Sodium is a naturally occurring mineral that is essential to life. It helps regulate the fluid balance of cells and plasma by soaking up water to keep fluid in our blood and body tissues. It's important to have a proper balance of sodium in our diets. Not enough sodium can result in the body's cells being unable to retain enough water and can lead to dehydration. On the other hand, too much sodium may result in shortness of breath or edema (swelling) and contribute to hypertension (high blood pressure).
Cutting down on the amount of sodium, or salt (which is 40 percent sodium), in the food we eat can be very helpful in reducing the buildup of excess fluid in our bodies. When excess fluid in our tissues is reduced, the amount of blood our heart has to pump is also reduced.
The most significant effect that excess sodium has on the heart is hypertension. Too much sodium can lead to water retention in the blood. Healthy kidneys are able to eliminate this excess water from the blood. But kidneys that aren't working well can have trouble eliminating the excess fluid. This increases the volume of blood being pumped through the blood vessels and can lead to high blood pressure.
Pumping a larger volume of blood through the body puts an additional burden on the heart, which may become dilated or enlarged. The extra volume of fluid may also leave the bloodstream and enter body tissues, causing edema in the parts of the body where it builds up.
People with certain health conditions should be particularly concerned about consuming too much sodium. If a person already has high blood pressure, kidney function may slow down and excess salt and fluid will collect in the body, adding to the hypertension problem. Hypertension is a risk factor for heart attacks, kidney disease and strokes. A diet too high in sodium can place overweight people at greater risk of heart disease or stroke.
On the next page, we'll look at more reasons to limit your sodium intake.
Why limit sodium intake?
Healthy people should try not to consume an excessive amount of sodium to avoid placing undue stress on the heart and to maintain a lower blood pressure. A low-sodium diet lowers blood pressure in most people. People taking diuretics (water pills) should maintain a diet low in sodium to help the diuretic work better.
Other conditions that may improve with a low-sodium diet include asthma, Meniere's disease (a disorder of the inner ear), migraine headaches, kidney stones, gastritis, ulcers and bone loss in postmenopausal women.
Your body's daily requirement for sodium is only about a half gram, and the American Heart Association recommends a daily consumption of no more than 2.3 grams a day (about a teaspoon of table salt). It further recommends that if you have heart failure, you should reduce your sodium to 2 grams per day. However, the average daily consumption of sodium in American is at least 9 grams.
It's relatively easy to reduce the amount of sodium in the typical American diet. Making changes such as eliminating the addition of extra salt in cooking and at the table, and eating fewer processed foods and more fresh fruits and vegetables, will result in a substantial reduction in sodium in your diet. Our tastes change in response to our diets; if you lower the amount of salt in your diet, especially if you do so gradually, your taste for salt will decline after awhile. You will also probably notice other flavors that you weren't as aware of when your food was saltier.
Strategies for Reducing Sodium
The widespread use of salt is one of the challenges of lowering sodium intake in a typical diet. Seventy-five percent of the sodium in the average American's diet comes from the manufacturing of processed foods. Only about 12 percent of it is naturally occurring in the food. Sodium quickly adds up when it is added in the following ways:
You can use a number of strategies to reduce sodium intake:
- Don't use salt in cooking.
- Don't add salt at the table (or even have a salt shaker on the table).
- Don't eat fast food, which tends to be very salty.
- Include more fresh fruits and vegetables in your diet.
- Limit prepared and processed foods as much as possible.
- Limit salty snacks.
- Limit milk and dairy products, which contain significant amounts of sodium.
- Read food labels and learn which brands have the highest sodium content.
- Use alternative flavors and spices such as lemon juice, vinegar, peppers, onion, and fresh herbs to season food.
Eat bananas and other potassium-rich foods. Studies have shown that these foods can reduce the effect of sodium on blood pressure.
Salt substitutes (like Nu Salt® and Mrs. Dash®) are fine to use, but because some are high in potassium, you should check with your doctor before adding them to your diet.
To find out more ways to reduce sodium in your diet, take a look at the links on the next page.
Related HowStuffWorks Articles
- How Your Heart Works
- How Your Lungs Work
- How Your Kidneys Work
- How Blood Works
- How Ultrafiltration Works
- What are the symptoms of heart failure?
- How Vasodilator Drugs Work
- How Fluid Overload and Edema Work
- How Orthopnea Works
- How Jugular Venous Distension Works
- How does heart failure affect quality of life?
- How Inotropic Drugs Work
- How Diuretics Work
- How Electrolytes Work
More Great Links
- Bentley B, Moser DK. Dietary sodium in heart failure: what to tell your patients. Prog Cardiovasc Nurs. 2007;22:41-42.
- Cailar G, Mimran A. Non-pressure-related effects of dietary sodium. Curr Hypertens Rep. 2007;9:154-159.
- Cutler JA, Roccella EJ. Salt reduction for preventing hypertension and cardiovascular disease: a population approach should include children. Hypertension. 2006;48:818-819.
- Haddy FJ. Role of dietary salt in hypertension. Life Sci. 2006;79:1585-1592.
- McGinnity JG. Establishing sound goals for hypertension management. JAAPA. 2007;Suppl Hypertension:9-13.
- O'Shaughnessy KM. Role of diet in hypertension management. Curr Hypertens Rep. 2006;8:292-297.
- Penner SB, Campbell NR, Chockalingam A, et al. Dietary sodium and cardiovascular outcomes: a rational approach. Can J Cardiol. 2007;23:567-572.