Review Article Carbohydrates, proteins, fats and other essential components of food from native trees in West Africa Anne Mette Lykke a , Elie Antoine Padonou b, c, * a Department of Bioscience, Aarhus University, Vejlsøvej 25, DK 8600, Silkeborg, Denmark b School of Tropical Forestry, National University of Agriculture, BP 43, K etou, Benin c Faculty of Agronomic Sciences, University of Abomey-Calavi, Laboratory of Applied Ecology, 01 BP 526, Cotonou, Benin ARTICLE INFO Keywords: Agriculture Food science Food analysis Nutrition ABSTRACT Native tree foods contribute to food and nutrition security, health and income generation in sub-Saharan Africa. However, the specific contribution of native tree foods to nutrition is poorly documented in science and often not acknowledged in poverty reduction strategies. This review gives an overview on the content of carbohydrates, proteins, fat, fibers, ash and dry matter of 98 native food tree species from sub-Saharan Africa. Data were grouped according to the food providing organ (seeds, fruits and leaves). In general, seeds had high content of fat, protein and dry matter; while leaves had high content of protein and ash. There was no significant difference between the three organs on the content of fibers and carbohydrate. Some tree foods species were good sources to provide carbohydrates, proteins, fat, fibers, ash and dry matter. 1. Introduction In sub-Saharan Africa, it is well-known that indigenous trees tradi- tionally contribute to food and nutrition security, health and income generation (Hyacinthe et al., 2015; Otori and Mann, 2014; Stadlmayr et al., 2013). The more specific contribution of food from native trees to nutrition, however, is poorly documented in science and often not acknowledged in poverty reduction strategies (Schreckenberg et al., 2006; Ngome et al., 2017). Therefore, several trees may be considered for food uses, but their nutritional value is underestimated (FAO, 2013). Information on the nutrient composition of food is essential to estimate adequate nutrient intake both at individual and group levels (Joyanes and Lema, 2006). This information may facilitate the selection of priority tree food species for domestication programs aimed at improving food and nutrition security and income generation (Stadlmayr et al., 2013) as well as for natural resource management and conservation. Nutritional components generally analysed are carbohydrates, pro- teins, fat, fibers, ash, vitamins, minerals and dry matter. Carbohydrates hold a special place in human nutrition providing the largest single source of energy in the diet and satisfying instinctual desire for sweetness (Brand-Miller, 2002). A high carbohydrate content is a major source of readily available energy (Assogbadjo et al., 2012; Bamidele et al., 2015). Proteins are fundamental elements for metabolism of enzymes, hormones and many other molecules essential for life. Proteins are composed of 20 amino acids of which nine are essential and need to be provided through the diet (histidine, isoleucine, leucine, lysine, methionine, phenylala- nine, threonine, tryptophan and valine). In early childhood a number of amino acids, which are not essential in adults, cannot be formed in adequate amounts. These are conditionally essential, because of the limited ability of their endogenous formation relative to the magnitude of demand (arginine, cysteine, glycine, glutamine, histidine, proline and tyrosine) (Jackson, 2002). There may be disease situations during adult life whereby a particular amino acid, or group of amino acids, becomes conditionally essential (Jackson, 2002). Some tree food species are promising as sources of dietary protein and amino acid supplement for domestic and industrial use (Djenontin et al., 2009; Igwenyi and Aku- bugwo, 2010; Lohlum, 2010; Ayessou et al., 2014; Otori and Mann, 2014). Fats are a major source of energy and are the essential fuel for the brain and growing fetus (Stubbs et al., 2018). They enhance flavour and palatability of food and make an important contribution to health con- taining essential fatty acids that cannot be synthesized in the body and are furthermore required for a range of metabolic and physiological processes to maintain the structural and functional integrity of cell membranes (Mann and Skeaff, 2002). High content of fat make certain oils from native trees a good alternative or supplement to conventional oil (Bazongo et al., 2014; Niyi, 2014). Fiber has many health benefits and * Corresponding author. E-mail address: padonouelie@gmail.com (E.A. Padonou). Contents lists available at ScienceDirect Heliyon journal homepage: www.heliyon.com https://doi.org/10.1016/j.heliyon.2019.e01744 Received 7 May 2019; Received in revised form 11 May 2019; Accepted 14 May 2019 2405-8440/© 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Heliyon 5 (2019) e01744