Estimating life expectancy gains through sustained adoption of healthier diets

A recent study published in Nature Food reports that a sustained shift toward healthier diets can improve life expectancy.

Study: Life expectancy can increase by up to 10 years following sustained shifts towards healthier diets in the United Kingdom. Image Credit: RossHelen / Shutterstock.com

Improving healthy diet habits in the U.K.

Unhealthy diets cause over 75,000 premature deaths in the United Kingdom every year. Thus, evidence of the mortality benefits of food choices is needed for the U.K. to achieve the sustainable development goal of reducing premature deaths from non-communicable diseases.

The Eat-Lancet Commission and Global Burden of Diseases and Injuries (GBD) Consortium encourage healthy eating. Likewise, the U.K. government and Public Health England (PHE) urge people to follow the dietary patterns recommended in the Eatwell guide.

Increased adherence to Eatwell guide recommendations is associated with decreased mortality in the U.K. Nevertheless, it remains unknown how sustained improvements in dietary patterns at different stages of life translate into life expectancy gains.

Estimating life expectancy gains provides a measure of possible health gains in a population and informs which policies would be effective. However, most people do not follow healthy eating guidelines, with less than 0.1% of the population in the U.K. following Eatwell guide recommendations.

About the study

In the present study, researchers estimate gains in life expectancy from a sustained change from unhealthy or median dietary patterns to Eatwell guide recommendations or longevity-associated dietary patterns in the U.K. A previously reported model was used to estimate sex- and age-specific life expectancy gains or losses following sustained changes in food consumption.

Data on median dietary patterns in the U.K. Biobank cohort were categorized into food groups, including whole grains, nuts, fish, eggs, legumes, vegetables, fruits, white meat, processed meat, red meat, sugar-sweetened beverages, milk/dairy, and refined grains. Intake of all food groups was split into quintiles, and the median dietary patterns were based on the mid-quintile.

The longevity-associated dietary patterns were quintiles with the lowest mortality association. The longevity-associated diet was characterized by a low intake of sugar-sweetened beverages, red meat, eggs, processed meat, and refined grains, a moderate intake of fruit, white meat, fish, and whole grains, and a high intake of milk, nuts, legumes, and vegetables.

Study findings

Stronger inverse associations were observed for mortality with white meat and nuts, a reduced positive association was observed between mortality and red meat, and a slight decrease in inverse associations was associated with mortality for fruits, vegetables, and whole grains.

Unhealthy dietary patterns were quintiles with the highest mortality risk estimates. This dietary pattern included no or limited quantities of fruits, vegetables, legumes, nuts, whole grains, fish, and milk/dairy and a substantial consumption of sugar-sweetened beverages, refined grains, eggs, and processed meat. A strong inverse association was observed with mortality for nuts and whole grains, whereas a strong positive association was associated with the consumption of processed meat and sugar-sweetened beverages.

Life expectancy, which was defined as the remaining estimated period of life, was 41.5 years for males and 44.7 years for females in the 40-year age group following the median dietary pattern. Likewise, the life expectancy of 70-year-old adults with a median eating pattern was 15.5 years for males and 17.6 years for females.

Estimated life expectancy gains from a sustained change from the median diet to the longevity-associated diet were 3.4 and 3.1 years for 40-year-old males and females, respectively. By contrast, estimated gains from a sustained shift to the Eatwell dietary pattern were 1.4 years for males and 1.3 years for females.

In addition, estimated gains in life expectancy from a sustained change from unhealthy diets to longevity-associated diets were over 10 years for the 40-year age group and over five years for those aged 70. Likewise, estimated gains from a sustained change to Eatwell dietary pattern were over 8.6 years for adults aged 40 and more than four years for the 70-year age group.

Conclusions

The study findings reveal that 40-year-old adults could gain nearly three years in life expectancy by shifting from the median U.K. diet to a longevity-associated diet. Notably, the estimated life expectancy gain was almost one decade for those switching from the unhealthiest diets.

Initiating dietary changes at an older age was associated with lower life expectancy gains. Increased intake of nuts and whole grains and reduced intake of processed meat and sugar-sweetened beverages were associated with the highest life expectancy gains. Thus, these food groups should be targets for clinicians and policymakers.