Green tea is a type of tea made solely with the leaves of Camellia sinensis that has undergone minimal oxidation during processing. Green tea originates from China and has become associated with many cultures in Asia from Japan to the Middle East. Recently, it has become more widespread in the West, where black tea is traditionally consumed. Many varieties of green tea have been created in countries where it is grown. These varieties can differ substantially due to variable growing conditions, processing and harvesting time. Green tea leaves steeping in an uncovered gaiwanOver the last few decades green tea has been subjected to many scientific and medical studies to determine the extent of its long-purported health benefits, with some evidence suggesting regular green tea drinkers may have lower chances of heart disease and developing certain types of cancer. Green tea has also been claimed as useful for "weight loss management" - a claim with no scientific support according to medical databases such as PubMed. An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol or water. Extracts may be sold as tinctures or in powder form. The aromatic principles of many spices, nuts, herbs, fruits, etc., and some flowers, are marketed as extracts, among the best known of true extracts being almond, cinnamon, cloves, ginger, lemon, nutmeg, orange, peppermint, pistachio, rose, spearmint, vanilla, violet, and wintergreen.