Study shows how feasible reductions in ultra-processed food consumption positively impact the nutritional quality of diets

By Bhavana KunkalikarSep 8 2022Reviewed by Danielle Ellis, B.Sc.

In a recent study published in Nutrition, Metabolism, and Cardiovascular Diseases, researchers assessed the association between consumption of ultra-processed food and dietary nutrient profiles.

Background

Cardiometabolic diseases such as diabetes, obesity, stroke, coronary heart disease, hyperlipidemia, and other cardiovascular diseases (CVD) are major causes of death and premature chronic disability. The World Health Organization (WHO) has acknowledged that diet is one of the most important risk factors for these diseases. The American Heart Association has recommended choosing foods that have undergone minimal processing instead of ultra-processed foods in their dietary guidance to decrease mortality and morbidity due to CVD.

About the study

In the present study, researchers estimated the proportion of diets having excessive free sugars content or energy density and diets having insufficient fiber content that could be negated if people reduced the consumption of ultra-processed food.

The team obtained data from national dietary surveys conducted across Brazil, Chile, Colombia, Mexico, Australia, the UK, Canada, and the US. Characteristics of the survey, such as age groups assessed, sample sizes, food composition tables, and dietary assessment methods, were also recorded. The analytical samples for the study included participants who had three or four days of entries in a food diary in the UK, two dietary recalls in Brazil, one dietary recall in Canada, Colombia, and Mexico, and up to two dietary recalls in the rest of the tested countries.

The food items mentioned in the 24-hour food diaries or recalls were categorized into four groups as per the purpose, and extent of industrial food processing: (1) minimally processed or unprocessed foods, (2) processed culinary ingredients, (3) processed foods, and (4) ultra-processed foods. For each daily recall or record, the team summed up the energy intake derived from ultra-processed foods to calculate the relative energy contribution of these ultra-processed foods.

Additionally, the relative energy contribution of ultra-processed food items per participant was estimated by calculating the average of the relative energy contributions for the total number of available records or recalls.

Furthermore, the team obtained participant relative contributions using the average of three or four days of food diaries in the US, the first and second day of dietary recall data in Brazil, and one day of dietary recall in Canada, Colombia, and Mexico. For the rest of the countries, the average of the first and second-day data for dietary recall was calculated for participants having two-day recalls. The team calculated the energy density and content of saturated fats, free sugars, and fibers for each daily recall or record.

The study described the mean values for dietary contribution in terms of the percentage of total energy uptake of ultra-processed foods, ultra-processed food population attributable fraction (PAF), along with the percentages of diets having insufficient energy density, or contents of saturated fats, free sugars, and fibers. Furthermore, the team estimated the ultra-processed food PAF for diets having one or more, two or more, three or more, and four nutrient inadequacies that can be avoided if the level of ultra-processed food consumption is reduced to levels similar to those in the 20% lowest consumers.                                      

Results

The study results showed that the average ultra-processed foods contribution to total energy intake varied between 15.8% in Colombia to 56.8% in the UK. Significant variations were observed in the mean content of free sugars from 11.5% to 14.8% and mean saturated fat from 8.6% to 12.1% of total energy intake, and fiber from 15.4 g/2000 kcal to 24.4 g/2000 kcal, and mean energy density from 1.5 kcal/g to 1.9 kcal/g. Furthermore, 3.8% of diets in Colombia and 22.9% in Canada had an excessive energy density, 49.5% in Australia and 64.5% in Brazil had excessive free sugars content, 31.4% in Colombia and 74.0% in the UK had excessive saturated fats, and 60% in Mexico and 87.3% in the US had inadequate fiber content.

If the contribution of ultra-processed foods were reduced to levels reported in each country's first quintile, statistically significant reductions in inadequate energy density or free sugar, saturated fat, and fiber content would be detected in all eight countries. Energy density reductions range from 50.4% in Chile to 76.8% in the United States, free sugar reductions from 15.5% in Colombia to 68.4% in Australia, saturated fat reductions from 9.5% in Canada to 35.0% in Mexico, and fiber reductions from 10.3% in the United Kingdom to 37.9% in Mexico.

Conclusion

Overall, the findings of the study indicated that reducing the dietary contribution of ultra-processed foods down to levels similar to those in the lowest quintile of ultra-processed food consumption in each region is a potentially effective strategy for improving the cardiometabolic-related nutrient profiles of diets and thus reducing the burden of cardiometabolic diseases.