Salt May Restrict Blood Flow to Heart
Low-Salt Diet Improves Blood Vessel Function
Jan. 22, 2009 -- Reducing the salt in your diet can help lower your blood pressure, but it may also lower your risk for having a heart attack or stroke in another important way.
Results from a new study suggest that eating a low-sodium diet can also help keep blood vessels working properly.
The study measured the impact of salt restriction on the endothelium, the thin layer of cells that line the interior of the blood vessels and help regulate blood flow.
Overweight and obese study participants with normal blood pressure who restricted the sodium in their diets showed evidence of improved endothelial function compared to participants who did not restrict salt.
The improvement appeared to be unrelated to the impact on blood pressure, suggesting that salt restriction is independently protective of blood vessel function.
"We found that if we reduced the salt in the diet, we saw a direct, positive impact on blood vessels," nutrition researcher and study co-author Jennifer B. Keogh, PhD, tells WebMD.
Salt and the Blood Vessels
It is generally recommended that healthy people eat no more than 2,400 milligrams of sodium a day -- about the amount found in one teaspoon (6 grams) of table salt.
But the average American eats more than twice that, even if they rarely pick up a salt shaker, says Mayo Clinic cardiologist Gerald Fletcher, MD, who is a spokesman for the American Heart Association.
"Processed foods are often loaded with salt, even those that don't taste all that salty," Fletcher tells WebMD. "That is why it is so important to read labels."
The newly published study included 29 overweight and obese men and women who ate either 3 1/2 grams of salt a day (low salt) or 7 1/2 grams a day (normal salt) for two weeks. Then they switched to the other diet for two weeks.
None of the participants had high blood pressure when they entered the study.
While on the salt-restricted diet, but not the normal diet, the study participants showed improvements in endothelial function in tests designed to measure blood vessel dilation and blood flow.