The American Heart Association (AHA) recently published a scientific statement on “Dietary Approaches to Prevent and Treat Hypertension” (Hypertension, January 2006). This document reviews a whole host of dietary factors that have researchers have studied and published in reputable medical journals. The authors of this statement conclude that there are five major lifestyle modifications that effectively lower blood pressure:
- Weight loss
- Reduced salt intake
- DASH-type dietary patterns
- Increased potassium intake
- Moderation of alcohol intake
There is a large body of evidence that documents that being overweight is associated with high blood pressure. This holds true for adults, adolescents, and children. There is also good documentation that losing weight can lower blood pressure. Although many individuals who are overweight and have high blood pressure will require medications to get their blood pressure into a healthy range (lower than120/80), weight loss can help reduce the amount of medication needed and can, in some individuals, lead to a discontinuation of medication altogether. The AHA recommends that individuals attain and maintain a BMI (body mass index) of less than 25 kg/m2.
Reduced salt intake
Although individuals vary in their sensitivity to salt (sodium chloride), on average, blood pressure rises as salt intake increases. African-Americans, middle-aged and older persons, and individuals with high blood pressure, diabetes, or chronic kidney disease are particularly sensitive; they respond to reductions in salt intake to a greater degree than others. The AHA guidelines call for lowering salt intake as much as possible, ideally to 1500 mg/day of sodium or 3800 mg/day of sodium chloride. This is equal to about 2/3 of a teaspoon of table salt. Since processed foods tend to be high in sodium, this means, as much as possible, eating fresh, non-processed foods. If you do eat processed foods, check the labels—even low sodium versions of soy sauce and teriyaki sauce have lots of salt in them…so do pickles, olives, bacon, and ham. It also means taking the salt shaker off of the table.
DASH-type dietary patterns
DASH is short for “Dietary Approaches to Stop Hypertension”. DASH-diets are rich in fruits and vegetables (no surprise here) as well as low-fat dairy products. They are also reduced in saturated fat and cholesterol. The National Institutes of Health’s “DASH Eating Plan,” available on the internet, outlines the details of the diet and provides helpful hints on how to be a DASH-dieter. An important note about this diet is that it was not designed to promote weight loss. The diet recommends consuming multiple servings of grains and grain products, fruits, and vegetables each day. Complying with DASH without careful attention to portion size and caloric intake could lead to weight gain or, at the very least, interfere with weight loss.
Increased potassium intake
High potassium intake, preferably by consuming a diet high in potassium-rich foods, such as fruits and vegetables, is associated with reduced blood pressure. Individuals taking drugs that interfere with the elimination of potassium from the body, such as ACE inhibitors—a type of blood pressure medication—and nonsteroidal anti-inflammatory agents, (ibuprofen, for example) and individuals with certain medical conditions associated with impaired potassium excretion (e.g., kidney or heart failure) need to be careful not to take in excessive amounts of potassium. If you have these conditions, it is best to talk this over with your doctor before dramatically increasing your potassium intake.
Moderation of alcohol intake
Many studies have documented a direct, dose-dependent relationship between alcohol intake and high blood pressure, particularly as the intake of alcohol increases above about 2 drinks per day. As we all know, moderation in all things, including alcohol, is the way to go. The AHA recommends that, if you drink, have no more than 2 drinks per day if you are male and 1 if you are female. Note: 1 drink is 12 oz of regular beer, 5 oz of wine (12% alcohol), and 1.5 oz of 80-proof distilled spirits (“hard drinks”).
Other dietary factors reviewed were found to have limited or uncertain effects on blood pressure. These factors include fish oil supplementation, fiber, calcium and magnesium, carbohydrate, intake of fats other than the omega-3 fats, protein intake, cholesterol, and vitamin C. That doesn’t mean these things aren’t either good or bad for you, only that they do not appear to have an independent effect on lowering blood pressure.
So there you go…drink less, salt less, lose weight, and eat your fruits and vegetables. Can’t you just hear your mother saying, “I told you so!“