Heart : Dietary Changes

Fortunately, a blood-pressure-friendly diet also supports necessary weight loss, along with healthy levels of blood sugar, lipids, and cholesterol. When you make smart dietary changes, you’re creating a climate in which your body can find overall balance and well-being. “Dietary Approaches to Stop Hypertension”—known as the “DASH” diet—is widely recommended for hypertensive patients. The DASH diet restricts salt and saturated fat and emphasizes fruits, vegetables, and low-fat dairy products. The Joint National Committee on Prevention, Detec­tion and Treatment of High Blood Pressure recommends the DASH diet for all hypertensive patients.

Specific recommendations of the DASH diet are as follows:

• Only 30 percent of total caloric intake from fats.
• Eight to 10 servings of fruits and vegetables daily.
• Seven or eight servings of whole grains daily.
• No more than five servings of seeds and nuts each week.

The evidence supporting the blood pressure benefits of DASH is clear, but compliance appears to be poor. Phillip B. Mellen, MD, MS, of the Hat­tiesburg Clinic in Hattiesburg, Miss., and colleagues, investigated some of the data from the 1988-1994 and 1999-2004 NHANES study. Only 7.3 percent of individuals diagnosed with hypertension were following the DASH diet. The rate of dietary compliance was lowest among young people, the obese, and African-Americans.

Effect of Diet on Weight

If you’re overweight and you start eating a healthy diet, you will lose weight. That may have the biggest impact on blood pressure. The University of Pavia’s Robert Fogari, MD, and colleagues challenged 220 overweight—but not obese—hypertensive adults to lose five percent of their body weight within six months. These men and women had been diagnosed with stage 1 hypertension, which refers to blood pressure between 140/90 to 159/99.

After six months, 59 percent of the women and 53 percent of the men had met this goal. A little more than half of that group brought their blood pres­sure down to a healthy range, below 120/80.The results of this study were presented at the American Heart Association’s 61st Annual Fall Conference of the Council for High Blood Pressure Research, in Tucson, Ariz., in 2007.

The moral of the story? Even modest weight loss—as little as 10 pounds—can normalize blood pressure readings. And we can achieve weight loss through a diet high in fruits, vegetables, whole grains, and low-fat dairy foods, and low in fat, sodium, and refined sugar and flour.

Role of Dietary Fat

Early humans were hard-wired to crave high-fat foods because they are dense in calories and helped ensure the survival of the species. In modern societies, famine is unlikely, but we still have that primitive craving. Fur­thermore, since most of the flavors in foods are fat soluble, fattier foods taste better. Paradoxically, the craving that once ensured our survival now appears to be threatening it. To protect our blood pressure and overall health, we need to cut down on saturated fat and trans-fatty acids (also known as hydrogenated fat). Sources of saturated fat include meat, poultry, butter, cheese, whole milk, and coconut oil. Trans fat, a kind of artificial fat, is found in many mar­garines, baked goods, cookies, and crackers. In 2006, the Food and Drug Administration began requiring mandatory trans-fat labeling.

First, cutting down on saturated fats and trans fatty acids can help you reduce or control your weight. Second, saturated fat appears to contribute to insulin resistance, which is implicated in high blood pressure. Third, trans fatty acids are believed to raise LDL (“bad”) cholesterol and lower HDL (“good”) cholesterol. When cholesterol builds up along the artery walls, it causes the arteries to get harder and more clogged up. As a result, blood pressure rises.

However, not all fats are harmful. Fish oil, rich in omega-3 fatty ac­ids, appears to reverse insulin resistance. A 60-day trial among overweight people in Surrey, England, showed an increase in insulin sensitivity, as well as a significant decrease in diastolic blood pressure, with the use of fish oil supplements.