A silent killer in the kitchen

Thou shalt prove how salt is the taste of another’s bread.

Dante, Inferno

Who hath desired the sea?—the sight of salt water unbounded.

Rudyard Kipling

All over the world salt continues to be regarded as an important ingredient of food. There is hardly any cuisine, in any country, that does not exploit the properties of salt either for imparting taste to food or as a flavouring agent or as a preservative or as a nutrient. Salt is used in a certain specific manner to the desired extent in Peking dumplings, Turkish egg plant preparations, Italian pasta and Indian curries to impart exclusive taste. It is used in large quantities, throughout India, particularly in pickles like Avakaya and Gongura in Andhra Pradesh, and many varieties of pickles in several other states as well.

Salt and pepper shakers are condiment dispensers, which allow diners to mix grains of edible salt and ground peppercorns, to dishes in restaurants and homes all over the world. The salt shaker has fewer holes, than the pepper shaker. This essay would throw light on why this is so.

In recent years, there has been an increasing awareness of the harmful effects of salt, particularly its tendency to raise blood pressure. A definite connection has been established between the quantum of salt that a population consumes and the incidence of hypertension. In countries where the diet has a high salt content, the incidence of hypertension is also high.

The average Japanese whose diet largely consists of fish, pickled vegetables and soy sauce, consumes about three teaspoons of salt (sodium chloride) a day. In the north-eastern provinces of Japan salt is used as a preservative and the average consumption is higher, about six teaspoons a day. This high intake of sodium in the diet (probably the highest in world, results in the highest percentage of heart problems in the world–( about 40 per cent of the residents in some villages).

Thus in Japan, which otherwise, has the largest number of aged people in the world, stroke caused by sodium-induced hypertension now seems to be the leading cause of death. Similarly, in the United States, communities with a high salt diet have shown relatively higher levels of hypertension. For instance, in the eastern part of Virginia, where the death rate due to hypertension is the highest in that state, the high sodium content in the drinking water has been identified as the ‘culprit’.

Leaving aside Japan and the United States, where people are subjected to all kinds of variables that contribute to hypertension, one should probably turn to simpler societies to look for evidence against sodium. In this context, the diets of tribesmen of New Guinea, the Amazon Basin, rural Uganda and the high lands of Malaysia consist of very little salt. In all these areas hypertension is virtually unknown and the blood pressure of individuals does not rise steadily with age. However, if salt were to be introduced in their food, the blood pressure starts climbing. Six tribes in Solomon Islands were studied by a team from Harvard. These tribes were totally untouched by Western influence; three other tribes which were also primitive (no telephones, no roads) happened to eat tinned food that was heavily salted. Only in the latter group was there an elevation of blood pressure. The blood pressure was the highest in the tribe that cooked vegetables and fish in sea-water! Since the tribes did not differ in weight or any other factor that was medically significant, a diet rich in salt emerged as the common denominator. Similarly, a study conducted in several parts of America, proved that reduction in salt lowers the blood pressure.

The crucial question is: how exactly does salt contribute to hypertension? It is known that salt (sodium chloride) is essential for all living things. A briny solution thought to have approximately the same salinity as the primordial ocean from which life itself emerged constantly moistens the tissues of the human body. The balance of salt and water in the miniature sea encased in the skin has to be carefully maintained as all vital functions of the body depend on it. Keeping the proper balance is mainly the work of the kidneys.

Human blood pressure depends upon two factors: the blood volume and arterial resistance to the flow of blood. Arterial resistance increases when the walls of the arteries contract for any reason, decreasing the diameter.

The blood volume as well as the balance of salt and water are influenced by the quantity of sodium in the body.

A healthy body needs and uses only about 2300 mg sodium, per day. If more sodium is consumed, the kidneys have to excrete the extra sodium to maintain fluid balance. Normally, the body can easily get rid of excess salt, i.e. sodium chloride. But in people whose kidneys cannot excrete such excess sodium into the urine, the defect can lead to retention of fluid and, consequently, to an increase in the blood pressure.

Since it is difficult to determine in advance as who is and who is not sensitive to salt (as only certain individuals seem to develop hypertension no matter how much salt is used), medical experts like to play safe by advocating a drastic reduction of sodium intake for everyone, particularly for hypertensive patients.

Most ex-addicts of salt (or ex-saltaholics), who resort to a low salt intake, find that it takes three to six weeks for them to get adjusted to food with less salt. However, once people shed the salt habit, they prefer food with a low-salt content. A high intake of salt produces a salty background in the saliva, raising the threshold at which salt is noticed in food.

