A review of the genotoxic and carcinogenic effects of aspartame: does it safe or not?

Could Insulin Be a Better Regulator of Appetite/Satiety Balance and Body Weight Maintenance in Response to Glucose Exposure Compared to Sucrose Substitutes? Unraveling Current Knowledge and Searching for More Appropriate Choices

BACKGROUND

Insulin exerts a crucial impact on glucose control, cellular growing, function, and metabolism. It is partially modulated by nutrients, especially as a response to the intake of foods, including carbohydrates. Moreover, insulin can exert an anorexigenic effect when inserted into the hypothalamus of the brain, in which a complex network of an appetite/hunger control system occurs. The current literature review aims at thoroughly summarizing and scrutinizing whether insulin release in response to glucose exposure may be a better choice to control body weight gain and related diseases compared to the use of sucrose substitutes (SSs) in combination with a long-term, well-balanced diet.

METHODS

This is a comprehensive literature review, which was performed through searching in-depth for the most accurate scientific databases and applying effective and relevant keywords.

RESULTS

The insulin action can be inserted into the hypothalamic orexigenic/anorexigenic complex system, activating several anorexigenic peptides, increasing the hedonic aspect of food intake, and effectively controlling the human body weight. In contrast, SSs appear not to affect the orexigenic/anorexigenic complex system, resulting in more cases of uncontrolled body weight maintenance while also increasing the risk of developing related diseases.

CONCLUSIONS

Most evidence, mainly derived from in vitro and in vivo animal studies, has reinforced the insulin anorexigenic action in the hypothalamus of the brain. Simultaneously, most available clinical studies showed that SSs during a well-balanced diet either maintain or even increase body weight, which may indirectly be ascribed to the fact that they cannot cover the hedonic aspect of food intake. However, there is a strong demand for long-term longitudinal surveys to effectively specify the impact of SSs on human metabolic health.

The causal association between artificial sweeteners and the risk of cancer: a Mendelian randomization study

Artificial sweeteners (ASs) have been widely added to food and beverages because of their properties of low calories and sweet taste. However, whether the consumption of ASs is causally associated with cancer risk is not clear. Here, we utilized the two-sample Mendelian randomization (MR) method to study the potential causal association. Genetic variants like single-nucleotide polymorphisms (SNPs) associated with exposure (AS consumption) were extracted from a genome-wide association study (GWAS) database including 64 949 Europeans and the influence of confounding was removed. The outcome was from 98 GWAS data and included several types of cancers like lung cancer, colorectal cancer, stomach cancer, breast cancer, and so on. The exposure-outcome SNPs were harmonized and then MR analysis was performed. The inverse-variance weighted (IVW) with random effects was used as the main analytical method accompanied by four complementary methods: MR Egger, weighted median, simple mode, and weighted mode. Sensitivity analyses consisted of heterogeneity, pleiotropy, and leave-one-out analysis. Our results demonstrated that ASs added to coffee had a positive association with high-grade and low-grade serous ovarian cancer; ASs added to tea had a positive association with oral cavity and pharyngeal cancers, but a negative association with malignant neoplasm of the bronchus and lungs. No other cancers had a genetic causal association with AS consumption. Our MR study revealed that AS consumption had no genetic causal association with major cancers. Larger MR studies or RCTs are needed to investigate small effects and support this conclusion.

Association between consumption of sweeteners and endometrial cancer risk: a systematic review and meta-analysis of observational studies

The purpose of this study is to further investigate the relationship between sweetener exposure and the risk of endometrial cancer (EC). Up until December 2022, a literature search in an electronic database was carried out utilizing PubMed, Web of Science, Ovid, and Scopus. The odds ratio (OR) and 95 % confidence interval (CI) were used to evaluate the results. Sweeteners were divided into nutritional sweeteners (generally refers to sugar, such as sucrose and glucose) and non-nutritional sweeteners (generally refers to artificial sweeteners, such saccharin and aspartame). Ten cohort studies and two case-control studies were eventually included. The study found that in 12 studies, compared with the non-exposed group, the incidence rate of EC in the sweetener exposed group was higher (OR = 1·15, 95 % CI = [1·07, 1·24]). Subgroup analysis showed that in 11 studies, the incidence rate of EC in the nutritional sweetener exposed group was higher than that in the non-exposed group (OR = 1·25, 95 % CI = [1·14, 1·38]). In 4 studies, there was no difference in the incidence rate of EC between individuals exposed to non-nutritional sweeteners and those who were not exposed to non-nutritional sweeteners (OR = 0·90, 95 % CI = [0·81, 1·01]). This study reported that the consumption of nutritional sweeteners may increase the risk of EC, whereas there was no significant relationship between the exposure of non-nutritional sweeteners and the incidence of EC. Based on the results of this study, it is recommended to reduce the intake of nutritional sweeteners, but it is uncertain whether use of on-nutritional sweeteners instead of nutritional sweetener.

