As we are all aware, sodium or sodium chloride (table salt) is one of the major components of our daily food intake. While sodium has a reputation for being detrimental to our cardiovascular health, it is important to be aware that sodium serves a very important physiologic function in the human body.
It is the principal mineral in the serum of our blood vessels, which circulates many vital nutrients to our muscles, nervous system and internal organs. Sodium also has a very important role in the normal functioning of our body’s cells, especially with regards to transporting important molecules across cell membranes.
Based on national population health surveys (NHANES Study) the average sodium intake in the United States for adults is about 3,600 milligrams per day. Recommended intake set by the United States dietary guidelines group is 2,300 milligrams per day. The American Heart Association has set more stringent limits, of 1,500 milligrams per day. Interestingly, the average intake of sodium is significantly greater in men compared to women. (Most likely, this relates to higher average food intake consumed by men compared to women.)
Because of the widespread presence of salt in so many foods available for purchase, it is a challenge for even motivated individuals to scale back sodium intake. In a study published in 2010, 68 percent of sodium in the average American diet came from processed and prepared foods purchased from grocery stores, and 15 percent came from meals purchased in restaurants, and the rest from food prepared at home. I suspect that the restaurant percentage is much higher today as less home cooked meals are prepared.
Many of us are aware that excess sodium intake has an important role in the development of hypertension or high blood pressure. Conversely, most individuals that are able to reduce sodium intake lower their blood pressure readings, as reported in numerous scientific research studies. But not all individuals are salt sensitive. In general, there is a greater blood pressure reduction associated with reduced sodium intake in individuals who are African-American or in older age groups.
Despite its bad rap, it does appear that sodium is a very important mineral for the normal biologic functioning of the human body; nonetheless most Americans consume far too much. The DASH diet (recommended for people with high blood pressure) recommends that one consume whole foods like fruits, vegetables, fish, whole grains, poultry, low fat dairy foods and on occasion, lean meats. Nuts also are encouraged. Use spices to enhance flavor before you add salt. Stay away from overly processed foods like canned soups and frozen dinners, and limit your exposure to restaurant foods.
Based on the information we have from various sources on cardiovascular health, it does appear prudent to limit intake of sodium to 1,500 to 2,000 milligrams per day for those individuals with a diagnosis of hypertension or other types of cardiovascular disease. For those who have normal blood pressure and no known cardiovascular disease, the evidence for restricting salt intake is not nearly as strong.
Dr. Mark Roth is an internal medicine physician with University Hospitals.