Lima bean

The lima bean is a climbing or bushy annual legume with trifoliate leaves and small pale flowers. The pods are broad and slightly curved, like a crescent moon, and hold two to four plump seeds. Seeds vary from small and pale green or white (baby limas, sieva types) to large, flat, cream or speckled seeds of up to 3 centimetres, with colours that include red, purple and black in traditional types. The flavour is mild, starchy and rather buttery, which is why white-seeded forms are called butter beans, and the texture is soft and floury when well cooked. They are sold fresh in the pod, frozen, dried, and canned.

Two separate gene pools of lima bean exist: a large-seeded Andean group domesticated in the Peruvian region, perhaps more than 5,000 years ago, and a small-seeded Mesoamerican group domesticated in Mexico and Central America. The beans were spread across the Americas by traders and later carried to Europe, Africa and Asia by Spanish and Portuguese ships. The species name lunatus means moon-shaped, referring to the crescent pods. The common name comes from Lima, the capital of Peru, which was a major port from which the beans were shipped to Europe.

Archaeological finds in Peru, including at sites on the coast, show lima beans in diets and burial offerings for thousands of years. Lima beans were one of the three companion crops of pre-Columbian agriculture in some regions, planted beside maize and squash for mutual benefit.

After European contact, the Spanish took lima beans to Europe, the Philippines and West Africa. In North America, lima beans became a favorite of colonial and nineteenth-century gardens, and the Native American dish succotash combined lima beans with corn. In the southern United States, butter beans cooked with ham hocks became a cornerstone of regional cooking. Commercial production grew in California and Delaware during the twentieth century.

In Madagascar and Burma, lima beans became important food and export crops, giving rise to the names Madagascar bean and Burma bean. A key safety history is that some wild and coloured forms contain high levels of cyanogenic compounds, and farmers and regulators in many countries set limits for cyanide content in marketed varieties after poisonings were recorded.

Fresh lima beans are boiled or steamed and served as a vegetable, mixed into succotash, or added to soups and stews. Dried butter beans are soaked and simmered for casseroles, baked bean dishes, curries and Mediterranean salads with olive oil and herbs. In Peru, pallares are eaten in stews and as a side dish, and a traditional dish involves toasting. Canned lima beans are a pantry staple, and the mashed beans are used in dips similar to hummus. They are also grown as a cover crop and for green manure because they add nitrogen to the soil.

Lima beans are a good source of fibre, plant protein, folate, iron, magnesium and potassium and are low in fat. Their soluble fibre and slowly digested starch contribute to a low glycaemic response, and diets rich in pulses are linked to better cholesterol and heart health in population studies. As with other legumes, they can help increase fullness. They also provide molybdenum, which supports certain enzymes. Their benefits are best seen as part of an overall diet that includes many different plant foods.