At one time, the only dietary strategy people trying to lower their heart disease risk had was to cut back on fat and cholesterol. But recent research has shown that many other dietary factors may influence the development of heart disease. A new study in the Journal of the American Medical Association identifies what may be the most effective dietary strategies for preventing heart disease.

Reviewing previous research

Researchers from the Harvard School of Public Health reviewed 147 previously published studies that investigated the effects of various dietary factors on heart disease risk, including cholesterol, total fat, omega-3 fatty acids, trans fatty acids, monounsaturated fatty acids, carbohydrates, glycemic index, fiber, and folate. Some of the studies looked at overall dietary patterns, such as diets in which saturated fat is replaced with unsaturated fat or those that emphasize whole grains over refined grain products.

The Harvard researchers evaluated the results of each study for relevance and quality, paying particular attention to different studies that produced either consistent or conflicting results.

The most effective diets

Three dietary traits appeared to have the strongest evidence with regard to their ability to protect the heart. They were the following:

• Replacing saturated fats (like those found in butter, whole milk, and red meat), and trans fat (found in margarine and processed foods) with more healthful fats, such as those found in olive, canola, and soybean oils, as well as in fatty fish, avocados, nuts, and seeds.
• Eating more omega-3 fatty acids (found in fish oil, flaxseed, leafy greens, walnuts, tofu, and canola and soybean oils).
• Regularly eating more fruits, vegetables, nuts, and whole grains, and eating fewer refined grain products, such as white bread, potato chips, pastries, and cookies.

There are several reasons why these particular traits may improve heart health. For one, replacing saturated fat with more healthful fat has been shown to improve blood levels of total and LDL ("bad") cholesterol. In addition, evidence is accumulating that omega-3 fatty acids (a type of unsaturated fat) may help the heart, in part, by improving artery function and blood flow.

Of course, other factors may also play a role in heart protection, but according to the authors of this review, the evidence is such that many issues remain "unsettled". For example, there have been mixed results regarding the effectiveness of vitamin E as a preventive measure.

Choosing your best heart-health strategy

While researchers continue to try to identify the optimal diet for preventing heart disease, these findings underscore many current nutrition guidelines, including the advice of the Dietary Guidelines for Americans to eat a variety of fruits, vegetables, and whole grains, and of the American Heart Association to eat fish twice a week.

It's also important to remember that heart disease prevention includes not only diet, but also regular exercise, no smoking, stress management, and weight control. According to the researchers, all of these factors combined have the potential to prevent the "majority" of cases of cardiovascular disease in Western countries.

Source

Optimal diets for prevention of coronary heart disease.
FB. Hu, WC. Willett, JAMA, 2002, vol. 288, pp. 2569--2578

Links

• Studies Back Benefits of a Heart Healthy Diet
• Omega-3s, the Heart-Healthy Fat
• Meatless Meals are Linked to Lower Blood Pressure
• Food Shopping? Add Fish to Your List
• To quickly access additional accurate information on this and other nutrition-related topics, visit Tufts University's Nutrition Navigator