Getting more potassium and less salt may cut heart attack, stroke risk

Salt is a cheap, easy way to turn on taste buds. That’s one reason why it’s in so many of the foods we eat. It’s so commonly used that most Americans consume more than double the recommended daily limit for it.

Why limit salt? Because it is the body’s main source of sodium. We need a little bit of sodium to transmit nerve impulses, to contract muscle fibers, and, along with potassium, to balance fluid levels in all of our cells. But getting too much sodium 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 new 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. This technique is called meta-analysis. It showed 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 was also linked to lower risks of heart attack, stroke and heart failure.

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

The third study looked at potassium intake. Potassium is needed for many normal body functions, including heart and muscle function. In this review of 33 studies that included more than 128,000 people, consuming more potassium was linked to lower blood pressure and lower risk of stroke.

Putting it into practice

Current dietary guidelines recommend that Americans get no more than 1 teaspoon of salt a day. That’s the equivalent of 2,300 milligrams (mg) of sodium a day. Those with high blood pressure or other conditions such as kidney disease or heart failure and anyone over age 50 failure are urged to limit sodium to 1,500 mg a day.

Only about 10% to 20% of the salt that most people take in comes from the salt shaker at the table or in the kitchen. Most of the sodium we get is added to processed foods like canned soups and vegetables; breads, crackers, and other prepared baked goods; deli and other processed meats; chips and other snacks; and restaurant foods.

Here are some tips for limiting your salt intake:

• Know how much salt is in your 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. These tend to have a lot of sodium. When in doubt, eat fresh food or food you have prepared yourself.
• 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. Herbs and spices, for example, can add flavor to your food.

For more salt-reduction strategies, check out “Tasting Success With Cutting Salt,” prepared by the Culinary Institute of America and the Harvard School of Public Health.

What about potassium? Most healthy Americans consume less than half of the recommended amount of potassium (4,700 mg per day). Getting more of this mineral may help lower blood pressure. But too much potassium can be dangerous, especially for people with kidney problems. So the right amount is critical.

It’s best to get potassium from food, especially fruits and vegetables. Green leafy vegetables, beans, and bananas have a lot of potassium. The USDA has published a list of potassium in hundreds of foods.