Safety assessment of high fructose corn syrup and fructose used as sweeteners in foods.

High Fructose Corn Syrup (HFCS) and Fructose (FR) are widely used sweeteners in many foods and beverages. This study aimed at investigating the cytotoxic effects of HFCS (5%-30%) and FR (62.5-2000 µg/mL) using MTT assay in Human Hepatocellular Carcinoma (HepG2) cells, and genotoxic effects of using Chromosome Aberrations (CAs), Sister Chromatid Exchanges (SCEs), Micronuclei (MN) and comet assays in human lymphocytes. HFCS significantly reduced the cell viability in HepG2 cells at between 7.5% and 30% for 24 and 48 h. 30% HFCS caused a very significant toxic effect. FR had a cytotoxic effect in HepG2 cells at all treatments. However, as fructose concentration decreased, the cell viability decreased. HFCS (10%-20%) and FR (250-2000 µg/mL) decreased the mitotic index at higher concentrations. IC50 value was found to be a 15% for 48 h. IC50 value of FR was detected as 62.5 µg/mL for 24 h and 48 h. HFCS significantly increased CAs frequency at 15% and 20%. FR significantly increased the frequency of CAs at 250, 1000, and 2000 µg/mL for 48 h. Both sweeteners increased the frequency of SCEs at all concentrations. HFCS (15% and 20%) and FR (250, 1000, and 2000 µg/mL) induced MN frequency at higher concentrations. HFCS caused DNA damage in comet assay at 10% -30%. FR increased tail intensity and moment at 125-2000 µg/mL and tail length at 62.5, 250 and 500 µg/mL. Therefore, HFCS and FR are clearly seen to be cytotoxic and genotoxic, especially at higher concentrations.

HFCS and FR exhibited cytotoxic effect at HepG2 and human lymphocytes at higher concentrations.Both sweeteners increased the frequencies of CAs and SCEs at higher concentrations.HFCS caused DNA damage at 10% -30% concentrations.HFCS (15% and 20%) and FR (250, 1000, and 2000 µg/mL) induced MN frequency.

Updated systematic assessment of human, animal and mechanistic evidence demonstrates lack of human carcinogenicity with consumption of aspartame.

Aspartame has been studied extensively and evaluated for its safety in foods and beverages yet concerns for its potential carcinogenicity have persisted, driven primarily by animal studies conducted at the Ramazzini Institute (RI). To address this controversy, an updated systematic review of available human, animal, and mechanistic data was conducted leveraging critical assessment tools to consider the quality and reliability of data. The evidence base includes 12 animal studies and >40 epidemiological studies reviewed by the World Health Organization which collectively demonstrate a lack of carcinogenic effect. Assessment of >1360 mechanistic endpoints, including many guideline-based genotoxicity studies, demonstrate a lack of activity associated with endpoints grouped to key characteristics of carcinogens. Other non-specific mechanistic data (e.g., mixed findings of oxidative stress across study models, tissues, and species) do not provide evidence of a biologically plausible carcinogenic pathway associated with aspartame. Taken together, available evidence supports that aspartame consumption is not carcinogenic in humans and that the inconsistent findings of the RI studies may be explained by flaws in study design and conduct (despite additional analyses to address study limitations), as acknowledged by authoritative bodies.

Safety assessment of miraculin using in silico and in vitro digestibility analyses.

Miraculin is a glycoprotein with the ability to make sour substances taste sweet. The safety of miraculin has been evaluated using an approach proposed by the Food and Agriculture Organization of the United Nations and the World Health Organization for assessing the safety of novel proteins. Miraculin was shown to be fully and rapidly digested by pepsin in an in vitro digestibility assay. The proteomic analysis of miraculin's pepsin digests further corroborated that it is highly unlikely that any of the protein will remain intact within the gastrointestinal tract for potential absorption. The potential allergenicity and toxigenicity of miraculin, investigated using in silico bioinformatic analyses, demonstrated that miraculin does not represent a risk of allergy or toxicity to humans with low potential for cross-reactivity with other allergens. The results of a sensory study, characterizing the taste receptor activity of miraculin, showed that the taste-modifying effect of miraculin at the concentration intended for product development has a rapid onset and disappearance with no desensitizing impact on the receptor. Overall, the results of this study demonstrate that the use of miraculin to impact the sensory qualities of orally administered products with a bitter/sour taste profile is not associated with any safety concerns.

A histological assessment of effects of sucralose on liver of albino rats.

