This is SCIENCE IN THE NEWS, a program in VOA Special English. I'm Bob Doughty. And I'm Faith Lapidus. Herbs and spices help to sharpen the taste of many foods. Today, we tell about these food additives.
People have used herbs and spices in food for thousands of years. Some of these substances are valued for their sharp taste. Others are chosen for their smell.
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 ginger comes from the part of the ginger plant that grows underground.
Herb and spice plants grow in many countries. For example, the Molucca Islands in Indonesia are famous for producing spices like cloves, nutmeg or mace. Vanilla comes from plants growing in South America.
Many people grow herb and spice plants near their homes. Then they dry the plants for later use. Some spices can even be grown in a house if they are placed in sunny areas next to windows.
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.
Herbs and spices are commonly used because they can make food taste better. Several years ago, two American researchers reported another reason for spice use in cooking.
Researchers Paul Sherman and Jennifer Billing worked at Cornell University when their study was published in nineteen ninety-eight. They said spices contain substances that kill or slow the growth of dangerous bacteria in food. Some spices 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.
A more recent study found that adding spices to meat before cooking at high temperatures may reduce harmful chemicals. Researchers from Kansas State University reported last year on their experiments with steaks.
The researchers 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.
Research on HCAs has made some people afraid to prepare meat on a grill – 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 KSU researchers placed some steaks in already prepared spice mixes, or marinades. The meat then was grilled for five minutes on each side at a temperature of more than two hundred degrees Celsius. 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. The study appeared in the publication Journal of Food Science.
The Mayo Clinic operates three medical centers in the United States. Its Health Letter publication of November two thousand seven provided more evidence that herbs and spices can aid health.
For example, 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 problems like high blood pressure.
The experts said some plant chemicals are high in antioxidants - substances that remove harmful chemicals from the body. These plants include allspice, cloves, cinnamon, ginger, oregano, sage, thyme and turmeric.
The experts also said antioxidants like garlic, rosemary, saffron and turmeric have qualities that could fight cancer. And, it said limited evidence shows that cinnamon, fenugreek and turmeric may affect blood sugar levels in people with diabetes.
Not all studies agree that spices could help diabetes patients. But some studies have suggested they could because of a suspected link between inflammation and diabetes. Inflammation is the body's way of reacting to infection or other attack. Cinnamon may help reduce the inflammation in people with diabetes.
Last year, researchers from the University of Georgia reported 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 clove had the most polyphenols. Cloves were the most effective at calming inflammation of any spice or herb they tested. Cinnamon was second. But KSU scientist James Hargrove noted that cinnamon gets more use in cooking than ground cloves. He said that means it could affect the health of more people. But the Mayo Clinic warns that cinnamon cannot replace proven medicines for diabetes.
Other studies also note possible health effects from curry, a seasoning or sauce. Many people like to use curry to sharpen the taste of foods like meat, fish, rice and potatoes.
Several years ago, scientists in Singapore investigated curcumin, from the curry spice turmeric. The scientists based their study on earlier evidence that turmeric has strong antioxidant and anti-inflammatory qualities. They said turmeric also 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 curry users, compared with people who did not use curry. For that reason, the researchers designed a study that examined results from a mental-performance test of older Asian adults. The people in the study 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 than individuals who rarely or never ate curry. The American Journal of Epidemiology published a report about the study. The writers suggested that more studies were needed.
Black cohosh is an herb that comes from the root or underground stems of a tall plant in the buttercup family. Black cohosh is sometimes called bugbane. American Indians used it for a number of women's health conditions, including monthly menstrual pain. Some women today have continued the tradition. They use the herb to help fight unpleasant conditions at the end of their reproductive years. These include difficulty sleeping at night and hot flashes, or sudden hot sweats.
Millions of people have used black cohosh without problems. However, the Office of Dietary Supplements of the National Institutes of Health notes that pregnant women may want to avoid it. The same is true of women with breast cancer and patients with liver problems. Should signs of liver disease develop, people should stop taking black cohosh and contact a doctor.
This SCIENCE IN THE NEWS program was written by Jerilyn Watson. Our producer was Brianna Blake.
I'm Faith Lapidus. And I'm Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.
Transcript of radio broadcast: 18 May 2009
