Lifestyle and socioeconomic status influence the health effects of ultra-processed foods

Recent research published in the journal BMC Public Health To investigate the role of lifestyle and socio-economic factors in the adverse effects of ultra-processed foods (UPF) on health-related quality of life (HRQoL).

study: The association between ultra-processed food consumption and health-related quality of life varies across lifestyles and socio-economic classes.Image credit: beauty-box / Shutterstock.com

What is UPF?

UPF are highly processed, nutrient-poor foods that are often high in sugar, salt and unhealthy fats and lacking in fiber, protein and micronutrients.

Global consumption of UPF continues to increase, contributing to increased obesity, cardiovascular disease and reduced HRQoL. Previous studies have demonstrated a positive association between healthy eating habits and improved mental and physical health.

Socioeconomic and educational factors may contribute to UPF consumption and modify its impact on HRQoL. Most previous studies have investigated the relationship between these different factors in adolescents, whereas the present study included an adult population-based cohort.

About the Research

The study included 1,766 adults aged 18 to 78 years who were participants in the Tehran Lipid and Glucose Study. Study participants' UPF intake and HRQoL were assessed. Socioeconomic and lifestyle factors, such as smoking and physical activity, were also recorded.

Physical and mental health components were assessed separately and their associations determined across UPF consumption were stratified into three levels. The model was then extended to understand how lifestyle and socio-economic factors influence this relationship.

What did the results show?

There was an equal representation of men and women, and over 80% of study participants had low levels of education and were current smokers. The mean age of the study cohort was 39 years. Men had higher Physical Component Summary (PCS) and Mental Component Summary (MCS) scores than women, and smokers had higher PCS scores than nonsmokers.

The median intake of UPF was approximately 12% of total energy intake. UPF intake was higher among women, young unmarried participants, smokers, and those with a lower body mass index (BMI). These individuals were also more likely to consume more energy, saturated fat, unsaturated fat, meat, poultry, fish, and refined flour.

Unhealthy fats in the diet can contribute to insulin resistance and low-grade systemic inflammation. Muscle loss reduces an individual's functional status, promotes frailty and disability, and increases the risk of fractures, all of which reduce HRQoL.

Multivariate means (95% confidence intervals) of associations between ultra-processed foods, Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, stratified by sex, lifestyle and socioeconomic status. Data were adjusted for age, sex, BMI, energy intake, smoking status, physical activity level, marital status and education level.

In comparison, intakes of whole grains, fruits, dairy products, vegetables, and overall carbohydrates and protein decreased with increasing UPF intake. Previous studies have shown that improved nutritional status improves HRQoL in adolescents with excess BMI, but more recent studies have reported decreased emotional well-being following these interventions. Importantly, these studies have focused primarily on adolescents and are therefore not relevant to adults.

Conclusions: With increasing UPF intake, PCS scores for HRQoL decreased, but MCS scores were not affected. No adverse effect of UPF intake on PCS scores was observed in people with a healthy lifestyle and high socioeconomic status, suggesting that these factors may protect against insulin resistance and inflammation.

The relationship between PCS scores and UPF intake changed after adding parameters such as gender and occupation: for women, an increase in UPF intake was associated with a decrease in PCS scores.

Significant interactions were observed between this relationship and smoking, education, and physical activity status: smokers, people with low levels of physical activity, and people with low education tended to have lower PCS scores with increasing UPF consumption.

Both PCS and MCS scores declined among unemployed individuals with high UPF consumption.MCS scores did not reflect other significant differences due to changes in lifestyle or socioeconomic status.

One study in older Australians showed that every 10 grams of red meat added was associated with a 0.4 point reduction in MCS score. This observation was contradicted by two randomized controlled trials in which a high-protein diet was not associated with a change in MCS score. Of note, most of these studies had higher median UPF intakes than the present study.

Several extensive studies have shown that MCS scores do not correlate with diet quality. Furthermore, several prospective studies have reported that young women who eat a healthy diet have higher MCS scores than men with similar dietary patterns. Many studies have also shown that unhealthy eating habits are associated with lower MCS scores.

Conclusion

A high intake of ultra-processed foods was associated with poorer physical health, especially among women, people with unhealthy lifestyles and those from lower socio-economic backgrounds..”

Higher socioeconomic status, education level, and income level were associated with better physical HRQoL. Conversely, lifestyle factors such as smoking and low physical activity were associated with worse physical HRQoL. This is one of the first studies to report how smoking influences the association between HRQoL and UPF intake.

This study highlights the importance of healthy diet and good lifestyle choices for women and people of lower socioeconomic status.”