Retrospective analysis of dog study data from food and color additive petitions.

As part of the US FDA CFSAN's efforts to explore alternatives to animal testing, we retrospectively analyzed a sample of food additive (FAP) and color additive petitions (CAP) submitted to the FDA for the utility of dog study data in safety assessment. FAPs and CAPs containing dog studies (161 petitions) were classified as decisive (38%), supportive (27%), supplemental (29%) or undermined (6%) based on the impact the dog study data had on the final safety decision. Petitions classified as decisive were further categorized based on if the dog study data were used to a) address a safety concern (35/61); b) calculate an acceptable daily intake (ADI) (11/61); c) withdraw a petition (4/61); d) the effect was unique to the dog (2/61); or e) unclear (9/61). Of 11 petitions where the dog study was used to set an ADI, 7 contained studies where the points of departure (POD) from the dog studies were within an 8-fold range of the rodent with differences in study design likely contributing to the difference in PODs. Future research should include the development and use of qualified alternative studies to replace the use of animal testing for food and color additive safety assessment while ensuring human safety.

Use of acceptable daily intake (ADI) as a health-based benchmark in nutrition research studies that consider the safety of low-calorie sweeteners (LCS): a systematic map.

BACKGROUND: It is well-recognized that consumers face many challenges in understanding and applying nutritional guidance for low-calorie sweeteners (LCS). Thus, this research aims to (1) assess how benchmarks for safe levels of consumption of LCS are utilized by researchers, and (2) understand how varying use of such benchmarks may contribute to challenges in understanding and applying nutritional guidance for LCS consumption. METHODS: A systematic mapping exercise was employed to characterize when and how acceptable daily intake (ADI) values are used as health-based benchmarks in nutrition research studies that consider the safety of LCS. RESULTS: Based on results from charting 121 studies, our findings demonstrate that comparisons of LCS intake to an ADI derived by an authoritative body have been made in a diverse set of published literature, varying widely in their objectives, approaches, and populations of interest. The majority of studies compared the ADI to intake in a population under study; these represent the type of comparison that is most consistent with the intent of the ADI. Other applications of the ADI included use as a benchmark in experimental studies, risk-benefit analyses, and metabolism studies. CONCLUSION: Although most instances of ADI use were reasonable within the context of the individual studies' objectives, the diversity in use by original-study authors amplifies the continued need for development of "best practices" regarding the use and interpretation of the ADIs in current research. Using comparisons to the ADI can be a helpful way to provide context to research findings. However, in doing so, it is important that researchers utilize the value in a manner specific with its intent, as the ADI is a metric that represents an estimate of the amount of a substance that can be consumed daily over a lifetime without presenting an appreciable risk to health.

Toxicological evaluation of an olive extract, H35: Subchronic toxicity in the rat.

The safety of olive extract H35 containing 35% hydroxytyrosol (HT) was tested in a 90-day oral gavage study in Wistar rats. H35 was administered at 0, 345, 691 and 1381 mg/kg bw/day, equivalent to 0, 125, 250 and 500 mg HT/kg bw/day. Reductions in terminal body weight (9%), and a statistically significant reduction in body weight gain (17%, P < 0.05) at week 13 were observed in high dose males, as well as a statistically significant increase in relative weights of the liver, heart, and kidneys of high dose males and females. These changes were not accompanied by pathological or clinical observations and a trend towards reversal was observed in the recovery phase. H35 was well-tolerated and no toxicologically significant treatment-related changes were observed in condition and appearance of rats, neurobehavioral outcomes, motor activity assessments, functional observational battery (FOB), food intake, ophthalmoscopic examinations, hematology, clinical chemistry, urinalysis, necropsy findings, sperm parameters or estrus cycle. The lowest observed adverse effect level (LOAEL) was the 500 mg HT/kg bw/day based on statistically significant reductions in body weight gain and decreased body weight in males. The no observed adverse effect level (NOAEL) was 250 mg HT/kg bw/day, equivalent to 691 mg/kg bw/day of H35 extract.

The safety and regulation of natural products used as foods and food ingredients.

