Sweetened beverage consumption and risk of liver cancer by diabetes status: A pooled analysis

UNDERSTANDING the LINK BETWEEN ASPARTAME and CANCER

INTRODUCTION

Aspartame, invented in 1965 by GD-Searle, is an intense artificial sweetener taste approximately 200 times as sweet as sucrose and used as an additive in more than 6,000 products. Aspartame (APM) was submitted for pre-marketing safety evaluation in early 1980. The studies, performed by GD-Searle, produced controversial results.

AREAS COVERED

Because of the great commercial diffusion of aspartame, in 1997 the Ramazzini Institute (RI) started a large experimental project on rodents to test the carcinogenic effects of aspartame following an experimental model with more sensitive characteristics, namely a large number of rat and mice, starting treatment from prenatal life, observation until spontaneous death. Overall, the project included studying 2270 rats and 852 mice. These studies have shown that aspartame is a carcinogenic agent in experimental animals, inducing a significant dose-related increased incidence of several types of malignant tumors and, among them, hematological neoplasia, and liver cancer.

EXPERT OPINION

The results of these studies on aspartame by the Ramazzini Institute opened a real front on the evaluation of artificial sweeteners and their possible health risks. Adequate long-term carcinogenicity bioassays on other diffuse artificial sweeteners such as acesulfame-k, sucralose, saccharin, including their blends, are likewise important for public health.

Acesulfame potassium upregulates PD-L1 in HCC cells by attenuating autophagic degradation

Artificial sweeteners, which contain no or few calories, have been widely used in various foods and beverages, and are regarded as safe alternatives to sugar by the Food and Drug Administration. While several studies suggest that artificial sweeteners are not related to cancer development, some research has reported their potential association with the risk of cancers, including hepatocellular carcinoma (HCC). Here, we investigated whether acesulfame potassium (Ace K), a commonly used artificial sweetener, induces immune evasion of HCC cells by upregulating programmed death ligand-1 (PD-L1). Ace K elevated the protein levels of PD-L1 in HCC cells without increasing its mRNA levels. The upregulation of PD-L1 protein levels in HCC cells by Ace K was induced by attenuated autophagic degradation of PD-L1, which was mediated by the Ace K-stimulated ERK1/2-mTORC1 signaling pathway. Ace K-induced upregulation of PD-L1 attenuated T cell-mediated death of HCC cells, thereby promoting immune evasion of HCC cells. In summary, the present study suggests that Ace K promotes HCC progression by upregulating the PD-L1 protein level.

Ultra-processed foods and food additives in gut health and disease

Ultra-processed foods (UPFs) and food additives have become ubiquitous components of the modern human diet. There is increasing evidence of an association between diets rich in UPFs and gut disease, including inflammatory bowel disease, colorectal cancer and irritable bowel syndrome. Food additives are added to many UPFs and have themselves been shown to affect gut health. For example, evidence shows that some emulsifiers, sweeteners, colours, and microparticles and nanoparticles have effects on a range of outcomes, including the gut microbiome, intestinal permeability and intestinal inflammation. Broadly speaking, evidence for the effect of UPFs on gut disease comes from observational epidemiological studies, whereas, by contrast, evidence for the effect of food additives comes largely from preclinical studies conducted in vitro or in animal models. Fewer studies have investigated the effect of UPFs or food additives on gut health and disease in human intervention studies. Hence, the aim of this article is to critically review the evidence for the effects of UPF and food additives on gut health and disease and to discuss the clinical application of these findings.

Association between healthy beverage index and nonalcoholic fatty liver disease in the Ravansar noncommunicable disease cohort study

The quality of drinks affects the functioning of the liver. In recent decades, the variety of high-calorie and sweet drinks has increased. The objective of this study was to explore the association between Healthy Beverage Index (HBI) and the risk of nonalcoholic fatty liver disease (NAFLD) among adults. We included 6,276 participants aged 35 to 65 from the Ravansar Non-Communicable Disease (RaNCD) cohort study at baseline. NAFLD is defined based on the fatty liver index (FLI), calculated using anthropometric measurements and non-invasive markers. The HBI was developed using a combination of water, low-fat milk, 100% fruit juice, sugar-sweetened beverages, met fluid requirement and % energy from beverages. Logistic and linear regression models were employed to investigate the associations of the HBI and high FLI. The average FLI was significantly lower in the first tertile of HBI compared to the third tertile (47.83 vs. 45.77; P = 0.001). After adjusting for confounding variables, the odds of high FLI decreased by 28% (OR 0.72, 95% CI 0.63, 0.82) in the second tertile of HBI and by 21% in the third tertile (OR 0.79, 95% CI 0.70, 0.91). There was no correlation between gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate transaminase (AST) levels with HBI. The study findings indicate an inverse association between high FLI and HBI. Therefore, it is recommended to consume healthy beverages and without added sugar. However, additional longitudinal studies are required to examine the association between beverage consumption and the development of NAFLD.

