Fruits and vegetables are under-consumed in nearly all regions of the world, despite carrying high antioxidant, micronutrient, and fibre content essential to human health. According to a press release by EurekAlert, the “extraordinary low diversity” of our current global food supply poses several consequences not only for our health but for the health of our planet. In a new study published in People and Nature, Merel Jansen and her team of researchers argue that the solution might lie right above our heads: in the abundance of tree-sourced foods.
According to a previous study by Seunghyeon Kim and colleagues in 2015, 14 of the world’s 100 most nutritious foods are delivered from trees. This study evaluated foods based on their “nutritional fitness.” Kim and colleagues defined nutritional fitness as “the nutrient balance of a food.” According to a National Geographic post on the study, nutritional fitness is a measurement of how likely a food would meet our daily nutritional needs when placed in the context of other foods.
Of these tree-sourced foods, almonds have the highest nutritional fitness of any raw food. A BBC list of “the world’s most nutritious foods,” also derived from the study, further includes grapefruit, apricots, walnuts, red cherries, and plantain. Notably, tree-sourced foods cover several food groups: fruits and vegetables, fats and oils, legumes, nuts and seeds, and even herbs and spices.
Instead of consuming these nutrient-rich foods, however, Jansen and her team note that almost half of the calories consumed by humans come from just four crops: wheat, rice, sugar, and maize. As a result, “micronutrient deficiencies are a global issue,” with Vitamin A intake falling far below the recommended amount in nearly all countries. Vitamin C deficiencies also vary, but can be common in low-income populations due to limited access to fruits and vegetables.
Tree-sourced foods, however, provide four times as much Vitamin C and nine times as much Vitamin A as other foods. For example, according to Jensen’s study the camu-camu Myrciaria dubia from the Amazon has a Vitamin C content 54 times higher than oranges.
Beyond providing nutrients, Jansen and her team note that tree planting is one of the most effective nature-based solutions for mitigating climate change. Trees provide more than 75 per cent of global carbon storage on agricultural land, and helps with soil restoration, habitat preservation, and water security.
These tropical trees extend their branches into issues of poverty reduction and food security in rural and local communities. By developing this alternative food supply system, Jansen argues, we provide opportunities for regional skills to be used and developed (i.e. producing and harvesting the foods). Jensen’s new research shows that supporting local food systems in this way is increasingly important in the face of pandemics like Covid-19.
If tropical tree-sourced foods are the superhero of foods, why aren’t we all eating kumquats, golden kiwis, and cherimoya for breakfast? In their study, Jansen and her team identified various interventions and obstacles. First, redesigning the system can’t happen without consumer demand for tropical tree-sourced foods. Jansen suggests that efforts must be made to inform consumers of the nutritional benefits of these foods, and to make these foods accessible. Thankfully, history shows us this is possible: the production of avocados has doubled over the last three decades thanks to the recent consumer demand.
Other factors to consider include honouring Indigenous land rights, as well as developing and incorporating new techniques and technologies in the planting and post-harvest processes. According to Jansen, the largest concern in bringing forward this new system is ensuring sustainable production. In other words, the benefits of promoting tropical tree-sourced foods would suffer at the cost of large-scale deforestation or other unwanted side effects. Jansen notes that ensuring sustainable production requires consideration for the environmental, political, economic, and social implications.
If we can overcome these obstacles, increasing the production and consumption of tropical tree-sourced foods can provide substantial benefits to both humans and our planet. As Jansen and colleagues note in their study, we can create a system that is “more sustainable and socially equitable, provides better-quality diets, significantly contributes to tree-based restoration of ecosystem services, and helps to mitigate climate change.” If any food rises to this large task, it’ll come from above.