Abstract
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.
Generated Summary
This study employed a comparative risk assessment approach to evaluate the consumption of major foods and nutrients across 195 countries and quantify the impact of their suboptimal intake on non-communicable disease (NCD) mortality and morbidity. The research involved estimating the disease-specific burden attributable to each dietary risk factor among adults aged 25 years or older. The analysis incorporated data on dietary factor intake, the effect size of the dietary factor on disease endpoints, and the level of intake associated with the lowest risk of mortality. The study’s core methodology involved calculating the number of deaths and disability-adjusted life-years (DALYs) attributable to diet for each disease outcome. This comprehensive approach allowed for a detailed assessment of the potential impact of suboptimal diets on NCD mortality and morbidity, emphasizing the need for dietary improvements across nations. The study highlights the importance of understanding dietary habits and their effects on chronic diseases. It underscores the necessity for global efforts to enhance the quality of human diets, emphasizing the need for collaboration across various sectors of the food system. The goal is to inform evidence-based dietary interventions and establish a platform for evaluating their impact on human health annually, contributing to the reduction of NCDs.
Key Findings & Statistics
- 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.
- The largest gaps between current and optimal intake were observed for nuts and seeds (mean consumption at 12% of optimal levels), milk (16% of optimal levels), and whole grains (23% of optimal levels).
- Globally, the consumption of sugar-sweetened beverages (49 g per day) and processed meat (4 g per day) and sodium (6 g per day) exceeded optimal levels.
- The global intake of red meat (27 g per day) was 18% greater than the optimal intake.
- Cardiovascular disease was the leading cause of diet-related deaths (10 million deaths) and DALYs (207 million).
- Across the 21 GBD regions, in 2017, the highest age-standardised rates of all diet-related deaths and DALYs among adults aged 25 years or older were observed in Oceania (678 deaths per 100,000 population and 17804 DALYs per 100,000 population).
- In 2017, 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.
- In 2017, across the 21 GBD regions, a diet low in whole grains was the most common leading dietary risk factor for deaths (in 16 regions) and DALYs (in 17 regions).
- In low-middle SDI countries, low intake of fruit was the leading dietary risk for deaths and low intake of whole grains was the leading dietary risk for DALYs.
- Since 1990, the number of deaths and DALYs attributable to dietary risks increased to 11 million deaths and 255 million DALYs in 2017.
Other Important Findings
- The study found a significant relationship between dietary habits and chronic non-communicable diseases (NCDs).
- The research highlighted that the consumption of all healthy foods and nutrients was suboptimal in 2017.
- The analysis revealed that men generally had a higher intake of both healthy and unhealthy foods than women.
- The highest intake of sugar-sweetened beverages and legumes was observed among young adults, showing a decreasing trend with age.
- The highest age-standardised proportions of diet-related deaths and DALYs from cardiovascular disease were observed in Oceania and East Asia.
- The lowest age-standardised rates of all diet-related deaths and DALYs were observed in high-income Asia Pacific.
- In 2017, among the world’s 20 most populous countries, Egypt had the highest age-standardised rate of all diet-related deaths and DALYs, while Japan had the lowest.
- The highest age-standardised proportion of all diet-related deaths and DALYs in adults aged 25 years or older were observed in Egypt, and the lowest were in Nigeria.
- In 2017, the highest age-standardised rates of all diet-related deaths and DALYs were observed in low-middle SDI countries, and high-middle SDI countries.
Limitations Noted in the Document
- The study acknowledges that the strength of evidence supporting a causal relationship between dietary risks and disease endpoints was weaker than that for other established risk factors.
- The study used mixed sources for dietary data, which were not available for all countries, increasing the statistical uncertainty of estimates.
- The assumption of independence in the distribution of dietary factors within each unit of analysis (country, age, and sex group) might have resulted in under- or overestimation of the combined effect of dietary factors.
- The analysis did not account for the potential for some dietary risk factors to not be mutually exclusive, which could lead to an overestimation of disease burden.
- The study’s reliance on observational studies for causal relationships and the varying strength of evidence across different foods and nutrients are noted as limitations.
- The study highlights the need for improved data collection and the development of new dietary assessment methods.
- The study also points to the need for more accurate estimation of nutrient intake, particularly for fiber, calcium, and polyunsaturated fatty acids, which remains a challenge.
- The reliance on meta-analyses of cohort studies to derive relative risks, with the potential for publication bias and residual confounding, is also acknowledged.
- The varying definitions of dietary factors across studies and the impact of energy adjustment on relative risk estimations are further limitations.
Conclusion
The study’s findings underscore that poor dietary habits significantly contribute to NCD mortality worldwide, emphasizing the urgent need for global action to improve human diets. The research clearly identifies that a diet high in sodium, low in whole grains and fruits, and other factors contributes to the global burden of disease, which highlights the need for coordinated global efforts to improve diet quality. These efforts require collaboration across the food system, including production, distribution, and consumption. The study suggests that focusing on the intake of whole grains, fruits, and vegetables, as well as reducing sodium, might be more effective than policies that narrowly target sugar and fat, highlighting the need for comprehensive food system interventions. The study also points out the need for nationally representative data on intake of key foods and nutrients, and the establishment of national surveillance and monitoring systems for key dietary risk factors. The increase in deaths and DALYs attributable to dietary risks since 1990, primarily due to population growth and aging, is concerning. However, the decrease in age-standardised death and DALY rates indicates a positive trend. The study emphasizes the importance of addressing the interconnected factors within the food system to improve dietary habits and reduce the burden of NCDs. The comprehensive scope of the study, with its insights into dietary patterns across 195 countries and the impact of specific dietary factors, provides a valuable basis for informing policy and intervention strategies to improve global health. The study promotes extensive changes in various sectors of the food system at the global, regional, and national levels to improve diet.