Dont Take It With A Pinch Of Salt

Updated: Jun 30 2002, 05:30am hrs
March 12, 1930. A procession of about 10,000 people under the leadership of 61-year-old Mohandas Karamchand Gandhi set out from Sabarmati Ashram in Ahmedabad. Destination: the sea coast at Dandi, 241 km away.

The now well-known Dandi March was to protest the imperial rule of the British Crown, which had imposed a monopoly tax on salt in the country. As a result of the march, the colonial government was forced to lift the tax.

Since then, salt has been held in very high political esteem even by the governments of independent India. Exalted in its status as a most essential food item, it has always been left untouched by taxes.

The Sensitivity Factor
Salt could prove a killer to even those people who are not prone to high blood pressure. According to a research study published in a London medical journal, Hypertension, salt sensitivity increases the risk of death, whether or not a person has high blood pressure.

Some people appear to have an unexplained, genetic sensitivity to salt, and estimates suggest that up to a quarter of people who have normal blood pressure are actually salt sensitive. Instead of excreting excess salt away through urine, the bodies of such people actively retain much of it through the kidneys.

Explains Dr S C L Gupta, president of the Delhi Medical Association, You can see some people sweat very heavily, while some people sweat only a little. This is because of genetic factors. Those who sweat very little are more salt sensitive in the sense that their bodies retain more sodium on a given amount of salt through the kidneys and hence retain more fluid. These people should cut their salt intake more than those who sweat heavily.

The research study published in Hypertension was conducted by the National Heart, Lung And Blood Institute of the US. The salt sensitivity test included more than 700 patients over a period of 25 years. The patients salt sensitivity was tested first by giving them a saline solution followed by a diuretic drug, and then the subtle variations in their blood pressure and volume over the following two days were checked.

The research team found that 123 of the patients had died from cardiovascular diseases or another cause. People who had normal blood pressure at the time of the first test, but were salt-sensitive, fared no better than those who had high blood pressure from the outset, even though it would have been expected that hypertensive patients would have done worse.

According to Dr Myron Weinberger, who led the study: Salt sensitivity increases the risk of death, whether or not a person has high blood pressure. We can take advantage of this finding. Such people dont need to cut back on salt intake drastically to reduce their risk of death. We should be careful about the sodium content in prepared, preserved and processed foods. Srikumar Bondyopadhyay
But much water has flowed through the Sabarmati since the time of the Dandi March. Lifestyles have changed. Work environments have changed. Food habits have changed. Medical theories have changed. In all this, salt, too, has been toppled from its pedestal and is coming to be regarded as a slow poison.

Medical experts and food standard agencies of several developed countries are increasingly campaigning for raising consumer awareness about the hidden effects of the salt that they take through manufactured foods and pushing for reducing daily salt intake at the table or in cooked food.

Medical specialists in the UK, backed by the Food Standards Agency, are calling on manufacturers to cut down on the amount of salt they add to ready meals and other processed foods. In the US, the Food And Drugs Administration (FDA) has come out with a guideline on salt intake and it is urging people to reduce their daily salt consumption to 6-8 grams from the present level of 10-12 grams.

A reduction of salt intake by three grams is predicted to reduce the incidence of strokes by 25 per cent and heart attacks by 16 per cent.

In adults, when the level of sodium is too high, the body retains excessive water and the volume of bodily fluids increases. Scientists believe that with high levels of fluid circulating through the brain, there is a greater chance of weaknesses in the brains blood vessels being exposed and consequently bursting, causing a stroke.

Similarly, a greater volume of fluid passing through the heart can place additional strain on the organ, increasing the possibility of coronary artery disease (CAD).

For most of us, processed foods are a main source of salt in our diet, but few of us take note of the quantity of sodium or salt hidden in manufactured foods. Dr Wynnie Chan, a nutrition scientist for the British Nutrition Foundation, says, Everybody should look to reduce the amount of salt in his diet. It would have a significant effect on those people who need to reduce their salt levels because they are susceptible to hypertension, but will not harm others who are not susceptible.

In recent years, scientists have begun to discover further health dangers that excessive salt consumption poses. And these health hazards extend beyond hypertension and heart attack.

Professor F P Cappuccios research, published in the American Journal Of Clinical Nutrition, reveals that excess salt in the diet can lead to excessive calcium loss and thereby increase the risk of osteoporosis.

In another study, researchers from Leuven University in the Netherlands reviewed the dietary habits of people from 24 different countries and discovered that a high intake of salt can significantly increase the risk of stomach cancer. The research study was published in the International Journal Of Epidemiology.

Medical researchers point out that salt is a mainstay only for poor people, who cannot afford to eat a lot of vegetables and fruits (which also contain sodium), eggs and fish (which contain sodium in small quantities) and processed foods.