Sugar sweetened beverages, natural fruit juices, and cancer: what we know and what still needs to be assessed

Cancer is known as one of the leading causes of death in the world. In addition to early mortality, cancer is associated with disability in affected patients. Among environmental risk factors, special attention has been paid to the role of dietary factors. In recent decades, the consumption of sugar-sweetened beverages (SSBs) and natural fruit juices has increased. Several studies have assessed the effects of these beverages on human health and found that a higher intake of SSBs is associated with a greater risk of obesity, diabetes, cardiovascular diseases, hypertension, and non-alcoholic fatty liver disease. However, current evidence for cancer incidence and mortality is not conclusive. In the current review, we concluded that SSBs intake might be positively associated with cancer incidence/mortality through their increasing effects on obesity, inflammatory biomarkers, serum levels of insulin-like growth factor-I (IGF-I), and advanced glycation end-products. Such a positive association was also seen for natural fruit juices. However, types of natural fruit juices were not considered in most previous studies. In addition, some types of cancer including brain, lung, and renal cancers were not assessed in relation to SSBs and natural fruit juices. Therefore, further studies are needed in this regard.

Perspectives on recent reviews of aspartame cancer epidemiology

Aspartame is a dipeptide non-sugar sweetener that was first marketed in the US in carbonated beverages in 1983, before gaining prominence globally. The Joint Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) and the WHO International Agency for Research on Cancer (IARC) completed evaluations of aspartame and cancer in July 2023. JECFA reaffirmed the safety of aspartame, stating that epidemiology evidence is "not convincing," and that there are no consistent associations between aspartame and cancer (JECFA/IARC, 2023; JECFA, 2023). JECFA also noted "reverse causality, chance, bias and confounding by socioeconomic or lifestyle factors, or consumption of other dietary components, could not be completely ruled out" in relevant epidemiology studies (JECFA/IARC, 2023). In contrast, IARC stated that there are three "high quality" studies on liver cancer (Riboli, 2023), but that the evidence is limited because "chance, bias or confounding could not be ruled out as an explanation for the positive findings" (JECFA/IARC, 2023). IARC does not provide an explanation as to how these studies can be both high quality and have these weaknesses, most notably potential exposure misclassification, or how inconsistent associations from studies with these weaknesses constitute limited evidence. Further, when IARC concludes an agent has limited or inadequate human evidence (and no sufficient animal or strong mechanistic evidence), it classifies that agent as either Group 2B, a possible human carcinogen, or Group 3, not classifiable as to its carcinogenicity. Ultimately, the interpretations of Group 2B and Group 3 classifications are intended to be similar. However, a Group 2B designation may make it appear to scientists and non-scientists alike that the evidence is pointing in the direction of causality. This can lead to unnecessary confusion with respect to the evidence, as well as a perception of a disagreement within WHO regarding aspartame. This apparent contradiction could have been avoided by assigning the IARC classification most consistent with the conclusion that the human evidence for cancer is inadequate: Group 3.

Sugar-Sweetened and Artificially Sweetened Beverages and Risk of Liver Cancer and Chronic Liver Disease Mortality

Importance

Approximately 65% of adults in the US consume sugar-sweetened beverages daily.

Objective

To study the associations between intake of sugar-sweetened beverages, artificially sweetened beverages, and incidence of liver cancer and chronic liver disease mortality.

Design, Setting, and Participants

A prospective cohort with 98 786 postmenopausal women aged 50 to 79 years enrolled in the Women's Health Initiative from 1993 to 1998 at 40 clinical centers in the US and were followed up to March 1, 2020.

Exposures

Sugar-sweetened beverage intake was assessed based on a food frequency questionnaire administered at baseline and defined as the sum of regular soft drinks and fruit drinks (not including fruit juice); artificially sweetened beverage intake was measured at 3-year follow-up.

Main Outcomes and Measures

The primary outcomes were (1) liver cancer incidence, and (2) mortality due to chronic liver disease, defined as death from nonalcoholic fatty liver disease, liver fibrosis, cirrhosis, alcoholic liver diseases, and chronic hepatitis. Cox proportional hazards regression models were used to estimate multivariable hazard ratios (HRs) and 95% CIs for liver cancer incidence and for chronic liver disease mortality, adjusting for potential confounders including demographics and lifestyle factors.

