Shaking the salt habit doesn't mean turning off the tap
by Thair Peterson

In the name of their health, humans have been trying to bag those pretzels, blow off the bacon, give ham the heave-ho, cut out the corned beef and stash the salt shaker.

Guess what. There's salt in drinking water, too. Is it time to turn off the tap?

A review of the literature shows that the death-to-salt campaign should be taken with a few grains of NaCl.

Yes, humans consume far more sodium chloride (NaCl, alias table salt) than they really need. The minimum recommended requirement for sodium is about 500 milligrams per day, which is about one-quarter teaspoon of salt. The average person consumes closer to 3,500 milligrams per day-nearly a teaspoon.

About one-third of the population is salt-sensitive, which means that reduced sodium consumption could prove especially beneficial in battling high blood pressure, a condition associated with coronary heart disease, stroke, heart failure and kidney failure. Moreover, a 2001 National Health Lung and Blood Institute study showed that salt sensitivity increases the risk of death even for those with normal blood pressure.

With those kind of figures, it's no wonder that in the minds of many, this crystallizes into—Salt is the enemy.

In recent years, health warnings were issued in Toronto and Louisiana— among other parts of the country—advising people with high blood pressure or heart problems to check with their doctor before drinking tap water.

It usually happens when drought or some other factor causes sea water to creep inland and impact groundwater wells. It matters little that water contributes a negligible percentage of our average sodium intake, or that a group of dissenters say that researchers have been selective in interpreting sodium research, or that even salt-sensitive individuals would be well-advised to take additional steps—such as exercising more or eating less salt.

As long as concerns are raised about the "salinity" of our water supply, there's a chance that salt-phobic individuals may decide that their water poses a human health threat and decide that they'll cut down on their water consumption. Ironically, reducing water consumption can increase the amount of sodium in the blood, leading to precisely the kind of outcome that these individuals are hoping to avoid.

"From a public health perspective, persons concerned about sodium and their cardiovascular health should be watching and reading the (food) nutrition label... more so than reading the report of their water quality," said Kathryn Harben of the U.S. Centers for Disease Control in Atlanta.

A symbiotic relationship

Salt and water have had a symbiotic relationship. If life emerged from the sea, then it's hardly a surprise that humans and animals would utilize both water and salt. Animals were drawn to salt licks, and humans would follow the trails they made.

To understand the importance of salt, just look inside the human body.

Just as the world's waterways were used to transport salt, so does the bloodstream transport salt throughout the human body.

There's a reason blood tastes salty. Maybe Dracula knew something we don't. Human blood contains about 0.9 percent sodium chloride. That's about 9,000 parts per million—or about nine times the maximum salinity level set by state regulators for drinking water.

Sodium and chloride are both electrolytes. They're not metal, but they conduct electricity through water and allow electrical nerve impulses to pass from cell to cell. A body without electrolytes would collapse like an unplugged robot. The human body is obsessed with balance. Like a fanatic accountant, it perpetually balances the books. If the ledgers get out of whack, the consequences can be extreme. It's not like a market economy, where things are supposed to work out in the long run. Here, if corrections aren't made quickly, there is no long run.

To look at how the salt-water balance works in the body, let's break down how the components of salt works with the body.

Sodium plays a key part in maintaining osmotic pressure in the cells—the same force at play in reverse osmosis. In reverse osmosis, you're trying to overcome that resistance, but in the human body, the loss of osmotic pressure would cause water to flow inside and outside cells at random, which would cause organs and tissues to swell and shrivel. Chloride is an anion—a negatively charged ion. It is a vital part of digestion and respiration and helps create hydrochloric acid in the stomach, which helps break down food.

Sodium is what's known as a cation—an ion with a positive electrical charge. Different electrolytes are found in different bodily fluids. When it comes to cations lurking in the fluid between the tissue cells, sodium is king. It allows cells to communicate—linking those electrical impulses that course through our bodies

If the balance of water and salt is upset, muscles don't work together. The heart can't function properly. We can't concentrate - the nervous system goes a bit haywire.

When sodium levels dip dangerously low, it's called hyponatremia. When they soar too high, it's called hypernatremia. More people fall victim to the former extreme, than the latter.

Low sodium levels make people feel nauseous or lethargic, then they start feeling disoriented, agitated, before developing seizures. In acute cases, it can lead to coma.

It's all part of nature's way of keeping the body balanced.

Peggy Agron, a public health nutritionist at the California Department of Health Services, notes that humans evolved a need for sodium, but that our behavior has changed since then.

"We didn't used to eat processed foods, we weren't eating out in restaurants. The American diet over time has gone way way up in sodium," Agron said. "(Because of salt's continued popularity as a flavoring and preservative) there's a lot of hidden sodium in processed and packaged food."

For the opposite extreme of too much salt, most people tend to think of the feeling they get when they swallow ocean water, which is about 3.5 percent salt.

While albatrosses can drink seawater, sailors abhorred it, convinced it would bring certain death. A few mariners adrift at sea lived dangerously and sipped it in small quantities, and survived. Yet there is scant scientific research on the effects of seawater on humans.

Hypernatremia very rarely happens from a salt overdose. It's more likely to happen from dehydration, often in nursing home or hospital patients whose thirst impulse has disappeared, according to medical experts.

Whatever the reason—excess salt or lack of water—the body goes through its own desalination process to restore the balance.

Fish survive by excreting large amounts of salt through their gills. Humans excrete sodium through their kidneys. But there is only so much sodium that can be urinated away, and salt-sensitive individuals excrete less sodium than others do.

If the body can't reduce the salt, the next best way to hit the right level is to increase the amount of water.

