Dietary Insulin Index and Insulin Load in Relation to Breast Cancer: Findings from a Case-Control Study

Associations Between Dietary Factors and Breast Cancer Risk: A Systematic Review of Evidence from the MENA Region

BACKGROUND

The Middle East and North Africa (MENA) region is witnessing a continuous rise in the incidence of breast cancer (BC). This region is characterized by distinct cultural and lifestyle habits. Despite the importance of diet as a modifiable risk factor for BC, its role in the development of BC within the MENA context has not been extensively studied. This systematic review aims to identify and synthesize existing evidence regarding the effect of different dietary factors on BC risk among women from this region.

METHODS

We systematically reviewed the scientific literature for observational studies that examined the association between specific dietary factors and the risk of BC in MENA, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Our comprehensive search included databases such as PubMed, Web of Science, ScienceDirect, and Scopus, identified a total of 18,085 records, of which 65 met our inclusion criteria and were assessed for quality using the National Institute of Health Quality Assessment Tool.

RESULTS

The findings of the 65 included studies were categorized into food groups, nutrients, and dietary patterns. Studies in the MENA region have consistently shown that the consumption of fruit and vegetables, fish and seafood, and black tea are associated with a reduced BC risk. In contrast, the intake of milk and white bread is linked to an increased risk. Specific dietary patterns such as the Mediterranean diet, a healthy plant-based diet, dietary antioxidant index, and overall healthy dietary patterns have shown a negative association with BC risk. Conversely, the dietary insulin index and load, dietary glycemic index, dietary inflammatory index, and unhealthy dietary patterns are associated with an increased risk of BC. For the remaining dietary factors, research was too limited or inconsistent to draw conclusions.

CONCLUSIONS

Our findings highlight the significant role of dietary factors in modulating BC risk among women in the MENA region, an area that faces a notable gap in research on this topic. Further studies are essential to deepen our understanding and develop targeted dietary recommendations for BC prevention in this population.

Dietary insulin indices and low-carbohydrate diet and the odds of colorectal cancer: a case-control study

BACKGROUND

Regarding the role of insulin and insulin-inducing dietary factors in some cancers' etiology, we hypothesized that the risk of colorectal cancer may be lessened by following a lower carbohydrate and insulinogenic diet. Therefore, we performed this study to explore the association between a low-carbohydrate diet and insulin indices and the odds of colorectal cancer.

METHOD

This hospital-based case-control study was conducted on 150 newly diagnosed colorectal cancer patients and 300 healthy age- and sex-matched hospitalized controls. A valid and reliable food frequency questionnaire was used to calculate the insulin indices and low-carbohydrate diet score. Multivariate logistic regression was used to estimate the association between insulin indices and low-carbohydrate diet and the odds of colorectal cancer.

RESULT

After adjusting for potential confounders, individuals in the highest tertile of insulin indices had a higher risk of colorectal cancer (OR insulin index  = 3.46; 95% CI, 2.00-5.96; OR insulin load  = 2; 95% CI, 1.17-3.41). No association was found between a low-carbohydrate diet and colorectal cancer (OR = 1.55; 95% CI, 0.85-2.84).

CONCLUSION

Current results demonstrated that a high insulinemic diet was associated with a higher risk of colorectal cancer.

The association of dietary insulin load and index with the risk of cancer and cancer mortality: a systematic review and meta-analysis

Purpose

Insulin levels play an important role in cancer development. However, the link between an insulinogenic diet and cancer is still unclear. Therefore, we performed a systematic review with meta-analysis to investigate the association between dietary insulin index (II) and load (IL) with cancer risk and mortality.

Methods

A comprehensive search between electronic databases (Web of Science, PubMed/Medline, Scopus, and Google Scholar) was conducted to identify relevant studies up to January 2022. The relative risks (RR) and Odds ratios (OR) were extracted from eligible studies, and meta-analysis was performed to calculate the pooled effect size.

Result

12 papers including 14 studies (10 cohorts and 4 case-control) were included for the meta-analysis. Among them, 10 studies reported effect size for the risk of cancer, and 4 studies reported effect size for cancer mortality. We observed no significant association between II and IL with cancer overall (RR_II: 1.03, 95%CI: 0.91-1.17, RR_IL: 1.16, 95%CI: 0.94-1.42) and in cohort studies, however, in case-control studies was related with higher odds of cancer (OR_II: 2.30, 95%CI: 1.21-4.38, OR_IL: 2.57, 95%CI: 1.64-4.02). Higher II and IL scores were associated with the increased risk of total (RR_II: 1.29, 95%CI: 1.02-1.63) and (RR_IL: 1.39, 95%CI: 1.06-1.83) and colorectal cancer mortality (RR_II: 1.29, 95%CI: 1.13-1.48) and (RR_IL: 1.37, 95%CI: 1.18-1.60).

Conclusion

Higher dietary II and IL were not associated with cancer risk in overall and cohort studies, whereas related with a higher risk of cancer in case-control studies. We observed a significant positive relation of II and IL with cancer mortality, especially CRC mortality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01013-3.