BEATING THE BLOOD PRESSURE BLUES FOR A HEALTHY HEART: SODIUM RESTRICTION
For many years we have heard the unequivocal advice that all Westerners should significantly reduce their salt consumption. This was based on the fact that a percentage develop a type of high blood pressure that is aggravated by a salty diet. For some patients, the need to cut back on salt is very real, and most of us could be more moderate with the salt shaker.
But the total picture on salt and sodium consumption is not so clear. Not everyone needs to greatly restrict salt intake. On the other hand, most Westerners consume far too much. View this entire discussion as a call for moderation.
The International Intersalt study is the most comprehensive population study yet undertaken to get some answers. Researchers looked at blood pressures and sodium intake in people in 32 countries. The results revealed little link between sodium intake and blood pressure in people around the world.
Yes, in populations where sodium intake is extremely low—at a level at which most of us would find the diet virtually inedible— blood pressure is low. That was true in 4 out of 52 centres studied. But in the other 48 centres where there was wide variation in sodium intake there was little if any difference in blood pressure. These findings suggest that unless sodium intake is very severely limited, most people will not see any improvement. Any drop in blood pressure will be clinically insignificant.
A study published in the Archives of Internal Medicine (January 1990) also failed to show a strong sodium-hypertension link. For three years, 841 men and women were observed for the blood pressure-lowering effects of diet. Some restricted sodium alone, a second group cut back on kilojoules, a third group reduced both sodium and kilojoules, while a fourth group was put on a low-sodium, high-potassium diet. The group with the greatest drop in blood pressure was that which reduced kilojoules. Those cutting back on sodium showed little benefit.
It may even be possible that a low-salt diet may hurt more than help. Dr Brent Egan reported his findings at the American Heart Association meeting in New Orleans in 1989. He and other researchers at the Medical College of Wisconsin in Milwaukee found that a low-salt diet will not reduce blood pressure in 50 per cent of people with higher-than-normal blood pressure and in 80 per cent of those with normal blood pressure. In fact, for some people, salt restriction actually may result in higher blood pressure.
Dr Egan takes a very practical approach with his own patients. He has them monitor their blood pressure for a week before starting a low-salt diet in order to establish a baseline. Then they keep track of their pressure after cutting down on salt. If there is no reduction in blood pressure after one to two months, he tells them to discontinue salt restriction.
Dr Carter Newton, a cardiologist at the University of California at Los Angeles who practises in Santa Monica, believes this is the best approach, but points out that it takes co-operation and time. He suggests that patients might have to “push” their MDs to do this with them.
Certainly some people are salt-sensitive. It is estimated that 25 to 60 per cent of people with high blood pressure, or about 10 to 15 per cent of the general population, is sodium sensitive. Only those individuals are likely to benefit from stringent sodium restriction. Eventually we’ll have a test for such sensitivity, but right now the only way to tell is by trial and error.
Moreover, it appears now that not all sodium can be clumped in the same “villain” category as salt. While you may be sensitive to salt and may need to cut back on intake, you may not respond at all to other sodium compounds in the diet such as MSG (monosodium glutamate). Again, trial and error is the only completely effective way to tell just what you can and cannot consume without adversely affecting your pressure.
Advocates of salt and sodium restriction for everybody across the board say that such an approach will mean that some individuals will benefit, and no one will be harmed since no one needs the salt or sodium in the diet anyway. At first glance this makes sense, but upon closer examination, there are two major flaws in such thinking.
First, why give something up when you don’t have to? Second, salt makes food taste better. For those of us trying to keep the fat content of our diets down, overly restricted salt intake might torpedo our efforts.
As in most things, moderation should be the watchword in salt and sodium intake. The National Health and Medical Research Council indicates that a “safe and adequate” daily sodium intake is about 100 mmol daily for adults. This is equivalent to 2.3 grams of sodium or 6 grams of salt. To put that into perspective, one teaspoon of salt contains about 2000 milligrams of sodium. That’s how much we need to maintain good health under normal circumstances. Australians consume from 8 to 12 grams daily. Many people consume much more than that. There’s a big difference between salting all food until it’s virtually white and sprinkling on a few grains here and there.
Actually, researchers have demonstrated that the best way to cut back on salt is to reduce or eliminate it in cooking. That way you can enjoy a sprinkle at the table. When they measured the amount consumed in that way, the total intake was way down.
Actually, most of the salt and sodium in the Western diet gets there by way of processed foods and foods in fast-food restaurants. Those are the same foods which are highest in saturated fats and cholesterol. So if you cut down on them in your efforts to lower your cholesterol level, you’ll automatically reduce your salt and sodium intake.
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Cardio & Blood/ Cholesterol
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