Trade mediates global marine nutrient supply and methylmercury exposure

Seafood is a valuable source of micronutrients and the single largest source of consumed methylmercury (MeHg). MeHg consumption has adverse impacts on neurodevelopment and cardiovascular health. Many micronutrients that are abundant in seafood are vital contributors to healthy development such as vitamin B12 and folate during pregnancy. In addition, micronutrients such as selenium may limit the health impacts of MeHg exposure. Here, we combine global trade data that includes disaggregated species and nutrient profiles with global modeled MeHg concentrations to assess the global distribution of nutrient supply and mercury exposure attributed to seafood consumption. Our study 1) examines a nutrient-mercury trade-off index for distinct countries, species, and products; 2) identifies the countries and regions that deviate positively and negatively by MeHg exposure and nutrient benefits; and 3) showcases species trade flows that have particularly beneficial nutrient (relative to country nutrient inadequacies) and adverse MeHg profiles (relative to upper safety limits). Our study highlights nutritionally vulnerable and high-risk MeHg exposure locations that would benefit the most from a shift in current seafood trade flows.