Michael H. Bradshaw and G. Morgan Powell, Sodium in drinking water, Kansas State University, October 2002

Bradshaw, Michael H.

Powell, G. Morgan

K-State Research Exchange

Kansas State University Agricultural Experiment Station and Cooperative Extension ServiceSodium in DrinkingWaterThe U.S. Department of Health and Human Services andU.S. Department of Agriculture recommend that Americansreduce their sodium intake. Too much sodium intake in foodand water has been identified as a contributor to high bloodpressure. Nine out of 10 middle-aged Americans will develophigh blood pressure during their lifetime.The American Heart Association and National Academyof Sciences recommend sodium levels between 500 and 2,400milligrams (mg) per day. However, sodium less than 1,800 mgis belived to be healthier. This (1,800 mg) is obtained from 3/4teaspoon of table salt, sodium chloride. But, typical Ameri-cans consume about twice this amount of sodium in food anddrinks.Sodium and HealthAbout 42 million adults, 20 percent of the population,have persistent high blood pressure (hypertension). About halfof those with high blood pressure are sensitive to sodium andcan reduce blood pressure by reducing sodium. Althoughsome people can consume excessive levels of sodium withoutincreased blood pressure, many cannot. Other risk factors forhigh blood pressure include excess weight, alcohol consump-tion, and a family history of high blood pressure. Many scien-tists believe sodium sensitivity is inherited. If this is true,susceptible people may be able to avoid hypertension by mini-mizing high sodium intake (limiting dietary sodium to lessthan 1,800 mg per day).High levels of sodium may aggravate existing high bloodpressure. Factors to help reduce high blood pressure include alow sodium diet, increased fruit and vegetable consumption,exercise, weight control, and medication if necessary.Studies of more than 20 cultures worldwide, fromGreenland Eskimos to natives of the Solomon Islands, showthat hypertension is rare in populations using little salt. Kungbushmen of Africa and Yanomamo Indians of Brazil havevirtually no hypertension. Their diets are extremely low insalt. Their blood pressure does not rise with age as it does inpeople who live in industrialized societies.By contrast, in countries where people consume largeamounts of salt, hypertension is a serious concern. People innorthern Japan, where salt is used as a food preservative, areamong those with the highest incidence of high blood pres-sure. They may consume 30,000 mg (1/8 cup) of salt each day,about 60 times as much as 500 mg for the African and Brazil-ian tribes.Excess salt in the diet causes increased sodium in theblood. In some people the volume of blood increases, thuscausing blood pressure to increase and the heart to workharder. The danger of high blood pressure is possible damageto the heart and arteries, which may result in heart attack,stroke, or possible damage to other body organs.Sodium in DietAbout 15 million people in the United States have a dailydiet characterized by moderate to severe restrictions for so-dium intake. Most foods and beverages contain some sodium.Many foods, such as meat and milk, contain sodium naturally.However, sodium is also added in processing, preserving andpreparing food. More than 100 times as much sodium is addedto some foods during processing than is contained in the foodingredients (see Table 1). Sodium is often highest in conve-nience snacks and processed foods.Many people have acquired the taste for salted food anduse the salt shaker liberally to satisfy this taste. Because theaverage person in this country consumes several times therecommended daily allowance for sodium, most of us wouldbe healthier with reduced sodium consumption. We could alleducate ourselves about the benefits of a reduced sodium diet,wean ourselves from the taste of salted foods, and reduce theuse of salt.Sodium in Water SuppliesThe Environmental Protection Agency (EPA) has a draftguideline for sodium in drinking water of 20 milligrams perliter (mg/L). Sodium in Kansas public water supplies variesfrom less than 10 to more than 300 mg/L. To find out howmuch sodium is in your public water supply refer to the mostrecent Consumer Confidence Report for your water supply, orTable 1. Sodium in Some Common FoodsFood Weight Sodium (mg)(grams)               LS Reg.Frankfurter (2), beef and pork, 10/pkg 100 - 1008Cod, poached, no salt 100 - 61Salmon (canned), drained 100 75 487Tuna (canned), in oil, drained 100 50 354English muffin 57 - 264Bread (slice) 25 34 126Crackers (Low sodium vs. saltines) 30 198 390Dry cereal* 30    2      275-350Cooked cereal 100 1      200-285Cheese, American Processed 30 3 430Cheese, cheddar 30 - 85Cottage cheese 30 4 120Whole milk (8 oz) 240 - 120Hot chocolate (8 oz) 240 - 175Peanut butter (I Tbs) 15 1 73Pork and beans, canned 100 - 440Diet soda* (12 oz) 360 -        20-70Regular cola* (12 oz) 360 - 14Butter 5 1 41Margarine 5 0-1        37-47Mayonnaise and Mayonnaise type 15 17        85-180*variation among brands may be considerable; read label.