Buckwheat groats are commonly used in western Asia and eastern Europe. The porridge was common, and is often considered the definitive peasant dish. It is made from roasted groats that are cooked with broth to a texture similar to rice or bulgur. The dish was brought to America by Russian and Polish immigrants who called it "kasha" and mixed it with pasta or used it as a filling for knishes and blintzes, and hence buckwheat groats are most commonly called kasha in America. Groats were the most widely used form of buckwheat worldwide during the 20th century, with consumption primarily in Russia, Ukraine and Poland. The raw groats can also be sprouted and then eaten raw or cooked. Buckwheat contains no gluten and can thus be eaten by people with coeliac disease or gluten allergies.

The fruit is an achene, similar to sunflower seed, with a single seed inside a hard outer hull. Buckwheat contains no gluten and can thus be eaten by people with coeliac disease or gluten allergies. Many bread-like preparations have been developed. However, Buckwheat can be a potent and potentially fatal allergen by itself. In sensitive people, it provokes IgE-mediated anaphylaxis.

Buckwheat contains a glucoside named rutin, a medicinal chemical that strengthens capillary  walls, reducing hemorrhaging in people with high blood pressure and increasing microcirculation in people with chronic venous insufficiency.

Buckwheat contains D-chiro-inositol, a component of the secondary messenger pathway for insulin signal transduction found to be deficient in Type II diabetes and Polycystic ovary syndrome (PCOS). It is being studied for use in treating Type II diabetes. Research on D-chiro-inositol and PCOS has shown promising results.

A buckwheat protein has been found to bind cholesterol tightly. It is being studied for reducing plasma cholesterol in people with hyperlipidemia.

In recent years, buckwheat has been used as a substitute for other grain in gluten free beer. Although it is not a cereal, buckwheat can be used in the same way as barley to produce a malt  that can form the basis of a mash that will brew a beer without gliadin or hordein  (together gluten) and therefore can be suitable for coeliacs or others sensitive to certain glycoproteins.

Raw buckwheat groats have a nut-like flavor and are high in protein which makes them a perfect complement to hearty foods such as beef, roasted peppers, eggplant, cabbage and root vegetables. These groats can be used as a side dish alternative to rice, stuffing and potatoes.

Full Nutrition Facts

References
wikipedia.org

Recipes
ChowHound Blog on Uses for Buckwheat Flour
How to Use Buckwheat in Gluten-Free Recipes

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