Study Reveals How Eating Fish Helps the Heart
For older adults, eating fish helps the heart by regulating its electrical activity, according to a report in the Journal of the American College of Cardiology (JACC).
And just a couple of meals a week of the right kind of fish - rich in omega-3 fatty acids, baked or boiled, but not fried - will do the job, researchers say.
The finding "supports studies suggesting that fish intake reduces the risk of sudden death," says study lead author Dr. Dariush Mozaffarian, a cardiologist at Brigham and Women's Hospital in Boston.
It has long been known that eating fish such as tuna, mackerel, lake trout, and salmon, which are rich in omega-3 fatty acids, is good for the heart. Dr. Mozaffarian and his colleagues set out to discover why.
They analyzed data from more than 5,000 men and women ages 65 and older in the federally funded Cardiovascular Heart Study.
The participants were asked whether they ate fish, what kind, and how often. The researchers compared the answers to those dietary questions with electrocardiogram (ECG) tests of the study participants.
What they found was that eating fish was associated with a lower heart rate, a slower interval between when the heart received a signal to pump blood and when blood was pumped, and a lower likelihood that the heart would take a long time to reset its electrical system after a beat.
That last effect is important, says Dr. Mozaffarian. "The heart resets its electrical activity after every beat," he notes. "When there is heart disease, the resetting can be delayed. That is dangerous."
Animal studies have indicated why the omega-3 fatty oils confer their beneficial effect, says Dr. Mozaffarian.
"The fish oils get into the membrane of heart cells and affect the function of their protein channels," he explains. "Potassium, sodium, and calcium pass through those channels, controlling the whole electrical cycle."
While the new study found that the more fish consumed, the greater the benefits, most gains were achieved with just one or two meals of fish a week. That was especially true for the lower heart rate, says Dr. Mozaffarian .
But it had to be the right kind of fish, and prepared the right way. No effect on the heart's electrical activity was seen with fried fish, such as fish burgers or fish sticks. Those commercial products do not increase blood levels of omega-3 fatty acids.
And people who think they can take a shortcut by using fish-oil supplements could be wrong, says Alice H. Lichtenstein, D.Sc., professor of public health and family medicine at Tufts University School of Medicine, and a spokeswoman for the American Heart Association.
"Recent studies have cast doubt on the belief that fish-oil supplements are beneficial," says Dr. Lichtenstein.
Always consult your physician for more information.
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The food guide pyramid is a guideline to help you eat a healthy diet.
The food guide pyramid can help you eat a variety of foods while encouraging the right amount of calories and fat.
The United States Department of Agriculture (USDA) and the US Department of Health and Human Services (HHS) have prepared the following food pyramid to guide you in selecting foods.
The Food Pyramid is divided into six colored bands representing the five food groups plus oils:
Orange represents grains: Make half the grains consumed each day whole grains. Whole-grain foods include oatmeal, whole-wheat flour, whole cornmeal, brown rice, and whole-wheat bread. Check the food label on processed foods - the words “whole” or “whole grain” should be listed before the specific grain in the product.
Green represents vegetables: Vary your vegetables. Choose a variety of vegetables, including dark green- and orange-colored kinds, legumes (peas and beans), starchy vegetables, and other vegetables.
Red represents fruits: Focus on fruits. Any fruit or 100 percent fruit juice counts as part of the fruit group. Fruits may be fresh, canned, frozen, or dried, and may be whole, cut-up, or pureed.
Yellow represents oils: Know the limits on fats, sugars, and salt (sodium). Make most of your fat sources from fish, nuts, and vegetable oils. Limit solid fats like butter, stick margarine, shortening, and lard, as well as foods that contain these.
Blue represents milk: Get your calcium-rich foods. Milk and milk products contain calcium and vitamin D, both important ingredients in building and maintaining bone tissue.
Purple represents meat and beans: Go lean on protein. Choose low fat or lean meats and poultry. Vary your protein routine - choose more fish, nuts, seeds, peas, and beans.
Activity is also represented on the pyramid by the steps and the person climbing them, as a reminder of the importance of daily physical activity.
Always consult your physician for more information.
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