nutrients might lower the risk of dementia. Despite these circumstances, supplementation of specific nutrients is not clinically established or routinely adopted in the cognitive management of AD. In the present review, recent findings on the relationship between nutritional state and dementia, together with the perspective of an efficient nutritional intervention for the management of dementia in clinical practice, will be described.
Nutritional status and cognitive function Nutritional status is compromised among older adults in general, and the risk of malnutrition is prevalent in an aging population.11 A changes in nutritional status, specifically the presence of or the risk of malnutrition, has been associated with cognitive impairment among elderly patients in hospital and the community-dwelling elderly population.6,12–18 The cause of malnutrition is usually multifactorial and unintentional weight loss at doi: 10.1111/ggi.12252
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17
S Ogawa
any bodyweight as a result of loss of appetite, poor food intake, pain and acute gastrointestinal symptoms, which are well recognized as sensitive malnutrition indicators.19 These indicators are incorporated into various screening and assessment tools, such as subjective global assessment (SGA),20 the Mini-Nutritional Assessment (MNA)21,22 and the Malnutrition Universal Screening Tool (MUST),23 which were developed and validated to identify malnutrition or those at risk of malnutrition. Serum albumin and rapid turnover proteins, as well as white blood cells, are the useful indicators of nutrition status, especially in acute care settings (or hospitalized patients),24 whereas the markers need to be carefully evaluated along with other test values that might affect the assessment results. It was shown that there was a positive relationship between nutritional status and cognitive function in a large sample of older adults living independently or in specialized housing,14 and that chronic malnutrition can lead to cognitive decline.25 In parallel, obesity is also suggested to be one of the major causes not only of insulin resistance and hyperinsulinemia, but also of cognitive impairment.26–28 It was also reported that mild cognitive impairment (MCI) might be associated with nutritional risk in elderly patients.13 In that study, 38.3% of patients were diagnosed with MCI, and 51.6% were either in a state of malnutrition or at risk of malnutrition (n = 120). There was a significantly higher frequency of malnutrition or nutritional risk among older adults with MCI compared with those who had no cognitive impairment (P = 0.002), suggesting that older adults who were malnourished or at risk of malnutrition were more likely to suffer from MCI.6 Malnutrition often accompanies AD, ranging from 15 to 50%.29–31 A longitudinal study in older adults aged more than 65 years showed that accelerated weight loss might precede diagnosis with AD.32 This result suggests that weight loss might be a preclinical indicator of AD, and that people with dementia tend to change their dietary habits. It is important to assess the actual nutritional status of older adults using scales such as the MNA. Assessment with the MNA scale among patients with mild-tomoderate dementia (MMSE = 22 ± 6) showed that 9% belonged to the malnutrition group (MNA
Geriatr Gerontol Int 2014; 14 (Suppl. 2): 17–22
REVIEW ARTICLE
Nutritional management of older adults with cognitive decline and dementia Sumito Ogawa Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
Age-related cognitive decline is a main predictor of disability among elderly people, and with the continued expansion of the aging population and the increase in life expectancy, the prevalence of mild cognitive impairment and dementia represented by Alzheimer’s disease (AD), which is a multifactorial neurodegenerative disorder of older adults, have increased. Recent epidemiological and observational studies suggest a relationship exists between lifestyle factors, including nutrition and diet, and cognitive function in aging adults. It is also suggested that malnutrition and nutrient deficiencies are associated with cognitive decline in patients with dementia. There are a variety of nutritional factors, including nutritional status and dietary patterns, that might be associated with cognitive function, and specific micronutrients and dietary components have been suggested to have an association with cognitive function as well. Based on these findings and evidence, evaluation of nutritional state, as well as nutritional intervention, might be able to play a role in the management and prevention of dementia. Geriatr Gerontol Int 2014; 14 (Suppl. 2): 17–22. Keywords: Alzheimer’s disease, dementia, nutrition.