OBJECTIVE OF THE STUDY: Sucralose is an artificial sweetener freely available under different brand names over the counter. This study is aimed at evaluating the histopathological changes in the liver after administration of sub lethal dose of pure sucralose. MATERIALS AND METHODS: Inbred adult Wistar albino rats weighing about 150-200g of either sex, were divided into 6 control rats and 6 experimental rats. Experimental rats were given sucralose orally by gavage in the dose of 3g/kg/day dissolved in distilled water for 30 days whereas Control rats received equal quantity of distilled water by the same route. The animals were anesthetized with anesthetic ether and then perfused with 10% formal saline. Livers were dissected out. Pieces each having thickness 5mm were taken for paraffin sectioning. 5 micron thick sections were cut using a rotary microtome. Hundred slides were made from each liver and stained with hematoxylin and eosin, periodic acid-schiff (PAS) and Masson's trichrome stain. Slides were evaluated for histomorphological changes. RESULTS: Experimental rats showed features of patchy degeneration of hepatocytes along with Kupffer cells hyperplasia, lymphocytic infiltration, sinusoidal dilatation and fibrosis indicating a definite hepatic damage on regular ingestion of sucralose. Sinusoidal width was also found to be increased in experimental animals as compared to controls. CONCLUSION: It is suggestive that sucralose should be taken with caution to avoid hepatic damage. Effects of ingestion of sucralose on human subjects should be investigated further.

Safety assessment of nebulized xylitol in beagle dogs.

Xylitol, a potential cystic fibrosis treatment, lowers the salt concentration of airway surface liquid and enhances innate immunity of human airways. The study objective was to evaluate the potential toxicity/recovery from a 14-consecutive day (7 days/week), facemask inhalation administration of nebulized xylitol solution in Beagle dogs. Aerosolized xylitol was generated through three Aerotech II nebulizers operating at approximately 40 psi driving pressure. Test article groups were exposed to the same concentration of aerosolized xylitol for 1, 0.5, or 0.25 h for the high, mid, and low exposures, respectively. A control group was exposed for 1 h to a nebulized normal saline solution. Animals were sacrificed the day following the last exposure or subsequently after 14 non-exposure days. Study endpoints included clinical observations, body weights, ophthalmology, and physical examinations, food consumption, clinical pathology, urinalyses, organ weights, and histopathology. Mean xylitol aerosol concentrations for all groups were approximately 3.5 mg/l. Mean total deposited doses to the pulmonary region were estimated as 21, 11, and 5 mg/kg, for the high-, mid-, and low-exposure groups, respectively. All dogs survived to the scheduled necropsy. No treatment-related findings were observed due to xylitol exposure in any end point examined. Lung findings (mild interstitial infiltration, macrophage hyperplasia, alveolitis, and bronchitis) were consistent among exposed and control groups. No exposure-related effect of xylitol in any parameter assessed was seen during or after the 14-day exposure in Beagle dogs. The No Observed Effect Level was the high-exposure level and suggests that inhaled xylitol is safe for clinical administration.

In vitro and in vivo assessment of the mutagenic activity of N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate (advantame).

Advantame (N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate), an N-substituted analogue of aspartame, has been developed as a high-intensity sweetener. It is approximately 100 and 20,000 times sweeter than aspartame and sucrose, respectively. In this study the safety of advantame has been evaluated using a series of in vitro and in vivo genotoxicity assays including, bacterial mutation, mammalian cell mutation, and mouse micronucleus tests. Advantame did not induce reverse mutations in Salmonella typhimurium and Escherichia coli at concentrations of up to 5000 µg/plate. In the mammalian cell mutation assay, advantame did not induce mutation at the Hprt locus of L5178Y mouse lymphoma cells in two independent experiments, either in the absence or presence of S9. In vivo, there was no effect on the incidence of micronucleated immature or mature erythrocytes in bone marrow after oral administration of the test substance at any dose level (up to 2000 mg/kg body weight) or sampling time (24 and 48 h). The results of these studies demonstrate that advantame is without genotoxic potential.

Safety assessment of high fructose corn syrup (HFCS) as an ingredient added to cigarette tobacco.

A tiered testing strategy has been developed to evaluate the potential for new ingredients, tobacco processes, and technological developments to alter the biological activity that results from burning tobacco. A series of studies was initially conducted with cigarettes containing 3% high fructose corn syrup (HFCS) as an alternate tobacco casing material to corn syrup/invert sugar, including determination of selected mainstream cigarette smoke (MS) constituent yields, Ames assay, sister chromatid exchange (SCE) assay in Chinese hamster ovary (CHO) cells, a 30-week dermal tumor-promotion evaluation of cigarette smoke condensate (CSC) in SENCAR mice, and a 13-week subchronic inhalation study of MS in Sprague-Dawley rats. A second series of studies was conducted with cigarettes containing 3%, 4% and 5% HFCS including MS chemistry, Ames assay, SCE assay in CHO cells, and a neutral red cytotoxicity assays. Collectively, mainstream smoke chemistry, genotoxicity, dermal tumor-promotion, and inhalation toxicity studies demonstrated no differences between cigarettes with 3% HFCS and cigarettes with 3% corn syrup/invert sugar. Also, mainstream smoke chemistry and genotoxicity of cigarettes with 4% and 5% HFCS were not different from cigarettes with 3% HFCS. In conclusion, the addition of up to 5% HFCS to cigarette does not alter the mainstream smoke chemistry or biological activity of mainstream smoke or mainstream smoke condensate as compared to cigarettes with 3% corn syrup/invert sugar with regard to the parameters investigated and presented.

