Heart Health

Heart Health
July 1999 -- Nutrition Notes

By: Andrea Platzman, R.D.
Contributing Editor

  Over a million-and-a-half Americans will suffer from cardiovascular disease this year. Charles Hennekens, M.D., Dr.P.H. (doctor of public health), professor of epidemiology, Harvard School of Public Health, Boston, predicts that by the year 2020, cardiovascular disease will be the number one cause for years of life lost, or premature death.

  Among the known, uncontrollable risk factors for cardiovascular disease are age, gender, race and heredity. Controllable risk factors include smoking, inactivity, high blood cholesterol, obesity, homocysteine level, stress and diet.

  A desirable total cholesterol level is less than 200 mg per deciliter, with low-density lipoprotein (LDL, or "bad") cholesterol below 130 mg per deciliter and high-density lipoprotein (HDL, or "good") cholesterol above 60 mg per deciliter.

Fat facts

  "A heart-healthy diet is low in fat (less than 30%) and saturated fat; high in fruits and vegetables, including more than five a day; and low in sodium, less than 2400 mg," states Nancy Cohen, Ph.D., R.D., professor and acting head, department of nutrition, University of Massachusetts, Amherst. "The type of fat does seem to matter, as well as the amount of fat," she observes.

  Such a diet is in accordance with the "step by step" diets specified by the National Institute of Health's National Cholesterol Education Program. The step I diet calls for less than 10% of a day's total calories from saturated fat, and less than 300 mg cholesterol. The step II diet, for people with more severe hyperlipidemia, calls for less than 7% saturated fat and less than 200 mg cholesterol a day. Both diets recommend 10% to 15% monounsaturated fat and up to 10% polyunsaturated fat.

  According to the latest findings from the ongoing Harvard-affiliated Nurses' Health Study, women who consume diets higher in saturated fatty acids are more likely to develop heart disease than those who consume fewer saturates. In addition, the researchers estimate that replacing 5% of total daily calories from saturated fatty acids with those from unsaturated fatty acids could reduce risk of heart disease by approximately 42%.

  "Saturated fat and polyunsaturated fat are linked with higher incidence of cardiovascular disease, compared to monounsaturated fats such as olive and canola oils. However, too much fat of any type in the diet can increase calories and possibly lead to obesity, which is a risk factor for cardiovascular disease," says Cohen. The American Heart Association recommends a 1:1:1 ratio of saturated, polyunsaturated and monounsaturated fatty acids in the diet.

  Fatty acids are often represented by two numbers separated by a colon. The first digit indicates the number of carbon atoms, and the second indicates the number of double bonds. A zero in the second-digit position indicates no double bonds, meaning that the fatty acid is saturated. Fatty acids of a 12:0 and 14:0 construction, such as those found in coconut oil, are most detrimental, because they raise LDL levels. Stearic acid (18:0) has a neutral effect on blood cholesterol, while palmitic acid (16:0), one of the most prevalent saturated fatty acids in the diet, is considered intermediate in its effect. It can be neutral, when combined with 18:0 chains, but can also be detrimental, when combined with 12:0 or 14:0 chains.

  Keeping trans fatty-acid intake to a minimum is also important in reducing cardiovascular-disease risk. Omega-3 polyunsaturated fatty acids, found in fish oil, have been associated with lowered cardiovascular disease risk. (For additional information on omega fatty acids, see Catch of the Day," in the October 1998 Food Product Design).

Dietary directives

  Diets high in fiber - found in fruits, vegetables and whole grains - lower cholesterol and reduce risk of cardiovascular disease, as well as prevent many gastrointestinal disorders. However, most people consume only about half of the recommended 25 to 30 grams each day.

  Soluble fibers, such as gums, pectin and mucilages, reduce cholesterol by increasing viscosity in the intestine, thereby slowing the absorption of cholesterol, which may help to reduce the risk of cardiovascular disease. Over the past five years, beta-glucan soluble fiber - such as that found in oat bran - and soluble fiber from psyllium seed husk have been linked to lowering cholesterol levels, and have received FDA approval for health claims.

  Low levels of folic acid, vitamin B6 and vitamin B12 have been shown to result in elevated homocysteine levels. Since aging decreases the production of these vitamins, it is suggested that people over 50 years of age take supplements containing 400 mg of folic acid, 2 mg of vitamin B6 and 6 mg of vitamin B12.

  Antioxidants such as vitamins E and C and coenzyme Q10 can also help reduce cardiovascular disease by reducing cholesterol levels. "Coenzyme Q10 can be used to prevent heart disease, and recent research has found that it is also beneficial in the treatment of this disease, especially those on statin medications," states Lester Packer, Ph.D., director of the Packer Laboratory, University of California at Berkeley and author of The Antioxidant Miracle. "The most important item to remember is to have a balance between oxidants and antioxidants," he continues, also noting that more research is needed in this area.

  Selecting products endorsed by the American Heart Association's (AHA) Food Certification Program helps consumers easily choose food items that are part of a heart-healthy diet. In order to be certified by the AHA and display the red heart-check symbol, the product must have 3 grams or less of total fat, 1 gram or less of saturated fat and 20 mg or less of cholesterol per serving.

  "The most important thing to do to prevent cardiovascular disease is to eat a diet low in fat and rich in fruits, vegetables and fiber. Scientists are learning more each day about the benefits of these items, which are full of phytochemicals and antioxidants that can promote health and reduce the risk of heart disease," says Cohen.

  Andrea D. Platzman is a registered dietitian who is a consultant to the food industry, and regularly writes for nutrition publications. She earned a master's degree in nutrition from New York University, and has a culinary and business background.

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