Nutrition and exercise are important considerations for those who decide to be active participants in their ageing process because these are like fences that protect the elderly from many age-related diseases. While many people know that good nutrition and adequate exercise will contribute to their health in old age, they do not eat well or exercise adequately in spite of this knowledge. This is the paradox of human behaviour: knowing what is good does not necessarily guarantee that it will be done.
Healthy choices are often difficult choices for many people around the world and how people make choices and options in later life are influenced by education, upbringing and the attitudes and expectations of society.
Nutritional status can be identified by measuring the Body Mass Index (BMI) or Mid Upper Arm Circumference (MUAC) (Powell-Tuck, Hennessy, 2003). Lean body mass, which is composed mainly of skeletal muscles, decreases in size with ageing and this affects both strength and mobility. Those who are at greatest risk of falls due to poor muscle strength are those whose lean body mass is below 63 percent of total body weight (Phillips, 2003). Sarcopenia is the term that refers to this decrease in muscle mass with ageing. Wasting refers to the loss of muscle mass associated with insufficient food intake while cachexia refers to muscle wasting as a result of an inflammatory disease process.
The elderly have decreased thirst sensation and are prone to dehydration.
Fruits and vegetables with vivid colours contain substances called carotenoids. Beta carotene, found in carrots, is a well-known carotenoid. Other carotenoids like lycophene (imparting pink or red colour) and lutein and zeaxanthin (imparting a deep yellow colour) are also important. Lycophene appears to have protective effects against prostate cancer and cardiovascular disease while lutein and zeaxanthin have similar beneficial effects against cataracts and age related macular degeneration. Tomatoes and tomato sauce are good sources of lycophene and have been shown in the Health Professionals Follow-up study to significantly reduce the risk of prostate cancer if 10 or more servings are used per week (Gioyannucci, et al. 1995).
Current expert recommendations for healthy ageing stress on providing adequate amounts of the following micronutrients in diet because of strong evidence for their protective effect on health: folic acid, Vitamin B12, Vitamin C, Vitamin D, Vitamin E, Selenium, Iron and Zinc (Bates, et al. 2002).
Exercise has a profound influence on ageing. Helen Hayes, an American actress, has been quoted as saying “resting is rusting”. Exercise blunts the age-related rate of loss of muscle bulk and strength. Those who do not exercise regularly show a greater decrease in the mass of their skeletal muscles as they become older when compared to those who do regular endurance exercises like walking. The Honolulu Heart Program study (Hakim et al. 1998) showed that those who walk more than 2.4km daily had half the relative risk of adverse cardiac events when compared to those who walk less than 0.8km per day. A randomised control trial called the Fitness for the Ageing Brain Study (FABS) from Australia showed that when elderly people walk for at least 150 minutes per week, there is a significant reduction in the risk of developing Alzheimer’s disease (Lautenschlager, et al. 2008).