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Sodium in Public Water Supplies: An Increasing Public Health Concern


Sodium is an important mineral ion essential for the maintenance of electrolytic composition and consistence of bodily fluids.

It is found in foods and beverages consumed by man. The presence of sodium in most processed foods is becoming an important health concern to consumers, worldwide. Sodium is associated with noted diseases such as hypertension, cardiovascular diseases, renal failure, liver dysfunction, and diabetes type 1 and type 2. Recently, sodium was found above the recommended EPA guideline of 20 mg/L in the public water supplies in certain states across the US. This has prompted concern by Public Health Scientists, because sodium is associated with noted health risks in susceptible individuals leading to disability and death.

Introduction: The US Department of Health and Human Services and US Department of Agriculture found that Americans consume too much sodium. A major health problem associated with sodium consumption is hypertension or high blood pressure.

It is estimated that 9 out of 10 Americans will develop high blood pressure during their lifetime. It is estimated that Americans consume twice the amount of sodium (3,600 mg) in food and drinks. However, the American Heart Association recommends sodium levels less than 1,800 mg or less than 3/4 teaspoon of table salt.

Sodium, Health & Diet: It is estimated that 8.4 million adults have persistent high blood pressure or hypertension. About 4.2 million of these adults are sensitive to sodium and can reduce blood pressure by reducing sodium in the diet.

Although some people may not be sensitive to consuming excessive amounts of sodium, others may be very sensitive and cannot tolerate moderate increases in sodium levels (greater than or equal to 1,800 mg per day). Sodium levels above 1,800 mg per day may aggravate high blood pressure and precipitate hypertension and cardiovascular problems. In sodium sensitive people the volume of blood increases causing blood pressure to increase and the heart to work harder causing damage to the heart and arteries, which may result in heart attack, stroke or possible damage to other body organs.

Many foods that are consumed on an every-day basis, in particular meat, milk and their products contain sodium naturally. In addition, sodium is added during processing, preserving and preparing foods. Sodium is the highest in convenience and processed foods. The average person consumes several times the recommended daily allowance for sodium; it would be a healthier practice for most of us to reduce sodium consumption.

Sodium in Water Supplies: Sodium in the public water supplies varies from less than 10 mg/L to more than 300 mg/L in some states in the US. In most cases the levels of sodium far exceeds the 20 mg/L draft guideline for drinking water proposed by the Environmental Protection Agency (EPA). The guidance sodium level of 20 mg/L is determined based on the American Hearth Association (AHA) findings that 3 % of the population must fallow a severe, salt-restricted diet, and should not consume more than 500 mg of sodium per day. AHA suggests no more than 50 mg of sodium or 10 % should come from drinking water. In keeping with this recommendation EPA has set the sodium level of 20 mg/L for drinking water in order to protect susceptible people from hypertension and cardiovascular diseases.

Water Softening & Sodium: Water softening is a process of removing or replacing heavy minerals such as calcium and magnesium with sodium or potassium by passing water through an ion exchange bed. Water softening systems that utilize this approach and exchange sodium will contain a higher level of sodium added to water.

Most public water systems use a process that precipitates the hardness minerals that settle and are filtered rather then using ion exchange, osmosis or distillation.

Reducing Sodium in Drinking Water: It may be easier and more practical for many people to reduce sodium in their drinking water rather than in their food. People on a sodium-restricted diet certainly should avoid as much sodium in water as possible. Sodium in drinking water may be controlled in two ways: the first involves knowing how much sodium is in the water supply and the second involves avoiding sodium added by softening.

Recommendations on Reducing Sodium in Drinking Water:

Need to set a definite mandatory standard for sodium level in drinking water, enforced by EPA and Food and Drug Administration.

Introduce Public Health Educational Programs on the health benefits of drinking low sodium water.

Increase consumption of fruits and vegetables (5-7 serving per day).

Exercise regularly for at least 30 min. every day.

Maintain a healthy body weight (body mass index not more than 25).

Take necessary medication if required.

Decrease the consumption of processed and ready-to-eat foods.

Drink and eat foods low in sodium by first reading labels properly before consuming.

Conclusion: Sodium is an important mineral required for the proper maintenance of the electrolytic composition of bodily fluids. Sodium is often present in amounts exceed the stipulated 20 mg/L proposed by the EPA, in meats, dairy and most convenient and processed foods. Drinking water also contains sodium at a level exceeding 20 mg/L in most public water supplies in US. It is more practical and easier to limit the intake of sodium from drinking water than from food. Health educational programs, setting definite mandatory limits for sodium, and restricting the use of high sodium foods may serve to reduce the intake of sodium in diet.

Reference:

Effects on Blood Pressure of Reduced Dietary Sodium and the Dietary Approach to Stop Hypertension (DASH) Diet. New England Journal of Medicine, Vol. 334 No. 1, Jan. 4 2001.

H. Bradshaw and G. Morgan Powell, Sodium in Drinking Water, Kansas State University, October 2002.

The Effects of Home Water Softeners: Added Sodium May Be Hazardous to Your Health. Gopal Das, MD. Janine Finis, Journal of Environmental Health, Vol. 50, No. 7, July/August 1980.

Too Much Salt. Consumer Reports, p. 48-50, January 1990.

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