Can a Low-Carb Diet Cause Low Blood Pressure?

Not only do low-carb diets help you lose weight, but they may also lower blood pressure. If you've had a hard time losing weight and managing your blood pressure on other diet plans, a low-carb diet may work for you. Consult with your doctor first, though, before you change your eating habits.

About Blood Pressure

Blood pressure is the measurement of the force of blood against artery walls when the heart is beating and at rest. The systolic, or top number, measures the pressure during the heartbeat, while the diastolic, or bottom number, measures the pressure when the heart is at rest. High blood pressure affects about 80 million people in the United States, according to the American Heart Association. It doesn't cause any symptoms, but excess pressure against the artery walls causes them to stretch and weaken, which can lead to a heart attack or stroke. While there are a number of causes of high blood pressure, including genetics and age, factors such as poor food choices, inactivity and carrying excess weight may also increase your risk.

Losing weight and making healthier food choices are part of the treatment plan for high blood pressure. Although the typical diet to manage blood pressure is high in fruits, veggies, whole grains and dairy foods, a low-carb diet might work to improve your numbers, too.

Low-Carb Diet Basics

The premise behind a low-carb diet is that it helps your body burn fat instead of storing it. While there are no set rules, many low-carb diets kick-start your weight loss by severely restricting your intake of carbs -- 20 to 50 grams a day -- during the early stages. This causes your body to go into a state of ketosis, burning fat instead of glucose to fuel your brain. Then, carbs are slowly added back in phases, depending on the low-carb plan you're following, to slow weight loss and help you find the right amount of carbs to maintain weight loss, which can be as high as 150 grams a day. In addition to helping you burn fat, low-carb diets suppress appetite, which helps cut calories, too.

While low-carb diets offer a number of benefits for weight loss, they are not without some side effects. The most common complaints include constipation, diarrhea, muscle cramps, fatigue and skin rash. All ill effects should be discussed with your doctor, especially if you're taking medication for any illnesses, including those to lower blood pressure.

Low-Carb Diet and Blood Pressure

Losing just 5 percent of your current body weight may help lower blood pressure, according to the American Heart Association. While it's true that low-carb diets can help lower your blood pressure simply by helping you lose weight, there may be more to it, according to a 2010 clinical study published in the Archives of Internal Medicine. This study compared the effects of a low-carb diet vs. a low-fat diet plus orlistat -- a weight loss medicine that blocks fat absorption -- on weight loss and blood pressure in a group of people with obesity. The researchers found that while both groups lost similar amounts of weight, the group following a low-carb diet had better improvement in blood pressure than the group on the low-fat diet with orlistat. More studies may be necessary, however, to determine the relationship between a low-carb diet and blood pressure.

About Sodium and Low-Carb Diets

Most Americans get way too much sodium in their diet, according to the American Heart Association, primarily from processed foods such as potato chips, frozen meals and fast food. Excessive intake of sodium makes your body retain fluid, which affects blood pressure. A low-carb diet eliminates many of the carb-heavy processed foods and encourages you to eat more whole foods, which might play a role in lowering blood pressure. Additionally, some of the weight you lose on a low-carb diet is water weight, which may also reduce your numbers.

No matter which diet you follow, if you have a history of high blood pressure, you may need to reduce the amount of salt in your diet. The association suggests 1,500 milligrams a day.

Some foods allowed on a low-carb diet are high in sodium, including bacon, sausage, deli meat and cheese. To keep sodium intake and blood pressure in check, you may need to limit your intake of these salty foods.