Epigallocatechin gallate (EGCG) is a potent plant compound belonging to the catechin family, a subset of polyphenols. This naturally occurring substance is widely recognized for its powerful antioxidant properties, helping protect the body’s cells from damage caused by free radicals. EGCG is the most abundant and well-studied catechin, making it a primary focus when examining the benefits associated with consuming certain plant-based foods and beverages. Identifying dietary sources high in EGCG is the first step toward incorporating this beneficial compound into a daily diet.
Green Tea: The Primary Source of EGCG
Green tea, derived from the leaves of the Camellia sinensis plant, stands out as the single richest and most concentrated source of EGCG in the human diet. Unlike black or oolong tea, green tea leaves are not subjected to an extensive oxidation (fermentation) process, which preserves the EGCG content. A typical 8-ounce cup of optimally brewed green tea can contain a wide range of EGCG, often falling between 50 and 120 milligrams, depending on the specific preparation.
The EGCG content varies significantly across different tea types based on processing. Black tea, which is fully oxidized, contains substantially less EGCG—often nine times lower than green tea—because catechins are converted into compounds like theaflavins and thearubigins. White tea, which is minimally processed, generally retains high EGCG levels, placing it second to green tea in concentration.
Matcha, a Japanese green tea, represents a particularly potent source because the entire tea leaf is ground into a fine powder and consumed, rather than just the infusion. Consuming the whole leaf means a much higher total intake. A standard serving of Matcha (about two grams of powder) can easily provide over 100 milligrams of EGCG. The age of the leaf also plays a role, as the youngest leaves and buds contain higher concentrations of EGCG than older, more mature leaves.
EGCG in Other Common Foods
While green tea is the dominant source, EGCG is also found in measurable, albeit significantly lower, concentrations in a variety of other common plant foods. These sources contribute to the overall intake of beneficial catechins, providing a secondary route for consumption.
Cocoa, and subsequently dark chocolate with a high percentage of cocoa solids, contains EGCG along with other catechins like epicatechin. The total catechin content in dark chocolate is notable, though the specific EGCG fraction is small, and processing greatly influences the final amount. EGCG is also confirmed in various berries, particularly cranberries, which are recognized for their high polyphenol content.
Certain nuts also contribute EGCG to the diet, with pecans and pistachios being two examples that contain small, measurable amounts of the catechin. These food sources, while not providing the same EGCG load as green tea, are valuable because they offer a diverse profile of complementary antioxidants and nutrients.
Maximizing EGCG Retention and Absorption
To ensure the highest EGCG yield from green tea, proper preparation and consumption methods are essential. The temperature of the water used for brewing directly affects extraction, with higher temperatures (around 85–95°C) and steeping times of three to ten minutes maximizing the release of EGCG from the dried leaves. However, excessively long steeping can also increase bitterness, requiring a balance between flavor and catechin extraction.
EGCG is highly sensitive to degradation, making proper storage of the tea leaves crucial for retention. Exposure to oxygen and light accelerates the breakdown of the compound, so tea should be kept in opaque, airtight containers stored in a cool, dark place. The addition of a small amount of ascorbic acid, commonly found in citrus juices like lemon juice, can significantly enhance EGCG’s chemical stability and its subsequent absorption in the body.
The timing of consumption also dramatically impacts how much EGCG the body can absorb. Studies show that EGCG bioavailability is substantially inhibited when consumed with a meal, particularly one high in protein or iron. To maximize systemic uptake, it is most effective to drink EGCG-rich tea on an empty stomach or at least an hour away from main meals. This strategy minimizes binding interactions that prevent the catechin from entering the bloodstream.