Aging: Nutrition and immunity

In the U.S., life expectancy at birth is now 75 years, compared with about 47 years at the beginning of this century. The average age and the proportion of the older population within the total population are also increasing at a rapid rate. Individuals over age 65 now comprise 12% of the population compared with 4% in 1900, and this percentage is expected to rise to 21% by the year 2030. People who survive to old age are also living longer. For example, persons reaching age 65 in 1984 had an average life expectancy of an additional 17 years (19 years for women and 14.5 years for men), and life expectancy at age 65 has increased 2.5 years just since 1960. This increased life expectancy for older Americans is resulting in an even more rapid growth in the populations age 75 to 85 and over age 85.