Considerations for deriving a safe intake of propylene glycol.

The use of propylene glycol (PG) in food and other applications is widespread, and some estimates of dietary exposure to PG approach or exceed the Acceptable Daily Intake (ADI) of 25 mg/kg bw-day. The current ADI for PG applies a cumulative uncertainty factor of 100, which includes factors of 10 for both interspecies and intraspecies differences. Available toxicology studies and human data, however, indicate a plausible mode of action (MoA) that would support a chemical-specific adjustment factor (CSAF) of 1 for interspecies toxicodynamic differences, reducing the total uncertainty factor from 100 to 40. The MoA involves an increase in serum PG concentrations after metabolic saturation, leading to serum hyperosmolarity, which can ultimately cause hemolytic changes and red blood cell damage. Therefore, the species similarities in toxicodynamic response for this critical effect could support increasing the ADI from 25 to 62.5 mg/kg bw-day, applicable to both children and adults.

Beverage Consumption Patterns among U.S. Adolescents and Adults from a New 24-h Beverage Recall Survey Compared to the National Health and Nutrition Examination Survey (NHANES) 2017-2018.

Beverages are major dietary components of the United States (U.S.) population. Understanding the current consumption pattern of beverages is an important element in supporting healthy diets. Our objective was to assess the validity of the 24-h beverage consumption recall data collected in 2021 through a self-administered online questionnaire (referred to as the American Beverage Association-Brandscapes Worldwide survey, ABA-BSW) by comparing it to the 24-h dietary recall data collected in the 2017-2018 National Health and Nutrition Examination Survey (NHANES). Summary statistics on the reported consumption amounts and consumption occasions (COs) of 13 beverage types (e.g., bottled water, carbonated soft drinks (CSD), tea, and others) by participants aged 13-64 years were compared between ABA-BSW (n = 20,553) and NHANES (n = 4437). The average daily consumption amount among consumers of all 13 beverage types combined was higher in ABA-BSW than in NHANES (1903 mL/day vs. 1704 mL/day). Within each beverage type, the average daily consumption amounts among consumers were generally lower in ABA-BSW except for CSD, plant-based drinks, and still juices and fruit-flavored drinks. Compared to NHANES, ABA-BSW participants reported consuming a wider variety of beverage groups, a higher number of COs per day, and lower consumption amounts within a given CO. Overall, beverage consumption patterns observed in ABA-BSW and NHANES were generally similar, supporting the design and implementation of the former survey. Further, the ABA-BSW data provide additional information on the within-day temporal beverage consumption patterns among adolescents and adults in the U.S. Differences in the observed consumption patterns between the surveys may be the result of various factors, including the survey implementation method, a consumption pattern shift between the survey time periods, beverage type availability, and impact of the COVID-19 pandemic on dietary patterns.

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.

Low- and no-calorie sweetener intakes from beverages - an up-to-date assessment in four regions: Brazil, Canada, Mexico and the United States.

The current assessment estimated exposure to four low- and no-calorie sweeteners (LNCS) (aspartame, acesulfame potassium (AceK), steviol glycosides and sucralose) from beverages in Brazil, Canada, Mexico and the United States, using up-to-date nationally representative consumption data and industry reported-use level information. Two modelling scenarios were applied - the probabilistic model was guided by reported use level data, with estimated intake for an individual leveraging market-weighted average use level of a particular LNCS in any given LNCS-sweetened beverage type, while the distributional (brand-loyal) model assumed consumer behaviour-led patterns, namely that an individual will be brand loyal to a pre-determined beverage type. Consumer-only and general population intake estimates were derived for the overall population and individual age categories, and compared to the respective acceptable daily intake (ADI) as established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) for each LNCS. The mean, 90th percentile and 95th percentile intake estimates were substantially lower than the ADI in both modelling scenarios, regardless of the population group or market. In the probabilistic model, the highest consumer-only intake was observed for AceK in Brazilian adolescents (95th percentile, 12.4% of the ADI), while the highest 95th percentile intakes in the distributional model were observed for sucralose in Canadian adults at 20.9% of the ADI. This study provides the latest insights into current intakes of LNCS from water-based non-alcoholic LNCS-sweetened beverages in these regions, aligning well with those published elsewhere.

Extended One-Generation Reproductive Toxicity (EOGRT) study of benzoic acid in Sprague Dawley rats.

