The relationship between ultraprocessed food consumption and obesity indicators in Iranian adults

Ultra-processed food consumption and cardiovascular events rate: An analysis from Isfahan Cohort Study (ICS)

BACKGROUND AND AIMS

The contribution of ultra-processed foods (UPFs) to daily energy intake and, therefore, their health effects may vary between countries. We aimed to investigate the association between UPFs and the incidence risk of cardiovascular events (CVEs) and cardiovascular mortality in the Isfahan cohort study.

METHODS AND RESULTS

In 2001, 6504 participants aged ≥35 years were enrolled and followed until 2017. Dietary intake was assessed using a validated food frequency questionnaire, and the NOVA system was applied for UPF classification. Any new case of CVE, including fatal and non-fatal myocardial infarction (MI) or stroke, unstable angina (UA), and CVD death, was recorded. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated through Cox proportional hazards regression models. A total number of 819 CVE, 164 MI, 348 UA, 172 strokes, and 181 cardiovascular deaths were recorded during 61352.5 person-years of follow-up. The median (IQR) of UPF consumption was 2.47 (1.00-5.23) times/week. In the fully adjusted model, individuals in the fourth quartile of UPFs had no higher risk for incident MI and UA (HR = 1.12, 95% CI: 0.87, 1.46; P for trend = 0.364), stroke (HR = 0.93, 95% CI: 0.58, 1.46; P for trend = 0.601), cardiovascular mortality (HR = 0.95, 95% CI: 0.61, 1.47; P for trend = 0.596), and CVE (HR = 1.08, 95% CI: 0.88,1.34; P for trend = 0.515) in comparison with those in the first quartile.

CONCLUSION

This mid-term prospective cohort study provides no evidence for a significant association between UPF and CVE risk. Longer studies are required to confirm this association.

Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Evidence of associations between ultra-processed foods (UPF) and increased risk of cardiovascular disease is emerging, but it is unclear how much this is influenced by the methodology used to assess the UPF intake or by the level of consumption. We conducted a meta-analysis to evaluate 1) the association between UPF consumption and risk of diabetes, hypertension, dyslipidemia, and obesity, using prospective cohort studies; 2) the differential associations depending on the methodology used to assess UPF intake and the level of UPF consumption and 3) the quality of evidence using the NutriGrade scoring system. A systematic literature search was conducted in PubMed/MEDLINE, ISI Web of Science, and Scopus through 1 April, 2023, on studies conducted in humans providing data for the highest compared with the lowest UPF consumption categories. Summary relative ratios (RRs) and 95% confidence intervals (95% CI) were estimated using a random-effects model. Out of 4522 articles retrieved from the literature search, 25 reports met the criteria for inclusion in the meta-analysis, 7 for diabetes, 5 for hypertension, 3 for dyslipidemia, and 13 for obesity. A consistently positive association between high UPF intake and increased risk of developing diabetes (37%), hypertension (32%), hypertriglyceridemia (47%), low HDL cholesterol concentration (43%), and obesity (32%) was observed, even if the quality of evidence was not satisfying. However, these risks varied significantly depending on the methodology used to assess UPF consumption, with a difference of more than 50% between the methods. Based on the level of intake, we did not observe significant differences in the results. These findings show that UPF consumption is associated with higher risk of diabetes, hypertension, dyslipidemia, and obesity, but the level of risk consistently changes depending on the methodology used to assess UPF intake. Therefore, caution should be used when interpreting and extrapolating the results.

The association between ultra-processed foods and conventional markers of cardiovascular risk in an adult Iranian population

BACKGROUND AND AIMS

According to the NOVA classification system, ultra-processed foods result from extensive industrial processing and use ingredients derived from food and non-food products, which can negatively impact on cardiovascular disease risk factors. Despite this, few studies have investigated UPFs in Middle Eastern populations regardless of high consumption in this region.

