What is Sodium? What are the sources of Sodium Are all salts alike? How much sodium do we need every day? How much sodium is too much? Is it possible to take in too little sodium? How can I limit sodium intake?

What is Sodium?

Sodium is an element that is found in all of the cells of our body and is required to maintain our body’s fluid balance. The kidneys, various metabolic systems and hormones are involved in maintaining this balance.

We need sodium to survive, but too much can be harmful to our health. Some individuals are particularly sensitive to the effect of sodium on blood pressure. For these individuals, taking in more than 1,500 milligrams of sodium a day can raise blood pressure significantly by holding fluid and making it harder for the heart to pump. Those with serious heart or kidney conditions may have to lower their intakes below that number. Some evidence suggests that a low sodium diet may also have benefits for bone health by helping to reduce calcium losses, especially when calcium intake is low.

What are the sources of Sodium?

Sodium, consumed as sodium chloride or salt, accounts for approximately 90 percent of the total sodium intake in the United States. Some of this sodium occurs naturally in foods, but most of the excess sodium in our diets comes from processed foods rather than from the salt shaker.

Sodium in foods serves many functions besides providing flavor. Salt used in yeast breads helps the dough to rise and functions as a dough conditioner, strengthening the gluten protein that gives bread its texture. In frozen foods, salt preserves texture. Sodium chloride reduces the growth of harmful bacteria and is used as a preservative in meats and in smoked, pickled and fermented products. Other forms of sodium found in processed foods include sodium bicarbonate (leavening agent), monosodium glutamate (flavor enhancer), sodium phosphates (emulsifiers or leavening agents), sodium carbonate (anti-caking agent and stabilizer), and sodium benzoate and sodium bisulfite (preservatives).

Fresh meats, fruits, and vegetables are generally low in sodium. Salt or some forms of sodium are added when foods are processed and packaged. Products that are higher in sodium include pickles, olives, luncheon meats, processed convenience foods, canned goods, soups, gravies and sauces, and restaurant meals. Sodium can “hide” in products such as some herb and spice blends, meat tenderizers, and bouillon cubes, so it is important to check the Nutrition Facts label for sodium content. There are “reduced Sodium,” “no added salt,” and “low sodium” products available, and some food manufacturers are formulating their conventional products to deliver less sodium.

Another often overlooked source of sodium is “softened” water. Depending on the initial hardness of your water, a sodium-based ion-exchange system can add either a minimal amount of sodium or as much as 100 milligrams per 8 ounces to the sodium already existing in your tap water. Click here for more information on this topic. http://www.mayoclinic.com/health/sodium/AN00317

Are all salts alike?

There are various types of salt available. Almost all of these products contain sodium. The main differences are in flavor, texture, and what they are used for.

• Table salt –fine grained, may contain sodium iodide (iodized salt) and an anti-caking agent. One teaspoon of table salt contains 2,300 milligrams of sodium.
  
• Kosher salt – coarse grained, not iodized, delivers a “clean” taste. Often used in pickling and brining.
  
• Sea salt – coarse grained, obtained by evaporating sea water, also not iodized. Available in a rainbow of colors depending on its origin and the minerals it contains.
  
• Seasoned salt – flavored with herbs and other ingredients.
  
• Rock salt – very coarse grained. Generally not used in food but often added to ice in an ice cream maker.
  
• Salt substitute – may contain other salts such as potassium chloride. Check with your physician before using these, especially if you are taking medications.

How much sodium do we need every day?

The Institute of Medicine of the National Academy of Sciences has developed recommendations for adequate intake of sodium for normal individuals of different age groups.

The Adequate Intake is the amount needed to replace the sodium lost through sweat as well as to achieve a diet that provides the essential nutrients our bodies need. These amounts are generally sufficient to cover sodium losses for the average person who is suddenly exposed to a higher temperature or who becomes physically active. Competitive athletes and workers exposed to extreme heat and physical activity (such as fire fighters, laborers working in hot conditions) may need higher amounts of sodium to replace sweat losses. Children and older adults need somewhat less sodium because they generally eat fewer calories. Your physician may suggest a specific level of sodium for you.

How much sodium is too much?

The Institute of Medicine recommends these limits for sodium for normal individuals of different age groups.

The major adverse effect of increased sodium intake is elevated blood pressure, which can lead to cardiovascular disease and kidney diseases. Individuals with hypertension, diabetes, and chronic kidney disease, as well as older persons and African Americans, are most likely to benefit from a reduction in sodium intake. Some individuals are more “salt sensitive” which means that they will experience a greater reduction in blood pressure when they reduce their salt intake. There are other individuals with certain medical conditions who may need to increase their sodium intake. Discuss your specific sodium needs with your physician.

Is it possible to take in too little sodium?

Overall, there is little evidence of any adverse effect of low sodium in healthy individuals because the kidneys will conserve sodium when intake is low. Individuals who are losing great amounts of body fluids through prolonged perspiration as a result of strenuous exercise or activity, or through vomiting and/or diarrhea, may become dehydrated.

During dehydration there is an excessive loss of sodium from the body. Dehydration can also occur as a result of impaired kidney function or as a side effect of medications. Dehydration requires prompt medical attention to correct.

How can I limit sodium intake?

If you have not already done so, get your blood pressure checked. If it is elevated, visit your physician to develop a plan to manage your specific condition. More than likely, you will be advised to reduce your sodium intake. The first step in controlling your sodium intake is to check the Nutrition Facts labels and select products that are lower in sodium. Choose fresh fruits, vegetables, and meats as much as possible and eat a variety of foods each day for a balanced diet. Go to the www.MyPyramid.gov website for an individualized meal plan based on your gender, age, weight, height, and activity level.

Here are some tips for controlling your sodium intake:

• Limit cured, pickled, salted or brined products.
  
• Remove the salt shaker from your table and use the pepper mill instead.
  
• Don’t add salt to your food during cooking. In fact, most recipes will turn out just fine if you reduce the salt by half or eliminate it altogether. You do not need to add salt to boiling water for cooking pasta, oatmeal, rice, or vegetables.
  
• Yeast breads, however, do require some salt for flavor and proper rising – about _ teaspoon salt for 4 cups of flour.
  
• Try flavored vinegars, onions, garlic, lemon juice, herbs and spices to add flavor to your foods.

Reducing the amount of salt you use will retrain your taste buds to sense other flavors and you won’t miss the salt after a while.

The National Heart, Lung, and Blood Institute developed the DASH diet (Dietary Approaches to Stop Hypertension) to help individuals lower their blood pressure. This eating plan focuses on decreasing sodium and increasing the consumption of foods rich in nutrients that help to reduce blood pressure.

For details of the DASH Eating Plan, including menus and recipes.
http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf

References:

Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academy Press, Washington, DC. 2004.

Wigertz K, Palacios C, et al. Am J Clin Nutr. 2005;81:845-50.

Heaney RP. J Am Coll Nutr. 2006;25:271S-276S.

American Medical Association. Press release June 13, 2006.
http://www.ama-assn.org/ama/pub/category/16461.html