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High Dietary Salt Intake Associated with an Epidemic of Hypertension in the United States

(Jerry Seals, MD) -- Approximately one million Americans die each year due to complications of heart and vascular diseases caused by hypertension.

Hypertension is generally defined as a systolic blood pressure (the highest number) of greater than 140 and a diastolic pressure (lowest number) of greater than 90. The causes of hypertension are numerous and include genetic inheritance, smoking, older age, stress, excess weight, and diet. High salt intake in foods is considered one of the most important culprits in the surge of hypertension in the United States.

The daily dietary intake of salt worldwide averages between 2300 to 4600 mg per day.  Many Americans, however, consume salt at the high level of 4,000 mg per day. Since the 1970's, American salt intake daily has increased 55%. This dietary change is thought to be related to a 50% growth in hypertension in the U.S. during the same period.  Lower income Americans, who tend to consume more processed food, have a disproportionate level of salt intake. Processed foods are cheaper and produced with high levels of salt.

In the U.S., 70% of dietary salt is derived from processed and restaurant food; 12% from natural food; 6% from addition at the table; and 5% is added during cooking. Processed foods may contain as much as 1OOO mg per serving. Surprisingly, a restaurant meal may contain 2300 to 4600 mg of salt.

The American Heart Association and other national public health experts have recommended a salt intake of less than 2400 mg per day.

Unfortunately, in the United States federal agencies such as the FDA do not limit how much salt the food industry may use in processed or restaurant food.  As a result a commercially produced frozen pot pie may contain 690 to 1180 mg of salt, and a restaurant meal of chicken fajitas may have more than 3,500 mg.

Several European governments such as, the U.K., Finland and Ireland have taken a major role in decreasing salt consumption by their citizens. They have worked closely with food producers to decrease salt content in foods. They have also sought to educate heath care providers and consumers about the relationship of lowered salt intake to safer blood pressure levels and to good overall health. In these countries, producers use color coding and easy to read labeling to make it easier for consumers to avoid foods with high salt content. In addition, continued health education by government agencies, health care providers, food producers and restaurant owners has been credited for at least a 40% decrease in salt consumption.

The medical opinion that high salt intake increases risk of hypertension is not disputed.
Consequently, in the United States we need to make a priority of promoting continued patient and health care provider education about salt levels in foods and its relationship both to hypertension and to medical problems secondary to hypertension. Government involvement at some level is required to encourage food producers and restaurant owners to present foods that contain a safe level of salt; to assure that food labels are easy to understand, and that the salt content of restaurant foods is listed on the menu.


References
1-Cutler JA: Salt reduction for preventing hypertension and cardiovascular Disease.
Hypertension. 2006; 48(5); 818-819

2-Karppanen et al Sodium intake and hypertension
Prog. Cardiovascular Dis. 2006; 49(2); 59-75