What is the Right Menu to Control Hypertension?
Dietary interventions like DASH shown to improve high blood pressure.
If you're worried about high blood pressure, a new systematic review of scientific evidence has good news: Changing your diet really can make a difference. Not surprisingly, the most effective diet for reducing hypertension was one designed specifically for that purpose - the Dietary Approaches to Stop Hypertension (DASH) plan. But other interventions, including cutting salt and calories, also were associated with blood-pressure benefits.
"Many 'healthy' diets have common elements, whether they are a named diet such as DASH, or not,” says Alice H. Lichtenstein, DSc, director of Tufts Cardiovascular Nutrition Laboratory and executive editor of the Health & Nutrition Letter. "Common elements include cutting calories, decreasing salt and refined carbohydrates, increasing fruits and vegetables, and focusing on healthy fats. To get the most benefit from any diet, the critical element is making small but sustainable - and, if necessary, incremental changes - to ensure long-term benefits."
REVIEWING THE EVIDENCE: The new meta-analysis, published in the journal Hypertension, looked at data from 24 randomized controlled trials with a total of 23,858 participants conducted over the past 25 years. Such studies are considered the "gold standard" of scientific research and are designed to elicit cause and effect.
Overall, the net effect of dietary interventions averaged reductions of 3.07 mmHg for systolic pressure (the top number in a blood-pressure reading) and 1.81 mmHg for diastolic pressure (the bottom number). The DASH diet produced the largest improvements in blood pressure: minus 7.62 mmHg for systolic pressure and minus 4.22 mmHg for diastolic pressure. Low-sodium, low-sodium/high-potassium, low-sodium/low-calorie and low-calorie diets were all also associated with reductions in both systolic and diastolic pressure. Participants on a Mediterranean diet saw only a small reduction in diastolic blood pressure (-1.44 mmHg).
Dietary interventions were more effective for people with pre-existing hypertension and those who were not already taking medication for high blood pressure.
"As with any treatment," Tufts' Lichtenstein adds, "some people will reap greater benefit than others, particularly for blood pressure where we know responsiveness to dietary modification is highly variable. We can't predict who those people will be ahead of time. Given that the characteristics of a diet good for blood-pressure lowering will have general benefits in other areas, we should all strive to achieve them."
IMPORTANCE OF CONTROL: The numbers when you get your blood pressure checked represent the amount of force pushing against your artery walls when the heart is contracting (systolic) and when the heart is at rest (diastolic). When pressure rises in the vessels, the heart has to work harder and the arteries have to stretch more. Over time, high blood pressure damages the artery walls, making them more vulnerable to damage and prone to plaque buildup (atherosclerosis).
Since hypertension increases the workload on the heart, it can eventually damage those muscles and valves and cause heart failure, in which the heart can no longer keep up with the body’s demands. High blood pressure puts you at greater risk of heart attack, heart disease and aortic dissection (tearing in the heart).
This type of damage to the arteries can also affect the brain, and high blood pressure is a leading cause of stroke. High blood pressure is also associated with a greater risk of dementia.
Other risks from uncontrolled hypertension include kidney damage, vision loss, erectile dysfunction, fluid in the lungs, angina (chest pain) and peripheral artery disease. But these are effects, not symptoms- uncontrolled high blood pressure is sometimes called "the silent killer" because it has no symptoms. Until a doctor diagnoses hypertension, you may not be aware that it's damaging your arteries, heart and other organs. It's estimated that of all people with high blood pressure, more than 20% are unaware of their condition.
DASH DETAILS: The DASH eating plan shown to be effective against hypertension requires no special foods; it shares common elements with most “healthy” diet plans. Built on daily and weekly nutritional goals (see box), the DASH plan recommends:
- Eating vegetables, fruits and whole grains.
- Including fat-free or low-fat dairy products, fish, poultry, beans, nuts and vegetable oils.
- Limiting foods that are high in saturated fat, such as fatty meats, full-fat dairy products, and tropical oils such as coconut, palm kernel and palm oils.
- Limiting sugar-sweetened beverages and sweets.
When following the DASH eating plan, it is important to choose foods that are:
- Low in saturated and trans fats, replacing these fats with those high in monounsaturated and polyunsaturated fats.
- Rich in potassium, calcium, magnesium, fiber and protein.
- Lower in sodium.
To learn more about the DASH plan, see <www.nhlbi.nih.gov/health/health-topics/topics/dash>.