Nutritional value and utilization of indigenous vegetables in Kenya

Lucy Mathenge
KENGO, Nairobi, Kenya

Introduction

Conservation and sustainable use of the genetic resources of indigenous food crops offer a tremendous tool for addressing the problem of food security - meaning both inadequate quality and quantity - at both national and household levels. The food base for the rural population, especially in the marginal and semi-arid areas, has become narrower, leaving communities more vulnerable to food shortages and nutrient-deficiency diseases. Wild and weedy species, commonly used as vegetables in the past, are disappearing as a result of changes in customs and land use. Local knowledge about the cultivation and management of these species is on the decline as well. At the same time, producers lack knowledge of more efficient, intensive production and management techniques. There is also a lack of knowledge about nutritive value and cooking methods that minimize nutrient leaching during food preparation.

To respond to concern about the lack of integration of indigenous food crops in the national food system, KENGO (Kenya Environment Non-Governmental Organization) has been working over the past several years to develop a network in Kenya to stimulate, encourage and facilitate research and information-sharing among scientists, farmers and the public at large. With other NGOs, KENGO has embarked on community campaigns to promote the use of indigenous vegetables, and hence their production, by carrying out research on nutritive value, agronomy and product development, in particular focusing on the role of vegetables in alleviating malnutrition among certain vulnerable groups in the community.

Utilization

KENGO has concentrated on the indigenous vegetables most commonly used by the local communities in Western and Coast provinces of Kenya. These are:

· Solanum nigrum
· Gynandropsis gynandra
· Amaranthus sp.
· Vigna unguiculata
· Crotalaria brevidens
· Corchorus olitorius
· Asystasia shimperi
· Basella alba
· Brassica carinata
· Cucurbitaceae spp.

Indigenous vegetables are also commercialized as fresh leaves, in dried or powdered form and as enriched food flavours (e.g. weaning flour). There is some trade in these species in both rural and urban areas in Kenya, but this is very limited. In part, this is because of the lack of public awareness of their superior nutritive quality. However, they fetch a higher price than exotic vegetables on the urban and rural markets. This implies that they offer potential to entrepreneurs in the 'jua kali' (informal) sector. There are other constraints to use, as listed below.

Taste. In many communities, indigenous vegetables are eaten for their bitterness, just as pepper is taken for its 'hot' taste. However, some people find this bitter taste unpleasant and reduce it by blending with other, blander vegetables such as cabbage.

Yield. Some indigenous vegetables have poor foliage yield, e.g. Crotalaria brevidens. It is therefore often difficult for the women to collect enough leaves. Some of these poor leaf yielders have strong tastes and are used to spice food, especially exotic vegetables.

Availability. Production and consumption of indigenous vegetables is mainly confined to the rural areas, where small-scale farmers grow them in kitchen gardens or harvest them from the bush. Production is not sufficient to fulfil even limited demand in urban areas.

Nutritional value

Many people in Kenya are undernourished, especially children being weaned and pregnant and lactating mothers, and nutrient-deficiency diseases such as night blindness, scurvy and rickets are common in rural areas and slums. To counter these nutritional problems, it is important that the most commonly consumed foods should be nutritious. Since vegetables are consumed frequently and in large quantities, those which provide most of the required nutrients should be favoured. However, common vegetables such as cabbage are nutritionally poor on cooking compared with indigenous vegetables like Gynandropsis gynandra.

Nutritional studies have been done on the priority indigenous vegetables, including mineral analysis, effects of cooking and blanching on vitamins A and C, analysis for oxalates, and the effect of sun-drying on vitamins A and C.

Seed bulking for these species is ongoing and the harvested seed is processed, packaged and distributed to farmers. This is done at the KENGO/JKUAT (Jomo Kenyatta University of Agriculture and Technology) research project in Juja. There is a KENGO community-based project on weaning foods in Bungoma district, where sun-dried indigenous vegetables are incorporated into porridge flour. Porridge is the most commonly used weaning food, and the addition of indigenous vegetables adds important vitamins and minerals.