The dietary guidelines say that Americans should cap their sodium intake at 2,300 mg( about 1 teaspoon of salt) per day. But this may be too low, suggests a new study. Drawing from data from 130,000 people in 49 countries, researchers found that sodium intake below 3,000 mg per day ( or 1 1/3 teaspoons of salt) was associated with increased risk of stroke ,heart attack or cardiovascular disease-regardless of weather a person had high or healthy  blood pressure.