Inca Peanut

Inca peanut grows on a perennial, semi-woody climbing vine with heart-shaped leaves and small greenish flowers. Its fruit is a distinctive capsule with four to seven pointed lobes, giving it the look of a green star that turns brown and woody as it dries. Each lobe holds one flat, oval seed about the size of a large coin, with a dark brown, slightly mottled shell and a pale, soft kernel inside.

Roasted kernels taste like a cross between peanut and sunflower seed, with a faint green, grassy edge that some people describe as similar to flax. The texture is tender and slightly waxy rather than crunchy like a true peanut.

On the market the seed appears as shelled roasted kernels, flavored snack seeds, protein powder made from the pressed cake, and cold-pressed oil sold in small dark bottles.

Inca peanut is native to the Peruvian Amazon and neighboring humid tropical parts of South America, where it grows from lowland forest up into the foothills of the Andes. It was cultivated by Indigenous communities long before European contact, and pottery from ancient Peruvian cultures is often cited as showing the unmistakable star-shaped capsule.

The common name sacha inchi is usually explained as coming from Quechua, with sacha meaning forest or wild and inchik referring to a peanut-like seed, so the whole name can be read as forest peanut. The English name Inca peanut and the Spanish sacha maní reflect the same idea.

The plant belongs to the spurge family, which also includes cassava, castor and rubber, and the species name volubilis refers to its twining, climbing habit.

For Amazonian peoples the seeds were a traditional food, roasted and eaten as a snack or ground into sauces, and the oil was used in cooking and as a skin application. Because the plant lived at the edge of the world of staple crops, it remained a regional food for most of recorded history and was little known outside Peru and nearby countries.

Interest outside South America grew in the late twentieth and early twenty-first centuries when analyses showed that the seeds contain an oil with an unusually large share of omega-3 fatty acid, at a level comparable to or higher than most other common seed oils. Peruvian growers and cooperatives began to plant it in the San Martin region and other lowland areas, and the crop was promoted as an alternative to coca and as a way to give small farmers a high-value export.

The seed then spread into cultivation in Thailand, Vietnam, Cambodia, Laos and parts of China, as well as other tropical regions, because the vine fits well with agroforestry and trellis systems. Sacha inchi oil and roasted seeds are now sold as health foods in North America, Europe and Asia, and the oil is also used in cosmetics. Researchers continue to study varieties and the plant's wild relatives in the Plukenetia genus.

The most common use is as a snack: raw seeds are always roasted first, then eaten plain, salted or flavored. Roasted kernels can be chopped into granola, trail mix, salads and baked goods, and the pressed cake is milled into a protein powder used in shakes and bars.

The cold-pressed oil is used as a finishing oil on salads and cooked vegetables. It is low in heat stability because of its high polyunsaturated fat content, so it is not suited to frying. In traditional Amazonian practice the oil also served as a topical skin treatment, and today it appears in lotions and hair products.

The young leaves of some related plants are cooked as a green, but the seed and its oil remain the main commercial product.

The oil is a notable plant source of alpha-linolenic acid, an omega-3 fatty acid that the body can partly convert to longer-chain forms, and the seeds also provide protein, fiber, vitamin E compounds and minerals. Small human studies on blood lipids and inflammation markers have been reported, but they are limited in size and duration, so the seeds are best viewed as a nutritious addition to a varied diet rather than a treatment for any condition. Conversion of plant omega-3 to the long-chain forms found in fish is modest.