Today, Sight and Life is joining hands with FAO to celebrate World Food Day. This year, in fact, marks the 75th Anniversary of the founding of FAO, and World Food Day 2020 aptly has the theme “Grow, nourish, sustain. Together. Our actions are our future.”
Here at Sight and Life, we have been working for many years on food fortification programs designed to enhance the diet quality of vulnerable populations. In this blog, we take a closer look at how micronutrient deficiencies are measured, and we challenge researchers and policy-makers to re-think current dietary metrics in the face of the Covid-19 pandemic.
Improving the quality of diets worldwide
The latest SOFI report reminds us that access to nutritious food is one of the most pressing issues of our time (2). Globally, the majority of consumed calories are derived from grains (45%), followed by sugars and fats (20%), then fruit and vegetables (11%) (1). These numbers illustrate a recurring situation: people in low-income countries rely on the consumption of staples due to the high cost of fresh and nutritious foods such as fruit, vegetables, and animal-source foods. This is not surprising when we reflect that healthy and diverse diets are five times more expensive than staple-based diets (2).
The current pandemic has intensified an already unacceptable situation by compromising access to school feeding programs, disrupting nutritious food value chains, and further reducing the purchasing power of consumers. Food fortification is a recognized and cost-effective approach to improve the nutritional status of populations in both high-income and low-income countries. It benefits especially those who rely on a staple-based diet that is generally poor in essential micronutrients.
When access to nutritious foods is limited, the fortification of staple foods can help ensure an adequate intake of essential micronutrients. Moreover, fortified foods help support the body’s immune defenses against infections (3) (read more: the role of nutrition in the immune system). In short, food fortification enhances dietary diversity, a key element of diet quality, and has important health benefits too.
Dietary diversity: What is it and how do we measure it?
Dietary diversity was found to serve as a proxy indicator to assess and predict the intake of micronutrients (4,5,6). To easily assess the dietary diversity of a population, a practical tool was developed: the Dietary Diversity Score (DDS) (7). The score reflects the number of different (and pre-defined) food groups that have been consumed by a sample of the population during the previous 24 hours, as described by Krebs et al in 1987. The score is calculated by summing up the number of food groups consumed.
Today, the DDS has been differentiated according to the intended target groups and counts up to 12 food groups, depending on the target group of the score (Figure 1). In both the DDS for women and the DDS for children, we find a differentiation for some specific fruits and vegetables to adequately reflect their specific micronutrient composition. Globally, less than one in three children aged 6–23 months (29%) were found to consume five out of eight pre-defined food groups and thus meet the minimum dietary diversity (MDD) (2). The percentage of children meeting the MDD varies greatly across the globe. In Burkina Faso and Guinea respectively, for example, only 5.2% and 5.9% of children received the MDD, whereas in Turkmenistan and Peru respectively, 82.5% and 82.9% of children met the MDD score (8). The MDD-W (W = women) was included as a core indicator in the Demographic and Health Survey (DHS) in 2019. To date, three countries have published data (2). The available data indicate poor dietary diversity and consequent micronutrient inadequacy.
Overall, the advantage of DDS indicators is the ease with which the data can be collected, analyzed and interpreted. DDS is a practical tool for use in resource-poor settings, and its results can easily be communicated. The most remarkable limitation of DDS, however, is the fact that it does not reflect the intake of fortified food.
Even more astonishing is the fact that the DDS guideline strongly recommends documenting the consumption of these foods (9). The extent to which we can accurately predict micronutrient adequacy in populations with a diet based on cereals and/or other staples, which are often fortified, is still entirely unknown.
Figure 1: Food group classification for different dietary diversity scores
What about fortified foods?
In scientific literature, the lack of differentiation between fortified and non-fortified foods appears to be recognized by two studies only, both from the Philippines. One study by Tsz-Ning Mak et al, suggested to improve the sensitivity of DDS by differentiating between nutrient-rich or fortified foods and energy-dense foods that are low in micronutrients (10). Likewise, Daniel et al experienced difficulties when attempting to classify certain nutrient-dense foods, such as organ meat, in the DDS scoring system. This proved to be difficult, as great differences in micronutrient composition exist between the same foods within the same food group (11).
