- Researchers investigated how global dietary patterns changed between 1990 and 2018.
- They found that diets became modestly healthier by 2018.
- They concluded that dietary recommendations should be based on localized nutrition data.
Data shows that poor diets are responsible for around 26% of global preventable mortality. Existing evidence suggests that different foods and nutrients have synergistic and complementary effects when consumed together.
While what makes up an optimal dietary pattern is largely well-established and validated, how common it is globally consumed remains unclear.
Previous studies have been limited to small subsets of countries and typically did not include those under 25 years old.
Studies investigating various countries’ dietary patterns across a wider age range could improve dietary guidelines and recommendations.
Recently, researchers analyzed global, regional, and national dietary patterns and trends among adults and children from 185 counties.
They found that between 1990 and 2018, diets became slightly healthier, although the extent of this varied by country.
“In general, healthy diets have become more affordable as countries have become richer,” Dr. Boyd Swinburn, Professor of Epidemiology and Biostatistics at the University of Aukland, not involved in the study, told Medical News Today.
“Also, the globalization of food means that the variety of whole foods has increased, which is good. But the countervailing forces of ultra-processed foods taking over from whole foods and the widening wealth inequalities are creating unhealthier diets,” Dr. Swinburn added.
The study appears in Nature Food.
Global dietary data analysis
The researchers collated data from nationally and subnationally-representative surveys on individual-level dietary intake alongside biomarker surveys.
Altogether, they compiled data from 1,248 dietary surveys from 188 countries. Among the surveys, 73.9% included data on children ages 0- 19 and 64.5% from adults ages 20 or over.
The researchers obtained data on individual-level dietary intake of up to 53 foods, beverages, and nutrients alongside demographic data, including age, sex, education, and urban or rural residence.
The researchers used the Alternative Healthy Eating Index (AHEI) to define a healthy diet. Victoria Miller, Ph.D., a research fellow at the PHRI Population Health Research Institute and Visiting Scientist at Tufts University, one of the study’s authors, told MNT:
“The AHEI recommends that individuals consume lots of fruit, vegetables, whole grains, nuts and legumes, polyunsaturated fats, and omega-3 fats, and limited quantities of red and processed meat, sugar-sweetened beverages, and sodium.”
In the end, the researchers organized diets on a scale of 0 to 100- with 0 being a poor diet, and 100 being an optimal diet.
They found that between 1990 and 2018, the global AHEI score increased modestly by 1.5 points- from 38.8 in 1990 to 40.3.
They also found that in 2018 only ten countries representing less than 1% of the world’s population had dietary scores of 50 or above. These included Vietnam, Iran, Indonesia, and India, with average scores of 54.5.
Meanwhile, the lowest scoring countries included Brazil, Mexico, the United States, and Egypt, with scores ranging between 27.1- 33.5.
The researchers noted that the mean AHEI scores in 2018 for children and adults were similar: ranging between 38.2 and 42. However, in most regions, those ages 5 and under and 75 and over tended to have the highest AHEI scores.
They further wrote that globally, children tended to consume less fruit, non-starchy vegetables, and seafood omega-3 than adults. However, they also consumed more sodium and polyunsaturated fats than adults.
The researchers further noted that higher education attainment was linked to a higher AHEI score in most regions apart from the Middle East, North Africa, and Sub-Saharan Africa, where they observed no differences.
Improving dietary choices
When asked how these findings could improve dietary choices around the world, Dr. Miller said:
“Our findings are useful for informing the design and implementation of future research and national policies to improve dietary quality. Although South Asia and Sub-Saharan Africa had the highest dietary quality in 2018, consumption of fruit, vegetables, legumes/nuts, seafood omega-3 fat, and polyunsaturated fats were far from optimal in these regions. Policies to increase the intakes of produce, seafood, and plant oils will have the largest impact on dietary quality in these countries.”
“In Asia and Latin America and the Caribbean, we found that red/processed meat and sodium increased over time, and policies focused on lowering the intake of these foods and nutrients will greatly improve dietary quality,” she added.
“Low consumption of unhealthy foods and nutrients, such as sugar-sweetened beverages, red/processed meat, and sodium, led to higher dietary quality in many countries, including Vietnam. In the USA, a dual focus on increasing healthful foods (fruits, vegetables, plant oils) and lowering unhealthy foods (sugar-sweetened beverages, sodium) is needed to improve dietary quality,” she noted.
Dr. Marco Springmann, Senior Researcher on Environment and Health at the University of Oxford, not involved in this study, also told MNT:
“The study also highlights that there has been little progress in improving diets worldwide. This should come as a wake-up call to policymakers who routinely brush off the need for progressive food policies as interfering too much in the market.”
“Without clear policy measures that would empower citizens to make healthy and sustainable dietary choices, we risk having another decade without progress on improving diets and the health and environmental impacts associated with them,” he added.
The researchers concluded that their findings highlight the need for specific national and subnational policies to improve nutrition.
Nutritional study limitations
When asked about limitations to the study, Dr. Swinburn said: “Data on diets is notoriously challenging. There is always massive under-reporting- about 20% of calories under optimal conditions of data collection are never recorded.”
“Nevertheless, by taking a zoomed-out approach like this, you start to see patterns which can tell you very useful things about the underlying changes over time and differences between populations,” he added.
Dr. Rob M. van Dam, Professor of Exercise and Nutrition Sciences at the Milken Institute School of Public Health, George Washington University, also told MNT: “The limitation of these findings is that the survey instruments and accuracy of the data varied across countries.”
“Also, the dietary quality indices used in the study were developed in high-income countries to prevent chronic diseases but may be less suitable for low-income countries where nutrient deficiencies are common,” he added.
Salim Yusuf MD, D. Phil, Distinguished Professor of Physiology and Pharmacology at McMaster University, not involved in the study, agreed that guidelines based on data may not apply to most other regions of the world. He noted that undernutrition is a challenge for many, alongside getting an adequate variety of food. He added that cultural habits, taste, and cost also influence what people eat.
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