Salt and Blood Pressure

High blood pressure is often called a “silent killer.” This may sound dramatic, but it’s gotten this ominous nickname because high blood pressure quietly damages your cardiovascular system without causing any symptoms that you can see or feel, without a blood pressure reading.

This is bad news for the 30 percent of U.S. adults who have high blood pressure. Unfortunately, rates are even high among older adults and non-Hispanic blacks, impacting 65 percent and 42 percent, respectively (1).

The good news is, we know quite a bit about how to prevent and control high blood pressure. The best line of defense: reducing sodium intake, maintaining a healthy weight, and following a specific eating and exercise and plan called the Dietary Approaches to Stop Hypertension (DASH).

Before we dive into the specific strategies, let’s take a look at what high blood pressure is and how it does its damage.

What is High Blood Pressure?

High blood pressure, also known as hypertension, is when the force of your blood pushing against the walls of your blood vessels is consistently high. Your physician will determine if you have high blood pressure based on a simple blood pressure reading.

• Systolic blood pressure: Systolic blood pressure (the top number in a blood pressure reading) indicates how much pressure your blood is exerting against your artery walls when the heart beats. A systolic number of less than 120 mm Hg is considered normal. A systolic number of 140 or higher indicates hypertension. In most people, systolic blood pressure rises with age.

• Diastolic blood pressure: Diastolic blood pressure is the lower number in a reading. It indicates how much pressure your blood is exerting against your artery walls while the heart is resting between beats. A reading of less than 80 mm Hg is considered normal. A reading of over 90 is indicative of hypertension. Generally, more attention is given to systolic blood pressure, but your physician will take both numbers into consideration.

How High Blood Pressure Does Its Damage

High blood pressure is a leading risk factor for cardiovascular disease. This is because higher pressure means your heart has to work harder and less efficiently to pump blood throughout your body.

Additionally, the friction caused by high blood pressure can damage the lining of your arteries, causing the arteries to narrow over time. This forces the heart to work even harder, creating a vicious cycle that eventually leads to arrhythmia (irregular heartbeat), heart attack, or stroke.

The Role of Sodium in Increasing Blood Pressure

A large-body of scientific research has confirmed a relationship between salt intake and blood pressure (2). In general, the more salt you eat, the higher your blood pressure will likely be. In fact, the amount of salt you eat is widely recognized as the most common and important risk factor contributing to hypertension (3).

This is because eating too much salt can make it harder for your kidneys to remove fluid, so you’re left with an abundance of fluid in your blood. This extra fluid puts stress on your heart and blood vessels, making them work harder to pump blood through your body.

How Much Sodium is Okay?

Your goal should be to eat less than 2,300 mg of sodium per day. However, if you’re particularly motivated to care for your heart, or if heart disease runs in your family, I’d recommend trying to keep your sodium intake below 1,500 mg per day.

Think of it this way: for millions of years, our human ancestors ate well less than 1,000 mg of sodium per day. Now, the vast majority of adults eat more than 3,400 mg of sodium per day, an amount that our kidneys simply can’t efficiently handle (4).

What Foods Have the Most Sodium?

True, salt adds flavor to food, but it can add up quickly. One slice of bread can have anywhere from 80 to 230 mg of sodium. And a cup of vegetable soup and a turkey sandwich may seem like a healthy meal, but can have more than 2,000 mg of sodium.

The best way to cut back on sodium is to ditch the salt shaker at home and minimize processed foods in your diet. Based on national data, the following foods contribute the most sodium to Americans’ diets:

• Burgers and sandwiches (contribute 21% of sodium in the average diet);
• Grains, snacks and sweets (contribute 19% of sodium in the average diet); and
• Protein foods, especially processed meats (contribute 14% of sodium in the average diet) (5).

Lower Your Blood Pressure with the DASH Eating Plan

In addition to cutting back on salt, government-funded research has shown that a specific eating plan, called the DASH Eating Plan is extremely effective at lowering blood pressure, especially when it’s coupled with sodium reduction (around 1,500 mg per day).

In a nutshell, the DASH Eating Plan emphasizes fruits, vegetables, grains and low-fat dairy products and minimizes saturated fat and processed foods. More specifically, it involves eating:

• 4-5 vegetables per day;
• 4-5 servings of fruit per day;
• 7-8 servings of grains per day;
• 2-3 servings of low-fat dairy per day;
• 2 or fewer servings of lean meat per day;
• 4-5 servings of nuts, seeds and beans per week; and
• 2-3 tablespoons of healthy oils per day.

When people follow the DASH Eating Plan with sodium reduction, they typically can see improvements in their blood pressure within as little as two weeks, comparable to the improvements seen with drug therapy, as well as improvements in LDL cholesterol levels (6, 7).

What’s more, when people add an exercise component to their sodium reduction and DASH eating plan, they typically see improvements in weight management and insulin sensitivity, in addition to improvements in blood pressure (8).

Final Thoughts

Remember that high blood pressure is a silent disease. The only way to know if you have it is to have a simple blood pressure reading done and receive a diagnosis from your doctor. Whether or not you have high blood pressure, reducing the sodium in your diet, eating more fruits and vegetables, and getting some moderate exercise daily are sure-fire ways to care for your overall health and your heart.

Wishing you health and wellness,
Dr. Zivich