9.6: Summary

Heart disease is the leading cause of death in the United States. The underlying cause of most heart disease is atherosclerosis, a disease in which arteries are narrowed and damaged. Atherosclerosis not only affects the arteries that feed the heart but other arteries as well. For this reason, atherosclerosis can be the underlying cause of other diseases such as stroke and kidney disease. One of the greatest concerns is that a clot might form in the blood and completely block a narrowed artery leading to the heart or brain. This could lead to sudden death or disability from a heart attack or stroke.

The major risk factors for atherosclerosis are a high LDL-cholesterol, diabetes, genetic predisposition, male gender, smoking, aging, and, high blood pressure.

To maintain normal blood pressure, we’re advised to maintain a normal weight, and avoid ex cess salt and alcohol. To avoid raising blood levels of LDL (“bad”)-cholesterol, we’re advised to eat a diet low in saturated (and trans) fat and cholesterol, and a diet rich in soluble fiber. Although extremely high amounts of nicotinic acid (a form of niacin, a B-vitamin) also lowers LDL-cholesterol, taking such amounts is not recommended, except under the supervision of a physician. To maintain normal blood levels of HDL (“good”)-cholesterol, one should avoid smoking, lose weight if overweight, and get regular exercise.

We’re also advised to eat fish twice a week, since this dietary pattern is associated with a lower risk of dying suddenly from a heart attack. Fatty fish is a rich source of certain omega-3 fatty acids, and it’s thought, but not proven, that it is these fatty acids in fish that reduce risk.

Cancer is the second leading cause of death in the U.S. and the leading cause among those under age 85. Lung cancer is our leading cause of death from cancer, and is mostly due to smoking. Our next most common fatal cancers—colon, breast, and prostate cancers—are all associated with diets high in animal fats. But keep in mind that such diets tend to be high in calories, and low in plant foods and fiber. The relationship between diet and cancer isn’t as well understood as that between diet and atherosclerosis, but a diet rich in vegetables and fruit is linked to less cancer in countries throughout the world.

The percent of calories from fat in a food gives a more realistic picture of a food’s fat content, and can be calculated from the grams of fat and total number of calories. These two values are found on food labels, as well as in tables of food composition.

Although there are various dietary recommendations to lower risk of atherosclerosis and cancer, it’s simplest to focus on lowering the amount of saturated and trans fat. A diet low in these solid fats tend to be low in cholesterol, salt, and calories, and tends to be high in plant foods and fiber—a diet plan that emphasizes principal dietary recommendations.