Eat wisely to live longer / by Barbara Millen Posner and Muda Hurad

Eat wisely to live longer by Barbara Millen Posner and Huda Murad T he youthful profile of limited access to health services, and the world's population may suffer from malnutrition. So is changing. The United health policies looking forward into the Nations estimates that next century will have to consider the by the year 2025, only a prevention of chronic diseases, as well quarter of individuals worldwide will be as the needs of those older persons aged under 14. Some 14% will be 60 whose social or economic circum- years or older, and in the developed stances put them at particular risk. countries the proportion of older adults will exceed the 0 to 14 years age .~ group. The current 380 million per- ~ sons aged 60 and older will nearly ~ double to 610 million by the turn of Q., the century; 7CflJ of the projected .S 1121 million who will be 60 years and .f over by 2025 are expected to live in ~ the developing world. In the past, the youthfulness of the world's population focused the atten- tion of health policy-makers on the needs of infants and children. Pro- grammes on birth control, maternal and infant nutrition, immunization against major infectious diseases, and related health services dominated the landscape. Relatively little attention was paid to the impact the success of such programmes would have on population demographics, such as reduced infant mortality, increased fer- tility, increased life expectancy and the overall aging of the population. Eating for health Particularly in industrialized coun- tries, aging is often synonymous with the development of certain chronic diseases that could be prevented or delayed by better personal health prac- tices. In the USA, for example, 80% or more of those 60 years and older are estimated to suffer from one or more of the following: coronary heart disease, hypertension, diabetes, cancer, osteoporosis, and arthritis. These chronic diseases have often been linked to modifiable life-style beha- viours, as in the case of coronary heart disease, which has been associated with diets high in fat, particularly animal fat and cholesterol, cigarette smoking and insufficient physical exercise. At the other extreme of the health continuum, a smaller but significant proportion of a nation's older popu- lation may be economically and socially disadvantaged, with extremely 22 living dangerously! Does she know? Diet is one of the cornerstones of a health policy for successful aging and the prevention of chronic diseases. A recent study on certain life-style predic- tors of mortality from coronary heart disease showed that populations that experienced marked increases in such cases over the past 15 years, namely Bulgaria, Czechoslovakia, Greece, Hungary, Romania, Spain and Yugo- slavia, had also increased their total fat intake, particularly of animal fats. Con- versely, rates of coronary heart disease have declined in countries where cholesterol and fat intakes had decreased, as in Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Japan, Netherlands, Norway, Por- tugal, Sweden, Switzerland, the United Kingdom, and the USA Two recent studies in the USA both recommended that preventive health measures such as proper nutrition should be instituted as early as pos- sible, preferably in childhood or early adulthood. In fact the scientific evi- dence which links dietary practices with the prevention and treatment of major chronic diseases is increasingly abundant. There are particularly con- vincing data on the role of diet (low fat, particularly animal fats, and low chole- sterol) in heart disease prevention. There are also data suggesting that eating foods with a higher fibre and lower fat content and possibly other nutrients helps to prevent certain forms of cancer (especially cancers of the large bowel and breast). Excessive calorie intake and the excess body fat that goes with it is also associated with the development of diabetes in adults. Of course, certain genetic determi- nants will predispose an individual to specific chronic diseases. Nevertheless, preventive dietary practices offer con- sumers a pivotal role to play in maintaining their own health. The Food and Nutrition Board of the US National Research Council (NRC) recently concluded: "There is clear evidence that the total amounts and types of fats and other types of lipids in the diet influence the risk of atherosclerotic cardiovascular (heart) diseases and, to a less established extent, certain forms of cancer and possibly obesity. The evidence that the intake . of saturated fatty acids and cholesterol are causally related to atherosclerotic cardiovascular diseases is especially strong and convincing." The report points out the potential benefits of a dietary pattern that includes low fat products {like fresh fruit and vegetables, legumes and whole-grain cereals) and is more con- centrated in food sources of caroten- oids (dark green and yellow-orange vegetables and fruit) and ascorbic acid (in citrus and tropical fruits and ber- ries). The study showed the relatively adverse effects of higher fat-containing animal foods {like fattier meats, cheeses and higher-fat dairy products), excess calories, alcohol and salt. The NRC's recommendations can be summarized as follows: • Reduce total dietary fat intake to 30% or less of calories. Reduce saturated fatty acid intake to less W OR LD HEALTH . May- June 1991 than 10% of calories, and intake of cholesterol to less than 300 mg daily. • Eat several servings every day of a combination of vegetables and fruit, especially dark green and yellow vegetables and citrus fruitS. • Increase the intake of starches and other complex carbohydrates by eating several daily servings of a combination of whole-grain breads, cereals, and legumes. • Maintain protein intake at moderate levels. • Balance food intake and physical activity to maintain appropriate body weight. • For those who drink alcoholic beverages, limit consumption to the equivalent of less than one ounce of pure alcohol in a single day. • Limit total daily intake of salt (sodium chloride) to 6 g or less. • Maintain adequate calcium intake. • Avoid taking (unnecessary) vitamin and mineral supplements. • Maintain an optimal fluoride intake, particularly during periods of tooth formation and growth. The US Surgeon General published a report on Nutrition and Health which describes the vital influence of diet on health and underscores the potential adverse consequences of certain dietary practices in relation to the major chronic diseases. Its recom- mendations are, in principle, quite similar to those of the NRC report. With reference to aging populations, the report states that "diet, exercise, and other personal and socioeconomic factors can help prolong good health W ORLD HEALTH. May-J une 1991 for most people". It also noted that those older adults who are economically, socially and functionally disadvantaged are likely to have unique nutritional needs. One particularly important issue raised in the Surgeon General's report is that education and counselling efforts designed to improve nutrition among consumers should give con- sideration to the social, cultural and psychological dimensions of food. Consumers' food preferences and habits are rooted in beliefs and customs, and are strongly influenced by such factors. Food is also a great source of pleasure in most people's lives. Education and counselling efforts must therefore consider the potential difficulties involved in changing con- sumers' food behaviour and attempt to overcome barriers to those changes. Practical dietary recommendations must be placed in the larger context of consumers' social and cultural frame- works, preferred types and sources of foods, and overall environmental cir- cumstances. Dietary guidelines The US Departments of Agriculture and of Health and Human Services have developed practical recommen- dations, called the Dietary Guidelines for Americans, which are valid in many parts of the world and are summarized in the box on the next page. As the world population has aged, chronic diseases have increasingly become major causes of death and disability. Many of these conditions, Obesity is a threat to children too. A balanced diet from childhood is the best guarantee of good health in adulthood. especially cardiovascular disease, certain forms of cancer and diabetes, can be prevented, minimized or delayed by paying attention to life-style behaviours, including improved diet, increased exercise and reduced tobacco consumption. As the 21st century approaches and the needs of adults, particularly older adults, are considered, preventive health practices offer considerable promise in promot- ing successful aging. Dietary practices which should be particularly empha- sized are those that are lower in total fat intake (particularly saturated animal fat) and cholesterol; lower in salt, sugar, and alcohol; higher in complex carbohydrates, fibre, whole grains and cereals, and fresh fruits and vegetables; and those that are balanced in total energy and essential nutrients. • Professor Barbara Millen Posner is Assistant Director for Research Development and Director of Nutrition Research . The Framingham Stud y, Boston University School of Public Health. 80 East Concord Street Boston. Massachusetts 02118. USA. Ms Huda Murad is Research Associate of The Framingham Study at the same address. 23