If you're not drinking enough water, the body finds that extra water by robbing its own cells. In these extreme cases, neurons shrink and begin to stretch; brain and spinal membranes may begin hemorrhaging. The brain shrinks. Too high a concentration of salt in the body can lead to irritability, muscle twitching, seizures, brain damage, coma and sometimes death. Usually the results aren't quite so drastic. Dr. Myron Weinberger, an Indiana University medical school professor who authored the salt sensitivity study, says that given the "horrendous excess of salt that we end up with every day," some individuals can't get rid of it all, especially those born with subtle kidney problems that may go undiagnosed.

Part of the problem is the chemical attraction between sodium and water, he said.

"Every grain of salt that is retained in the body carries with it 20 times its weight in water which increases the (amount of) fluid in circulation," Weinberger said. "If you think of the blood vessels as piping, as you push more fluid in them, then the pressure goes up.

"The other thing that happens is that the increased salt gets inside the blood vessels making them thicker and narrower, and that increases the pressure. You don't need to hold onto much salt day by day to produce a tremendous buildup over 30 years."

Harben, who works in the CDC's chronic disease prevention department, says, "there is substantial evidence that reducing sodium intake (especially in the setting of a diet that is rich in fruits and vegetables) can lower blood pressure and improve cardiovascular health. For most people, the lower the salt intake, the better the health outcome."

Agron, the DHS nutritionist, draws an analogy to cholesterol.

"Our body needs cholesterol, but the body takes up more than you need," Agron said.

Agron's counterparts in the DHS drinking water and environmental management division have never set a health-related standard for sodium or even a secondary standard dealing with taste and odor. But that's because the state adheres to the U.S. Environmental Protection Agency's standards set forth in it primary drinking water regulations.

Rufus Howell, assistant division chief, said that DHS simply includes sodium into the larger category of "total dissolved solids"—a fancy term for salts and minerals. In terms of a sodium policy, it takes its cue from the U.S. Environmental Protection Agency.

The EPA has "special monitoring" for sodium as part of its National Primary Drinking Water Regulations.

Sodium is listed on the Drinking Water Contaminant Candidate list, but as a "research priority." Mainly, that's to see whether the EPA should reassess whether its sodium guideline of 20 milligrams per liter is too stringent, and whether higher levels would be acceptable. The EPA will then decide whether sodium should be dropped from the contaminant candidate list entirely.

Metropolitan's Colorado River water supply ranges from 60 milligrams a liter for the State Water Project to 100 milligrams per liter on the Colorado River. In other words, if someone managed to cut all the salt out of their diet, they have to drink roughly six gallons a day to hit the 2,400 milligrams daily limit recommended by the National Institutes of Health, the National Academy of Science and the Food and Drug Administration.

Salt and human history

Our current attitude toward salt is a decided break from human history. Throughout the ages, humans have tried to manipulate the salt content of water. These days, we're trying to take the salt out. But for most of history, humans were trying to do the opposite.

For example, in times past, brine—highly salty water—wasn't something to be thrown away; it was something to be cultivated. For governments and traders alike, salt was a source of power and money. For thousands of years prior to the refrigeration era, being a reliable salt supplier could be as important as being a reliable water supplier today. Those who could make salty water even saltier could greatly increase their salt production, and therefore, their profits. (In contrast, the modern-day water industry considers brine a bad thing. It is the byproduct—like trash, or even hazardous waste—of desalination and is an unwanted intruder into groundwater).

While salt was used in a variety of manufacturing processes, it was mainly produced for human consumption—as a method for preserving food.

According to "Salt - A World History," the European per-capita consumption of salt in 16th century stood at 40 grams per day; by the 18th century, it had hit 70 grams per day per person. That's like eating three to six pounds of potato chips a day.

However, Weinberger noted, 18th century life expectancy about 30 years, but it takes 50 years to build up high blood pressure from too much salt, so there weren't a lot of people getting it.

Whatever the danger level might be for salt concentration, it's much harder to reach that point with water than with food. Sodium and other constituents begin affecting the taste of water at a lower threshold to where most humans simply don't want to drink it. However, even there it can be a matter of taste or subjectivity—a case of whatever one is used to. To those who grow up with water supplies with high levels of total dissolved solids- water with lower levels can taste "funny."

In terms of sodium's partner—chloride—there is a federal goal of 250 parts per million that was put in place mainly because of taste concerns. It can cause an objectionable taste. Otherwise, its main drawback is that it's usually consumed as a part of salt, and if one is consuming lots of chloride, then they may be consuming lots of sodium.

Similar to what happens in a dehydrated body, drought conditions can lead to higher concentrations of salt in water.

In Chesapeake, Virginia, chloride levels hit nearly 800 parts per million during a 1995 dry spell—turning iced-tea into salt-spiked cocktails and sending sodium levels to nearly 20 times the recommended level. And even that was better than 1,600 parts per million experienced during a bad spell in the mid-1980s.

Salinity and water

All of this brings us to the term "salinity"—a condition being hotly discussed these days as water officials consider how to deal with high salinity, imported water, and groundwater at risk for brine-water contamination. There is a difference between "salinity" and what we call salt. Salinity refers to many different types of salts or minerals found in the water that go under the catchall phrase of "total dissolved solids."

The terms salinity and total dissolved solids are used interchangeably. TDS encompasses a broad range of mineral constituents that include aluminum, calcium, magnesium, phosphorous, sodium, sulfate, potassium and chloride.

While many of the same minerals are essential to human health, salinity has been called the most under-recognized water quality problem in California and in the nation. It affects our groundwater, and the plumbing and appliances in our homes. It affects even the production of fruits and vegetables.

That's why leaders from throughout the water industry have formed a coalition to determine what needs to be done to remedy the salinity issue. Until then, we have to take our tap water…with a grain of salt.

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