Association between Consumption of Artificial Sweeteners and Breast Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

This study intends to conduct a meta-analysis based on existing research results to further investigate their relationship between artificial sweetener exposure and breast cancer risk. An electronic database literature search was performed up to July 2022, using PubMed, Web of Science, Ovid and Scopus. The relationship between artificial sweetener exposure and breast cancer (BC) incidence was evaluated by odds ratio (OR) and 95% confidence interval (CI). Among the five studies (two case-control studies and three cohort studies) that met the inclusion criteria, 314,056 participants were recruited in the cohort study, 4,043 cancer cases and 3,910 controls were recruited in the case-control study. It was found that exposure of artificial sweeteners was not related to the risk of BC (OR = 0.98, 95% CI = [0.94-1.03]). Subgroup analysis showed that compared with the non-exposure/very-low-dose group, the exposure to low, medium and high doses of artificial sweeteners were not associated with the risk of BC, which were OR = 1.01, 95% CI = [0.95-1.07], OR = 0.98, 95% CI = [0.93-1.02], OR = 0.88, 95% CI = [0.74-1.06], respectively. This study confirmed that there was no relationship between the exposure of artificial sweeteners and the incidence of BC.

Can Artificial Sweeteners Increase the Risk of Cancer Incidence and Mortality: Evidence from Prospective Studies

Cancer has become a major challenge in the global disease burden. Artificial sweeteners are a class of chemical compounds that are used as food and beverage addition agent to replace sugar. However, the health effects of consuming artificial sweeteners are still unclear. This meta-analysis was performed to evaluate the role of artificial sweeteners on cancer. The databases PubMed, Cochrane Library, MEDLINE, Web of Science and EMBASE were searched up until July 2022. A Newcastle−Ottawa scale (NOS) was used to estimate the study quality. A total of 25 observational studies were included with a total of 3,739,775 subjects. The intake of artificial sweeteners had no apparent association with overall cancer incidence and mortality. However, in Europe, artificial sweeteners’ intake could increase the risk of cancer incidence (HR/RR = 1.07, 95% CI = [1.02, 1.12], I2 = 25.8%, P = 0.223), which appears to be related to a shift in nutritional behaviors in the countries. Significant results were also observed in subgroups with aspartame and a mixed intake of artificial sweeteners. Moreover, higher risk was observed for artificial sweeteners intake in all-cause mortality (HR/RR =1.13, 95% CI = [1.03, 1.25], I2 = 79.7%, p < 0.001) and a J-shaped association between them was found. More data from well-conducted studies and clinical trials are required.

The possible role of the seaweed Sargassum vulgare as a promising functional food ingredient minimizing aspartame-associated toxicity in rats

Thirty-two male Wistar albino rats were chosen to test the possible protective role of antioxidants of the edible seaweed Sargassum vulgare as a functional food additive to alleviate oxidative stress and toxicity associated with consumption of the artificial sweetener 'aspartame (ASP)'. Biochemical and spleen histopathological analyses of the orally ASP-administrated rats, at a dose of 500 mg/kg for one week daily, showed different apoptotic and inflammatory patterns. Rats treated with ASP and then supplemented orally with the S. vulgare-MeOH extract, at a dose of 150 mg/kg for three consecutive weeks daily, showed significant positive reactions in all investigated assays related to ASP consumption. The protective and immune-stimulant efficacy of S. vulgare-MeOH extract, inferred from combating oxidative stress-induced lipid peroxidation, modulating the low levels of the endogenous antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and of the thyroid hormones T3 and T4, attenuating the elevated levels of apoptotic CASP-3 and inflammatory biomarkers TNF-α and IL-6, as well as heat shock proteins (Hsp70), can be most likely ascribed to the synergistic effect of its potent antioxidant phenolics (mainly gallic, ferulic, salicylic, and chlorogenic, and p-coumaric acids) and flavonoids (rutin, kaempferol, and hesperidin). Mechanism of action of these natural antioxidants was discussed.