Results

During a median follow-up of 20.9 years, 207 women developed liver cancer and 148 died from chronic liver disease. At baseline, 6.8% of women consumed 1 or more sugar-sweetened beverage servings per day, and 13.1% consumed 1 or more artificially sweetened beverage servings per day at 3-year follow-up. Compared with intake of 3 or fewer servings of sugar-sweetened beverages per month, those who consumed 1 or more servings per day had a significantly higher risk of liver cancer (18.0 vs 10.3 per 100 000 person-years [P value for trend = .02]; adjusted HR, 1.85 [95% CI, 1.16-2.96]; P = .01) and chronic liver disease mortality (17.7 vs 7.1 per 100 000 person-years [P value for trend <.001]; adjusted HR, 1.68 [95% CI, 1.03-2.75]; P = .04). Compared with intake of 3 or fewer artificially sweetened beverages per month, individuals who consumed 1 or more artificially sweetened beverages per day did not have significantly increased incidence of liver cancer (11.8 vs 10.2 per 100 000 person-years [P value for trend = .70]; adjusted HR, 1.17 [95% CI, 0.70-1.94]; P = .55) or chronic liver disease mortality (7.1 vs 5.3 per 100 000 person-years [P value for trend = .32]; adjusted HR, 0.95 [95% CI, 0.49-1.84]; P = .88).

Conclusions and Relevance

In postmenopausal women, compared with consuming 3 or fewer servings of sugar-sweetened beverages per month, those who consumed 1 or more sugar-sweetened beverages per day had a higher incidence of liver cancer and death from chronic liver disease. Future studies should confirm these findings and identify the biological pathways of these associations.

Associations between food groups and liver cancer: a systematic review and meta-analysis of observational studies

CONTEXT

Diet is emerging as a modifiable component of lifestyle for influencing the incidence of liver cancer.

OBJECTIVE

To investigate and quantify the potential relationship between food groups and liver cancer.

DATA SOURCES

PubMed and Web of Science were searched for eligible observational studies until 31st March, 2023.

DATA EXTRACTION

The meta-analysis was conducted by pooling relative risk (RR), odds ratio (OR) or hazards ratio (HR) with 95% confidence intervals (CIs). Potential sources of heterogeneity were detected by subgroup analysis. Sensitivity analysis and publication bias test were also carried out.

DATA ANALYSIS

Through stepwise screening, a total of 27 studies were included. The pooled estimates of liver cancer for whole grains and legumes intake were 0.66 (95% CI: 0.54-0.82; I² = 25.3%) and 0.86 (95% CI: 0.75-0.99; I² = 14.3%), respectively. However, there were null associations of nuts, poultry, egg and sweetened beverages consumption with liver cancer and the association between refined grains and liver cancer was inconclusive. In dose-response meta-analysis, the pooled estimates of liver cancer were 0.77 (95% CI: 0.65-0.91) for every 50 g/day increment in whole grains intake. Non-linear dose-response relationship (P = 0.031) was observed in the association between the intake of legumes and liver cancer, and the protective effect occurred with the dose ranging from 8 g/day to 40 g/day.

CONCLUSIONS

This meta-analysis shows that whole grains and legumes were inversely associated with liver cancer, whereas intake of nuts, poultry, egg and sweetened beverages may not be associated with liver cancer. Further quantitative research needs to be undertaken within a range of populations to investigate the relationship between food groups and liver cancer.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021246142.

Non-sugar sweeteners and cancer: Toxicological and epidemiological evidence

Several toxicological and epidemiological studies were published during the last five decades on non-sugar sweeteners (NSS) and cancer. Despite the large amount of research, the issue still continues to be of interest. In this review, we provided a comprehensive quantitative review of the toxicological and epidemiological evidence on the possible relation between NSS and cancer. The toxicological section includes the evaluation of genotoxicity and carcinogenicity data for acesulfame K, advantame, aspartame, cyclamates, saccharin, steviol glycosides and sucralose. The epidemiological section includes the results of a systematic search of cohort and case-control studies. The majority of the 22 cohort studies and 46 case-control studies showed no associations. Some risks for bladder, pancreas and hematopoietic cancers found in a few studies were not confirmed in other studies. Based on the review of both the experimental data on genotoxicity or carcinogenicity of the specific NSS evaluated, and the epidemiological studies it can be concluded that there is no evidence of cancer risk associated to NSS consumption.