Sucralose: assessment of teratogenic potential in the rat and the rabbit.

The teratogenic potential of sucralose was examined following gavage administration to pregnant rats and rabbits during organogenesis. Groups of 20 mated rats were dosed on days 6-15 of gestation inclusive at 500, 1000 or 2000mg/kg/day; groups of 16 to 18 inseminated rabbits were dosed on days 6 to 19 of gestation inclusive at 175, 350 or 700mg/kg/day following preliminary studies at higher doses. Concurrent control groups received vehicle alone. Rats were killed on day 21 and rabbits on day 29 of gestation. Foetuses were evaluated at necropsy and after processing for possible soft tissue and skeletal alterations. There was no evidence of teratogenicity for either species. The only observed response to treatment in rats was a slight increase in water intake. Some adult rabbits receiving 700mg/kg/day exhibited marked gastrointestinal disturbance, also seen at higher doses in preliminary studies. Gastrointestinal effects such as these occur non-specifically in response to high doses of poorly absorbed compounds, and in the present study were considered to be responsible for two maternal deaths and four abortions. Full evaluation of rabbit foetuses in the main study (up to 700mg/kg/day) and necropsy of foetuses in a preliminary study with pregnant animals (up to 1000mg/kg/day) showed no evidence of adverse foetal response to sucralose. These teratology studies in both pregnant rodent and non-rodent animal models demonstrate that maternal consumption of high levels of sucralose during the period of organogenesis has no effect on normal foetal development in the rat or rabbit.

Assessment of the carcinogenicity of stevioside in F344 rats.

The carcinogenic potential of stevioside, a compound that is used as a sweetener for food and drink, was examined in F344 rats of both sexes. Stevioside was added to powdered diet at concentrations of 0 (control), 2.5 and 5%. The doses were selected on the basis of results from a 13-wk subchronic toxicity study and administered to groups of 50 male and 50 female rats ad lib. for 104 wk. All surviving rats were killed at wk 108. Body weight gains were slightly depressed in line with the dose of stevioside, in both sexes, and a significant decrease in the final survival rate was observed for the 5% treated males. Histopathologically, however, there was no significantly altered development of neoplastic or non-neoplastic lesions attributable to the stevioside treatment in any organ or tissue, except for a decreased incidence of mammary adenomas in females and a reduced severity of chronic nephropathy in males. It is concluded that stevioside is not carcinogenic in F344 rats under the experimental conditions described.

Saccharin mechanistic data and risk assessment: urine composition, enhanced cell proliferation, and tumor promotion.

Sodium saccharin (NaSac) produces bladder tumors consistently in male rats only after lifetime exposure that begins at birth. NaSac is not metabolized and is negative in most genotoxicity tests. NaSac-induced cell damage and proliferation have been proposed as important factors in tumor promotion, and dose-response information demonstrating a threshold for these parameters is available. One theory proposes that high levels of NaSac, combined with protein in a high Na+, high pH environment found only in the male rat, form toxic microscopic crystals; therefore, NaSac-induced tumors may not be relevant to human carcinogenesis.

Role of mathematical models in assessment of risk and in attempts to define management strategy.

Risk assessment of food-borne carcinogens is becoming a common practice at FDA. Actual risk is not being estimated, only the upper limit of risk. The risk assessment process involves a large number of steps and assumptions, many of which affect the numerical value estimated. The mathematical model which is to be applied is only one of the factors which affect these numerical values. To fulfill the policy objective of using the "worst plausible case" in estimating the upper limit of risk, recognition needs to be given to a proper balancing of assumptions and decisions. Interaction between risk assessors and risk managers should avoid making or giving the appearance of making specific technical decisions such as the choice of the mathematical model. The importance of this emerging field is too great to jeopardize it by inappropriately mixing scientific judgments with policy judgments. The risk manager should understand fully the points and range of uncertainty involved in arriving at the estimates of risk which must necessarily affect the choice of the policy or regulatory options available.