Toxicological and Nutraceutical Screening Assays of Some Artificial Sweeteners

Artificial sweeteners are food additives worldwide used instead of fructose or glucose in many diet beverages. Furthermore, diet beverages intake has been increasing every year. Thus, some food agencies should regulate it based on toxicological studies. Debates and controversial results are demonstrated, and authority can revise its decision on the basis of new data reporting toxicological effects since cyclamate has been forbidden in some countries. Therefore, the aim of this study was to report new data about the toxicity of acesulfame-k, aspartame, and cyclamate, which are useful for authority agencies, determining the toxic potential and nutraceutical capabilities of these compounds. The toxicity, antitoxicity, genotoxicity, antigenotoxicity, and life expectancy assays were carried out in Drosophila as an in vivo model. In addition, in vitro HL-60 line cell was used to evaluate the chemopreventive activity determining the cytotoxic effect and the capability of producing DNA damage due to internucleosomal fragmentation or DNA strand breaks. Furthermore, the methylated status of these cancer cells treated with the tested compounds was assayed as a cancer therapy. Our results demonstrated that all tested compounds were neither toxic nor genotoxic, whereas these compounds resulted in antigenotoxic and cytotoxic substances, except for cyclamate. Aspartame showed antitoxic effects in Drosophila. All tested compounds decreased the quality of life of this in vivo organism model. Acesulfame-k, aspartame, and cyclamate induced DNA damage in the HL-60 cell line in the comet assay, and acesulfame-k generally increased the methylation status. In conclusion, all tested artificial sweeteners were safe compounds at assayed concentrations since toxicity and genotoxicity were not significantly induced in flies. Moreover, Aspartame and Cyclamate showed protective activity against a genotoxin in Drosophila Regarding nutraceutical potential, acesulfame-k and aspartame could be demonstrated to be chemopreventive due to the cytotoxicity activity shown by these compounds. According to DNA fragmentation and comet assays, a necrotic way could be the main mechanism of death cells induced by acesulfame-k and aspartame. Finally, Acesulfame-K hypermethylated repetitive elements, which are hypomethylated in cancer cells resulting in a benefit to humans.

Intake of artificial sweeteners among adults is associated with reduced odds of gastrointestinal luminal cancers: a meta-analysis of cohort and case-control studies

The association between artificial sweetener (AS) consumption and the risk of organ-specific cancers has been debated for decades. We hypothesized that AS consumption is associated with reduced risk of gastrointestinal (GI) cancers. We aimed to test this hypothesis by conducting a systematic review with meta-analysis of the association between AS and GI cancers. We searched four databases for comparative studies of AS consumption (exposed) versus no consumption (nonexposed) and the odds or risk of GI luminal or non-luminal cancer (primary outcome). Estimates were pooled using a random-effects model. Studies were evaluated for quality, bias, and heterogeneity. We analyzed 8 (4 prospective, 4 case-control) studies comprising data on 1,043,496 individuals, among whom 3271 pancreatic, 395 gastric, 304 esophageal, 3008 colorectal, and 598 oropharyngeal cancers occurred. While there was no significant association between AS consumption and odds of GI cancer overall, AS consumption was associated with 19% reduced likelihood of luminal GI cancer (OR 0.81, 95% CI:0.68–0.97). There was no association between AS consumption and non-luminal GI cancer. Meta-regression demonstrated no difference in effect estimates based on study type. Based on this first meta-analysis of AS and GI cancer, we demonstrated that AS consumption is associated with a significantly lower likelihood of luminal, but not non-luminal, GI cancer.

