Organic soya beans (Glycine max). These are one of the very best dietary sources of protein, and have been cultivated for over 3000 years. They are also a good source of most of the B-complex vitamins, and the essential minerals iron and potassium. They can be prepared in a variety of ways, including tofu, which is a curd used as an alternative to meat. Organic farming methods aim to minimise the use of synthetic materials.