Thursday, June 7, 2012

A balanced view on salt

Those of us convinced that high sodium intake is a primary cause of the high rates of heart attacks, strokes, etc. in the United States — you'll even see some of that in my earlier posts — need to fold into our kitchen knowledge a generous helping of recent science and a dash of common sense.

A 2010 Scientific American article "It's time to end the war on salt" is a long but worthwhile read on how the junk science of low-sodium diets as a one-size-fits-all solution got a foothold in medicine of industrialized countries. The article says real science is starting to silence the low-sodium mantra.

Sometimes even the scientists come to conclusions that defy common sense and should be considered with a grain of salt. (Elisabetta Grondona photo via Creative Commons license)


In 1981, Louis Tobian Jr., who headed the hypertension unit at the University of Minnesota School of Medicine, said in testimony to the U.S. House of Representatives Committee on Science and Technology, “One must realize that prehistoric man for 3 million years was on a low-salt diet. …We were never intended to have access to so much salt.” This was the premise of Dr. Tobin's 1979 article "Dietary Salt (sodium) and Hypertension" in the American Journal of Clinical Nutrition.

I would ask how do we know what kind of diet "prehistoric man" ate 3 million years ago? Has some archaeologist find an ancient 3 million year old cookbook to tell us exactly what these "prehistoric" men and women ate all those years ago? Likely, he extrapolated from the observation of diets of more recent "primitive" peoples. That may make for an interesting hypothesis, but it's unprovable.

He also glossed over other equally valid observations of low incidence of hypertension in "primitive" populations, including their tendency to consume less sugar, meat and calories in general than those who live in industrialized populations. Their diets also tend to include more vegetables, which have sodium-balancing potassium too.

Gary Taubes, M.D., wrote in a recent New York Times editorial:

In the United States, for instance, it (salt consumption) has remained constant for the last 50 years, despite 40 years of the eat-less-salt message. The average salt intake in these populations — what could be called the normal salt intake — was one and a half teaspoons a day, almost 50 percent above what federal agencies consider a safe upper limit for healthy Americans under 50, and more than double what the policy advises for those who aren’t so young or healthy. This
consistency, between populations and over time, suggests that how much salt we eat is determined by physiological demands, not diet choices.
Throughout most of human culinary history, most foods were preserved with salt. University of California at Davis' Geology Department details several examples of how access to salt changed the course of history, including the U.S. Civil War.

It wasn't until the widespread use of refrigeration, particularly post-WWII, that our salt consumption dropped, and refrigeration replaced salt as the main means of food preservation.

In a comedic twist of history, at about the time the first study — published in France in 1904 by Drs. Ambard and Brochard — hypothesized the links between high sodium consumption and high blood
pressure and heart disease, refrigeration was reducing the need for salt in food preservation.

"Our current salt consumption (1.5 to 1.75 teaspoons per day) is about one half of the amount consumed between the War of 1812 and the end of World War II, which was about three to 3.3 teaspoons of salt per day," according to the Weston A. Price Foundation.

That suggests sodium is not the reason for the steady increase in the post-WWII rate of chronic disease on either side of the Pacific. Salt intake in Korea and the U.S. was even higher before the advent of refrigeration than it is now, yet we now have higher rates of heart disease than our ancestors did, not less.

According to the World Health Organization, modern Koreans eat an average of 13.4 grams of salt per day, while the average American eats 8.5 grams of salt per day. The main source of sodium in the Korean diet are traditionally Lactobacillus-fermented foods such kimchi. Americans mainly eat salt via highly processed, mass-produced foodstuffs that line grocery store shelves.


Man can not live on fruit alone, really. (Photo by Roger Kirby, Creative Commons license)

What makes this mad dash to the low-sodium finish line even more preposterous comes from a recent sodium study released online by the American Journal of Preventative Medicine. The 2010 U.S. government guideline of 1.5 grams of sodium for those
older than 50, all African-Americans and those who have already been diagnosed with hypertension, heart disease or diabetes is impossible to reach unless one becomes a fruitavore. That's consumption of only eats fruits, nuts and seeds — no meat, dairy, eggs or vegetables.

A fruitavore diet is not a nutritionally balanced diet, particularly for men, according to Drs. Mattieu Mallot and Adam Drewknowski as reported in the same medical journal. Other diets still have too much sodium to reach that goal.

In other words, if one already has diabetes, high blood pressure or African-American heritage, the person's U.S. government-recommended sodium-reduction goal too low to be attainable without a starvation-susceptible diet of only botanical bounty.

The government goal for healthy Americans not of African lineage is 2.3 grams of sodium per day. That's still much lower than current consumption levels. The study found this goal was a little more attainable and could be reached by substituting high-sodium foods and condiments with low-sodium versions such as replacing regular soy sauce with low-sodium versions.

The question still remains as to whether this sodium hand-wringing is necessary. Based on the study, reported in Scientific American, and other recent ones like it, the answer seems to be "no."

If a person lives on an old-fashioned, vegetable-heavy Mediterranean or Korean diet, one probably can easily and effectively balance of sodium, potassium, iodine and other minerals. Yet dietary sodium still will be above 1.5 grams a day.

The best balanced diet is not a super-low sodium diet for most healthy people, according to Mallot and Drewknowski. The following are a few tips on controlling sodium naturally and sensibly.

Balance sodium with potassium 

Sodium and potassium work together closely to initiate muscle contraction and nerve transmission and to maintain the body's fluid balance.

Sea salt, which is not pure sodium chloride (NaCl), generally has more potassium than regular table salt. Legumes, such as soybeans, lentils, kidney beans and pinto beans and fruits like bananas are excellent sources of potassium. Korean garden favorites such as potatoes, cabbage, ginger, pyogo (shiitake) mushrooms and spinach also are excellent sources of potassium.

Kimchi, when made with cabbage, sea salt and ginger, can provide a balance of potassium and sodium.

Even though Koreans traditionally have eaten what most people would call a high-sodium diet, their traditional diet has a long history of potassium-rich foods that help the body process sodium efficiently.

Replace refined table salt with sea salt 

Strictly speaking, sea salt, rock salt and mineral salt have nearly the same composition of sodium and trace elements. Salt mines where rock salt originates are just ancient underground dried-up ocean beds.

However, mined salts aren't simply mined and bottled for the dinner table. Rock salts destined for human consumption usually are refined, removing most of the trace minerals and providing the consumer with nearly pure sodium chloride. Sea salt, whether Celtic or Korean, maintains more of the natural trace minerals.

Replace the iodine from table salt with iodine-rich foods

Various sea vegetables such as kelp, wakame, kim (nori) and dulse are excellent sources of iodine and have been a part of the traditional diets of many coastal cultures for hundreds, even thousands of years. (Jeff Quackenbush photo)


In the U.S., iodine-enhanced salt is the primary source of iodine in the diet. It is an important mineral for thyroid function, but iodine is sorely lacking in American soil in the northern U.S. This is why Americans have been supplementing salt with iodine for more than 100 years.

Because Americans get very little of it in an otherwise healthy and balanced diet, those who replace table salt with sea salt may develop a lack of this crucial mineral and will need to proactively find alternative sources of iodine.

One of the best sources of iodine are sea vegetables, including kelp, wakame, kim (nori) and dulse. Dairy products such as natural yogurts are also an excellent source of iodine.

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