High Blood Pressure: Is Salt the Enemy?
Friday, March 16, 2012
‘Salt’ comes from Latin salarium, which is the basis for the word for salary. Legend has it that the Roman soldiers were either paid in salt or paid so they could buy salt. The discovery of salt allowed for extended travel and exploration as salting of food would preserve it. Salt discourage the growth of bacteria that would spoil the food. Salt also brings out the flavor in food, making it taste much better than when there is no salt. In fact, the positive attributes of salt are basis for sayings, such as someone being “worth his salt” or the “salt of the earth”.
Salt and your blood pressure
Sodium’s relationship to blood pressure is due to sodium’s role in fluid balance. Sodium is the main mineral outside of all cells and potassium is inside the cell. Water moves across the cell membrane using a gradient, or osmosis, to equalize the concentration of minerals on either side of the membrane. When the amount of sodium outside the cell increases, water leaves the cell to dilute the mineral content. This water can then increase the volume of water in the blood, which can increase blood pressure.
It's not the food itself that's the problem
There are very few foods that naturally contain sodium. The vast majority of the sodium in the US diet is from foods that are processed or packaged, as the sodium helps increases the shelf-life. This includes the obvious like canned soups, sauces, etc but also baked goods like crackers and most commercial bread, rolls and bagels. If you did not use processed foods you could add to your food easily up to 1 measuring teaspoon each day to your food, which is quite a lot of table salt. The other major source of dietary sodium is fast food restaurants and most restaurants.
What about potassium?
Although the focus for blood pressure lowering has been to decrease sodium or the mineral outside the cell, there is more recent evidence that if you increase the potassium, which is inside the cell, you could also decrease blood pressure. Potassium is found primarily in all fruits, vegetables, potatoes and legumes. The DASH (Dietary Approaches to Stop Hypertension) study showed that eating 9 servings per day of vegetables and fruits would lower blood pressure. A serving is ½ a cup and the study used 2 ½ cups of vegetables and 2 cups of fruit.
Go virgin (olive oil)
Extra virgin olive oil has also been shown to lower blood pressure when used at 2 tablespoons/day. This is probably related to extra virgin olive oil’s ability to make insulin work better. Cooking your vegetables in olive oil makes them taste better and can help to lower your blood pressure. If your diet is low in processed foods, you can add some sea salt to your vegetables. Sea salt is a better choice than commercial salt as it has more flavor than table salt and the particles are large so you can better control what you are adding.
So, if you want to help control your blood pressure using diet, eat less processed foods and more vegetables and fruits. Cook your vegetables in extra virgin olive oil and add some sea salt. Your vegetables will taste better so you will eat more. This will help lower your blood pressure and other health benefits.
Mary Flynn, PhD, RD, LDN is a research dietitian at the Miriam Hospital.
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