Authors: C.N.S. Ph.D. Ann Louise Gittleman
Get the Salt Out (2 page)
Whether you consider the minerally unbalanced condition of the salt we use, the anticaking agents that prevent salt from doing some of its most important jobs in the body, or the chemicals and sugar that are added to it, table salt should be avoided because it is, without a doubt, hazardous to human health. The next section will show you just what kinds of health problems refined salt can cause.
SALT AND SODIUM
Current research is uncovering dozens of connections between disease and excess use of salt, but hypertension remains the most serious, the most prevalent, and the most recognized condition associated with a high intake of salt.
HYPERTENSION
Hypertension, which is defined as consistent blood pressure readings above 140/90, affects about one in every four adults, making it the most common medical problem in the United States today. High blood pressure is especially
dangerous because it is a “silent killer.” It can cause tissue damage for up to twenty years before any discernible symptoms arise, and all too often, people become aware of their condition only when they suddenly and unexpectedly suffer one of the often life-threatening complications of hypertension:
heart attack
stroke
arteriosclerosis (hardening of the arteries)
serious kidney damage or kidney failure
bleeding in the eyes, impaired sight, or blindness
enlarged heart
congestive heart failure
With devastating consequences like these, we should do everything in our power to prevent or control high blood pressure. Cutting back on salt is one of the easiest things we can do. Over the last fifty years, exhaustive research from both animal studies and human epidemiological studies (those that compare populations and their incidence of disease) support the salt-hypertension connection. Here are some highlights of that research:
No other animal besides man develops high blood pressure in its natural habit. By 1953, however, scientists found that mice, kangaroo rats, albino rats, rabbits, dogs, and cows all develop high blood pressure if they eat a lot of salt.
A recent study involving chimpanzees, the species genetically closest to humans, has provided even more definitive proof that a high intake of salt can cause hypertension. In the results reported in the October 1995 issue of
Nature Medicine,
chimps ate their typical diet, which is
low in sodium, until halfway through the study, when half of them received salt supplements equivalent to the amount of salt consumed by the average human. Shortly thereafter, the blood pressures of the chimps in the test group rose dramatically, but their blood pressures went back to normal when the added salt was removed.
Intersalt, a 1988 international study of more than ten thousand people in thirty-two countries, found that high blood pressure is exceedingly rare in places where the diet is low in sodium. As sodium intakes increase, however, blood pressure readings tend to rise.
The Japanese provide proof of the real-life dangers of too much sodium in the diet. They consume more sodium than the citizens of any other nation in the world: the average intake is 6,000 to 10,000 milligrams of sodium per person per day, and some residents consume as much as 20,000 milligrams. With so much sodium, the Japanese have a hypertension rate that is almost double the hypertension rate in the United States. In addition, their rate of stroke (a common consequence of high blood pressure) is the leading cause of death in their society.
Sensitivity to salt—and the high blood pressure that usually results—is partly hereditary. Not all animals fed a diet high in salt develop hypertension; those who do are often genetically predisposed to the disease. In the late 1950s, though, researcher Lewis K. Dahl found that a diet low in salt could keep rats free of hypertension
even in rats that were genetically programmed to develop it
Subsequent studies on humans have shown that lowering sodium intake does not always lower blood pressure in hypertensive patients, but it does so in about half of the people who have the condition.
Part of the problem with identifying the true relationship between sodium and hypertension is that many factors besides sodium play a part in the development of the condition. Other contributing factors to hypertension include:
Heredity (whether one or both parents had
hypertension or were salt-sensitive)
Being a male or being a female past menopause
Excessive consumption of alcohol
Smoking
Obesity
Lack of physical exercise
Stress
Arteriosclerosis (hardening of the arteries)
Insulin resistance or elevated blood glucose levels
Excessive sugar and nonessential fat intake
Deficiencies of potassium, magnesium, and calcium
The last factor is not understood well by the American public, but it is particularly interesting. Recent research shows that obtaining adequate potassium, magnesium, and calcium may be as significant for blood pressure prevention and control as lowering salt consumption. The typical American diet is as
high
in sodium as it is
low
in these other essential nutrients. The Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure now admits that potassium, magnesium, and calcium play a role in reducing the risk of high blood pressure. Numerous studies have revealed that these often-overlooked minerals not only help lower blood pressure but they also prevent heart attacks. Therefore, it is important to realize that while reducing sodium intake is crucial for the prevention and treatment of hypertension (especially for saltsensitive
individuals), other dietary and lifestyle factors also need to be considered. The evidence against salt and sodium is certainly convincing enough to warrant a consensus among health organizations and nutrition experts that our intake should be reduced.