The in vitro cytotoxic, genotoxic, and oxidative damage potentials of the oral artificial sweetener aspartame on cultured human blood cells

Background/aim

Aspartame (APM, L-aspartyl-L-phenylalanine methylester) is a low-calorie, nonsaccharide artificial sweetener widely used in foods and beverages. When metabolized by the body, APM is broken down into aspartic acid, phenylalanine amino acids, and a third substance, methanol. Since the amino acid phenylalanine serves as a neurotransmitter building block affecting the brain, and methanol is converted into toxic formaldehyde, APM has deleterious effects on the body and brain. Thus, its safety and, toxicity have been the subjects of concern ever since it was first discovered. Although many studies have been performed on it, due to the presence of conflicting data in the literature, there are still numerous question marks concerning APM.Therefore, the safety of aspartame was tested using in vitro methods.

Materials and methods

We aimed to evaluate the in vitro cytotoxic effects by using 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase release tests, genotoxic damage potential by using chromosome aberration (CA) assay, and antioxidant/oxidant activity by using total antioxidant capacity (TAC) and total oxidative stress (TOS) analysis in primary human whole blood cell cultures.

Results

The results of the MTT test showed that APM led to significant decreases in cell viability in a clear concentration-dependent manner. Moreover, an increase in CA frequency was found in the cells treated with APM. However, APM treatments did not cause any significant changes in TAC and TOS levels in whole blood cultures.

Conclusion

Overall, the obtained results showed that APM had genotoxicity potential and a concentration-dependent cytotoxic activity in human blood cells.

Sugars and Sweeteners: Structure, Properties and In Silico Modeling

Several studies report the effects of excessive use of sugars and sweeteners in the diet. These include obesity, cardiac diseases, diabetes, and even lymphomas, leukemias, cancers of the bladder and brain, chronic fatigue syndrome, Parkinson's disease, Alzheimer's disease, multiple sclerosis, autism, and systemic lupus. On the other hand, each sugar and sweetener has a distinct metabolic assimilation process, and its chemical structure plays an important role in this process. Several scientific papers present the biological effects of the sugars and sweeteners in relation to their chemical structure. One important issue dealing with the sugars is the degree of similarity in their structures, focusing mostly on optical isomerism. Finding and developing new sugars and sweeteners with desired properties is an emerging research area, in which in silico approaches play an important role.

Self-Assembly of Artificial Sweetener Aspartame Yields Amyloid-like Cytotoxic Nanostructures

Recent reports have revealed the intrinsic propensity of single aromatic metabolites to undergo self-assembly and form nanostructures of amyloid nature. Hence, identifying whether aspartame, a universally consumed artificial sweetener, is inherently aggregation prone becomes an important area of investigation. Although the reports on aspartame-linked side effects describe a multitude of metabolic disorders, the mechanistic understanding of such destructive effects is largely mysterious. Since aromaticity, an aggregation-promoting factor, is intrinsic to aspartame's chemistry, it is important to know whether aspartame can undergo self-association and if such a property can predispose any cytotoxicity to biological systems. Our study finds that aspartame molecules, under mimicked physiological conditions, undergo a spontaneous self-assembly process yielding regular β-sheet-like cytotoxic nanofibrils of amyloid nature. The resultant aspartame fibrils were found to trigger amyloid cross-seeding and become a toxic aggregation trap for globular proteins, Aβ peptides, and aromatic metabolites that convert native structures to β-sheet-like fibrils. Aspartame fibrils were also found to induce hemolysis, causing DNA damage resulting in both apoptosis and necrosis-mediated cell death. Specific spatial arrangement between aspartame molecules is predicted to form a regular amyloid-like architecture with a sticky exterior that is capable of promoting viable H-bonds, electrostatic interactions, and hydrophobic contacts with biomolecules, leading to the onset of protein aggregation and cell death. Results reveal that the aspartame molecule is inherently amyloidogenic, and the self-assembly of aspartame becomes a toxic trap for proteins and cells, exposing the bitter side of such a ubiquitously used artificial sweetener.

Effect of l-carnitine on aspartame-induced oxidative stress, histopathological changes, and genotoxicity in liver of male rats

