Broccoli is a member of the Brassica genus of vegetables, high in phytochemicals. Other members include bok choy, brussels sprouts, cabbage, kale, kohlrabi, mustard greens and turnips. Photo by Radek Bayek | SXC.
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An enzyme or other organic molecule that reduces the rate of particular oxidation reactions and can counteract the damaging effects of oxygen in tissues. Although the term technically applies to molecules reacting with oxygen, it is often applied to molecules that provide protection from any free radical (i.e., a molecule with an unpaired electron). While new foods seem to appear every day touting higher levels of antioxidants (the latest is the açaí berry from the rainforests of Brazil), the highest level of antioxidant foods generally found in supermarkets are, in order of strength: undutched cocoa powder; bittersweet chocolate (particularly that which has 85% or more in cocoa solids); white tea; green rooibos tea; green tea; red rooibos tea; oolong tea; and black tea.
Highbush blueberries. Photo courtesy U.S. Agricultural Research Service.
Some studies claim that the blueberry (especially wild blueberry, a.k.a. bilberry) contains more antioxidants than any other mainstream fruit or vegetable, when compared on the basis of equal calories. Others give the top award to Montmorency cherry juice—which does have more calories than blueberries, but is accessible year-round. Other fruits and berries that are high in antioxidants include the blackberry, raspberry, cranberry, cherry (especially the Montmorency, also known as the tart or sour cherry), dried plum (prune), dark grapes (including raisins, purple grape juice and red wine), crowberry (a North American berry that looks similar to a blueberry), kiwi, pomegranate, papaya (a source of vitamin E, lycopene and beta-carotene, three very powerful antioxidants), citrus fruit such as orange and grapefruit (the highest concentration of antioxidants are in the pulp, where the pectin is found); and leafy, dark green cruciferous vegetables (broccoli, brussels sprouts, cabbage, cauliflower, daikon radish, kale, kohlrabi, mustard/chard greens, parsnip, rutabaga, turnip and watercress). See the chart below for a more extensive list.
Biochemically, catechins are monomers (molecules that can be chemically bound as a unit of a polymer) of flavanol, a subclass of flavonoids, which are themselves a subclass of polyphenols. Catechins make up some 25% of the dry weight of a fresh tea leaf. The concentration of catechins is higher in green and white tea†; in black and oolong teas the oxidation process inactivates the catechins. Tea contains four main catechin substances: EC, EG, EGC and ECGC, all of which are inclusively called “catechin.” Epigallocatechin gallate (EGCG) is the one most abundant in tea. EGCG as an antioxidant is about 25 to 100 times more potent than the antioxidant vitamins C and E.
†White tea is substantially more expensive than green tea, and has a few more catechins per serving. Photo courtesy SXC.
(Tea flavor, color and astringency are in part due to the condensation of the catechins to form the bright orange-red pigment thalami.) Researchers believe that catechin is effective because it easily sticks to proteins, blocking bacteria from adhering to cell walls and disrupting their ability to destroy them. Viruses have hooks on their surfaces and can attach to cell walls. The catechin in green tea prevents viruses from adhering and causing harm. Catechin reacts with toxins created by harmful bacteria and harmful metals such as lead, mercury, chrome and cadmium.
Epigallocatechin gallate, a specific antioxidant compound found in green tea and elsewhere, is a key biological and biochemical driver for many health benefits, for reasons noted in the “Catechin” definition. It can reduce cancers and tumors, prevent cancer cells from growing, lower cholesterol, help digest excess fat and even protect against the common cold virus. Worldwide studies are ongoing and reports regularly discover new health benefits.