I’ve heard a lot about coffee, tea, and pomegranate juice being loaded with antioxidants. But coffee and tea don’t have any significant antioxidants listed on their labels, and pomegranate juice bottles claim only a small amount of antioxidants. Please explain this.
Maybe because they vary so widely between brands and such.
My labels just say ‘tea’ in the ingredients.
Tea has a relatively high level of flavonoids. The major type of flavonoid is catechin, which constitutes 30 to 40 percent of the soluble makeup of green tea, and about 10 percent of black tea.[sup1]1[/sup] A fruit-and-vegetable rich diet can provide up to 1,000 mg of flavonoids every day. Tea contains around 200-300 mg per cup.
There are four principal antioxidants in tea: Epigallocatechin gallate (EGCG), Epicatechin gallate (ECG), Epigallo catechin (EGC), and Epicatechin (EC).
You didn’t ask about caffeine, but drip coffee contains about 60-80 mg per cup. Black tea contains about 25-110 mg, Oolong tea 12-55 mg, and green tea 8-36 mg. Black tea is oxidised the most, and green tea the least. Oolong is in the middle.
Of course the amounts of antioxidants and caffeine in tea vary with they type of tea and how it is brewed.
I’m on my second cuppa tea. I’ll have two or three more before the morning is done.
[sup]1[/sup]Tea Basics, Wendy Rassmussen, Executive Director of the American Premium Tea Institute.
My morning tipple ranks right up there, too. 
But still nothing on the label about it.
Antioxidants aren’t part of the nutrition labeling laws. Any mention of them goes under the category of advertising.
Pomegranate juice needs a reason for people to buy it. Tea and coffee don’t. 
To expand a little on what Exapno Mapcase said, there is no established standard for how much anti-oxidant an adult needs in a day. So, even if they know exactly how much is in the stuff, there’s no reference point.
Remember when green tea was the new big antioxidant? Then it was blueberries, then pomegranates. Now the latest antioxidant craze is açai, a fruit from Brazil, which makes claims it’s higher in antioxidants than any of the others. I like açai juice, it’s strongly flavored but really good.
I’ve heard (no cite – just something ISTR) that the body naturally produces antioxidants, and that increasing antioxidant intake causes the body to reduce its output. So it might be a bit of a zero-sum game.
I’ve also heard that taking betacarotene supplements might increase the risk of cancer. (IIRC the studies that show this were studdying supplement pills, and not diets rich in betacarotene.)
Tea still has loads of antioxidants. So do fruits and vegetables. I don’t think it’s so much that one should eat or drink this or that; but that one should eat a healthy diet. This includes increasing the amount of vegetables – especially leafy green vegetables – fruits, legumes, using olive oil instead of hydrolysed oils, reducing the intake of meats and so forth. And of course regular exercise is an excellent way to maintain health. Note that I don’t practice what I preach. Maybe that will be a ‘New Year’s Resolution’.