Degree of food processing and breast cancer risk in black urban women from Soweto, South African: the South African Breast Cancer study

Ultra-Processed Food Consumption and Gastrointestinal Cancer Risk: A Systematic Review and Meta-Analysis

INTRODUCTION

Ultra-processed food (UPF) intake has been associated with a higher risk of obesity, hypertension, type 2 diabetes, and cardiovascular diseases. The initial data on the relationship between UPF consumption and cancer risk were derived from retrospective observational studies with conflicting results. This systematic review and meta-analysis of prospective cohort studies aimed to investigate the association between UPF consumption and gastrointestinal cancer risk.

METHODS

PubMed, Embase, and Cochrane databases were searched for prospective cohort studies that compared the highest vs the lowest level of UPF consumption according to NOVA food classification and reported the risk of gastrointestinal cancers by subsite. The association with cancer was quantified as hazard ratios (HR) using a random-effects model.

RESULTS

Five prospective cohort studies were included in this review comprising 1,128,243 participants (241,201 participants in the highest and 223,366 in the lowest levels of UPF consumption). The mean follow-up ranged from 5.4 to 28 years. The highest UPF consumption was significantly associated with an increased risk of colorectal cancer (HR 1.11; 95% confidence interval [CI] 1.03-1.21; P = 0.01; I2 = 31%), colon cancer (HR 1.12; 95% CI 1.02-1.23; P = 0.02; I2 = 0%), and non-cardia gastric cancer (HR 1.43; 95% CI 1.02-2.00; P = 0.04; I2 = 0%) compared with the lowest UPF intake. However, no association was found between high UPF consumption and hepatocellular, esophageal, pancreatic, gastric cardia, and rectal cancer.

DISCUSSION

The highest level of UPF consumption was significantly associated with colorectal and non-cardia gastric cancer.

Dietary intake of low-income adults in South Africa: ultra-processed food consumption a cause for concern

OBJECTIVE

Given the rapidly changing food environment and proliferation of ultra-processed foods (UPF) in South Africa (SA), this study aimed to critically evaluate dietary quality and adequacy of low-income adults using the Nova classification system and WHO and World Cancer Research Fund dietary guidelines.

DESIGN

Secondary household data and 1-d 24-h recalls were analysed from two cross-sectional studies conducted in 2017-2018. Foods consumed were classified according to the Nova classification system. Compliance with WHO dietary guidelines and UPF consumption trends were evaluated.

SETTING

Three low-income areas (Langa, Khayalitsha and Mount Frere) in SA were included.

PARTICIPANTS

In total, 2521 participants (18-50 years) were included in the study.

RESULTS

Participants had a mean energy intake of 7762 kJ/d. Most participants were within the acceptable WHO guideline range for saturated fat (80·4 %), total fat (68·1 %), Na (72·7 %) and free sugar (57·3 %). UPF comprised 39·4 % of diets among the average adult participant. Only 7·0 % of all participants met the WHO guideline for fruit and vegetables and 18·8 % met the guideline for fibre. Those within the highest quartile of share of energy from UPF consumed statistically higher amounts of dietary components to limit and were the highest energy consumers overall.

CONCLUSIONS

Low-income adults living in SA are consuming insufficient protective dietary components, while UPF consumption is prevalent. Higher UPF consumers consume larger amounts of nutrients linked to increased chronic disease risk. Policy measures are urgently needed in SA to protect against the proliferation of harmful UPF and to promote and enable consumption of whole and less UPF.

Association between ultra-processed food consumption and risk of breast cancer: a systematic review and dose-response meta-analysis of observational studies

Background

Some epidemiological studies have examined the association between consumption of ultra-processed food (UPF) and the risk of breast cancer. However, the results were inconsistent. Therefore, we carried out a systematic review and dose-response meta-analysis to examine whether an association exists between high consumption of UPF and breast cancer risk.

Methods

PubMed/MEDLINE, ISI Web of Science, EBSCO and CNKI databases were systematically searched from inception to May 2023. The summary relative risks (RRs) and 95% confidence intervals (CIs) associated with UPF consumption and breast cancer were calculated using a random-effects model (DerSimonian-Laird method). Heterogeneity between included studies was examined using the Cochran's Q test and I-square (I2) statistics. Publication bias was studied by visual inspection of funnel plot asymmetry and Begg's and Egger's tests.

