...But maybe you should watch the tea.... but maybe you should watch the tea Many studies have shown that drinking tea can inhibit absorption of important dietary minerals dietary mineral Minerals required for optimal functioning of the body; dietary requirements for minerals range from molar to trace amounts/day; some–eg, nickel, tin, and vanadium, may be required by some plants or animals, but are not known to have a role in humans such as iron. Now researchers at the University of Wisconsin in Madison have begun identifying chemical clues to what might be happening, as well as possible ways to temper tea's adverse effects on nutrition. They focused on the solubility solubility Degree to which a substance dissolves in a solvent to make a solution (usually expressed as grams of solute per litre of solvent). Solubility of one fluid (liquid or gas) in another may be complete (totally miscible; e.g. of iron and calcium in brews of black, green, oolong oo·long n. A dark Chinese tea that has been partially fermented before drying. [Chinese (Mandarin) w and instant (black) teas. The reason, explains Lauren Jackson Lauren Elizabeth Jackson (born 11 May 1981 in Albury, New South Wales, Australia) is an Australian professional basketball player. She is often called LJ, Loz, or Lozza. She is a forward/centre with the Seattle Storm of the WNBA, the Australian national team The Opals and, until , one of the researchers, is because "in general any mineral is going to be more bioavailable if it's soluble." The data she and colleague Ken Lee report in the January/February Journal of Food Science show that iron was totally soluble in instant tea, but only 85 percent soluble in green and oolong, and just 69 percent soluble in regular black tea. Tea's effects on calcium were even more pronounced. Calcium was most soluble--88 percent--in oolong, 66 percent soluble in black, 46 percent soluble in green and only 35 percent soluble in instant teas. In an effort to identify what might be happening, the pair added either the enzyme tannase or lemon juice to each of the brews. Tannase, which had an effect on only black tea, increased iron solubility 17 percent and calcium solubility 11 percent. This suggests, Jackson says, that one reason for the minerals' initial insolubility in·sol·u·ble adj. 1. That cannot be dissolved: insoluble matter. 2. Difficult or impossible to solve or explain; insolvable: insoluble riddles. was their binding to some of the large polyphenolic molecules that tannase eventually broke down. Lemon juice increased calcium's solubility even more in two of the teas--24 percent in black and 15 percent in green tea. It also increased iron's solubility 7 percent in black tea. The researchers speculate that one or more of the juice's organic acids are responsible. Jackson and Lee believe their findings suggest the prospect of reducing some teas' detrimental effects on mineral bioavailability bioavailability /bio·avail·a·bil·i·ty/ (bi?o-ah-val?ah-bil´i-te) the degree to which a drug or other substance becomes available to the target tissue after administration. bi·o·a·vail·a·bil·i·ty n. , perhaps with something like a tannase pretreatment pretreatment, n the protocols required before beginning therapy, usually of a diagnostic nature; before treatment. pretreatment estimate, n See predetermination. . And for the calcium-conscious tea drinker, a wedge of lemon perhaps? |
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