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.contact your water supplier. K-State Research and Extensionpublication, Sodium in Public Water Supplies, MF-1114 has alist of sodium content for most public water systems. Peoplewith private water supplies need a water test to determine thesodium content of their water. Keep in mind that concentrationmay change with groundwater recharge, contamination andwater use.The American Heart Association (AHA) suggests thatthe 3 percent of the population who must follow a severe,salt-restricted diet should not consume more than 500 mg ofsodium a day. AHA suggests that no more than 10 percentof this sodium intake should come from water. The EPA’sdraft guideline of 20 mg/L for water protects people who aremost susceptible.Home Water Softening May Increase SodiumWhen water is softened at home, it is done by passing thewater through a bed of ion-exchange media that replaces hard-ness minerals (calcium and magnesium) with sodium or potas-sium. Most softeners add sodium to softened water. However,softeners that recharge with potassium do not add sodium;only softeners that recharge with sodium chloride (salt) addsodium to water. Most public water systems that soften wateruse a process that precipitates the hardness minerals that settleand are filtered rather than using ion exchange.Hardness is reported as grains per gallon (gpg), milli-grams per liter (mg/L), or parts per million (ppm). One grainper gallon equals 17.1 mg/L, or ppm. To determine theamount of sodium a home water softener adds, use water hard-ness in grains per gallon (gpg). If your water test is reported inmilligrams per liter or parts per million, convert it to grainsper gallon by dividing by 17.1. Ion exchange softening addsabout 8mg/L of sodium to the water for each grain per gallonof hardness removed (8 mg/L/gpg). To find the sodium inyour softened water use the formula:Sodium added (mg) = volume of water you drink (L)x hardness removed (gpg) x 8 mg/L/gpg.Example: A person who drinks two liters (2L) of soft-ened, extremely hard water (assume 30 gpg) will consumeabout 480 mg more sodium (2L x 30 gpg x 8 mg/L/gpg = 480mg), than if unsoftened water is consumed.Reducing Sodium in Drinking WaterIt may be easier and more practical for many people toreduce sodium in their drinking water rather than in their food.Anyone on a sodium-restricted diet certainly should avoid asmuch sodium in water as possible. Even for healthy people itmay be more practical to limit excess sodium in drinkingwater rather than from food. Controlling sodium in drinkingwater involves two steps – knowing how much is in the watersupply and avoiding sodium added by softening. Becausemuch of the groundwater in Kansas is hard or extremely hard,softening can add significant amounts of sodium.The easiest and least expensive way to avoid sodium fromwater softening is to drink unsoftened water. This can be doneby supplying unsoftened water at the cold water faucet or aseparate bypass faucet. Another option is to use bottled waterfor drinking purposes. However, not all bottled water is low insodium, so read the label or contact the bottler to find thesodium content. We recommend that you choose a water thatis less than 20 mg/L. Finally, water treatment may be a practical way to re-move sodium and other minerals, whether natural or added bysoftening. Reverse osmosis or distillation are the treatmentoptions. See Extension publications, Reverse Osmosis, MF-884, and Distillation, MF-885. If the liquids you drink each day have less than 100 mg/Lof sodium, it probably adds less than 5 percent of the sodiumcontent of the average adult’s diet. People whose water hasmore than 100 mg/L of sodium may want to consider takingsteps to reduce sodium in their water. The methods mentionedabove apply. Remember, the average person wanting ahealthier life should also reduce sodium (salt) in foods, espe-cially snack foods and beverages.High Perspiration and SodiumWhen people perspire, they loose sodium from their body.However, most people who perspire a lot do not have to in-crease their sodium intake significantly because most arealready consuming enough. Those who perspire profusely mayneed to drink more than 4 quarts of liquid a day to replace thewater lost through perspiration. Most athletes and laborersobtain adequate sodium from food at meal times, or by usingthe salt shaker at the table if food is low in salt.Additional Information SourcesAttitudes and Actions: American’s Diet and the DietaryGuidelines For Americans, 2000. USDA-ARSwww.barc.usda.gov/bhnrc/foodsurvey/2000dga.htmlEffects on Blood Pressure of Reduced Dietary Sodium andthe Dietary Approach to Stop Hypertension (DASH) Diet.New England Journal of Medicine, Vol. 334 No. 1, Jan. 42001.The Effects of Home Water Softeners: Added Sodium MayBe Hazardous to Your Health.  Gopal Das, MD. Janine FinisJournal of Environmental Health, Vol. 50, No. 7,July/August 1980.Too Much Salt. Consumer Reports, p. 48-50, January 1990.Brand names appearing in this publication are for product identification purposes only. No endorsement is intended,nor is criticism implied of similar products not mentioned.Publications from Kansas State University are available on the World Wide Web at: http://www.oznet.ksu.eduContents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Michael H.Bradshaw and G. Morgan Powell, Sodium in Drinking Water, Kansas State University, October 2002.Michael H. BradshawExtension SpecialistHealth and SafetyG. Morgan PowellExtension EngineerWater QualityKansas State University Agricultural Experiment Station and Cooperative Extension ServiceMF - 1094 (Revised) October 2002It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all persons shall have equal opportunity andaccess to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age or disability. Kansas StateUniversity is an equal opportunity organization. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. KansasState University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Marc A. Johnson, Director.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.

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