Abstract
Abstract: Poor folate status is implicated in a wide variety of health disorders including megaloblastic anaemia, neural tube defects, and cardiovascular diseases. Human diet remains the main provider par excellence. Despite several public-health options to overcome this micronutrient deficiency, dietary folate intakes of women of childbearing age and children are still below recommendations in many African countries. Therefore, this review aims at presenting the current knowledge on folate contents in various African foods, and on folate losses during food processing. Seventy one food sources were evaluated in this study. These various food sources included thirty six vegetables, six cereals, height cereal products, six processed leafy vegetables, six pulses, three fruits, three legumes and three roots. All of them were originated from six African countries including Burkina Faso, Côte d’Ivoire, Egypt, Ethiopia, Nigeria, and South Africa. Folate content ranged between 11 and 73.4 μg/100 g in cereals, 1.8 and 39 μg/100 g in cereal-based processed foods, 8.48 and 48.6 μg/100 g in cooked leafy vegetables, 11.6 and 633 μg/100 g in vegetables, 10 and 22 μg/100 g in pulses, 52 and 148 μg/100 g in legumes, 8 and 106 μg/100 g in fruits. The structure of the food matrix has been shown to influence folate digestibility in foods. High bioaccessible folate, assessed by in vitro digestion, was observed among food products with dense porosity structures while low bioaccessible folate was recorded among food products with open porous structures such as porridges and some gelatinized doughs. Numerous food processing steps have also been shown to influence negatively folate contents in foods.
References
1 . Homocysteine and risk of ischemic heart disease and stroke: a meta-analysis. JAMA. 2002;288(16):2015–22.
2 . A meta-analysis of plasma homocysteine as a risk factor for arteriosclerotic vascular disease and the potential preventive role of folic acid. J Am Med Assoc. 1995;274:1049–57.
3 . Global Report on Birth Defects. White Plains, New York: March of Dimes Birth Defects Foundation; 2006. Available from http://www.marchofdimes.org/materials/global-report-on-birth-defects-the-hidden-toll-of-dying-and-disabled-children-full-report.pdf
4 . Prevalence of anaemia and its associated factors in African children at one and three years residing in the Capricorn District of Limpopo Province, South Africa. Curationis. 2014;37(1):1160.
5 . Megaloblastic anemia in North Africa. Haematologica. 2006;91(7):990–1.
6 . Worldwide prevalence of anaemia, WHO Vitamin and Mineral Nutrition Information System, 1993–2005. Public Health Nutr. 2009;12(04):444–54.
7 . Decline in the prevalence of neural tube defects following folic acid fortification and its cost-benefit in South Africa. Birt Defects Res A Clin Mol Teratol. 2008;82:211–6.
8 Neural tube defects are rare among black Americans but not in sub-Saharan black Africans: The case of Yaounde – Cameroon. J Neurol Sci. 2008;270(1–2):13–7.
9 . Neural tube defects in the middle belt of Nigeria. J Trop Pediatr. 1992;38(1):27–30.
10 . Folate and folic acid. In Vitamin and mineral requirements in human nutrition. (2nd ed). Geneva, Switzerland; 2005.
11 Folate status of women and children in Africa – current situation and improvement strategies. Food Rev Int. 2019;36(1):1–14.
12 . Grain Fortification Progress and Opportunities in Africa. Available from: https://www.ffinetwork.org/africa
13 . Dietary intake and status of folate and vitamin B12 and their association with homocysteine and cardiovascular disease in European populations. Eur J Clin Nutr. 2009;63(1):18–30.
14 . Folic acid and folates: physiology and health effects. Encycl Food Heal. 2016;1:724–30.
15 . Lost Crops of Africa. Volume II. Vegetables. Washington. DC: National Academy Press; 2006.
16 The African baobab (Adansonia digitata, Malvaceae): Genetic resources in neglected populations of the Nuba Mountains, Sudan. Am J Bot. 2014;101(9):1498–507.
17 . Lesser-known Nigerian Fruits and Vegetables: Post-harvest Handling, Utilization and Nutritional Vallie. lbadan, Nigeria: Ibadan University Press; 2014.
18 Total folate in West African cereal-based fermented foods: Bioaccessibility and influence of processing. J Food Compos Anal. 2020;85:103309.
19 . Influence of fermentation and other processing steps on the folate content of a traditional African cereal-based fermented food. Int J Food Microbiol. 2018;266:79–86.
20 . Folate content in foods commonly consumed in Egypt. Food Chem. 2010;121(2):540–5.
21 . Estimation of folate content of cultivated and uncultivated traditional green leafy vegetables in Nigeria. Afr J Food Sci. 2019;13(9):191–5.
22 . The role of wild vegetables in household food security in South Africa: A review. Food Res Int. 2015;76:1001–11.
23 . Available from: https://www.fao.org/faostat/en/#data
24 . Quantification of folate in the main steps of traditional processing of tef injera, a cereal based fermented staple food. J Cereal Sci. 2019;87:225–30.
25 . Potential probiotic Pichia kudriavzevii strains and their ability to enhance folate content of traditional cereal-based African fermented food. Food Microbiol. 2017;62:169–77.
26 Improved processing for the production of cereal-based fermented porridge enriched in folate using selected lactic acid bacteria and a back slopping process. LWT. 2019;106:172–8.
27 . Production of folates by yeasts in Tanzanian fermented togwa. FEMS Yeast Res. 2008;8(5):781–7.
28 . Changes in micro- and macronutrient composition of pearl millet and white sorghum during in field versus laboratory decortication. J Cereal Sci. 2011;54(3):425–33.
29 . Lactic acid fermentation as a tool for increasing the folate content of foods. Crit Rev Food Sci Nutr. 2017;57(18):3894–910.
30 . Yield response of African leafy vegetables to nitrogen, phosphorus and potassium: the case of Brassica rapa L. subsp. Chinensis and Solanum retroflexum Dun. Water SA. 2018;33(3):355–62.
31 African leafy vegetables in South Africa. Water SA. 2007;33(3):317–26.
32 . Linolenic acid and folate in wild-growing African dark leafy vegetables (morogo). Public Health Nutr. 2007;12(4):525–30.
33 . Nutrient content of eight African leafy vegetables and their potential contribution to dietary reference intakes. J Food Compos Anal. 2014;33(1):77–84.
34 . Nutritional value of leafy vegetables of sub-Saharan Africa and their potential contribution to human health: A review. J Food Compos Anal. 2010;23(6):499–509.
35 . Nutritional potential of the leaves and seeds of black nightshade-Solanum nigrum L. Var virginicum from Afikpo-Nigeria. Pak J Nutr. 2007;6(4):323–6.
36 . Teff: Suitability for different food applications and as a raw material of gluten-free, a literature review. J Food Nutr Res. 2018;6(2):74–81.