Results

Overall, six articles involving 462,292 participants, were eligible to be included in this study. Compared to the lowest consumption, highest consumption of UPF was related to a higher risk of breast cancer (RR = 1.10; 95%CI: 1.00-1.22, p = 0.056). Besides, the linear dose-response analysis showed that each 10% increment in UPF consumption was related to a 5% higher risk of breast cancer (RR = 1.05; 95%CI: 1.00-1.10, p = 0.048). Subgroup analyses suggested that UPF consumption was positively associated with breast cancer risk in case-control studies (RR = 1.13; 95%CI: 1.01-1.26, p = 0.028). Additionally, there was also a significant positive association between UPF consumption and breast cancer risk in the subgroup with sample size<5,000(RR = 1.17; 95%CI: 1.02-1.35, p = 0.028).

Conclusion

Our results indicate that higher consumption of UPF is slightly related to a higher risk of breast cancer. Further studies in particular of large prospective cohort studies are warranted to confirm these results.

Association between ultra-processed foods and risk of cancer: a systematic review and meta-analysis

Background

Despite increasing evidence that has shown the association of ultra-processed foods (UPFs) with cancer risk, the results remain inconclusive. We, therefore, conducted the meta-analysis to clarify the association by including recently published studies.

Methods

A comprehensive search was conducted in PubMed, Embase, and Web of Science to identify all relevant studies from inception to January 2023. To pool data, fixed-effects or random-effects models were used where appropriate. Subgroup analyses, sensitivity analyses, and publication bias tests were performed.

Results

A total of 13 studies (4 cohort studies and 9 case-control studies) were included in the analysis, with a total of 625,738 participants. The highest UPFs consumption was associated with increased risk of colorectal cancer (OR = 1.23, 95% CI: 1.10-1.38), colon cancer (OR = 1.25, 95% CI: 1.14-1.36), and breast cancer (OR = 1.10, 95% CI: 1.00-1.20) but not rectal cancer (OR = 1.18, 95% CI: 0.97-1.43) and prostate cancer (OR = 1.03, 95% CI: 0.93-1.12). In addition, the subgroup analyses showed that a positive association between UPFs consumption and colorectal cancer was observed among men (OR = 1.31, 95% CI: 1.15-1.50), whereas no significant association was observed among women (OR = 1.10, 95% CI: 0.94-1.29).

Conclusion

The present meta-analysis suggests that high UPFs consumption is associated with a significantly increased risk of certain site-specific cancers, especially the digestive tract and some hormone-related cancers. However, further rigorously designed prospective and experimental studies are needed to better understand causal pathways.

Ultra-processed food consumption and cancer risk: A systematic review and meta-analysis

BACKGROUND

Ultra-processed foods (UPF) have become a staple of the diet in many countries, concomitant with increases in non-communicable diseases including cancer.

AIM

The aim of this systematic literature review was to evaluate associations between the consumption of UPF and cancer risk.

METHODS

A systematic literature search for observational studies investigating the association between cancer risk and UPF consumption, determined by the NOVA classification system, was performed. Random-effects meta-analyses were conducted. Independent review and risk of bias assessment was performed independently by the authors using the National Institutes of Health's Study Quality Assessment Tools.

RESULTS

Eleven reports were identified, including eight retrospective case-control studies and three prospective cohorts. The outcome was risk of total cancer and/or one or more of the following cancers: colorectal, breast, prostate, pancreatic, chronic lymphocytic leukemia and central nervous system tumors. Nine studies reported a significant positive association between UPF intake and all the assessed cancers except prostate, after adjustment for confounding factors including obesity and total energy intake. A 10% increment in the diet's proportion of UPF was associated with increased risk of overall cancer (HR = 1.13, 95% CI 1.07 to 1.18) and breast cancer (HR = 1.11, 95% CI 1.01 to 1.21). In addition, a high intake of UPF was associated with increased risk of colorectal cancer (ORT3 vs. T1 = 1.30, 95% CI 1.11 to 1.51) and pancreatic cancer (HRQ4 vs. Q1 = 1.49, 95% CI 1.07 to 2.07). More modest associations were found for chronic lymphocytic leukemia and central nervous system tumors. Common limitations of several of the studies included no prior assessment of diet before known diagnosis (the case-control studies), higher participation rates among cases, and likely misclassification of several foods as UPF or non-UPF.

CONCLUSION

In conclusion, the available suggestive evidence shows a consistent significant association between intake of UPF and the risk of overall and several cancers, including colorectal-, breast- and pancreatic cancer. These data may inform updated dietary guidelines, policy makers and the public towards improving public health.