Assessment of Levels of Nutrients in Selected ALVs at Different Harvesting Stages and Locations of Production in Western Kenya

Proper nutrition contributes to declines under-five mortality rates and improves the productivity of adults. Addressing nutritional problems requires adequate information on the diets of individuals and populations. African leafy vegetables (ALVs) are widely consumed and often harvested at different stages after planting with the help of different communities. Four ALVs namely Vigna unguiculata, Amaranthus hybridus, Cleome gynandra and Solanum scabrum are commonly grown vegetables in western Kenya, their potentials have not been evaluated to supply the nutrients. However, nutritional values may vary depending on the species, harvesting stage and location of production. The effects of species, harvesting stages and location of production on the nutritional value of selected ALVs were evaluated. The trials were laid out in a randomized complete block design in three replicates in Busia, Kisumu, and Lela. Leaves were sampled at different harvesting stages and analyzed for N, P, K, Na, Ca, Mg, Mn, Fe, and Zn levels. Amaranthus hybridus had significantly (P≤0.05) higher levels of P, Ca, Zn, Mn, and Na. The N, P, K, Ca, Mg, Zn and Fe levels significantly (P≤0.05) increased then decreased with harvesting stage. The levels of nutrients significantly (P≤0.05) varied with location of production except for Na. The ALVs from Kisumu site had significantly (P≤0.05) higher levels of N, P, K, Ca, Mg and Zn, ALVs from Lela site had higher levels of Mn and Na while ALVs from Busia site had higher levels of Fe. Amaranthus hybridus is a better contributor of-of P, Ca, Zn, Mn, and Na. The Fe, Mg and Zn levels were above the Recommended Dietary Allowance and may be used to alleviate deficiencies associated with such nutrients. Harvesting the ALVs at the stage the nutrients attain their optimum levels is recommended. There is a need for the development of regional food composition tables for all ALVs in Kenya.