Steyn Nelia P, Wolmarans Petro, Nel Johanna H, Bourne Lesley T
Chronic Diseases of Lifestyle, Medical Research Council, P Bag 19070, Tygerberg 7505, Cape Town, South Africa.
Public Health Nutr. 2008 Mar;11(3):307-13. doi: 10.1017/S136898000700033X. Epub 2007 Jul 5.
A national survey found that micronutrient deficiencies are prevalent in South African children, particularly calcium, iron, zinc, riboflavin, niacin, vitamin B6, folate, vitamin A, E and C. Mandatory fortification of maize meal and wheat flour were introduced in 2003 to combat some of the deficiencies found in children. To date however, there has not been a national survey on dietary intake in adults.
The main objectives of this study were to evaluate the micronutrient intake of the diet consumed by the average adult South African by means of secondary data analyses and secondly to evaluate the effects of fortification on selected nutrient intakes.
Secondary data analysis was carried out with numerous dietary surveys on adults to create a database that included sampling (and weighting) according to ethnic/urban-rural residence in line with the population census, of which 79% were black Africans and the majority resided in rural areas. The effect of fortification was evaluated by substituting fortified foods in the diet for the unfortified products.
The combined database used in this study comprised 3229 adults.
Mean calcium, iron, folate and vitamin B6 intakes were very low particularly in women. Mean intakes of most micronutrients were lower in rural areas. Fortification of maize meal and wheat flour (bread) raised mean levels of thiamine, riboflavin, niacin, vitamin B6 and folate above the recommended nutrient intakes (RNIs). In women, despite fortification, mean iron intakes remained below the RNIs, as did calcium since it was not in the fortification mix.
The average dietary intake of adults was of poor nutrient density, particularly in rural areas. Fortification of maize meal and wheat flour (bread) considerably improved mean vitamin B6, thiamine, riboflavin, niacin, folate and iron intakes as well as the overall mean adequacy ratio of the diet.
一项全国性调查发现，南非儿童普遍存在微量营养素缺乏的情况，尤其是钙、铁、锌、核黄素、烟酸、维生素B6、叶酸、维生素A、E和C。2003年开始对玉米粉和小麦粉进行强制强化，以应对儿童中发现的一些营养素缺乏问题。然而，迄今为止，尚未对成年人的饮食摄入量进行全国性调查。
本研究的主要目的是通过二次数据分析评估南非普通成年人饮食中的微量营养素摄入量，其次是评估强化对选定营养素摄入量的影响。
对成年人进行了多次饮食调查，进行二次数据分析，以创建一个数据库，该数据库根据种族/城乡居住地进行抽样（和加权），与人口普查一致，其中79%为非洲黑人，大多数居住在农村地区。通过用饮食中的强化食品替代未强化产品来评估强化的效果。
本研究使用的综合数据库包括3229名成年人。
钙、铁、叶酸和维生素B6的平均摄入量非常低，尤其是女性。大多数微量营养素的平均摄入量在农村地区较低。玉米粉和小麦粉（面包）的强化使硫胺素、核黄素、烟酸、维生素B6和叶酸的平均水平高于推荐营养素摄入量（RNIs）。在女性中，尽管进行了强化，但铁的平均摄入量仍低于RNIs，钙也是如此，因为它不在强化混合物中。
成年人的平均饮食摄入量营养密度较差，尤其是在农村地区。玉米粉和小麦粉（面包）的强化显著提高了维生素B6、硫胺素、核黄素、烟酸、叶酸和铁的平均摄入量以及饮食的总体平均充足率。
