Less Salt, More Potassium Cut Stroke Risk

People who consume less salt and more potassium can reduce their risk of blood pressure and stroke, 3 reviews of medical evidence show. The journal BMJ published the review articles. One review put together the results of 34 studies. They included a total of 3,230 people. The review found that eating less sodium (mostly salt) could reduce systolic blood pressure by about 4 milligrams of mercury (mmHg). Systolic pressure is the first or top number in a blood pressure reading. Diastolic pressure (the second number) fell 2 mmHg. Another research review also looked at other effects of salt on health. It included results from 56 studies. The risk of stroke increased 24% for people who ate more salt. The risks of dying from stroke increased 63%. A third study looked at potassium in the diet. It put together results from 33 studies. They included a total of 128,000 people. Increased potassium was linked with lower blood pressure and a 24% lower risk of stroke. HealthDay News wrote about the studies April 8.

By Reena L. Pande, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Most Americans eat more than double the recommended daily allowance of sodium. And most do not even realize they are eating that much salt on a regular basis. Getting too much salt, and too little potassium, can have a major impact on overall health. It can increase blood pressure and the risk of heart disease and stroke.

Three recent studies in BMJ (formerly the British Medical Journal) once again confirm the relationship between salt intake and health problems. The first of these studies combined information from 34 earlier studies. It found that over the long term a reduction in salt intake led to a drop in systolic blood pressure (the top number of a blood pressure reading) of 4 millimeters of mercury (mmHg). There was also an average 2 mmHg drop in systolic blood pressure. Eating less salt also led to lower risks of heart attack, stroke and heart failure.

A second study combined information from 56 studies. Its findings were similar to the first study. Lower salt intake led to lower blood pressure and to lower risks of stroke and death from heart disease.

A last study looked at the mineral potassium. Potassium is required for many normal body functions, including heart and muscle function. Researchers reviewed information from 33 studies. The studies included a total of more than 128,000 people. The review showed that consuming more potassium was linked to lower blood pressure and lower risk of stroke.

What Changes Can I Make Now?

U.S. government guidelines say that people should consume no more than 2,300 milligrams (mg) of sodium per day. That's about as much as in 1 teaspoon of table salt. For those with high blood pressure or other conditions such as kidney disease or congestive heart failure, 1,500 mg is the recommended limit. This lower limit also is recommended for anyone over age 50.

It's not just the salt that you add to your foods that matters. Sodium is found naturally in many foods and also added to many foods and seasonings. Processed meats and canned soups and vegetables often have high sodium levels.

How can you limit your salt intake?

• Know how much salt is in your regular diet. Pay attention to labels. Some soup labels are misleading and will have two servings per can, with a large amount of sodium in each serving.
• Avoid processed and prepared foods. Most sodium in the typical American diet comes from packaged foods, such as deli meats, canned soup, bread, pizza and cheese. When in doubt, eat fresh food before anyone else has had their hands on it.
• Look for labels that say "low sodium" or "no added sodium." But be sure to read labels carefully. These products will tend to have less salt, but can still contain a fair amount of sodium.
• Use other seasonings in place of salt in your cooking. Herbs and spices, for example, can add flavor to your food.

What about potassium? Having enough potassium may help lower blood pressure. But too much potassium can be dangerous, especially for people with kidney problems. So the right amount is critical.

Potassium is found in many foods, especially fruits and vegetables. In particular, green leafy vegetables and bananas are known to have a lot of potassium. Most healthy Americans consume less than half of the recommended amount of potassium (4,700 mg per day).

What Can I Expect Looking to the Future?

High blood pressure, heart disease and stroke affect millions of adults worldwide. The impact is staggering. Simple changes, such as eating less sodium, can have a tremendous impact.

The food industry needs to lower sodium content in its products, but you also have the power to reduce sodium and take in more potassium. The first steps are to pay close attention to what you eat, read the labels carefully and stick with fresh foods and vegetables. Simple steps like these may save millions of lives around the world.