Everyone has heard of it, but what is tamarind? It comes from a tree originally native to Africa, though today it is primarily grown in India where it is an essential spice used in many dishes. Its tart taste balances well in many curry recipes and lentil stews.
The spice itself is actually a legume, found in the pod-like fruits which hang from the tamarind tree. While the dried powder form is most convenient, the fruit inside can also be eaten fresh. Given its strong flavor, you don't need much to spice up your sauces and chutneys.
How much antioxidants there are in tamarind would be considered high for a fruit, but somewhat low for a spice, simply because with spices you use such small quantities at any given time.
Other health benefits include being a good source of iron, magnesium, potassium, and thiamine. It can act as a natural laxative, thanks to its high dietary fiber content.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH Jan 2010