The relationship between blood pressure and dietary constituents including potassium, sodium, calcium, and protein was studied in 183 randomly selected men and women, 50-54 years of age. Twenty-five of the subjects were drug-controlled hypertensive patients. Subjects were investigated by automated BP measurements, 24-h urine collection, and blood sampling. Mean systolic BP (SBP) was 119 +/- 17 mm Hg, placing the sample between Shanghai and Sweden on the distribution chart of the Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study. Salt intake estimated by 24-h sodium excretion was 8.5 +/- 3.4 g/day, between Australia and Okinawa on the distribution chart. Potassium was 48.55 +/- 20 20 mEq/day, between Urumqi (China), and Beppu and Ohda (Japan). Calcium was 162.3 +/- 89.9 mg/day. Urea nitrogen, which might reflect protein intake, was 9.5 +/- 3.1 g/day. Cholesterol was 195.1 +/- 38.1 mg/dl, between Brazil and Hirosaki. The Israeli results, as well as the data on other countries participating in the CARDIAC Study, show wide variability in the profiles generated by the investigated parameters. Each parameter placed Israel with a different CARDIAC Study group.