Interestingly, the World Food Programme (WFP) recently introduced a new scoring methodology to monitor the impact of the consumption of their Super Cereal, which is distributed among vulnerable groups of women. Based on its nutrient composition, the fortified Super Cereal is now considered to be part of the food group ‘meat’, whereas traditionally, it would have been part of the food group ‘grains’ (12).
The lack of attention from the global nutrition community to the assessment of fortified food consumption seems misaligned with the extensive efforts and resources expended on food fortification. Foods fortified with crucial micronutrients such as iron, folic acid, vitamin A and iodine are recognized as increasing diet quality. However, without differentiating between fortified and unfortified food in the DDS, it will be impossible to accurately measure and monitor the results of our efforts on food fortification. Why do we acknowledge the varying micronutrient compositions of different groups of fruits and vegetables, but not those of fortified and non-fortified foods?
At Sight and Life, we urge researchers and policy-makers to re-think the need for a cost-efficient, practical, and rapid diet quality indicator that has the capacity to promote and acknowledge the contribution of fortified foods to diet quality worldwide. The necessity to re-think our dietary metrics was stressed in Miller et al’s recent review (13). Likewise, Walls et al’s recent paper highlights the inadequacy of existing dietary indicators for measuring the ongoing nutrition transition (14).
By adapting the DDS-W food classification to reflect the intake of the Super Cereal fortified food, WFP took a step in the right direction. However, we should not stop here. We therefore invite global stakeholders to tackle this issue. The inclusion of fortified foods in dietary metrics such as the DDS will enhance the visibility of their impact on the nutritional status of vulnerable populations. This, in turn, could encourage policy-makers (and other actors of the enabling environment) to strengthen food fortification standards, laws and regulatory monitoring.
All graphics created by Sight and Life’s Architect and Design Specialist Anne Milan.
1 Future Food Systems: For people, our planet, and prosperity 2020. The Global Panel on Agriculture and Food Systems for Nutrition.
2 UNICEF. The State of Food Security and Nutrition in the World 2020. Transforming food systems for affordable healthy diets. Rome FAO 2020
3 FOOD FORTIFICATION: A WEAPON AGAINST COVID-19 Food Fortification Initiative http://www.ffinetwork.org/FFI_COVID-19andFortification.pdf
4 Hatloy A, Torheim LE, Oshaug A: Food variety-a good indicator of nutritional adequacy of the diet? A case study from an urban in Mali, West Africa. Eur J Clin Nutr 1998, 52:891–898.
5 Ogle MM, Hung PH, Tuyet HT: The significance of wild vegetables in micronutrient intakes of women in Vietnam: an analysis of food variety. APJCN 2001, 10:21–30.
6 Torheim LE, Barikmo I, Parr CL, et al: Validation of food variety as an indicator of diet quality assessed with a food frequency questionnaire for western Mali. Eur J Clin Nutr 2003, 57:1283–1291.
7 Krebs-Smith SM, Smiciklas-Wright H, Guthrie HA, Krebs-Smith J. (1987). The effects of variety in food choices on dietary quality. Journal of the American Dietetic Association, 87(7), 897-903.
8 UNICEF. Expanded Global Database Complementary Feeding. 2019. Online. Access October 15, 2020. https://data.unicef.org/topic/nutrition/infant-and-young-child-feeding/
9 Kennedy G, Ballard T, Dop M. (2013). FAO Guidelines for Measuring Household and Individual Dietary Diversity. Rome, Italy: Food and Agriculture Organization of the United Nations.
10 Mak TN, Angeles-Agdeppa I, Lenighan YM, Capanzana MV, Montoliu I. Diet Diversity and Micronutrient Adequacy among Filipino School-Age Children.
11 Daniels MC, Adair LS, Popkin BM, Truong, YK (2009). Dietary diversity scores can be improved through the use of portion requirements: an analysis in young Filipino children. European Journal of Clinical Nutrition, 63(2), 199-208.
12 WFP. Minimum Dietary Diversity for Women (MDD-W), WFP Guidance. January 2019
13 Miller V, Webb P, Micha R, Mozaffarian D, Database GD. (2020). Defining diet quality: a synthesis of dietary quality metrics and their validity for the double burden of malnutrition. The Lancet Planetary Health, 4(8), e352-e370.
14 Walls HL, Johnston D, Mazalale J, Chirwa EW. (2018). Why we are still failing to measure the nutrition transition. BMJ global health, 3(1), e000657.