*4.2. Food Groups Provided*

The starchy staples, which contributed more than 60% of the entire diet, have been found to be the major foods fed to school children in developing countries [15] because they are easilyavailable and are a cheap source of energy compared to other food groups. Thompson and Amoroso [16] indicate a shift from a varied diet rich in micronutrients to one derived from predominantly high-carbohydrate starchy staples. Animal-source foods arethe least provided foods in school menus because they are expensive, in the context of school feeding in developing countries. A study by Cornelsen et al. [17] in Kenya found that price was the most frequently reported barrier to the provision of animal-source Foods (ASF), therefore affordability is the main hindrance to their service. Additionally, the study revealed that milk was providedonly by the national schools because they reared dairy animals in their school farms and therefore had a constant supply of milk. Azzarri et al. [18] sugges<sup>t</sup> that livestock ownership confers on households more opportunities to increase the consumption of animal-source food as it translates into cheaper or more reliable access to animal-source food supplies. A study by Kabunga et al. [19] showed that the adoption of improved dairy cow breeds at farm level led to increased consumption of milk in Ugandan households and translated to improved dietary quality among young children. Meat and eggs, the least-provided foods, contributed an estimated 2% to the total dietary intake among the high-school students. The major source of proteins were legumes, which are known to have lower protein quality compared to animal sources [16]. From the foregoing, school feeding policies should advocate for boarding schools to rear animals for milk, eggs, and meat for the cheaper supply of high-quality protein.

The provision of fruitsin private schools and not at all in county schools may be explained by the purchasing ability of the parents of children attending private schools, compared to those attending county schools. Fruits are known to be an expensive source of energy and therefore this could be the reason for the high intake in private schools. Review studies on the determinants of fruit and vegetables consumption among adolescents consistently show that high income levels largely influence fruit intake, often because of a ffordability [20–22].

The high provision of vegetables in county schools could be attributed to the parents who sometimes supply vegetables from their farms as a form of school fees payment, since most of these types of schools are commonly found in rural areas. A review on the determinants of vegetable consumption among adolescents by Rasmussen et al. [20] showed that availability of vegetables is one of the determinants that greatly influence vegetable intake, which may be true in this study. Furthermore, low vegetable provision in private schools could be attributed to the children'slack of engagemen<sup>t</sup> in school gardening activities owing to limited land sizes in private schools. Despite epidemiological evidence by He et al. [23] for the health benefits of a diet rich in fruits and vegetables, such as reduced risk of chronic diseases later in life, large numbers of adolescents do not meet the WHO requirement of a daily intake of at least 400 g (roughly equivalent to five servings per day) of fruits and vegetables [24]. A study by Peltzer and Pengpid [25] in seven African countries, including Kenya, found that most adolescents (77.5%) did not consume the recommended daily servings of vegetables. Similar results to this have been reported by Doku et al. [26], who found that 56% and 48% of adolescents in Ghana rarely consumed fruits and vegetables. According to South African dietary guidelines, it is recommended that adolescents consume at least one fruit and/or vegetable in a meal [24]. This recommendation was not met in this study. This could be due to the limited variety of fruits (banana and orange) and vegetables (kale and cabbage) that appear on most of the school menus. This study is in agreemen<sup>t</sup> with other studies that fruit and vegetable consumption is consistently low in many low middle income countries [27].This implies that nutrition guidelines for school feeding in Kenya should recommend the minimum fruit and vegetable portions that should be provided to students.

### *4.3. The Mean Amount of Nutrients Provided Daily from the Total Diet*

The higher consumption of proteins by the national compared to private schools may be explained by the fact that the major sources of proteins in the diets are cereals and legumes. The low values reported in private schools could be due to their low service of these grains. Private schools provided more rice and potatoes, which are poor sources of protein. However, they provided more beef, eggs, and sausages than the other schools— implying that though their protein intake is low, it is of higher quality, since it comes from animal sources.

The national schools' diet had high mineral content, probably because most of the meals served were wholemeal, and therefore the presence of bran in the foods leads to a high mineral content in the diet. In contrast, most of the foods servedin private schools such as rice, chapatti, and potatoes have low mineral content, and are processed with husks removed. For example, the processing of maize by dry milling and fractionation results in the removal of bran, which is the major constituent of the pericarp, and which contains B-vitamins and minerals [28]. Cornbran contains more iron, zinc, and phosphorous than corn starch [29]. This shows that the micronutrient content of cereals is greatly reduced after processing, and therefore serviceof processed foods provides a small proportion of the daily requirements for most vitamins and minerals. Nutrition guidelines should emphasize the use of whole grain for food and food products in adequate portions in school meals to contribute to mineral provision.

The service of higher amounts of fruits, and also spreads on bread that are fortified with vitamin A, to students in private schools may have resulted in their intake of higher amounts of retinol and vitamin A than the other types of school. Margarine has been found to be one of the most suitable vehicles for vitamin A [30]. A study involving Filipino pre-school children who consumed 27 g of vitamin A-fortified margarine per day for a period of six months showed that there was a reduced prevalence of low serum retinol from 26% to 10%, hence consumption of the margarine significantly improved the vitamin A status of the children [31]. Foods high in vitamin A should be deliberately included among those in school menus based on Kenyan nutrition guidelines.

