People often tout green tea's health effects, including its ability to lower cholesterol. However, experts at the National Center for Complementary and Alternative Medicine say more research is needed before many of these benefits can be confirmed, including claims that tea lowers cholesterol, helps people lose weight and protects skin from sun damage or cancer. Meanwhile, researchers continue to investigate how and why green tea may lower your cholesterol levels --- and how effective it may be for this use. Always consult a health care provider before trying a new supplement, even one as common as green tea.
Significance
Because green tea is believed to lower blood levels of cholesterol and triglyceride, it may reduce your risk for cardiovascular disease, note S.I. Koo and S.K. Noh, authors of a study published in The Journal of Nutritional Biochemistry. With coronary artery disease, plaque builds up in your arteries. This plaque is made of cholesterol deposits. The build-up causes your arteries can narrow, which is called atherosclerosis. This can weaken your heart and can lead to heart failure. Heart disease is the top killer of Americans, according to the Centers for Disease Control. About 785,000 people in the United States had new coronary attacks in 2009, and an estimated 470,000 had recurrent attacks. To put this in perspective, about every 25 seconds someone in the United States has a coronary event, note the experts at the CDC.
Function
The main green tea constituents are called catechins. One of these, called epigallocatechin gallate, or EGCG, appears partly responsible for green tea's purported cholesterol-lowering abilities. EGCG may reduce your cholesterol by increasing low-density-lipoprotein, or "bad" cholesterol, receptor-binding activity. It also appears to lower cellular cholesterol synthesis, according to C.A. Bursill and P.D. Roach, authors for a study published in the Journal of Agricultural and Food Chemistry. However, the mechanism by which green tea lowers cholesterol and triglyceride levels is still being investigated, and it may work in more than one way. For example, it appears that the catechins in green tea inhibit intestinal absorption of dietary fats and cholesterol, lowering the amount you absorb, note Koo and Noh. Tea's antioxidant and anti-inflammatory properties may play a role, too.
Expert Insight
While medical experts aren't sure why green tea appears to lower bad cholesterol levels, some clinical studies on people do show that it is effective for this use, according to University of Maryland Medical Center. In fact, the tea may not only lower total cholesterol, but also raise the amount of high-density-lipoprotein, or "good" cholesterol, according to UMMC.
Considerations
In theory, drinking three cups of green tea a day may cut your rate of heart attack by up to 11 percent, according to UMMC. However, evidence for this benefit is not strong enough for tea makers to make health claims for this on tea labels, according to UMMC. In May 2006, the U.S. Food and Drug Administration rejected a teamakers' petition to allow tea labels to claim that green tea cuts heart disease risk. In September 2010, the FDA warned two green tea drink makers not to make unwarranted claims about green tea's health benefits, reports Andrew Zajac of the Los Angeles Times. One company linked green tea consumption to reduced cholesterol for people who are at risk for heart disease, Zajac reports.
Types
You don't necessarily have to brew and drink green tea if you want to use it for a possible cholesterol-lowering benefit. It also comes in capsule form, note the experts at the National Center for Complimentary and Alternative Medicine.
Warning
Green tea is generally considered to be safe when consumed in moderate amounts. However, reports of liver problems are linked to concentrated extracts, according to NCCAM. Green tea also can cause anxiety, insomnia, upset stomach or frequent urination in some people. It also can make anticoagulant drugs like warfarin less effective. The experts at NCCAM suggest discussing green tea use with your health care providers prior to trying it.
References
- PubMed.gov: "Journal of Agricultural and Food Chemistry"; Modulation of cholesterol metabolism by the green tea polyphenol (-)-epigallocatechin gallate in cultured human liver (HepG2) cells; C.A. Bursill and P.D. Roach; 2006
- "The Journal of Nutritional Biochemistry"; Green Tea as Inhibitor of the Intestinal Absorption of Lipids: Potential Mechanism for its Lipid-Lowering Effect; Sung I. Koo and Sang K. Noh; 2007
- Centers for Disease Control: Coronary Artery Disease
- Centers for Disease Control: February is American Heart Month
- Los Angeles Times: FDA warns green tea makers against health claims; Andrew Zajac; September 8, 2010
- University of Maryland Medical Center: Green Tea
