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Skip Milk in Black Tea, Boost Antioxidant Power
< Jan. 10, 2007 > -- Those who like milk in their hot tea may want to consider leaving it off in order to get more health benefits.
Several studies have suggested that tea is beneficial in terms of heart health, but new research has found that adding milk may negate those benefits. The effect is similar to the way milk in chocolate reduces antioxidants found in dark chocolate.
Proteins called caseins interact with tea, decreasing the phytochemicals, which are responsible for tea's protective effects against heart disease, according to the study authors. The study findings were published in the European Heart Journal.
"There are a lot of studies that show that tea is protective against cardiac diseases," says lead researcher Dr. Verena Stangl, professor of cardiology at the Charite Hospital, Universitatsmedizin-Berlin, in Germany.
"If you look at the studies, you see that in Asia there are less cardiac diseases, but in England that's not the case. So the question is, is the addition of milk a reason for this difference between Asia and England, where tea is often taken with milk?" she says.
In the study, 16 healthy postmenopausal women drank either half a liter of freshly brewed black tea, black tea with 10 percent skimmed milk, or boiled water on three different occasions under similar conditions. The researchers then measured the function of the cells lining the brachial artery in the forearm, using high resolution ultrasound before and two hours after tea consumption.
Dr. Stangl's team found that black tea significantly improved the ability of the arteries to relax and expand. "But when we added milk, we found the biological effect of tea was completely abolished," she says.
Dr. Stangl notes that not only does milk block tea's benefits for blood vessels, it also destroys the antioxidant effects of tea and perhaps its cancer-protective effects as well.
She says her team is also comparing the effects of green and black tea on the function of blood vessels. "It's a question whether green tea, with its higher flavenoid [phytochemical] content, is better than black tea in regard to endothelial function [blood vessel elasticity]," she says.
One expert agrees that you should hold the milk when drinking tea. "This is actually something we tell patients to do - not to have milk in tea," says Dr. Robert Vogel, a professor of medicine at the University of Maryland Medical School.
Tea is one of the greatest sources of antioxidants, Dr. Vogel says. "In countries where they drink a lot of tea, heart disease is decreased, except for the British Isles. It is typical in Great Britain to add milk."
Dr. Vogel's advice is simple. "Add lemon not milk. You should not add milk or cream to tea - it's a very good drink, but not with milk," he says.
Always consult your physician for more information.
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According to the National Cancer Institute (NCI), antioxidants are substances that inhibit oxidation and protect cells from free radicals, which may lead to cancer.
Free radicals are the by-products of the body’s normal chemical processes, but they attack healthy cells, allowing tumors to grow.
Research is underway to investigate the role of antioxidants in decreasing the risk of developing cancer.
Phytochemicals are chemicals found in plants that protect plants against bacteria, viruses, and fungi. Eating large amounts of brightly colored fruits and vegetables and other plants such as tea, which contain phytochemicals, may decrease the risk of developing certain cancers and heart disease.
According to the National Institutes of Health (NIH), black tea is made from the dried leaves of Camellia sinensis, an evergreen shrub. Green tea, black tea, and oolong tea are all derived from the same plant.
The action of phytochemicals varies by color and type of food. Phytochemicals may act as antioxidants or preserve nutrients. They may also prevent carcinogens (cancer causing agents) from forming.
Researchers are discovering that eating fruits, vegetables, and cereal grains may halt development of cancers of the gastrointestinal tract and prostate gland. Many study results are preliminary, but new findings add to the scientific knowledge base each day.
Always consult your physician for more information.
(Our Organization is not responsible for the content of Internet sites.)
American Dietetic Association (ADA)
American Heart Association (AHA)
Centers for Disease Control and Prevention (CDC)
European Heart Journal
National Cancer Institute (NCI)
National Center for Complementary and Alternative Medicine (NCCAM)
National Institutes of Health (NIH)
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