The authors scanned 170 systematic reviews and review protocols, then looked nutrition guidelines, policy statements and implementation of nutrition policy.
“The findings from this analysis indicate that there is a substantial body of evidence reporting the use of food fortification as an intervention to combat micronutrient deficiencies. They also indicate that this evidence is translating into practice to a certain extent,” wrote the authors.
But they found the majority of interventions were nutrition-specific (NSpI), addressing only the immediate causes of undernutrition. In contrast, nutrition-sensitive interventions (NSeI) look at the underlying causes of undernutrition, such as agriculture, education or socio-economic factors.
“The dominance of NSpI-related reviews and protocols, guidelines and policy statements, and actions relative to NSeI is not congruent with public health best practice, including recommendations by UNICEF and the WHO, which encourage a strategic combination of evidence-informed interventions to combat micronutrient deficiencies,” the authors wrote.
“Consequently, policies and practices might not be as effective as they might be and may result in public health risks.”
The researchers noted that while NSpI can quickly treat and prevent the physiological symptoms of micronutrient deficiencies, they may not address the underlying causes as well as NSpI – and so may end up being less effective, sustainable or safe.
They also noted potential problems with NSpI: “Concerns about risks associated with the potential for harmful dietary exposure resulting from food fortification interventions have been raised in the context of low- to middle-income countries as well as high-income countries.”
When looking at reasons for the dominance of NSpI over NSeI, the authors noted that the orthodox approach to evidence tends to rate the results of studies using “reductionist methods” more highly than those using holistic methods.
“Investigations of relationships between single nutrients and single physiological outcomes are more amenable to reductionist methods than the inherently complex relationships that exist between NSeI and health outcomes,” they wrote.
They also noted vested political interests can support NSpI, increasing the likelihood that these approaches are given priority, from research agendas onwards.
“Food fortification and especially micronutrient supplementation interventions are dominating what evidence is being synthesised, which may subsequently determine what guidelines and policy statements are being produced,” the authors wrote.
“Effective and safe policies and actions to combat micronutrient deficiencies will require decisions to be informed by a body of evidence on a variety of interventions.”
They called for greater investment into research exploring alternative interventions that “go beyond linear relationships between nutrients and health outcomes, and extending to mid-stream and upstream interventions, such as those addressing socio-ecological and environmental determinants”.
“An increased variety in the types of interventions for which evidence synthesis is available would help inform a greater diversity of guidelines and policy statements and actions to counter the current dominance of supplementation and fortification interventions and increase the likelihood of comprehensive, sustainable, effective, and safe policies and actions to combat micronutrient deficiencies,” they concluded.