Oyster Nut

Telfairia pedata is a vigorous perennial vine that climbs trees with the help of branched tendrils. It bears large, ridged gourd-like fruits that are large and hold many flattened seeds. The seeds are several centimetres across and covered by a thin shell that encloses a creamy-white kernel with an oily texture. The kernel tastes mild and nutty, similar to almond or Brazil nut when cooked, and the raw seeds are bitter. The plant is dioecious, with separate male and female plants.

Oyster nut is native to the coastal forests and woodlands of East Africa, mainly Tanzania, Kenya and Mozambique, including the island of Zanzibar. It has been introduced elsewhere in the tropics as a garden crop. The vine grows in warm, humid areas and is usually propagated from seed. Fruits are collected when ripe and split open, and the seeds are washed, dried and cracked for their kernels. Because the plant takes several years to begin bearing, it is mostly a local and garden crop.

The oyster nut has long been a traditional food in East Africa, where the kernels are eaten and the oil is pressed for cooking and for use in soap and lamp fuel. The vine was brought to the attention of European botanists in the nineteenth century, partly through collection on the island of Zanzibar, which gave rise to the name Zanzibar oilvine.

Interest in the plant as a crop has remained modest, but it is described in surveys of underused African food plants. A related species, Telfairia occidentalis or fluted pumpkin, is far more widely grown for its leaves and seeds in West Africa. Oyster nut is still harvested and eaten locally and has been proposed as a tree-climbing crop for agroforestry, though development remains limited.

The seeds are boiled or roasted and the kernels are eaten as a snack or crushed to extract oil for cooking. In East Africa the seed is also used in soups and sauces as a thickener and a source of fat. Seed kernels may be ground into a paste or flour to enrich porridges. The oil is mild and used in food and in soap-making. The young shoots and leaves of the vine are sometimes eaten as a vegetable as well, although the seeds are the main product. Raw seeds should be cooked before eating, since they have a bitter taste.

Oyster nut kernels are high in fat, including a good proportion of unsaturated fatty acids, and contain protein and minerals. They are a useful, calorie-dense traditional food in the regions where they grow. Reliable composition data are limited, and the values shown are approximate. Evidence about specific health effects in people is lacking, so they are best viewed as a nutritious local food rather than a health supplement.