Background Aspartame (ASP) is used for treatment of obesity and diabetes mellitus. This study was designed to illustrate the biochemical responses and histopathological alterations besides the genotoxicity of ASP alone or with l-carnitine (LC) in the liver of rats. Methods Animals were separated into six groups: control, lower dose of ASP (ASP-LD; 75 mg/kg), higher dose of ASP (ASP-HD; 150 mg/kg), l-carnitine (LC; 10 mg/kg), ASP-LD plus LC, and ASP-HD plus LC. Treatment was carried out orally for 30 consecutive days. Results ASP raised the activity of some enzymes of liver markers and disturbed the lipid profile levels. The hepatic reduced glutathione (GSH) levels, the marker enzymes of antioxidant activities, were obviously diminished, and, possibly, the lipid peroxidation, C-reactive protein, and interleukins levels were increased. ASP significantly increased the DNA deterioration in comparison with the control in a dose-dependent manner. LC prevented ASP-induced liver damage as demonstrated by the enhancement of all the above parameters. Results of histopathological and electron microscopic examination proved the biochemical feedback and the improved LC effect on liver toxicity. Conclusions The co-treatment of LC showed different improvement mechanisms against ASP-induced liver impairment. So, the intake of ASP should be regulated and taken with LC when it is consumed in different foods or drinks to decrease its oxidative stress, histopathology, and genotoxicity of liver.

Revisiting the safety of aspartame

Aspartame is a synthetic dipeptide artificial sweetener, frequently used in foods, medications, and beverages, notably carbonated and powdered soft drinks. Since 1981, when aspartame was first approved by the US Food and Drug Administration, researchers have debated both its recommended safe dosage (40 mg/kg/d) and its general safety to organ systems. This review examines papers published between 2000 and 2016 on both the safe dosage and higher-than-recommended dosages and presents a concise synthesis of current trends. Data on the safe aspartame dosage are controversial, and the literature suggests there are potential side effects associated with aspartame consumption. Since aspartame consumption is on the rise, the safety of this sweetener should be revisited. Most of the literature available on the safety of aspartame is included in this review. Safety studies are based primarily on animal models, as data from human studies are limited. The existing animal studies and the limited human studies suggest that aspartame and its metabolites, whether consumed in quantities significantly higher than the recommended safe dosage or within recommended safe levels, may disrupt the oxidant/antioxidant balance, induce oxidative stress, and damage cell membrane integrity, potentially affecting a variety of cells and tissues and causing a deregulation of cellular function, ultimately leading to systemic inflammation.

Mutagenicity and genotoxicity studies of aspartame

Two studies were conducted to further assess its mutagenic and genotoxic potential. In a bacterial reverse mutation pre-incubation study, Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537 and Escherichia coli WP2 uvrA were treated with aspartame at concentrations of up to 5000 μg/plate with or without metabolic activation and showed no mutagenic potential. Similarly, in vivo micronucleus testing of aspartame following gavage administration (500-2000 mg/kg body weight) to Crlj:CD1(ICR) strain SPF male mice showed no increase in the proportion of micronucleated polychromatic erythrocytes in bone marrow cells collected and evaluated 24 or 48 h post administration. Overall, aspartame had no potential for mutagenic or genotoxic activity.

"Aspartame: A review of genotoxicity data"

Aspartame is a methyl ester of a dipeptide of aspartic acid and phenylalanine. It is 200× sweeter than sucrose and is approved for use in food products in more than 90 countries around the world. Aspartame has been evaluated for genotoxic effects in microbial, cell culture and animal models, and has been subjected to a number of carcinogenicity studies. The in vitro and in vivo genotoxicity data available on aspartame are considered sufficient for a thorough evaluation. There is no evidence of induction of gene mutations in a series of bacterial mutation tests. There is some evidence of induction of chromosomal damage in vitro, but this may be an indirect consequence of cytotoxicity. The weight of evidence from in vivo bone marrow micronucleus, chromosomal aberration and Comet assays is that aspartame is not genotoxic in somatic cells in vivo. The results of germ cell assays are difficult to evaluate considering limited data available and deviations from standard protocols. The available data therefore support the conclusions of the European Food Safety Authority (EFSA) that aspartame is non-genotoxic.

ANEMIC PATIENT AT GP’S OFFICE

In contemporary medicine anemia is not just a decrease of hemoglobin level, but risk factor for worse outcome in vascular patients. At the same time anemia usually is not stated in the diagnosis and is not registered in statistic reports. Anemia – is always a complication that is why it always requires diagnostic algorithm to explore the underlying reason. Low hemoglobin level must be always marked by general physician. However in practice this happens just in 25% cases. Due to time deficiency at outpatient visits there is a demand for algorithm to provide GP with. This article concerns such algorithms to investigate the patients with found low hemoglobin level.