Monday, November 28, 2005

More on tea, those crazy free radicals.

Most people I know, hardened tea drinkers among them, do not realize that green tea and black tea both come from the same plant -- Camellia sinensis. The difference is how they're processed. Black tea is fermented, and green tea is not. Teas like Oolong are partially fermented. Fermentation means that the leaves are smacked around a bit to bruise the cell walls, laid out to oxidize -- then dried later. The oxidation of the plant compounds changes the color and flavor of the tea considerably. This is why green tea, which is not oxidized, contains more antioxidants.

Whether green or black, to prepare the tea so that it tastes best, boil water, then let the water rest for a few minutes before adding the bag. The water should not be at boiling temperature (212 degrees F), but a bit lower (180 degrees F). A couple of minutes should do it.

Not so rooibos. You can put the bag right in when it's hot as heck, even boil the tea for a while and because it's different chemically it won't taste bad (just stronger).

Rooibos tea is processed in a similar manner as traditional tea - the fermented rooibos is very red, has a fruity flavor, and has less antioxidants than green, or unfermented Rooibos. (I prefer the green over the red for taste alone -- it is remarkably mild and very similar to green tea without the astringency. Astringency is that part of tea that makes you pucker slightly (or more than slightly if you overbrewed) and makes your mouth feel dry.

I've been testing the green rooibos, steeped or boiled for 10 minutes. The boiled has the highest antioxidant activity.

A bit on tea and cancer.

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Most people have heard of free radicals. Free radicals are formed when oxygen reacts with a normally stable molecule, making it unstable. To stabilize itself, it steals electrons from other formerly stable molecules and so on, until something puts a stop to it. So what the fuck does that mean?

Okay. Picture 10 fine fellows holding up a heavy glass ball. Along comes some bastard with only one shoe, and seeing that fellow #1 has a match to his own, he runs over, unties the damn thing and tears it off. Fellow #1 struggles to keep his footing, but the glass ball remains intact. But now he has only 1 shoe. And the floor is cold. So he lets go of the ball and steals the next fellow's shoe. All this activity upsets the ball, and it bangs against a wall and sustains a small crack. Now stuff can get in the ball, but it's still a ball. Fellow #1 goes back to holding the ball, but now fellow #2 is now stealing from the third guy, and so on. It upsets the balance. If two guys both simultaneously have shoes stolen, the ball topples and breaks.

And this is like a cell. Cell cracking = cell damage. Now a carcinogen has easier access to your genetic material -- your DNA.. Cell breaking = cell death, and you know, that can't be good.

An antioxidant is a fine fellow wearing two shoes and carrying a third. He runs up to Fellow #1, puts the extra shoe on his foot, laces it up and no one knows the better for it.

We make some antioxidants in our bodies, like superoxide dismutase, and we eat some, like Vitamin C, E and beta carotene, the precursor to Vitamin A. But like I said, as we age, we can use a bit of help. Like most things, it should be noted that oxidation is a balance. We need oxygen, and we even need some reactive oxygen species, because ironically, our immune system uses them to destroy bacteria. But not too much, or the good stuff goes too. If a cell is compromised enough, the free radicals mess with your DNA, the mutation survives, and cancer or other awful crap begins.

So...drink your tea. Eat your greens. And be nice. It couldn't hurt, especially around this time of year. Back with more gripping food smack in a bit.

Saturday, November 26, 2005

Rooibos Tea

I'm working on exiting school before my toddler begins. For my master's thesis, I'm researching rooibos tea. Specifically, I'm measuring the antioxidant activity of rooibos tea.

Rooibos tea is a little shrub that grows in one particular spot on Earth: Cedarberg, South Africa. It's a needly little guy with a very long taproot so that it can bake in the South African sun while gathering up the rare water. South Africans have been drinking the stuff for well over a century, but here in the U.S. I'd only heard of it about 4 years ago. (Now you can find it in Krogers/Ralph's, Whole Foods, Wild Oats, Trader Joe's, etc.)
Rooibos has a sweet taste, is caffeine free and low in tannins. It's an herbal tea (from Aspalathus linearis), whereas black, green and oolong teas are from a different plant (Camellia sinensis). More on teas and the fermentation that makes them next time, if I remember...

Now, all fruits and vegetables, as well as teas contain phytochemicals. The term refers to plant substances that affect humans (beyond being a carbohydrate, protein or fat). Many of these phytochemicals protect the plant. Among them are a group of compounds called polyphenols, and among those are some called flavonoids. Those are what I'm studying. They have antioxidant activity that, during the lifetime of the plant protects the leaves from sun damage and oxidation that could kill the plant. Our bodies have similar mechanisms designed to ward off the oxidative products of our own metabolism, and the oxidative effects of our environment (like pollution). As we age, our natural mechanisms work less efficiently and eventually we succumb to disease. The protection conferred by flavonoids to the plant often translates to antioxidant activity that might well protect us, and that's why it's being studied.

This is getting long so I'll explain oxidation in more detail later (it's a real page-turner!). What's important: oxidation is believed to cause aging and contribute to cancer, heart disease and possible Alzheimer's, Parkinson's and a host of other diseases that do us in. Also important: before you start megadosing on antioxidants, know that many antioxidants, when inhaled like candy on Halloween night (as pills or potions), perform as PRO OXIDANTS.

Next time: what the hell makes green tea green and black tea black and what the hell difference it makes, and if you're oh so lucky, some blathering on how oxidation works.