Low-Fat Diets Alone Do Not Reduce Health Risks
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This is SCIENCE IN THE NEWS, in VOA Special English. I'm Pat Bodnar. And I'm Bob Doughty. On our program this week: We tell about a discovery made on a mountain in eastern Indonesia. We also will talk about a report on the value of calcium in the human diet.
But first, we tell about low-fat diets and their effects in women.
An American study has examined the effects of a low-fat diet on the health of women. The study found that such a diet does not reduce the risk of at least one kind of cancer, heart disease or stroke.
For years, medical experts have thought that a diet that is low in fat helps reduce the risk of cancer and heart disease. Researchers with America's National Institutes of Health created a study to test this theory. It is one of the largest studies ever done on this subject.
The researchers studied the health of almost fifty thousand women for eight years. These women were between the ages of fifty and seventy-nine years.
The women in one group reduced the fat in their diet to twenty percent of their total daily food supply. They also increased their daily servings of vegetables, fruits and grains.
Another group of women did not make any dietary changes. The researchers compared the two groups.
The results of the study show the different diets had little effect on the health of the women. Both groups had the same rates of heart disease and colorectal cancer. The researchers said the women who followed the low-fat diet might have less risk of breast cancer. But the difference was so small that it is not considered important.
Experts say the results are important for both men and women. Some critics of the study fear many people will think that diet is not important. Other studies have shown that a healthful diet is still important, but so are other choices. For example, exercising, avoiding smoking, and keeping a normal body weight are also necessary for good health.
Other experts noted the study called for reducing total fat instead of the kinds of fats that are not healthful. For example, fats in some foods like fish and nuts are considered good for human health. Unhealthful fats include saturated and trans fats. The study did not note differences between these two kinds of fat.
Experts also said that dietary changes might need to begin earlier in life to have a greater effect on disease and cancer prevention. Some researchers suggest the study would have shown better results if the women had eaten even less fat.
Most American children are not getting enough of the element calcium in their diet. Calcium helps the body to make bones strong and hard. The hardness prevents bones from breaking later in life. Getting enough calcium can also reduce the risk of developing osteoporosis. Osteoporosis is a bone-thinning disease. It usually develops in old age and affects millions of Americans. Most people with osteoporosis are women.
Recently, the American Academy of Pediatrics released a report about the calcium needs of children. The academy represents thousands of children's doctors and researchers.
The report says that only during their first six months of life are most American children receiving enough calcium. All other ages are lacking calcium in their diet. Children between the ages of twelve and nineteen years are getting far less calcium than the amount that experts suggest. Calcium is especially important during this period, when most bone growth is taking place.
Doctors believe that one reason older children are not getting enough calcium is because they choose soft drinks like Coca-Cola instead of milk. Often young adults also choose soft drinks instead of natural fruit drinks that contain calcium.
Most people can receive the calcium they need from eating or drinking milk products three times each day. Older boys and girls require calcium in their diet four times each day.
Foods rich in calcium include milk, cheese and yogurt. Experts say milk products low in fat contain as much calcium as those with higher fat levels. Calcium can also be found in some green vegetables, although milk products are the most common way people get calcium.
Many people in the United States need more physical exercise. A recent study found that one-third of all Americans between the ages of twelve and nineteen years were in poor physical condition. Such persons also had an increased risk of health problems linked to heart disease.
Researchers at Northwestern University in the American state of Illinois organized the study. The research team used information from a four-year study that involved more than five thousand people. More than three thousand of them were twelve to nineteen years old.
The rest were adults between the ages of twenty and forty-nine years. None were known to have heart disease before the study.
The five thousand individuals were tested on a common piece of exercise equipment: a treadmill. The treadmill test measured their physical condition or cardio-respiratory fitness. Cardio-respiratory fitness is the ability of the heart and lungs to react to an increase in physical activity.
More than thirty percent of the teenagers were in poor physical condition. Almost fourteen percent of the adults also had poor test results. The researchers say the number of adults with poor physical health may be greater. They said some adults in the study did not take the treadmill test. Those adults already were at risk for heart disease.
Mercedes Carnethon led the study. She says women may be at greater risk because they are less likely to be in good physical condition. Doctor Carnethon said those in poor physical condition often have higher levels of blood pressure and cholesterol in the blood. They also can have a higher risk of developing the disease diabetes and gaining too much weight.
Scientists working in Indonesia have found many kinds of wildlife that had never been described before. The wildlife was discovered on top of a mountain in a forest on the island of New Guinea. The scientists explored the forest in the Foja Mountains of Papua Province late last year.
Bruce Beehler is vice president of the Melanesia program of the environmental group Conservation International. He described the forest as the closest to the Garden of Eden that humans will find on Earth. The writings of Jews, Christians, and Muslims tell of Eden as a beautiful place where the first man and woman lived until they violated God's law and were expelled.
Conservation International and the Indonesian Institute of Sciences organized the research. The team of scientists came from Indonesia, Australia and the United States. The Foja Mountain forest is part of more than one million hectares of land seemingly never influenced by humans.
Among the creatures discovered was the Berlepsch [pronounced BEAR-lapsh] Six-Wired Bird of Paradise. No researcher had seen this kind of bird since eighteen ninety-seven. At that time, German bird expert Otto Kleinschmidt identified it from wildlife skins in a collection owned by Hans von Berlepsch. The bird got the rest of its name from the strange wires that extend from its head.
The scientists also took the first pictures of a bird called the Golden-fronted Bowerbird. They reportedly saw a male Bowerbird hanging up fruit for a female Bowerbird. The male's actions were part of the mating process.
Conservation International says at least twelve attempts were made over about eighty years to find a Bird of Paradise and a Bowerbird.
In all, the team discovered more than forty animals that scientists have not identified before. The discoveries included four kinds of butterflies and twenty kinds of frogs.
They also found a larger animal new to Indonesia. It is called the golden-mantled tree kangaroo. Earlier, it was known to live on only one mountain in the nearby nation of Papua New Guinea.
Scientists thought that hunters had killed the last such animal. As its name suggests, the golden-mantled tree kangaroo lives in the trees. The scientists also found and took pictures of a huge rhododendron plant. Its flower measured about fifteen centimeters wide.
This program was written by Brianna Blake, Dana Demange, Lawan Davis and Jerilyn Watson. Cynthia Kirk was our producer. I'm Pat Bodnar. And I'm Bob Doughty. Join us again next week for SCIENCE IN THE NEWS, in VOA Special English.