US, global dietary quality increased modestly from 1990 to 2018

Key takeaways

• In 2018, the mean Alternative Healthy Eating Index score across 185 countries was 40.3 out of 100, an increase from the mean score in 1990.
• The U.S. had the second-most improved score, which increased 4.6 points. Overall, though, it had one of the lowest mean scores among the top 25 populous countries.

Dietary quality across 185 countries increased modestly over the past 3 decades, according to a recent study published in Nature Food.

On a scale from zero (least healthy) to 100 (most healthy), the mean Alternative Healthy Eating Index score among these countries was 40.3 in 2018, representing a 1.5-point increase since 1990.

“Poor diet is a leading cause of disease worldwide, responsible for an estimated 26% of global preventable mortality,” Victoria Miller, PhD, a visiting scientist in the Friedman School of Nutrition Science and Policy at Tufts University, and colleagues wrote. “These results have important implications for public health and inform priorities in each nation and subnational subgroup to improve nutrition security and health equity.”

The researchers characterized global and regional dietary patterns among adults and children, assessing sex, gender, education and urbanicity. The study utilized Global Dietary Database data from 2018, while its primary measure was the Alternative Healthy Eating Index (AHEI).

Miller and colleagues found that regional mean scores ranged from 30.3 (95% uncertainty interval, 28.7-32.2) to 45.7 (95% UI, 43.8-49.3). Among foods with the healthiest global scores included legumes and nuts (5; 95% UI, 4.8-5.3), whole grains (4.7; 95% UI, 4.5-5) and seafood omega-3 (4.2; 95% UI, 3.8-5.1).

The U.S. had the second-most improved AHEI score among populous countries between 1990 to 2018 (+4.6; 95% UI, 4.1-5.1), behind Iran (+12; 95% UI, 9.9-13.9). However, among the top 25 populous countries, the U.S. ranked with Brazil, Mexico and Egypt as those with the lowest mean AHEI scores in 2018 (28 to 31).

Improvements in dietary patterns are needed in the U.S., where obesity prevalence increased from 30.5% to 41.9% between 2017 to March 2020, according to the CDC. The Internal Food Council’s 2022 Food and Health Survey also found that 86% of Americans think a lot or a little about the healthiness of food, down from 93% in 2012.

Other results from the study showed that AHEI scores among high-income countries were the lowest among those aged 10 to 30 years, with late adolescents having scores below 30.

“We found that diet quality was generally highest among infants and young children and worsened into adolescence, emphasizing the need for initiatives to aim to improve dietary quality in older children, as well as promote healthy eating habits in early childhood to translate into improved dietary quality in adolescence and adulthood,” Miller and colleagues wrote.

The researchers cited previous studies that associated AHEI scores with non-communicable diseases, demonstrating that poor diets are leading to preventable chronic disease and morality.

“Pooled findings from two U.S. cohorts found a 24%, 33% and 6% reduction in the incidence of cardiovascular disease, diabetes mellitus and cancer, respectively, for the highest AHEI quintile compared with the lowest quintile,” they wrote.

Several study limitations were listed by Miller and colleagues, which include survey and data limitability in some countries and an absence of data on trans fat or alcohol use. The researchers concluded that the findings “highlight the substantial variation in dietary quality.”

References:

• Adult obesity facts. https://www.cdc.gov/obesity/data/adult.html. Accessed Sept. 21, 2022.
• Miller V, et al. Nat Food. 2022;doi:10.1038/s43016-022-00594-9.
• 2022 food & health survey. https://foodinsight.org/2022-food-and-health-survey/. Published May 18, 2022. Accessed Sept. 21, 2022.