Next to religion and politics, you can bet that the relationship between sodium and public health will stir up a lively discussion in any professional, nutritional or medical circle.

Our files on sodium and it's effect on health go back into the 1970's. We've seen massive swings in public and medical opinions as regards sodium during the last 20 years.

20 years ago the medical and health community was having trouble linking heart disease, hypertension and other physiological disorders to sodium intake. During` the 80's, we saw a resurgence in public health awareness---and with that awareness came jogging, better nutrition and a dramatic public awareness of the salt issue.

This awareness had a dramatic, negative effect on many American industries, including water softening companies and the salt industry in particular.

The most recent and all-encompassing information drawn from extensive testing and evaluation conducted at 11 major medical and health centers nationwide appears to be homing in on some conclusions that we as health-conscious individuals should take seriously.

These most recent studies, being reported in the Journal of the American Medical Association as this article you are reading goes to press, indicate that significant blood pressure reduction was observed in those test individuals who lost weight.

A nearly identical drop in blood pressure was noted for those individuals who were in the "salt-reduction" group.

Perhaps the most interesting result was that little or no blood pressure drop was noted for individuals in "stress reduction" or "nutritional supplement" programs.

Additional studies which will consider the link between hypertension and sodium are in progress and should be concluded in a short period of time.

THE SODIUM LINK

Sodium, as part of our body structure, is essential to good health. All our body fluids, including blood, seat and tears, contain sodium. It is vitally essential to maintain the proper balance of sodium in these fluids.

For example. Sodium ions comprise more than 90 percent of the basic ions of our blood and, since sodium retains water, this sodium ion directly influences blood volume. Excess sodium thus causes expansion of our body's blood volume. In addition, sodium acts in other ways to constrict arterioles, the smallest of our arteries.

Therefore, the strain of a greater volume of blood(caused by volumetric expansion due to excess sodium) coupled with constricted blood channels(also caused in part by excess sodium) causes our heart to work harder than normal.

Doctors tell us that this greater than normal heart activity causes the heart muscles to thicken and possibly enlarge. Unchecked, this process may cause permanent damage to the entire arterial network. Heart disease is America's #1 killer today.

TEMPERING THE CONNECTION

Most medical authorities seem to agree that the above scenario applies to perhaps 15-20% of the American population. Most studies have concluded that the other 80% are not affected by sodium intake to a degree that is easily noted by statistical studies.

According to the most recent AMA studies, reduction of sodium intake by that 20% group would cause up to a 6% drop in stroke deaths per year and a 4 percent drop in deaths from coronary heart disease.

Obviously there is much room for argument as to the exact percentile, but it is important to note that similar results have been documented for life extension and reduced pulmonary(lung and respiratory) diseases when individuals stopped smoking.

THE WATER LINK

Now we are talking about 20% of the American public, or roughly 50 million people, who are prone to high blood pressure, or perhaps hypertension, if they consume excessive sodium.

The FDA, the EPA and a whole lot of dietary groups have tried for at least a dozen years to determine what constitutes "low sodium", "no sodium", "very low sodium", etc for food and water product labeling.

On the other hand, the American Heart Association has consistently maintained(for at least 20 years) that a person whose sodium diet is restricted to 1/2 gram per day total intake, should not drink water which contains more than 20 milligrams/liter of sodium.

Our tap water in the Santa Clara Valley contains anywhere from 20 to 300 milligrams of naturally-occurring sodium per liter of water. An average we can find in the San Jose area runs between 50 and 100 milligrams per liter or up to five times the levels recommended by the AHA.

During the drought of 1975-77, in excess of 300 milligrams of sodium per liter was being measured in our tap water. Much of our local water comes from the Central Valley and the Delta areas where sodium intrusions from the San Francisco Bay(tidal action every 12 hours) causes higher than normal sodium levels to be present in dry years when less "flushing" water from the mountain rivers is available to clean out the Delta.

Water softeners are a major contributor to sodium levels for those in the 20% category. Softeners turn calcium and magnesium "hardness" to "soft salts" such as sodium.

If you are on a sodium restricted diet and are drinking "softened" water for all practical purposes you may as well throw away your sodium-free diet.

Such large amounts of salts are given out by regenerative water softeners that over 60 cities in Southern California have banned these units because of elevated salt levels in ground water reclamation projects(for irrigation of orchards, etc) caused by water softeners and other sources.

In many areas of the Valley, water hardness is quite acute and water softeners will add several hundred of milligrams per liter of sodium to the water portion of your diet, IN ADDITION TO the naturally occurring sodium which is already present in local tap water.

WHAT TO DO

If you fall into the 20% which has a sodium sensitivity, you have several alternatives. First, if you are drinking water from a water softener in your home---STOP IMMEDIATELY. If you have no other water source, at least use water which does not go through your softener---perhaps an outside water tap.

Secondly, if you are drinking tap water and, for whatever reason are using or considering using bottled or vended water, use water that is labeled "steam distilled water" or "for all steam distilled water uses". These types of water contain no sodium whatsoever.

Do not buy water labeled "drinking water" since it is usually only filtered with a carbon filter and will contain any and all sodium present in the source water.

If you are on a restricted sodium diet, do not invest in simple carbon filters for your home. They do nothing to reduce sodium, heavy metals such as lead, bacteria or other contaminants. In your case, they would be a total waste of money.

Reverse osmosis will reduce the amount of sodium in drinking water a significant amount when the equipment is new. As you use the system over a few weeks and months, the water from this type of system begins to look more and more like the tap water going into it.

This is particularly important if you are using a reverse osmosis system in conjunction with a water softener. The softener puts out copious amounts of sodium---and while the reverse osmosis unit may initially remove 80-90 percent of this sodium, it will quickly deteriorate to virtually pure sodium content in your so-called "purified" water.

The safest and most effective way to process tap water to remove sodium and other unwanted contaminants is through the use of a home steam distillation unit.

Small, inexpensive, compact and easy to maintain home distillers are becoming commonplace in homes in the valley where sodium and chemicals are unwanted in the family diet.

For small families, they now cost less to purchase and less to operate than reverse osmosis systems, providing cleaner and better tasting water, more reliably and under a wider range of input water.