5 Myths about Salt

Has recent research really cast doubt on earlier studies linking high-sodium diets with elevations in blood pressure and an increased risk for health woes such as heart disease and stroke?

Don't break out the salt shaker and the potato chips just yet. Here's a closer look at some of the most popular misconceptions, and why you should take some of the recent stories on sodium with a grain of salt.

A craving for salt is a signal your body needs more of it.

The amount of sodium required for such essential functions as maintaining fluid levels in our blood cells and trans-mitting information along nerve and muscle cells is a mere 200 mg—the equivalent of less than 1/10 of a teaspoon of table salt. (The majority of sodium in what we eat is in the form of sodium chloride, or salt; one teaspoon contains roughly 2,300 mg of sodium.) According to Dr. Michel Joffres, a physician, epidemiologist, and professor of health sciences at Simon Fraser University in Burnaby, BC, "that's more than double the 1,500 mg we recommend as safe" for healthy individuals.

Among other things, too much salt forces the kidneys and heart to work harder and increases blood volume, subjecting blood vessels to the type of stress that leads to cardiovascular disease. If we were able to go from the current consumption levels to recommended levels, it's estimated we might be able to reduce the burden of hypertension by as much as 30 per cent, and, as a consequence, cardiovascular disease by 15 to 20 per cent. Perhaps as much as a quarter of all cardiovascular disease Lan is attributed to sodium in the diet.

I don't have to limit my sodium intake because I'm not salt- sensitive.

While it's true that some people are more resistant to sodium's blood-pres-sure-boosting effects than others, an excess still poses problems. First, your sensitivity to salt increases with your age and your blood pressure, and the vast majority of us will end up with high blood pressure.

Even people who have normal blood pressures at age 55 to 60 have a 90 per cent chance of developing hyper tension if they live an average lifespan.A high- sodium diet seems to be one of the predisposing factors.

Increases in blood pressure heighten heart-disease risk even if your numbers fall below the "hypertension" range.  Just a 10 mm rise in your systolic (the top number) blood pressure translates to a 30 percent increase in your relative risk for stroke.Most heart attacks and strokes occur in people with only moderate risk.

What's more, recent research suggests salt intake influences heart-disease risk irrespective of its impact on blood pressure. There was a trial one of the most convincing of all that showed a direct relationship between decreasing sodium and decreasing heart disease. It didn't go through blood pressure. Finally, sodium's negative effects on health aren't limited to elevated blood pressure, or to heart disease and stroke. High intake has been implicated in a variety of other health problems as well, which leads us to.

High blood pressure—and thus, an increased risk for heart attack and stroke—is the only health problem that's been linked with salt intake.

While it's not as strong as that supporting a link between high-sodium diets and the risk for heart disease and stroke, there is plenty of evidence that sodium intake plays a role in several other common and debilitating health problems.

Scientists strongly suspect salt amplifies the cancer-causing potential of certain chemicals. High-salt diets also appear to promote bone loss by leaching calcium from the skeleton into the urine, likely increasing the risk for osteoporosis and Hp fracture. 

And too much salt stimulates thirst, which, if quenched with sugary drinks, can lead to weight gain. There are some analyses indicating that the excess salt consumed by adolescents results in 20 to 30 per cent more caloric consumption in beverages, and that it's one of the drivers of obesity in our children. There's also evidence that, with a high-sodium diet, not just the blood vessels get twitchy, but the respiratory muscles get twitchy, and it's been linked with increased severity and frequency of asthma attacks.

Excess sodium may take a toll on the brain, too. It's been linked with an increased risk for Alzheimer's disease, and a recent Canadian study found that physically inactive but otherwise healthy seniors who had diets high in sodium (more than 3,091 mg/day) were more likely to experience a decline in cognitive functioning over a three year period than those who consumed modest amounts (less than 2,263 mg/day, or just less than the 2,300 mg/day upper limit recommended for healthy adults under 50). 

High-sodium foods taste salty.

While it's no surprise that anchovies, for example, are loaded with sodium, many other high-sodium foods can fool your tongue. For instance, since both baking powder and baking soda contain ample amounts (488 mg and 1,259 mg per tea-spoon, respectively) and food manufacturers rely on salt to enhance flavour and extend shelf life, just one coffeeshop muffin or tea biscuit can contribute 500 mg, or a third of a day's supply. Many restaurant offerings, tinned and packaged foods, and even condiments contain massive amounts, too.

If you buy anything prepared, or eat out at all, you're going to get a lot of sodium. This is why many experts believe the government should step in and regulate sodium levels in our food. 

Recent studies have stirred up controversy over the health benefits of limiting dietary sodium.

In fact,  sodium's impact effect on blood pressure, and the cost of caring for those with cardiovascular disease, it turns out reducing sodium is one of the most effective, and cost-effective, ways of improving health.  Consequently, the World Health Organization has dubbed sodium-reduction strategies one of the best buys a government can make to improve the health of a nation's population.

Some research is questionable because it's carried out by scientists with close ties to the salt industry, which, like the tobacco industry before it, has formed organizations dedicated to creating an aura of controversy around the health effects of its product. Other research is scrupulously done but misinterpreted by the media.

Case in point: a recent study widely touted as calling current sodium guidelines into question. All participants had blood-vessel disease serious enough to warrant taking medication, and those in one arm of the trial. So it was hardly surprising when the results linked a low-sodium diet with a slight increase in the risk for death.