Aging is characterized by a host of changes in metabolic variables which have profound effects on disease development and on survival. The BLSA provides the opportunity to conduct analyses on these variables to relate them to other characteristics of the individual, and to analyze for long-term effects of these complex interactions. Variables which are potentially alterable by changes in life style characteristics (diet, body weight, activity level) are of especial importance in this respect. Age-specific normative data are required and can only be determined rationally by analyses such as these. Dietary diary information has been obtained on 445 men and women. This will provide an important update on secular changes in the diet since the 1961-1975 dietary information was obtained. Salt intake has been assessed by questionnaire (the perception of intake) and by 24-hr sodium excretion. There is little or no age difference in the perception of intake but actual intake (excretion) decreases significantly with age. There is a small but significant direct effect of salt intake on systolic blood pressure. The correlation between perceived intake and actual intake was very poor. Quantification of intake requires measurement, not history. Rectal and colonic polyps were associated with several dietary variables: alcohol (positive effect) and carbohydrate and fiber intake (negative effect).