VOA慢速英语2010年-SCIENCE IN THE NEWS - Scientists Look

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BOB DOUGHTY¹: This is SCIENCE IN THE NEWS, a program in VOA Special English. I’m Bob Doughty.

FAITH LAPIDUS: And I’m Faith Lapidus. Today, we will tell about herbs and spices, and some of their many uses.

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BOB DOUGHTY: People have been using herbs and spices for thousands of years. Generally, herbs come from the green leaves of plants or vegetables. Spices come from other parts of plants and trees. For example, cinnamon comes from the hard outer cover of cinnamon plants. The spice ginger² comes from the part of the ginger plant that grows underground.

FAITH LAPIDUS: Some herbs and spices are valued for their taste. They help to sharpen the taste of many foods. Others are chosen for their smell. Still others were used traditionally for health reasons.

Some herbs and spices may be gaining importance in modern medicine. For example, natural chemicals from black pepper and the Indian spice turmeric might help to prevent breast cancer. Researchers at the University of Michigan say a substance developed from the spices could reduce the possibility of breast tumors.

BOB DOUGHTY: Turmeric is a plant. It also is used to make the spicy⁴ food seasoning⁵ curry⁶. In the study, researchers tested curcumin, a chemical compound taken from turmeric. They also used peperine, which comes from black peppers.

Herbs and spices for sale in St. Paul, Minnesota

The researchers combined the two compounds, and placed the mixture on breast cancer cells in a laboratory. The mixture caused the number of stem cells to decrease. Normal breast tissue, however, was not affected⁷.

Results of the study were reported in the journal Breast Cancer Research and Treatment. Madhuri Kakarala was lead writer of the report. Doctor Kakarala teaches at the University of Michigan’s Medical School. She also works as a research investigator⁸ for the Veterans Administration Ann Arbor⁹ Healthcare System.

FAITH LAPIDUS: Doctor Kakarala says the cancer-fighting treatments known as chemotherapy do not control tumors containing cancer stem cells. Cancer stem cells are found inside tumors. They help the tumor³ continue growing without restriction¹⁰. This means the disease can spread and return. The disappearance¹¹ of cancer stem cells, then, is important for cancer control.

The doctor also says researchers could be able to limit the number of cells that can form tumors if they limit the number of normal stem cells. That would reduce the possibility of the disease appearing.

BOB DOUGHTY: Research involving turmeric is not new. Scientists have been studying its medical possibilities for many years. For example, researchers in Singapore completed one such study several years ago. The study was based on earlier evidence that turmeric has strong antioxidant and anti-inflammatory qualities. These qualities can help protect against damage to the body’s tissues and other injuries.

The researchers said turmeric has been shown to reduce evidence of damage in the brains of patients with Alzheimer’s disease. But, they said evidence was lacking about cases of Alzheimer’s in people who ate curry compared with people who did not use curry.

For this reason, the researchers designed a study that examined results from a mental-performance test of older Asian adults. The adults were sixty to ninety-three years old. None had severe memory losses. Those who sometimes ate curry, or ate it often or very often, did better on the tests than individuals who rarely or never ate curry.

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FAITH LAPIDUS: The work of the Mayo Clinic and its medical experts is world-famous. The Clinic operates medical centers in three American states. Its “Health Letter” publication of November, two thousand seven provided more evidence that herbs and spices can aid health. Mayo Clinic experts said people could reduce salt use by using herbs and spices instead. Too much salt is a problem for people with health conditions like high blood pressure.

The experts said some plant chemicals are high in antioxidants. In addition to turmeric, these include cloves¹², cinnamon, ginger, oregano, sage¹³ and thyme.

BOB DOUGHTY: The experts also said antioxidants like garlic, rosemary and saffron have qualities that could fight cancer. They said limited evidence shows that cinnamon, fenugreek and turmeric may affect blood sugar levels in people with diabetes¹⁴.

Not all studies agree that spices could help diabetes patients. But some research suggests that they could because of a suspected link between inflammation and diabetes. Inflammation is the body’s way of reacting to infection.

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FAITH LAPIDUS: Researchers from the University of Georgia reported two years ago that cinnamon could help reduce blood sugar. The researchers tested twenty-four common herbs and spices. The tests showed that many of the substances contained high levels of antioxidant chemicals known as polyphenols.

The researchers found that ground cloves had the most polyphenols. Cloves were the most effective at calming inflammation of any spice or herb they tested. Cinnamon was second. Other research has shown that cinnamon gets more use in cooking than ground cloves. This means it could affect the health of more people. Still, the Mayo Clinic warns that cinnamon CANNOT replace proven medicines for diabetes.

BOB DOUGHTY: Another American study found that adding spices to meat before cooking at high temperatures may reduce harmful chemicals. Researchers at Kansas State University reported on their experiments with steaks in two thousand eight. They found a major decrease in unwanted chemicals by preparing the meat with spice and herb marinades. The study showed that this may decrease formation of heterocyclic amines, also known as HCAs. The researchers say these chemicals may cause cancer in some people.

America’s National Cancer Institute says cooking meat at very high temperatures produces the most HCAs. The chemicals form when amino acids react with creatine, a chemical found in muscles. But meats from organs and non-meat protein sources have little or no HCA.

FAITH LAPIDUS: Research on HCAs has made some people afraid to prepare meat on a grill¹⁵ – the place where meat is cooked on hot coals or an open fire. Cooking meat this way is a traditional favorite of many Americans during warm weather.

The Kansas State University study, however, may show a way that reduces risk for people who grill on high heat. The researchers placed some steaks in already prepared spice mixes, or marinades. The meat then was grilled¹⁶ for five minutes on each side at a temperature of more than two hundred degrees Celsius¹⁷. The researchers also cooked steaks marinated without spices, and steaks that were not marinated. They were prepared at the same temperature as meat with the marinade mixes.

The researchers compared levels of the HCAs in all the steaks. They found the HCAs in the meat marinated in spices had decreased up to eighty-eight percent.

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BOB DOUGHTY: Herbs and spices are often used because they can make food taste better. Some spices also destroy bacteria. Spices have long been used to keep food safe to eat. In the past, spices also helped to prevent the wasting away of dead bodies.

Herb and spice plants grow in many countries. For example, the Molucca Islands in Indonesia are famous for producing spices like cloves, nutmeg or mace¹⁸. Vanilla¹⁹ comes from orchid²⁰ plants growing in South America and other places with warm, moist weather.

FAITH LAPIDUS: Spices have influenced world history. For example, the Goth people of Europe defeated Roman forces in battle more than sixteen centuries ago. After the fighting ended, the leader of the Goths is said to have demanded five-thousand pounds of gold and three thousand pounds of pepper.

More recently, Marco Polo and Christopher Columbus discovered new lands while seeking to expand trade with spice-growing areas in Asia. The Italian cities of Genoa and Venice became powerful because they were at the center of the spice trade. The trade was so important to national economies that rulers launched wars in their struggle to control spices.

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BOB DOUGHTY: This SCIENCE IN THE NEWS program was written by Jerilyn Watson. Our producer was Brianna Blake. I’m Bob Doughty.

FAITH LAPIDUS: And I’m Faith Lapidus. Join us again next week for more news about science in Special English on the Voice of America.