By Kathryn Doyle (Reuters Health) – As dietary sodium levels go up over time, so does the risk for high blood pressure, suggests a new study that followed more than 4,000 adults in Japan for four years. The study did not measure dietary sodium directly, instead using urine samples to estimate levels of sodium consumed, but the results align with other large studies of sodium intake and blood pressure risk, researchers say. “A small amount of salt (less than 3,000 milligrams a day) is necessary for us, but excessive salt is dangerous,” said coauthor Dr. Tomonori Sugiura of Nagoya City University Graduate School of Medical Sciences in Japan.