Furthermore, the significantly higher vitaminsB12, B6, and folic acid in private school menus compared to the other school types may be attributed to the higher service of animal-source foods such as eggs and beef. In contrast, the lowcalcium, phosphorous, and magnesium provision in private schools compared to other school types may be explained bythe low serviceof cereals and legumes, which are rich sources of magnesium and phosphorous [32]. The low intake of milk and milk products could further explain the low calcium levels in the students' diets. In national schools the provision of zinc was higher compared to private schools. This could be explained by the fact that they were served with more beans compared to other schools. They were also provided with milk, which is a rich source of zinc.

### *4.4. Fulfillment of the Di*ff*erent Nutrients*

The study's findings showed that school meals did not meet 100% of the energy needs of the students. This findings contradict those of Buluku [7] who found that energy was adequately met in the diets of girls in selected boarding schools in Nairobi, Kenya. However, this finding concurs with that of Nhlapo et al. [33] who found that the meals served under a South African school feeding scheme did not meet the energy needs of school children aged 11–18 years. Carbohydrates, proteins, and fats provided 57.6%, 11.8%, and 30.5% of energy, respectively. According to the School Food Trust [34], a minimum of 50% of the energy provided should be sourced from carbohydrates, less than 35% should be met from fats and the rest from proteins. The results of this study indicate that the meals provided met the recommendations regarding the contributions of the three macronutrients to the energy needs of the high school students. This finding is similar to that of Charrondiere et al. [35] on numerous food items from di fferent countries in which the total carbohydrate content supplied 50–80% of energy, and 7–11% of energy was from protein. Nutrition guidelines should recommend portion sizes for energy-providing foods that enable students in boarding high schools to meet all their energy requirements.

The ability of national schools to meet the required protein intake while the other school types fell short may be attributed to the provision of more food groups rich in proteins, and that this was the only school type that served milk. Protein is important in adolescent nutrition as it provides structure for the body and major components of the bones, blood, muscle, cell membranes, enzymes, and immune factors [32].

The high intake of dietary fiber in the public schools may be explained by the provision of starchy unrefined grains and pulses in meals such as githeri (a stewed mixture of maize and beans), wholemeal ugali, and vegetables such as kale, which are rich in fiber. This is an advantage, as high-fiber diets have a low glycemic index, therefore keeping students full for a longer time, which reduces the rate of hunger. For instance, a study by Ye et al. [36] showed that consumption of dietary fiber decreased hunger and increased satiety hormones in humans when ingested with a meal. This implies that that the students can concentrate in class for longer without feeling hungry. However, high-fiber diets

tend to be rich in phytates, and therefore could bind key mineral elements such as calcium and also reduce absorption of minerals such as iron and zinc [37]. Private schools reported a low intake of fiber compared to the other schools because of the low provision of githeri, ugali, and kale, and the provision of potatoes, which are low in fiber as stated earlier.

The percentage fulfillment of Vitamin A was high in private schools and lowin county schools due to the high intake of fruits, and Vitamin A-fortified spreads on bread. The low value reported in county schools is a result of the non-provision of fruits and spreads. This finding is similar to that of Buluku [7] on Kenyan boarding school meals that did not meet the nutrient requirements for adolescent girls. Vitamin A is a key micronutrient in adolescent nutrition. Vitamins play important roles in the body such as aiding vision, immunity (vitamin A), calcium absorption (vitamin D), and anti-oxidative protection in cell membranes (vitamin E) [32].

Calcium intake was highest in the national schools probably because of milk provision to students in national schools, compared to private schools, which did not providemilk. The ability of most school types to fully meet their phosphorous, zinc, and iron requirements in most school types could be attributed to the consumption of cereals and pulses, which are rich sources of these minerals [32]. The intake of iron and zinc appears to be overestimated because the diet was mainly composed of cereals and pulses. These minerals were mostly found in githeri, ugali, millet porridge, maize porridge, beans, and green grams, which were frequentlyprovided.

However, cereals and legumes contain phytates which chelate with minerals and metals such as calcium, magnesium, zinc, and iron, forming insoluble salts that are not easily absorbed by humans [38]. Phytates particularly form complexes which can severely impair the availability of zinc and iron [39]. Furthermore, most schools took beverages in the form of tea, co ffee, or cocoa, which may also contain tannins that could further bind the minerals [40]. Deficiencies of iron and zinc are a public health problem in developing countries, particularly among adolescents and women of reproductive age. A systematic review to evaluate iron and zinc intakes in adolescents from Ethiopia, Kenya, Nigeria and South Africa concluded that diet-related anaemia and zinc deficiencies are problems of public health significance [41]. Zinc is important in adolescence because of its critical function in growth and sexual maturation [42]. However, adolescents are at high risk of deficiency, often related to the consumption of plant-based diets, which have low zinc and iron bioavailability reported by Gibson et al. [43], which are similar to the diets providedin this study. From the forgoing it is noted that the studyonly focused on whatschools provided to their students and did not consider how much the adolescents consumed.
