Beans are one of the longest-cultivated plants. Currently, the world genebanks hold about 40,000 bean varieties, although only a fraction are mass-produced for regular consumption. Beans have significant amounts of fiber and soluble fiber, with one cup of cooked beans providing between nine and 13 grams of fiber. Soluble fiber can help lower blood cholesterol. Beans are also high in protein, complex carbohydrates[disambiguation needed], folate, and iron.