CALCIUM DEFICIENCY AND OSTEOPOROSIS
Too much dietary sodium also increases the risk for osteoporosis and probably for kidney stones as well. Excess sodium causes calcium to be lost from the body through the urine, and then the blood level of calcium falls. The hormone system then responds to low levels of calcium in the blood by prompting the withdrawal of calcium from the bones. A study reported in the June 1995
Journal of Human Hypertension
confirms that when more sodium is ingested than we need, there is a rise in urine hydroxyproline levels—which indicates that bone is being broken down.
FLUID RETENTION, WEIGHT GAIN, AND HEADACHES
Excessive sodium causes fluid retention, which stresses the heart and circulatory system and results in edema—swelling of tissues. Edema can manifest itself in tissue puffiness or bloating all over the body or it can be localized in such areas as the ankles, fingers, pelvic, and abdominal areas. Women with hormonal problems seem to be particularly susceptible to developing fluid retention and often can become irritable or depressed when they retain water during their premenstrual cycles. Some women have been known to gain as much as fifteen pounds in “water weight” for a few days every month. Although water weight gain is not the same as fat gain, women who suffer from it temporarily have trouble fitting into their clothes and almost always can benefit from reducing their salt intake.
Fluid retention probably also contributes to two other ailments associated with excessive salt use: headaches and migraines. Although it is unknown exactly how salt does its damage, Seymour Diamond, M.D., executive director of the Diamond Headache Clinic in Chicago, has found that patients often develop headaches a few hours after eating salty food. Although Dr. Diamond has focused on salt alone, other high-sodium food additives like monosodium glutamate (MSG), sodium sulfites, nitrites, and nitrates also can trigger headaches.
STOMACH ULCERS AND STOMACH CANCER
The stomach, which uses sodium to produce hydrochloric acid, seems to be particularly sensitive to unnatural, refined sources of sodium: excess salt contributes to the development of ulcers, and certain sodium additives can cause stomach cancer.
Amnon Sonnenberg, M.D., of Harvard Medical School, has seen a strong correlation between the incidence of gastric ulcers and the consumption of common (refined) table salt. According to Dr. Sonnenberg, the rise and fall of ulcers directly parallels the rise and fall of salt intake.
In addition, a high intake of salt-preserved, smoked, and cured foods is a known risk factor for stomach and esophageal cancer. The sodium nitrites and nitrates used in these foods can form nitrosamines in the stomach. These chemicals are some of the most potent cancer-causing agents known. The Japanese, who have the highest incidence of stomach ulcers and stomach cancers in the world, consume more salt-, nitrite-, and nitrate-treated foods than any other culture.
The evidence clearly shows that too much dietary sodium is a culprit in many health problems. But how much is too much? The amount actually differs from one individual to the next. The next section will help you understand why and will show you how to determine the right amount of sodium
for you.
The answer to “How much sodium do we need?” really depends on who you are.
Not only do your sodium needs vary depending on your genetic background, but they also change during different stages of your life, depending on such factors as how much you exercise, where you live, and what you eat.
While many health professionals today would like us to believe that all individuals can thrive on an extremely strict low-sodium diet, the issue is not nearly so black and white. There is great variance in our sodium needs and even in our tolerance to unrefined salt. If we learn about the factors that influence our sodium needs, each of us will be able to determine our individual ideal sodium intake.
GENETIC HERITAGE
The genetic blueprint each of us has inherited plays a significant but greatly overlooked role in many aspects of nutrition and body chemistry. In no area is that more apparent than in our varying reactions to salt.