Introduction Cognitive impairment and dementia are the major risk factors for disability among older adults, and optimizing mental health, as well as physical and social health, is important for maintaining independence and a good quality of life.1 With the increase in global life expectancy and the continual proportion of the aging population, the prevalence of mild cognitive decline and advanced forms of cognitive disorders represented by Alzheimer’s disease (AD) has also increased.2 Several epidemiological and observational studies suggest that nutritional status, as well as health behaviors, frailty, disability, functionality status and chronic diseases (e.g. hypertension, cardiovascular disease, diabetes mellitus and metabolic syndrome), is associated with cognitive impairment and dementia.1–6 Recent evidence has also shown that there is a relationship between lifestyle factors, including nutritional status, dietary patterns and cognitive function, in older adults.2,4,7–10 Advances in research into the mediators implicated in the pathogenic cascade of AD have suggested that specific nutrients and their combination might play Accepted for publication 19 December 2013. Correspondence: Dr Sumito Ogawa MD PhD, Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Email; [email protected]
© 2014 Japan Geriatrics Society
a role in modulating the potential mediators involved in the pathology of AD. An association between nutritional status, including the intake of certain dietary nutrients, and the development of AD has been also shown by epidemiological studies. In practice, malnutrition and nutrient deficiencies, associated with cognitive decline, are often observed in patients with dementia, and recent epidemiological studies have suggested that an increased intake of certain nutrients might lower the risk of dementia. Despite these circumstances, supplementation of specific nutrients is not clinically established or routinely adopted in the cognitive management of AD. In the present review, recent findings on the relationship between nutritional state and dementia, together with the perspective of an efficient nutritional intervention for the management of dementia in clinical practice, will be described.
Nutritional status and cognitive function Nutritional status is compromised among older adults in general, and the risk of malnutrition is prevalent in an aging population.11 A changes in nutritional status, specifically the presence of or the risk of malnutrition, has been associated with cognitive impairment among elderly patients in hospital and the community-dwelling elderly population.6,12–18 The cause of malnutrition is usually multifactorial and unintentional weight loss at doi: 10.1111/ggi.12252
|
17
S Ogawa
any bodyweight as a result of loss of appetite, poor food intake, pain and acute gastrointestinal symptoms, which are well recognized as sensitive malnutrition indicators.19 These indicators are incorporated into various screening and assessment tools, such as subjective global assessment (SGA),20 the Mini-Nutritional Assessment (MNA)21,22 and the Malnutrition Universal Screening Tool (MUST),23 which were developed and validated to identify malnutrition or those at risk of malnutrition. Serum albumin and rapid turnover proteins, as well as white blood cells, are the useful indicators of nutrition status, especially in acute care settings (or hospitalized patients),24 whereas the markers need to be carefully evaluated along with other test values that might affect the assessment results. It was shown that there was a positive relationship between nutritional status and cognitive function in a large sample of older adults living independently or in specialized housing,14 and that chronic malnutrition can lead to cognitive decline.25 In parallel, obesity is also suggested to be one of the major causes not only of insulin resistance and hyperinsulinemia, but also of cognitive impairment.26–28 It was also reported that mild cognitive impairment (MCI) might be associated with nutritional risk in elderly patients.13 In that study, 38.3% of patients were diagnosed with MCI, and 51.6% were either in a state of malnutrition or at risk of malnutrition (n = 120). There was a significantly higher frequency of malnutrition or nutritional risk among older adults with MCI compared with those who had no cognitive impairment (P = 0.002), suggesting that older adults who were malnourished or at risk of malnutrition were more likely to suffer from MCI.6 Malnutrition often accompanies AD, ranging from 15 to 50%.29–31 A longitudinal study in older adults aged more than 65 years showed that accelerated weight loss might precede diagnosis with AD.32 This result suggests that weight loss might be a preclinical indicator of AD, and that people with dementia tend to change their dietary habits. It is important to assess the actual nutritional status of older adults using scales such as the MNA. Assessment with the MNA scale among patients with mild-tomoderate dementia (MMSE = 22 ± 6) showed that 9% belonged to the malnutrition group (MNA
