Antioxidant Components of Tea: Polyphenols and Catechins
You've probably heard about antioxidants in tea , the positive effects of polyphenols and catechins , or ECGC (epigallocatechin gallate), but you probably don't know what they really are or how they work.
So you don't have to study medicine or chemistry to understand the beneficial properties of tea for your health, we've put together this short guide.
What are antioxidants?
Antioxidants are molecules that have the ability to fight free radicals present in your body. Free radicals are compounds that can cause cellular damage if their concentrations are too high. Free radicals have been linked to multiple diseases , including diabetes, heart failure, certain types of cancer, and premature aging.
Our bodies have their own antioxidants that keep free radicals at bay, but eating a diet rich in antioxidants can help keep us healthy.
How do free radicals work?
Free radicals are constantly forming in your body. Without antioxidants, free radicals would cause serious damage to our cells very quickly.
Free radicals also have a role to play in our bodies, as our immune cells use them to fight infections . For this reason, there needs to be a certain balance between free radicals and the antioxidants present in our bodies.
When free radicals outnumber antioxidants, a state called oxidative stress occurs. Prolonged oxidative stress can damage our DNA and other important molecules in our bodies. These factors can promote excessive free radical formation:
- Breathing polluted air.
- Smoke.
- Drink alcohol.
- High blood sugar levels.
- High-fat diets.
- Solar radiation.
- Viral and bacterial infections.
- Excessive or prolonged exercise.
Antioxidants in food
Antioxidants are essential for the survival of all living beings. The human body, for example, produces the cellular antioxidant glutathione .
Plants and animals also have their own antioxidant components to combat free radicals. Thus, many foods of plant and animal origin contain antioxidants, but the foods with the highest concentration and variety of antioxidant components are those of plant origin.
Blueberries, grapes, green tea, coffee, and chocolate are known for being great sources of antioxidants.
Antioxidants in tea
Tea, especially green tea, white tea , and black tea , is highly antioxidant . The antioxidant content of tea varies greatly, depending on the cultivation method and production process . As a general rule, black tea contains fewer antioxidants than green tea. Since green tea is not oxidized, it preserves its original molecules. Among green teas, Japanese matcha tea and Dragon Well or Lung Ching tea are by far the highest in antioxidants.
What are polyphenols?
Polyphenols are micronutrients found primarily in plant foods. They are naturally occurring chemicals, and scientists have documented more than 500 varieties. Polyphenols are characterized by their chemical composition of phenols and hydroxyl groups of acids.
Polyphenols give plants their characteristic colors and also help defend against disease and infection. They can be found in many different types of foods, as well as in supplement form. The polyphenol content of plants varies widely. Polyphenols have been linked to a number of health benefits thanks to their antioxidant power. Polyphenols and their subsets, such as tannins, are credited with boosting the immune system and scavenging free radicals.
Polyphenols in foods
There are many food sources you can use to add polyphenols to your diet. Most vegetables, fruits, and teas are packed with polyphenols that can improve your health. Within polyphenols, there are four main subgroups:
- Flavonoids: These polyphenols are found mainly in dark chocolate, fruit, legumes, red wine and green tea.
- Phenols: These are found in tea , coffee, and fruits like kiwi, apples, and cherries. These types of polyphenols are easily absorbed by the body, making them a great source of antioxidants.
- Lignans: Found mainly in cereals, algae, and seeds. Some of the richest sources of these compounds are olive oil, grape seeds, and sesame seeds.
- Stilbenes: They're not commonly found in foods. But grapes and red wine have a high concentration of these polyphenols.
What are tea catechins?
Catechins are natural polyphenols belonging to the flavonoid subgroup, also known as flavan-3-ols. The most important sources of catechins are tea and fruits such as apples and pears.
Not all teas contain the same amount of catechins, with green tea and matcha tea containing the highest levels. Green tea leaves from the Camellia sinensis plant are less processed and still maintain a high concentration of catechins and other antioxidant compounds.
Green tea contains high concentrations of four main types of catechins. The catechins in green tea are epigallocatechin gallate (EGCG), epicatechin (EC), epicatechin gallate (ECg), and gallocatechin (GC). Some of these catechins, including EGCG, are found only in tea. On average, catechins account for about 25% of the composition of green tea leaves.
EGCG or epigallocatechin gallate
EGCG, or epicalocatechin gallate, is the catechin most responsible for the health-promoting properties associated with green tea, such as its powerful antioxidant properties . Other health benefits of this tea catechin include:
- Anti-inflammatory effect.
- Helps in weight loss.
- Protects heart health.
- Protects the brain.
MORE ABOUT THE WORLD OF TEA
Tea for Beginners: Which to Choose and How to Prepare It >>
Sources
- Frédéric N Daussin, Elsa Heyman, Yan Burelle, Effects of (−)-epicatechin on mitochondria , Nutrition Reviews , Volume 79, Issue 1, January 2021, Pages 25–41.
- Christopher Masterjohn, Richard S Bruno, Therapeutic potential of green tea in nonalcoholic fatty liver disease , Nutrition Reviews , Volume 70, Issue 1, 1 January 2012, Pages 41–56.
- Susan B. Moyers, Ph D., MPH, Nagi B. Kumar, Ph D, Green Tea Polyphenols and Cancer Chemoprevention: Multiple Mechanisms and Endpoints for Phase II Trials , Nutrition Reviews , Volume 62, Issue 5, May 2004, Pages 204–211.
- Arpita Basu, PhD, Edralin A. Lucas, PhD, Mechanisms and Effects of Green Tea on Cardiovascular Health , Nutrition Reviews , Volume 65, Issue 8, August 2007, Pages 361–375.
- Catechin and Storage of Ascorbic Acid , Nutrition Reviews , Volume 6, Issue 11, November 1948, Pages 324–325.
- Jaime L. Clark, Peter Zahradka, Carla G. Taylor, Efficacy of flavonoids in the management of high blood pressure , Nutrition Reviews , Volume 73, Issue 12, December 2015, Pages 799–822.
- Roghayeh Ilghami, Abolfazl Barzegari, Mohammad Reza Mashayekhi, Didier Letourneur, Michel Crepin, Graciela Pavon-Djavid, The conundrum of dietary antioxidants in cancer chemotherapy , Nutrition Reviews , Volume 78, Issue 1, January 2020, Pages 65–76
- Matthew J. Picklo, Eric K. Long, Emilie E. Vomhof-DeKrey, Glutathionyl systems and metabolic dysfunction in obesity , Nutrition Reviews , Volume 73, Issue 12, December 2015, Pages 858–868.
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