People who eat plenty of fruits, vegetables and whole grains may still have an increased risk of elevated blood pressure if they consume a lot of salt, a new study from Northwestern University in Chicago suggests.
Eating high-sodium foods has long been associated with higher blood pressure readings, but some evidence suggests that body weight and other nutrients in the diet may offset the effects of sodium on blood pressure.
To see how diet might influence the connection between salt and blood pressure, researchers examined data from food surveys completed by 4,680 middle-aged adults, and then determined the amount of 80 nutrients in each person’s diet.
With the exception of potassium, none of these nutrients appeared to weaken the connection between eating a high-sodium diet and having higher average blood pressure readings than people who ate the least sodium.
“This matters because it indicates that the problem of excess salt intake and its adverse effects on blood pressure cannot be solved by augmenting the diet with other nutrients,” said the lead study author. “The solution is reduction in salt intake.”
Chronic high blood pressure is tied to an increased risk of heart disease, heart attack, stroke and heart failure.
To lower the risk of heart disease, adults should reduce sodium intake to less than 2 grams (2,000 mg) a day, or the equivalent of about one teaspoon of table salt.
Sodium is found not only in salt, but also in a variety of foods such as bread, milk, eggs, meat and shellfish as well as processed items like soup, pretzels, popcorn, soy sauce and bouillon cubes.
Extra sodium in the bloodstream can pull water into the blood vessels and boost blood pressure by increasing the amount of fluid the heart needs to pump through the body. Potassium can help remove excess sodium from the body.
About the study
In the current study, researchers examined data on sodium and potassium levels in urine, as well as blood pressure, height, weight and eating habits from adults aged 40 to 59 in Japan, China, the UK and the U.S.
Higher sodium levels were associated with elevated blood pressure for both men and women at all ages in the study, regardless of race and ethnicity or socioeconomic status.
The connection between sodium and blood pressure was similarly strong for both normal weight and obese people in the study, although the connection was weaker for overweight individuals who weren’t obese.
Potassium lessened effect of sodium on blood pressure in some people
Potassium appeared to weaken the connection between salt and elevated blood pressure only for people who had low sodium levels in their urine.
The study wasn’t a controlled experiment designed to prove whether or how dietary salt or other things people eat might directly alter blood pressure. Another limitation is that surveys used to assess eating habits can be unreliable snapshots of what people actually consume.
The American Heart Association recommends the Dietary Approaches to Stop Hypertension (DASH) diet or a Mediterranean-style diet to help prevent cardiovascular disease. Both diets emphasize cooking with vegetable oils with unsaturated fats, eating nuts, fruits, vegetables, low-fat dairy products, whole grains, fish and poultry, and limiting red meat and added sugars and salt.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.