Plain language summary
Suboptimal nutrition is an important risk factor for non-communicable diseases (NCDs). This study used data on food and nutrient consumption from 195 countries to evaluate the impact of 15 dietary risk factors on NCD mortality and morbidity and is part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017. Globally, consumption of nearly all healthy foods and nutrients was suboptimal, whilst daily intake of all unhealthy foods and nutrients exceeded the optimal level. Dietary risks were responsible for 11 million of all deaths among adults and 255 million disability-adjusted life-years (DALYs). Cardiovascular disease was the leading cause of diet related deaths, followed by cancers and type 2 diabetes. More than half of diet-related deaths and two-thirds of diet-related DALYs were attributable to high intake of sodium, low intake of whole grains and low intake of fruits. The lowest burden of exposure to dietary risk was observed in countries with a high Socio-demographic Index (SDI). The authors conclude that diet is the most important risk factor, even before smoking, globally and that improvements in diet could potentially prevent one in every five deaths. They state that their findings highlight the urgent need for coordinated global efforts to improve the quality of human diet.
BACKGROUND Suboptimal diet is an important preventable risk factor for non-communicable diseases (NCDs); however, its impact on the burden of NCDs has not been systematically evaluated. This study aimed to evaluate the consumption of major foods and nutrients across 195 countries and to quantify the impact of their suboptimal intake on NCD mortality and morbidity. METHODS By use of a comparative risk assessment approach, we estimated the proportion of disease-specific burden attributable to each dietary risk factor (also referred to as population attributable fraction) among adults aged 25 years or older. The main inputs to this analysis included the intake of each dietary factor, the effect size of the dietary factor on disease endpoint, and the level of intake associated with the lowest risk of mortality. Then, by use of disease-specific population attributable fractions, mortality, and disability-adjusted life-years (DALYs), we calculated the number of deaths and DALYs attributable to diet for each disease outcome. FINDINGS In 2017, 11 million (95% uncertainty interval [UI] 10-12) deaths and 255 million (234-274) DALYs were attributable to dietary risk factors. High intake of sodium (3 million [1-5] deaths and 70 million [34-118] DALYs), low intake of whole grains (3 million [2-4] deaths and 82 million [59-109] DALYs), and low intake of fruits (2 million [1-4] deaths and 65 million [41-92] DALYs) were the leading dietary risk factors for deaths and DALYs globally and in many countries. Dietary data were from mixed sources and were not available for all countries, increasing the statistical uncertainty of our estimates. INTERPRETATION This study provides a comprehensive picture of the potential impact of suboptimal diet on NCD mortality and morbidity, highlighting the need for improving diet across nations. Our findings will inform implementation of evidence-based dietary interventions and provide a platform for evaluation of their impact on human health annually. FUNDING Bill & Melinda Gates Foundation.