Foods That Protect Against Disease
This is Sarah Long. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell about research that says some foods may protect people against disease. We tell about why eating foods with vitamins E and C may help prevent Alzheimer's disease. We tell about why eating broccoli may prevent stomach ulcers and cancer. And we tell why eating fish is good for your heart.
Two new studies suggest that some vitamins found in foods can protect a person from developing Alzheimer's disease. Alzheimer's disease is a condition of the brain that usually affects older people. It begins slowly and becomes worse over time. At first, victims forget recent events. Later, they lose memory and the ability to care for themselves.
The latest studies were reported in the Journal of the American Medical Association. They both suggest that foods that contain vitamins E and C can protect against Alzheimer's. Foods high in vitamin E include nuts, seeds, vegetable oils, whole grains and green, leafy vegetables. Vitamin C is found in vegetables and fruits such as grapefruit and oranges.
Vitamins E and C are called antioxidants. These are substances that block damage to cells in the body. This damage is caused by oxygen molecules called free radicals during normal body processes. Researchers have found evidence of this cell damage in the brains of Alzheimer's patients. Scientists believe that a build-up of cell damage called by free radicals is linked to several other diseases.
The first study involved more than eight-hundred people in the American city of Chicago, Illinois. The people were older than sixty-four. Half of the people were white. The others were black. Researchers asked them about the foods they ate and studied their health for about four years.
About one-hundred-thirty people developed Alzheimer's disease during that time. The disease developed in fourteen percent of those who ate the smallest amount of vitamin E in foods. It developed in only about six percent of those eating the largest amount of vitamin E. The researchers said the group eating foods with the most vitamin E had a seventy percent lower chance of developing Alzheimer's than the others.
However, vitamin E did not provide a protective effect among people who have a gene that is linked to a higher risk for the disease.
The second study involved more than five-thousand people in the city of Rotterdam, the Netherlands. All of the people were older than fifty-four. Researchers studied them for six years. More than one-hundred-forty people developed Alzheimer's disease. The researchers found that eating foods with vitamins E and C were linked with lower rates of the disease.
Researchers say these studies do not prove that the vitamins can prevent Alzheimer's. They are looking for that proof in studies now being done. The studies are examining the health differences among groups of older people taking vitamins and those taking inactive substances. Results of these studies are not expected for five to seven years.
New research has shown that eating the green vegetable broccoli may protect a person from developing sores in the stomach called ulcers and stomach cancer. Researchers at Johns Hopkins University in Baltimore, Maryland have found that a substance in broccoli appears more effective than drugs against the bacteria that cause these diseases.
The substance is sulforaphane (sul-FOR-ah-fane). Ten years ago, these researchers showed that sulforaphane could destroy cancer-causing chemicals. Later, they found that it could prevent breast and colon cancers in mice.
Broccoli contains a chemical that the human body changes into sulforaphane. The researchers discovered that three-day-old broccoli plants called sprouts have at least twenty times more of this chemical than full-grown broccoli plants.
The researchers started a company to grow and sell broccoli sprouts to stores. They also decided to study the sprouts' effects on the bacterium called Helicobacter pylori (hell-e-ko-BAK-ter pie-LOW-ree). This bacterium causes stomach ulcers and increases the chances of developing stomach cancer.
They did the studies with scientists from the National Center for Scientific Research in Nancy, (nahn-SEE) France. The researchers published their findings in the Proceedings of the National Academy of Sciences.
In laboratory studies, they found that sulforaphane killed Helicobacter pylori better than antibiotic medicines. It even killed bacteria in human stomach cells. In other studies, the researchers gave mice a chemical known to cause stomach cancer. Mice that had been given sulforaphane had thirty-nine percent fewer cancerous growths than the other mice.
The researchers say their results do not mean that eating broccoli can cure ulcers or prevent stomach cancer in people. But they are trying to find out if this is true. They are preparing to begin studies in Japan to test broccoli sprouts in people infected with Helicobacter pylori.
About eighty percent of the people in Japan have the bacteria in their stomachs. The same is true among people in other parts of Asia, and in some parts of Central America, South America and Africa. Scientists say stomach cancer causes more deaths than any other cancer in many of these areas.
Helicobacter pylori bacteria can usually be treated with antibiotic medicines. But these medicines are very costly in some developing countries. The researchers say that finding a way to kill these dangerous bacteria without the use of drugs would be a great help to people in many parts of the world.
Researchers are reporting new studies showing that eating oily fish reduces the chance of dying from a heart attack. Oily fish have large amounts of a substance called omega-three fatty acid. These fish include herring, mackerel and salmon.
One study was published in the New England Journal of Medicine. Researchers in Boston, Massachusetts studied about twenty-two-thousand male doctors. The doctors took part in the Physicians Health Study in nineteen-eighty-two. All were free of heart disease. Fifteen-thousand of the doctors provided the researchers with small amounts of their blood.
Ninety-four of the men who had given blood died suddenly during the next seventeen years. The researchers measured the amount of omega-three fatty acid in their blood. They also measured the fatty acids in blood from one-hundred-eighty surviving members of the study.
The researchers found that the men who died had lower amounts of the fatty acids in their blood. The men with the highest levels of fatty acids had an eighty percent lower risk of sudden death than the men with the lowest levels.
A second study appeared in the Journal of the American Medical Association. Another group of researchers in Boston studied eighty-five-thousand female nurses. The women were part of the Nurses Health Study that began in nineteen-seventy-six.
The researchers spoke to the women five times in fourteen years to find out how much fish they ate. They found that the women who ate the most fish were least likely to suffer a heart attack or die of heart problems. Women who ate fish once a week had a thirty percent lower chance of heart attack or sudden death than those who never ate fish.
A third study appeared in Circulation, published by the American Heart Association. Researchers in Italy studied more than eleven-thousand people who had suffered heart attacks. Half the group took a fish oil pill every day. The others took an inactive pill.
The people who took the fish oil pills had a forty-two percent lower rate of sudden death from heart problems. The researchers said their findings must be confirmed by other studies before they would tell people to take fish oil in pills. But all the researchers said that eating oily fish two times a week can protect against heart disease.
This SCIENCE IN THE NEWS program was written by Nancy Steinbach. It was produced by Caty Weaver. This is Sarah Long. And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.