expert opinion

Healthier aging

April 15, 2012

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Dr. Phyo Kyaw Myint, Geriatrician, School of Medicine, University of East Anglia, Norfolk, UK

“Aging is associated with a gradual decline in physical functioning with or without mental frailty. The aging process is intrinsically complex, being driven by multiple causal mechanisms. Genome instability, telomere damage, mitochondrial dysfunction, and inflammation are established mechanisms of aging. Age related changes in body composition include a relative increase in fat tissue and a gradual decline in muscle mass. Not everyone ages in the same way, however, and the term biological age is loosely used to indicate how well someone has aged in terms of the degree of decline in their physical functioning and their ability to meet physiological demands. Aging is determined by complex interactions between biological, environmental, socioeconomic, and cultural factors, some of which are beyond the control of individuals. Factors that may contribute to the aging process which may be modifiable include poor nutrition, physical inactivity, smoking, and psychosocial characteristics (such as stress). These factors are associated with the development of chronic diseases that are, in themselves, associated with physical and mental frailty and could be tackled at an individual level throughout life.

Healthy aging in older age could be considered to be being free of any chronic disabling conditions and the prevalent conditions of older age; having the ability to be content or enjoy life; and being able to perform desired physical, mental and social activities without any limitations. Therefore, healthy aging is largely commensurate with a quality of life that is related to good health. Healthier aging is really aimed at the compression of morbidity in older age. Therefore, the ideal goal should be to maintain physical independence and biological reserve and enjoy psychosocial wellbeing well into older age. Many healthy lifestyle behaviors are positively associated not only with better physical and mental functional health (indicators of biological aging) but also with longevity, reduced risk of chronic diseases, and more quality adjusted life years. Although aging is not the sole cause of chronic disease, older age is strongly associated with many chronic diseases, such as arthritis, cardiovascular disease, and dementia. Because chronic diseases are associated with reduced physical function and poor quality of life, measures aimed at preventing chronic diseases are important basic steps towards healthier aging. Prospective epidemiological studies have shown that positive health behaviors are associated with reduced all cause mortality and cardiovascular disease, higher life expectancy, and greater health and wellbeing in older age (1, 2).

Because chronic diseases including diabetes, cardiovascular disease, cancer, osteoporosis and obesity are associated with dietary factors, a balanced diet is advisable. Although a balanced diet is achievable for most people, surveys of the UK population show that recommendations for food and nutrient consumption are largely not met for fruit and vegetables, oily fish, red and processed meat, sugars, saturated fat, fiber, salt, alcohol, and some vitamins and minerals; only those for percentage total fat and energy intake are met. Therefore, there is still a great need to encourage people to eat a balanced, healthy diet. The current UK, American, and international dietary recommendations for eating a healthy balanced diet represent current knowledge and consensus opinion. These guidelines can be met by following the “eatwell plate” model of healthy eating (3) and by eating different food types in the correct proportions. For example, people who do not eat fish or fish oils should be encouraged to consume rich sources of the plant based omega-3 polyunsaturated fatty acid alpha-linolenic acid, whose primary utility it is to be converted into the long-chain polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Some population groups, including those not able to eat a full range of foods, may need vitamin supple-ments. For example, as many as 15% of individuals in the UK are estimated to have low serum concen-trations of 25-hydroxy vitamin D and 80% have concentrations considered to be suboptimal (4). Adequate levels of vitamin D are essential for good bone health, and low serum concentration of 25-hydroxyvitamin D has been associated with osteoporosis; falls in adults; and more recently with higher rates of other chronic diseases. Dietary sources of vitamin D are limited mainly to animal products such as oily fish and to fortified margarines. Although exposure to sunlight is the major source of vitamin D, many adults avoid sun exposure as it has been associated with an increased risk of skin cancer. In the UK effective production of vitamin D from skin occurs between May and September. Vitamin D supplementation may be needed where neither diet nor sunlight exposure is adequate.

Because basal metabolic rate declines with age, even in physically active people, maintaining a balance between energy intake and expenditure is important throughout life, especially as the potential for physical activity to potentiate weight loss reduces with age. Furthermore, the amount of physical activity to achieve weight loss is considerable without taking into account energy intake. What the ideal range of body mass index is for older adults is not clear, especially for the oldest old people. Whereas being underweight in older age is known to be associated with poor health outcomes, the associations with overweight and obesity in older age are less clear. On the basis of the available evidence, both physical activity and a healthy diet seem to be needed for healthier aging.

Aging could be said to begin at the very beginning of life and to accelerate after age 30. Many chronic diseases are asymptomatic in their early stages, and the biological underpinnings of functional decline may begin before old age. Therefore, acting on the principle that it is never too early to start; minimizing risk factors throughout one’s life is prudent. As shown by large prospective population based studies, adherence to a healthy lifestyle in middle age reduces the risk of mortality and cardiovascular events (1), which suggests that it is also never too late to start.”

Based on: Myint P. K. and Welch A. A. Healthier aging. BMJ. 2012; 344:e1214.

References

  1. Khaw K. T. et al. Combined impact of health behaviours and mortality in men and women: the EPIC-Norfolk prospective population study. PLoS Med. 2008; 5:e12.
  2. Myint P. K. et al. Combined effect of health behaviours and risk of first-ever stroke in 20,040 men and women over 11 years’ follow-up in the European Prospective Investigation into Cancer (EPIC)-Norfolk prospective population study. BMJ. 2009; 338:b349.
  3. NHS Choices. A balanced diet. UK eatwell plate. www.nhs.uk/Livewell/Goodfood/Pages/Healthyeating.aspx
  4. Prescott-Clarke P. and Primatesta P. Health survey for England 1996: findings: a survey carried out on behalf of the Department of Health. Stationery Office, 1998. (series HS; No 6; vol 1.)