Dietary Salt Study
Why are we studying salt?
There is evidence to suggest that a high intake of dietary salt may lead to elevated blood pressure and blood vessel disfunction in certain individuals. This disfunction has to do with the way the endothelium (the cells which line the blood-vessels) communicates with the body's blood vessels via chemicals such as nitric-oxide. The importance in this lies in fact that the health of a person's blood vessels is directly related to their risk for stroke and heart attack. This study will measure blood pressure and test blood vessel function after a day of high salt intake and again after a day of low salt intake.
What is the endothelium?
The endothelium is the inner lining of cells in blood vessels. It performs functions essential to these vessels including the regulation of blood clotting by releasing a number of factors including nitric oxide. We are able to measure how well the endothelium works by using ultrasound and other techniques to assess blood vessel dilation.
What does the study involve?
During this study we will be testing blood vessel function and blood pressure during both a high and a low salt diet. You will be admitted to the General Clinical Research Center at Boston Medical Center on the first morning of the study for a complete medical history and physical examination. During the next 24 hours, you will be given a high salt diet. We will measure blood pressure by means of an ambulatory monitor which will be worn on the first and second days of the study. During the following 24 hours, you will be given a low salt diet. Blood vessel function will be measured by means of an ultrasound technique and by insertion of a catheter into the brachial artery on the second day of the study. Blood samples will be taken several times over the course of the study by means of an intravenous line. The entire study will take place over a 3 day hospitalization.
Are there risks involved?
There are no known risks associated with a short term high or low salt diet. Some people may experience a rise in blood pressure on the high salt day, but we expect this to return to normal during the low salt phase of the study. Blood samples will be taken intravenously throughout the study and may cause slight discomfort and/or mild bruising. While there are no known risks associated with having a ultrasound, insertion of a catheter into the brachial artery may lead to hematomas (black and blue areas caused by minor bleeding) at the puncture site. There is also a theoretical risk of injury to the artery, although there have been no such complications in over 400 cases.
Who is eligible for the study?
Any healthy individual between the ages of 18 and 80 with no history of smoking. All subjects must be able to give informed consent.
Who do I contact to participate?