Benzoic acid (BA) was administered in the diet to male and female Sprague Dawley Crl:CD(SD) rats in an OECD Test Guideline 443 Extended One-Generation Reproductive Toxicity (EOGRT) study to test for effects that may occur as a result of pre- and postnatal exposure. The study included cohorts of F1 offspring to evaluate potential effects of benzoic acid on reproduction, the developing immune system, and the developing neurological system with the inclusion of learning and memory assessments. Benzoic acid was incorporated in the diet at concentrations of 0, 7,500, 11,500, and 15,000 mg/kg diet (ppm). These concentrations were selected based on the results of preliminary studies, and, based on average food consumption, were intended to supply BA doses of approximately 0, 500, 750, and 1000 mg/kg bw/day. To avoid exceeding these target dose levels, the dietary concentrations were adjusted (based on historical control body weight and food consumption data) to maintain the target mg/kg bw/day dose levels during those life periods when food intake per unit of body weight was increased to support milk production by females (gestation and lactation) and rapid pup growth (post-weaning). In the parental (F0) generation, survival, clinical observations, organ weights, pathology, hematology, serum chemistry, urinalysis, and bile acids were unaffected by BA administration. Reproductive parameters were also unaffected by BA administration. In the F1 generation, survival, growth and developmental landmarks, organ weights, pathology, immunotoxicity assessment, and neurotoxicity and neurobehavioral parameters such as auditory startle response, locomotor activity, learning and memory assessments were unaffected by BA administration, as were clinical pathology (hematology, serum chemistry, urinalysis, bile acids and thyroid hormones) and reproductive performance. Similarly, no adverse effects or systemic toxicity were observed in the F2 generation. Overall, the highest dietary concentration (15,000 ppm), providing a dosage of approximately 1000 mg/kg bw/day, was the NOAEL for benzoic acid in this EOGRT study.

An updated estimate of benzoate intakes from non-alcoholic beverages in Canada and the United States.

In 2017, the results of a comprehensive assessment of intake for benzoic acid and its salts from non-alcoholic beverages were published for four regions (Brazil, Canada, Mexico, and the United States [U.S.]). These regions were among those identified as having the most prevalent use of benzoates in beverages globally. The results of the 2017 study did not indicate a safety concern relative to the acceptable daily intake (ADI) established for benzoates (5 mg kg body weight-1 day-1, as benzoic acid), and supported maintaining the Codex maximum benzoate level in water-based beverages (250 mg kg-1). Since this time, population-specific food consumption data have been released for public use for Canada, and updated beverage consumption data have become available for the U.S. To ensure estimated intakes remain relevant, these consumption data were incorporated with previously collected brand-specific benzoate use level and market volume data for beverages. Dietary exposure to benzoates from non-alcoholic beverages was assessed using statistical modelling, either probabilistic (non-brand loyal; considering the full distribution of use levels) or deterministic (brand loyal; assuming all regular carbonated soft drinks, the brand loyal beverage type, contain benzoates at the maximum use level, and all other beverage types in which benzoates are used contain benzoates at the market-weighted average use level). In both models, estimated daily intakes at the mean and 95th percentile were below the ADI (≤76% of the ADI) in all Canadian and U.S. population groups with a statistically reliable population size. The findings from updated Canadian and U.S. consumption data continue to support the Codex maximum benzoate level in water-based flavoured drinks at 250 mg kg-1.

Tiered intake assessment for low- and no-calorie sweeteners in beverages.

A tiered intake assessment approach is presented and applied to derive the maximum potential global low- and no-calorie sweeteners (LNCS) intake estimates. The US and Uk markets served as representative for the world and the EU region, respectively, to determine the maximum potential exposure for acesulfame potassium (AceK), aspartame, saccharin, steviol glycosides, and sucralose in various subpopulations, including brand-loyal consumers. Conservative intake estimates for LNCS used in non-alcoholic beverages were calculated for the general population 2 + y, toddlers (12-35 months (US) or 18-35 months (UK)), young children 3-9 y, adolescents 10-17 y, adults 18-64 y, elderly 65-74 y, and very elderly 75 + y based on assumed uses in high beverage consumption markets, leveraging either the 2-day food consumption data from the 2013-2016 US National Health and Nutrition Examination Survey or the 4-day food consumption data from the 2008-2017 UK National Diet and Nutrition Survey Rolling Programme. Strong concordance between the refined budget method and the brand-loyal deterministic approach was shown, the latter assumes the maximum industry-reported global LNCS use level is present in 100% of non-alcoholic beverages. This study shows that safety of LNCS in beverages at proposed use levels can be supported for any geography, with all intake estimates falling below the acceptable daily intake in refined assessments. Importantly, this study shows the refined budget method to be a valid first-tier screening assessment in prioritising those LNCS that may benefit from more refined intake assessments when warranted.