METHODS AND RESULTS

This cross-sectional study was conducted on data from the Prospective Epidemiological Research Studies in Iran Kharemeh cohort (n = 6611). Food frequency questionnaires were assessed and the ratio of total UPFs energy/total energy intake was calculated. Data was categorized into tertiles of UPF consumption using the NOVA classification system. Kruskal-Wallis tests were used to assess differences in nutrient and food intakes between tertiles and logistic regression analysis was applied to assess the associations between UPFs and CVD risk factors. After adjustment for potential confounders the logistic regression analysis revealed significant positive relationships between intakes of UPFs and waist circumference (WC) (T2: OR; 1.34, 95% CI; 1.13-1.60 - T3: OR; 1.41, 95% CI; 1.18-1.69, P ˂0.001), low-density lipoprotein cholesterol (LDL-C) (T2: OR; 1.20, 95% CI; 1.05-1.37 - T3: OR; 1.27, 95% CI; 1.11-1.45, P ˂0.001), non-high-density lipoprotein cholesterol (non-HDL) (T2: OR; 1.21, 95% CI; 1.07-1.37 - T3: OR; 1.24, 95% CI; 1.10-1.41, P ˂0.001) and LDL-C to HDL-C ratio (T2: OR; 1.15, 95% CI; 1.02-1.31 - T3: OR; 1.21, 95% CI; 1.07-1.38, P = 0.002).

CONCLUSION

The consumption of UPFs was positively associated with WC and atherogenic blood lipids. However, increased intakes of fiber and unsaturated fats were also found in those consuming more UPFs, which was not expected. These findings offer insights into an understudied population and warrant further research.

The relationship between ultra processed food consumption and premature coronary artery disease: Iran premature coronary artery disease study (IPAD)

Background

Ultra-processed foods (UPF) consumption may affect the risk of PCAD through affecting cardio metabolic risk factors. This study aimed to evaluate the association between UPFs consumption and premature coronary artery disease (PCAD).

Methods

A case-control study was conducted on 2,354 Iranian adults (≥ 19 years). Dietary intake was assessed using a validated 110-item food frequency questionnaire (FFQ) and foods were classified based on the NOVA system, which groups all foods according to the nature, extent and purposes of the industrial processes they undergo. PCAD was defined as having an stenosis of at least single coronary artery equal and above 75% or left main coronary of equal or more than 50% in women less than 70 and men less than 60 years, determined by angiography. The odds of PCAD across the tertiles of UPFs consumption were assessed by binary logistic regression.

Results

After adjustment for potential confounders, participants in the top tertile of UPFs were twice as likely to have PCAD compared with those in the bottom tertile (OR: 2.52; 95% CI: 1.97-3.23). Moreover, those in the highest tertile of the UPFs consumption had more than two times higher risk for having severe PCAD than those in the first tertile (OR: 2.64; 95% CI: 2.16-3.22). In addition, there was a significant upward trend in PCAD risk and PCAD severity as tertiles increased (P-trend < 0.001 for all models).

Conclusion

Higher consumption of UPFs was related to increased risk of PCAD and higher chance of having severe PCAD in Iranian adults. Although, future cohort studies are needed to confirm the results of this study, these findings indicated the necessity of reducing UPFs intake.

Ultra-processed foods and the development of obesity in adults

Ultra-processed foods (UPF) are ubiquitous in the modern-day food supply and widely consumed. High consumption of these foods has been suggested to contribute to the development of obesity in adults. The purpose of this review is to present and evaluate current literature on the relationship between UPF consumption and adult obesity. Cross-sectional studies (n = 9) among different populations worldwide show a positive association between UPF consumption and obesity. Longitudinal studies (n = 7) further demonstrate a positive association between UPF consumption and development of obesity, suggesting a potential causal influence of UPF consumption on obesity risk. However, only one randomized controlled trial has tested the causality of this association. The study included in this review found greater energy intake and weight gain with consumption of a high UPF diet compared to a high unprocessed food diet. The potential mechanisms by which UPF increase the risk of obesity include increased energy intake due to increased sugar consumption, decreased fiber consumption, and decreased protein density; however, more research is needed. Overall, the evidence identified in the current review consistently support a positive relation between high UPF consumption and obesity. While there is a need for more experimental research to establish causality and elucidate the mechanisms, the sum of the evidence supports a need for research on treatment modalities that include reductions in UPF consumption for the management of adult obesity.