The Indian Story

Under normal conditions, an adult with a body weight of 60 kg requires only six grams of salt (or 2.5 grams of sodium); as against this, the usual average intake is nine grams a day. Most of the mischief is caused by fast and processed foods and soft drinks, which together contribute more than three-quarters of our daily salt requirement! And thats not counting the salt we use in cooking and sprinkling over our plates at the table.

Says Dr Rajiv Sood, Head, Urology Department, Ram Manohar Lohia Hospital, Delhi, Salt is present in almost all the food items that we take these days. And today, the kind of work and work environment we are in, we hardly require more than 5-6 grams of salt a day to replenish our daily salt excretion. People who do very little physical work and spend most of their day in an air-conditioned office actually dont need any additional salt, either at the table or in cooking.

However, lovers of French fries and pizzas can vouch for how salt brings out the flavour of foods. But they must remember that as we grow older, our kidneys loses their efficiency in filtering urine and regulating the sodium quantity in body, says Dr Sood. By the time we attain 60 years of age, our kidneys become 50 per cent less efficient. Instead of throwing out excess sodium through urine, the kidneys start retaining it in the body, leading to diseases such as hypertension, oedema, stroke and other cardiovascular diseases.

Salt is the principal source from which our body gets its micro element, sodium, explains Dr S C L Gupta, president of the Delhi Medical Association. You cannot take salt away outright from your diet, for sodium is needed for normal body functioning such as muscle movement, fluid circulation and brain functioning.

It is the sodium part of salt that is important, says Dr Gupta. Sodium helps to maintain the concentration of body fluids at the correct levels. It also plays a central role in the transmission of electrical impulses in the nerves, and helps the cells to take up nutrients. Sodium retains water in the bodyone molecule of sodium retains one molecule of water. So, excess of sodium intake means more water is retained in the body. This increases the total blood volume and body fluid. And given the volume of blood vessels, the increased blood volume in circulation results in high blood pressure and, hence, strokes and cardiac attacks. So, it is advisable that people who dont do much physical work, cut on their salt consumption at the table and in cooking.

We require to consume salt daily because we lose it from our body every day, elaborates Dr Sood. There are two ways of losing salt from the bodyfirst, through excretion, and second, through skin or kidney diseases. Salt excretion happens through faeces, urine and sweat. Human faeces contain negligible sodium. While salt lost through skin, via sweat, is a permanent salt loss, the kidneys control the balance of sodium in the blood while filtering urine.

A healthy kidney can tolerate up to 15 per cent of excess sodium. Says Dr Sood, It is in the sense that 15 per cent of excess salt in the body is not reflected through any symptom. But excess salt more than that is retained in the body if the kidney is weak or damaged by, say, diabetes or an increase in blood cholesterol. The retention of excess salt is then reflected by hypertension or oedema (swelling or puffiness in the face, legs and hands).

It is mainly for replenishing permanent salt loss through the skin that we need to take additional salt, Dr Sood says, adding, otherwise, salt is present in almost all the food items, including fruits and vegetables, that we take, enough to keep our normal body functioning going.

There are four main ways of reducing salt intake:

* Dont add table salt to food once it is served.
* Choose food articles with a reduced sodium content.
* Carefully monitor the salt or sodium content of processed foods by reading the ingredient labels.
* Eat more fruit and vegetables. They contain potassium, which balances the effect of salt on the body.

Dr Purushotam Lal, director, Metro Hospitals & Heart Institute, Noida, says, The medications available for the treatment of hypertension are mostly diuretics, which help primarily in increasing urine excretion and thereby reducing the retention of fluids in the body. Most patients, who visit us with a heart problem, are suffering from hypertension. Juxtapose these two facts and what you get is that the normal sodium level in our body is increasing.

The rapid increase in the incidence of cardiovascular diseases (CVDs), the second most deadly category of non-communicable diseases after diabetes, also lends support to the fact that while our daily salt intake on the table and in cooking has remained at constant levels, our lifestyle has become more sedentary.

This, coupled with our growing predilection for manufactured and processed foods, has led to the growth of CVD incidence.

Not surprisingly, in India, the incidence of CVDs is higher among the upper income groups. Though there is no proper epidemiological study in India on the incidence of CVDs, our practical experience is that most of our patients are from the upper and upper-middle income groups, says Dr Lal.

Take, for example, the case of corporate executives, says Dr Gupta. They move in air-conditioned cars, work in air-conditioned officesa climatic condition that doesnt trigger sweating. So, for them, the sodium and water remain retained within their bodies. If they consume excess salt, it may lead to hypertension or kidney diseases at a later stage. They should stick to the lower limit of the minimum salt requirementsix grams a day.

There is no dearth of evidence against excessive salt intake, what is lacking is awareness about it.