Reference
Lane MM, Lotfaliany M, Forbes M, et al. Higher ultraprocessed food consumption is associated with greater high-sensitivity C-reactive protein concentration in adults: cross-sectional results from the Melbourne Collaborative Cohort Study. Nutrients. 2022;14(16):3309.
Study Objective
To determine if ultraprocessed foods are associated with biomarkers of inflammation, specifically high-sensitivity C-reactive protein (hs-CRP)
Key Takeaway
Ultraprocessed food intake was associated with a 4% increase in hs-CRP, and this association occurred independent of body mass index (BMI) or sex.
Design
Observational study of the Melbourne Collaborative Cohort Study (MCCS)
Participants
Between 1990 and 1994, 41,500 people (24,500 women and 17,000 men) aged 40 to 69 years (average age 57 years) were recruited to participate in the MCCS.1
The participants came from a sample of the MCCS for whom valid baseline dietary data and plasma hs-CRP measurements were available.
Authors excluded participants who had missing hs-CRP data, a total energy intake (kJ/day) below the 1st percentile or above the 99th percentile, or a hs-CRP concentration above the 99th percentile.
Ultimately, 2,018 participants remained for analysis, including both the cardiovascular disease death group (n=632) as cases and the random sample of all participants (n=1,386) from the original MCCS project as the subcohort.
Study Parameters Assessed
The study parameters included a variety of sociodemographic characteristics such as age, sex, country of birth, marital status, highest level of education, and socioeconomic indexes.
Investigators also assessed lifestyle and health-related behaviors such as smoking status, leisure-time physical activity over the last 6 months, and alcohol intake as covariates. Anthropometric data such as height and weight were measured to determine BMI. They also collected dietary information using a food frequency questionnaire specifically created for this multi-ethnic cohort.
Primary Outcome Measure
Researchers investigated the association between hs-CRP concentration (mg/L) and the intake of ultraprocessed foods as classified by the NOVA food classification system.
Key Findings
For each 100-g increase in the intake of ultraprocessed foods, there was a 4.0% increase in hs-CRP (95% CIs: 2.1–5.9%, P<0.001), and this appeared independent of BMI. There was no difference between the sexes.
Transparency
There was no external funding for this study.
Practice Implications
With the increasing prevalence of ultraprocessed foods in the Australian diet concomitant with the growing prevalence of chronic diseases and increased mortality, significant public health concerns have arisen.
While a few previous studies involving Brazilian subjects demonstrated direct cross-sectional associations between the consumption of ultraprocessed foods and the concentration of inflammatory cytokines, the authors of the study under review here note that the participants’ sociodemographic characteristics in those studies have been associated with lower consumption of ultraprocessed foods. In the Brazilian sample of adolescents, ultraprocessed foods contributed 26% of total daily energy intake compared to 40% in the current study.2
In the current study, authors found that hs-CRP increased as the ingestion of ultraprocessed foods increased. Testing for effect modification by sex showed no evidence of interaction. Authors note that “given the under representation of women compared to men in our study (37.5% were women), it is possible that we may not have had adequate power to detect this interaction.”
In the Brazilian sample of adolescents, ultraprocessed foods contributed 26% of total daily energy intake compared to 40% in the current study.2
These findings are consistent with recent systematic reviews and meta-analyses showing direct associations between intake of ultraprocessed foods and the prevalence and incidence of common chronic noncommunicable diseases, morbidity, and mortality, all of which include inflammation as part of their pathophysiology.3–5
Conversely, diet scores measuring adherence to healthy or Mediterranean-style diets—rich in fruits, vegetables, fatty fish, poultry, extra virgin olive oil, and whole grains—appear to be inversely associated with inflammatory biomarkers in cross-sectional analyses.6 In terms of experimental evidence, the current study results are also consistent with an earlier meta-analysis of intervention studies showing that Mediterranean diets higher in unprocessed or minimally processed foods were anti-inflammatory.7
It is possible that policy interventions that limit the production, distribution, and dietary intake of ultraprocessed foods may reduce their consumption.
Ultimately, these results, along with the findings of several other studies, underscore the importance of access to both nutrient-dense foods and healthcare professionals who can offer guidance on healthy eating choices and behaviors, thus creating a direct impact on morbidity and mortality reduction.
