2023
Abstract: Policies encouraging shifts towards more plant-based diets can lead to shortfalls in mi-cronutrients typically present in animal products (B-vitamins, vitamin D, calcium, iodine, iron, selenium, zinc, and long-chain omega-3 fatty acids). We modelled the effect of fortifying foods with these critical micronutrients, with the aim of achieving nutrition and sustainability goals, using food consumption data from Dutch adults (19–30 years). Three dietary scenarios were optimized for nutritional adequacy and 2030 greenhouse gas emissions (GHGE-2030) targets, respectively, with the fewest deviations from the baseline diet: (i) the current diet (mainly vitamin A- and D-fortified margarine, iodized bread, and some calcium- and vitamin D-fortified dairy alternatives and iron- and vitamin B12-fortified meat alternatives); (ii) all plant-based alternatives fortified with critical micronutrients; and (iii) fortified bread and oils. Optimizing the current diet for nutrition and GHGE-2030 targets reduced animal-to-plant protein ratios from ~65:35, to 33:67 (women) and 20:80 (men), but required major increases in legumes and plant-based alternatives. When fortifying all plant-based alternatives and, subsequently, bread and oil, smaller dietary changes were needed to achieve nutrition and GHGE-2030 targets. Fortifying food products with critical micronutrients, ideally with complementary education on plant-based foods, can facilitate the transition to healthier and more sustainable diets.
- Introduction
Current food systems are unsustainable [1,2] and responsible for 21–37% of global greenhouse gas emissions (GHGE) [3], depleting natural resources [3–5], and destroying biodiversity [6]. While diet-related chronic diseases are on the rise, almost one third of the world’s population lacks access to sufficient and nutritious food [7,8]. Therefore, the current food system needs to be redesigned to provide sustainable, nutritious, and affordable diets to a growing population [9]. To meet the goal of limiting global warming to 1.5 degrees, through GHGE reductions established by the UN’s Intergovernmental Panel on Climate Change (IPCC) [10], change is needed in food systems and diets. Increased availability of alternative (plant-based) proteins is one of the several actions proposed to help advance the European Union (EU) “Farm to Fork strategy” [11]. As a result, a shift towards more plant-based diets is warranted [12]. Consumer research shows that health and sustainability concerns are already driving consumers towards plant-based foods [13].
In comparison to foods from animal sources, plant-based foods such as legumes, nuts, and plant-based alternatives are typically low in saturated fats and rich in unsaturated fatty acids, dietary fiber, and phytonutrients such as polyphenols [14]. A (partial) replace-ment of animal products with plant-based foods may provide beneficial health outcomes, such as a reduced risk of type II diabetes, cancer, coronary heart disease, and premature mortality [12,15,16]. Plant-based foods also generally provide more thiamin, vitamin C, folate, and potassium than animal products [15]. On the other hand, animal foods are essential sources of macro- and micronutrients that are difficult to obtain from plant-based foods [14]. Plant-based foods and diets often have a lower quality [15] and content [16] of protein; choline; vitamins B2, B3, B5, B6, and D; iodine; selenium; and bioavailable calcium, iron, and zinc; and lack vitamin B12 and long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic, and docosahexaeonoic acids (EPA and DHA) [17–23]. Therefore, large shifts from animal- to plant-based diets will lead to nutritional advantages but also short-comings [20,24,25]. Studies on vegetarians and vegans, for instance, show lower levels of vitamin B12, vitamin D, iron, zinc, iodine, calcium, selenium, and long-chain omega-3 fatty acids [23,26–32].
Fortification of foods with nutrients that are scarce or absent in plant-based diets can support the achievement of nutrient recommendations while switching to more plant-based dietary patterns [33–36]. Several modelling studies have predicted nutritional benefits but also shortcomings when shifting towards more plant-based diets [19,22,37]. Only a limited number of studies have included scenarios that might bridge these shortcomings in a sustainable way, to guide policy making [36,38]. However, in these studies, not all population nutrient recommendations were considered, and the number of fortified food options and fortified nutrients was limited.
In this study, different scenarios are modelled to explore how the fortification of plant-based alternatives and commonly eaten foods with critical nutrients could enable a transition towards more plant-based diets in an average diet of young Dutch adults. This research fills a knowledge gap on the role of fortified food in future-proof diets and the associated environmental impacts. It could also play a role in defining dietary strategies that fulfill both nutrient recommendations and the need to reduce GHGE to limit the global average temperature rise to 1.5 ◦C.