One would be tempted to ask why people like salt so much though it is harmful? Some scientists believe that in prehistoric times the taste for salt may have aided man in finding valuable nutrients. According to one convincing theory, in places like the arid regions of Africa, a genetic ability to retain sodium was essential for survival and was preserved by natural selection. However, as evolution perhaps did not prepare itself for the salt glut in today’s society, people like the American Blacks, whose ancestors may have come from Africa, find themselves in a situation in which such a salt-retaining apparatus is not only not necessary but also leads to hypertension. This phenomenon would explain the relatively higher rate of hypertension in American Blacks.

Scientists have found no evidence to show that a taste for salt is inborn. Babies show a natural preference for sweets and are indifferent to the taste of salt. But, apparently, some babies like salt more than others and there is evidence to show that such babies have higher blood pressure, indicating a predisposition to hypertension in later life.

The only option for people therefore is to avoid salt or at least stick to a low salt diet to prevent or check hypertension.

One of the reasons people find it difficult to reduce the intake of salt in their diet is the tendency of salt as well as sodium to be present in the most unlikely food items. Ironically, sodium shows up even in instant chocolate pudding which may contain as much of the chemical as a bag of potato chips! A scoop of cottage cheese contains three times as much sodium as a handful of salted peanuts. The use of baking soda and baking powder introduces sodium in most cereals including cornflakes. Preservatives such as sodium benzoate and sodium nitrite and flavourings such as monosodium glutamate and vitamin C (as sodium ascorbate) are sources of sodium.

It would perhaps be useful to get a general idea of the sodium content in various vegetables and food products. Protein foods, certain varieties of bread, some fruits and vegetables, unsalted butter, plain corn, and potatoes, contain relatively, very little sodium. On the contrary, many other vegetables, Pizzas, sandwiches, Pretzels, Tortillas, hot dogs salted butter, sauces, salted potato chips, and cornflakes contain large quantities of sodium. A tablespoon of table salt contains 2325 mg of sodium, i.e. almost slightly more than the permissible limit of 2300 mgs per day. Other major culprits are, chicken pie, bacon, canned tuna , tomato sauce and tomato soup.

People in Western countries, however, are generally becoming more health conscious and are aware that an intelligent approach is necessary to reduce the salt content in their food, well before the danger signals appear. Low salt recipes are being made popular by the media. Books like “Killer Salt” have spread awareness about the dangers of salt addiction. A variety of courses are being conducted to educate people about the dangers of a salt-heavy diet and to enable people to exchange useful information on the subject.

In the meantime, the following guidelines would enable a person to choose foods with a low salt content:

 (1) Avoid canned foods that contain the words soda and brine or salt and sodium on the label (these would include many varieties of meat, vegetables and fish).

 (2) Avoid ham, cured meats, gravies, heavily salted sauces, tomato paste and canned tomatoes.

 (3) Avoid self-raising flour which contains soda and baking powder

 (4) Avoid all salted foods in grocery stores such as potato wafers, cashew nuts

 (5) Avoid cereals which use either sodium chloride or sodium in some other form (this would eliminate even cornflakes).

 (6) Avoid pickles of all kinds as their salt content is very high.

 (7) Avoid cheese, as most cheese contain a large quantity of sodium.

(8) Go in for fresh vegetables or raise a garden in your own backyard where you can grow vegetables with a low sodium content.

(9) Cook at home if you can so that you can control your sodium intake.

(10) Cultivate a taste for a low salt diet.

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Thanks to the general awareness of the dangers of salt, many people, particularly in the West are turning to salt substitutes, most of which are made of potassium chloride.

But these substitutes even if they taste salty enough, can be so bitter that gourmet cooks of high class restaurants in Paris or Hong Kong would not like to use them in special exotic foods. Even otherwise, large doses of potassium chloride could cause gastrointestinal ulcers. Similarly, in kidney patients even moderate doses of potassium chloride can prove fatal. Many fresh fruits and vegetables are very rich in potassium: Bananas, oranges, cantaloupe, honeydew, apricots, grapefruit (some dried fruits, such as prunes, raisins, and dates, cooked broccoli, sweet potatoes, mushrooms , spinach, zucchini, pumpkin, Juices like, tomato juice, orange juice, prune juice, and apricot juice. They should be strictly avoided by kidney patients.

Many varieties of seasonings and salad dressings are the best alternatives for potassium or sodium rich foods, A taste for such seasonings can be cultivated. It would be surprising how one can get rid of the craving for salt, by getting used to seasonings. Once a taste for seasonings develops, a person will not miss foods rich in salt and potassium.

An electronic pocket computer has been manufactured which, with proper programming, can correctly send a warning beep; whenever there is an indication of excess sodium intake in the food.