Tiered intake assessment for food colours.

A tiered intake assessment approach, ranging from the conservative default and refined budget method to refined dietary exposure assessments using national food consumption surveys is presented and applied to derive maximum potential global colour intake estimates. The US and UK markets served as representative for the world and the EU, respectively, to determine the maximum potential exposure ceilings for eleven colours in various sub-populations, including brand-loyal consumers. Industry-reported global use levels were assigned as the maximum level. Conservative intake assessments for food colours used in non-alcoholic beverages were estimated for the general population 2 + y, toddlers, children 3-9 y, adolescents 10-17 y, adults 18-64 y, elderly 65-74 y, very elderly 75 + y based on assumed uses in high intake markets. Refined dietary exposures were estimated using either the 2-day food consumption data from the 2013-2016 US National Health and Nutrition Examination Survey or the 4-day food consumption data from the 2008-2016 U.K. National Diet and Nutrition Survey Rolling Programme. In the most refined market-share adjusted assessment, brand-specific market volume data were used to place appropriate weight on corresponding beverage type uses. Strong concordance between the refined budget method and the brand-loyal deterministic approach was shown, in which the latter assumes that the maximum use level of the colour is present in 100% of non-alcoholic beverages. This study shows that safety of colours - both synthetic and natural - in beverages at proposed use levels can be supported for any geography, with all intake estimates falling below the acceptable daily intake in refined assessments. Importantly, this study demonstrates that the refined budget method is a valid first-tier screening assessment to prioritise food colours that may benefit from more refined intake assessments when warranted.

Evidence of impaired adipogenesis in insulin resistance.

To elucidate the roles of adipose tissue and skeletal muscle in the early development of insulin resistance, we characterized gene expression profiles of isolated adipose cells and skeletal muscle of non-diabetic insulin-resistant first-degree relatives of type 2 diabetic patients using oligonucleotide microarrays. About 600 genes and expressed sequence tags, which displayed a gene expression pattern of cell proliferation, were differentially expressed in the adipose cells. The differentially expressed genes in the skeletal muscle were mostly related to the cellular signal transduction and transcriptional regulation. To verify the microarray findings, we studied expression of genes participating in adipogenesis. The expression of Wnt signaling genes, WNT1, FZD1, DVL1, GSK3beta, beta-catenin, and TCF1, and adipogenic transcription factors, C/EBPalpha and beta and delta, PPARgamma, and SREBP-1, was reduced in the adipose tissue. The expression of adipose-specific proteins related to terminal differentiation, such as adiponectin and aP2, was reduced both in the adipose tissue and in the adipose cells isolated from portions of the biopsies. The adipose cells were enlarged in the insulin-resistant relatives and the cell size inversely correlated with the expression of the Wnt signaling genes, adiponectin, and aP2. Our findings suggest that insulin resistance is associated with an impaired adipogenesis.

Adiponectin gene activation by thiazolidinediones requires PPAR gamma 2, but not C/EBP alpha-evidence for differential regulation of the aP2 and adiponectin genes.

We examined the role of PPAR gamma 2 and C/EBP alpha for adiponectin and aP2 gene activation in C/EBP alpha(-/-) fibroblasts by stably expressing PPAR gamma 2 or C/EBP alpha. PPAR gamma 2, but not PPAR gamma 1, mRNA markedly increased during the differentiation to adipocytes in cells expressing C/EBP alpha. Both infected cell lines differentiated to an adipocyte phenotype and the mRNA for both aP2 and adiponectin increased in parallel. However, adiponectin mRNA was considerably higher when C/EBP alpha was present, suggesting that this transcription factor is important for full gene activation. Thiazolidinediones markedly activated the gene in PPAR gamma 2-expressing cells in the absence of C/EBP alpha, suggesting that the adiponectin promoter may have functional PPAR gamma-response elements. Several observations showed that the adiponectin and aP2 genes can be differentially regulated in adipocytes: (1) Topiramate, an anti-epileptic agent with weight-reducing properties, increased adiponectin mRNA levels and secretion, but did not, like the thiazolidinediones, increase aP2 expression; (2) IL-6 reduced adiponectin, but significantly increased, aP2 expression; and (3) TNFalpha inhibited adiponectin, but paradoxically increased, aP2 expression in PPAR gamma 2-infected C/EBP alpha null cells. These data show that activation of the adiponectin gene can be separated from effects on adipogenic genes.