ENCOURAGING CONSUMPTION OF SWEET POTATO LEAVES AS A VEGETABLE IN KENYAN URBAN AREAS

Abstract

Sweet potato leaves are a by-product of the plant and good source of nutrients. They are high in potassium, beta carotene, fiber, lutein and xanthine. In Kenya, kales, cabbages and other indigenous vegetables are the most consumed vegetables. This study is aimed at encouraging the consumption of sweet potato leaves as a vegetable in urban areas in Kenya. In Africa sweet potato leaves are popular in countries like Senegal, South Africa and Ghana. However, in Kenya and Uganda sweet potatoes are mostly grown only for its tubers. Very few communities which are based in the rural region consume the sweet potato leaves as vegetables. There is therefore need to encourage its consumption given its multiple nutritional and health benefits. Sweet potato leaves are high in Lutein and zeaxanthin (xanthophylls) which are said to have a number of benefits to the eye especially in the prevention of AMD (age-related macular degeneration) and cataracts. Lutein and zeaxanthin are the only carotenoids reported to be present in eye lens. They are widely distributed in tissues and are the principal carotenoids in the eye lens and macular region of the retina. Lutein has the ability to filter harmful short-wave blue light  and it is as an antioxidant which prevents oxidative damage to eye lens muscles which initiates age related cataracts. Xanthophylls may possess anti-mutagenic and anti-carcinogenic properties and play a role in the health of body tissues other than the eye as suggested by research studies related to carcinogenesis and the risk for cancer. Lutein has been identified to be one of three anti-mutagenic pigments present in vegetables. In humans, plasma lutein has been inversely associated with cytochrome CYP1A2 activity, a hepatic enzyme responsible for the metabolic activation of a number of putative human carcinogens. Intake of these xanthophylls may reduce the risk of certain major cancers like breast cancer, prostate cancer and lung cancer among others. A growing body of experimental evidence and observational studies suggest that lutein and zeaxanthin may play a role in the prevention of coronary heart disease and stroke. In a coculture model of the arterial wall, a study found lutein to be highly effective in reducing oxidation of low-density lipoproteins (LDL) and inhibiting the inflammatory response of monocytes to LDL trapped in the artery wall. This study is based on the general analysis of the nutritional qualities of the sweet potato leaves as demonstrated in previous research. Observations made in the vegetable market suggest the absence of the sweet potato leaves in the market. Urban area residents have either not heard or eaten these leaves, thus I recommend awareness of the nutritional benefits of the sweet potato leaves. This would help improve general health of the consumers through reduction of several vitamin-related deficiency diseases such as vitamin Adeficiency, cataracts and age-related macular disease (AMD) among other diseases.

A continuously growing body of evidence suggests that lutein and zeaxanthin will contribute to the protection against several age-related diseases, including cataract, AMD, heart disease, and some forms of cancer. Thus, there is a need of awareness of the sweet potato leaves. Given that the sweet potato thrives in semi-arid areas it would improve on food security and public health because vegetables like kales and cabbages require a lot of water for cultivation as compared to sweet potato which both the tubers and leaves are edible.