The use of botanicals and dietary supplements derived from natural substances as an adjunct to an improved quality of life or for their purported medical benefits has become increasingly common in the United States. This review addresses the safety assessment and regulation of food products containing these substances by the U.S. Food and Drug Administration (FDA). The issue of safety is particularly critical given how little information is available on the toxicity of some of these products. The first section uses case studies for stevia and green tea extracts as examples of how FDA evaluates the safety of botanical and herbal products submitted for consideration as Generally Recognized as Safe under the Federal Food, Drug, and Cosmetics Act. The 1994 Dietary Supplement Health Education Act (DSHEA) created a regulatory framework for dietary supplements. The article also discusses the regulation of this class of dietary supplements under DSHEA and addresses the FDA experience in analyzing the safety of natural ingredients described in pre-market safety submissions. Lastly, we discuss an ongoing interagency collaboration to conduct safety testing of nominated dietary supplements.

Oxidative stress alters base excision repair pathway and increases apoptotic response in apurinic/apyrimidinic endonuclease 1/redox factor-1 haploinsufficient mice.

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is the redox regulator of multiple stress-inducible transcription factors, such as NF-kappaB, and the major 5'-endonuclease in base excision repair (BER). We utilized mice containing a heterozygous gene-targeted deletion of APE1/Ref-1 (Apex(+/-)) to determine the impact of APE1/Ref-1 haploinsufficiency on the processing of oxidative DNA damage induced by 2-nitropropane (2-NP) in the liver tissue of mice. APE1/Ref-1 haploinsufficiency results in a significant decline in NF-kappaB DNA-binding activity in response to oxidative stress in liver. In addition, loss of APE1/Ref-1 increases the apoptotic response to oxidative stress, in which significant increases in GADD45g expression, p53 protein stability, and caspase activity are observed. Oxidative stress displays a differential impact on monofunctional (UNG) and bifunctional (OGG1) DNA glycosylase-initiated BER in the liver of Apex(+/-) mice. APE1/Ref-1 haploinsufficiency results in a significant decline in the repair of oxidized bases (e.g., 8-OHdG), whereas removal of uracil is increased in liver nuclear extracts of mice using an in vitro BER assay. Apex(+/-) mice exposed to 2-NP displayed a significant decline in 3'-OH-containing single-strand breaks and an increase in aldehydic lesions in their liver DNA, suggesting an accumulation of repair intermediates of failed bifunctional DNA glycosylase-initiated BER.

Haploinsufficiency in DNA polymerase beta increases cancer risk with age and alters mortality rate.

This study uses a base excision repair (BER)-deficient model, the DNA polymerase beta heterozygous mouse, to investigate the effect of BER deficiency on tumorigenicity and aging. Aged beta-pol(+/-) mice express 50% less beta-pol transcripts and protein (P < 0.05) than aged beta-pol(+/+) mice, showing maintenance of the heterozygous state over the life span of the mouse. This reduction in beta-pol expression was not associated with an increase in mutation rate but was associated with a 100% increase in the onset of hypoploidy. Aged beta-pol(+/-) mice exhibited a 6.7-fold increase in developing lymphoma (P < 0.01). Accordingly, 38% of beta-pol(+/-) mice exhibited lymphoid hyperplasia, whereas none of the beta-pol(+/+) exhibited this phenotype. beta-pol(+/-) mice were also more likely to develop adenocarcinoma (2.7-fold increase; P < 0.05) and more likely to develop multiple tumors, as 20% of the beta-pol(+/-) animals died bearing multiple tumors compared with only 5% of the beta-pol(+/+) animals (P < 0.05). In spite of accelerated tumor development, no gross effect of beta-pol heterozygosity was seen with respect to life span. However, the survival curves for the beta-pol(+/+) and beta-pol(+/-) mice are not identical. A maximum likelihood estimation analysis showed a modest but significant (P < 0.05) acceleration of the age-dependent mortality rate in beta-pol(+/-) mice. Thus, the beta-pol(+/-) mouse represents a model in which mortality rate and tumor development are accelerated and provides evidence supporting the role of genomic maintenance in both aging and carcinogenesis.