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Consultants in Human Health, Toxicology & Regulatory Affairs Safety Evaluation and Safety of Sweeteners Bernadene Magnuson, Ph.D.

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Presentation on theme: "Consultants in Human Health, Toxicology & Regulatory Affairs Safety Evaluation and Safety of Sweeteners Bernadene Magnuson, Ph.D."— Presentation transcript:

1 Consultants in Human Health, Toxicology & Regulatory Affairs Safety Evaluation and Safety of Sweeteners Bernadene Magnuson, Ph.D.

2 Outline Overview of safety evaluation –Risk assessment paradigm –Safety studies Overview of safety of sweeteners –Aspartame –Acesulfame K –Sucralose –Stevia extracts Conclusions

3 Safety Evaluation Risk assessment paradigm Identify Hazard Characterize Dose-Response Estimate Acceptable Daily Intake (ADI)

4 Premarket Safety Evaluation Comprehensive battery of studies are conducted in multiple species –Acute, sub-chronic, long-term toxicity –Pharmacokinetics, metabolism –Carcinogenicity –Genetic toxicity –Reproductive toxicity, teratogenicity –Human clinical studies Data reviewed by food authorities (FDA, Health Canada, EU, JECFA, etc.)

5 Acceptable Daily Intake (ADI) = amount considered safe to consume every day for a life time without adverse effects ADI is set by food authorities –No-Observed Effect Level (NOEL) in chronic studies –Apply “safety factors” to account for differences between individuals (10 X) differences between humans and animals (10 X) NOEL/100 = ADI (mg/kg/day) –Consumption greater than ADI still likely to have no effect because of conservative nature and “safety factor cushion” ADI

6 Risk assessment paradigm Identify Hazard Characterize Dose-Response Assess Exposure Characterize Risk What fraction of the population, if any, incurs intakes greater than the ADI? To what extent do intakes exceed the ADI? Estimate Acceptable Daily Intake (ADI) Estimate Range/Distribution of Human Intakes Food survey for target population

7 Aspartame Discovered in times sweeter than sucrose Approved in over 130 countries ADI: 40 (JECFA); 50 (FDA) Consumption studies: Australia, Brazil, Canada, Denmark, France, Germany, Italy, Korea, Netherlands, New Zealand, Portugal, Spain, Sweden, UK, US. Average users: <1-10% ADI; Highest users: 45% ADI No report of even highest user exceeding ADI

8 Food/BeverageAdult 70 kg Child 23 kg Carbonated soft drink (12 oz.) Powdered soft drink (8 oz.) Gelatin (4 oz.) Tabletop sweetener (packet) Number of Servings/Day to Reach ADI

9 Intestinal LumenMucosa Cell Methanol Aspartate Phenylalanine Aspartame Portal Blood Aspartame Esterases Methanol (10%) Asp/Phe Aspartate (40%) Phenylalanine (50%) Peptidases + Dipeptide Transport System Aspartame Esterases Methanol Asp/Phe Aspartate Phenylalanine Peptidases + + Aspartame metabolism Aspartame does not enter blood

10 Is aspartame linked to effects on behavior or the nervous system? –Many animal studies: Healthy, genetically predisposed, induced disorders –Many human studies Normal children, hyperactive children, children with PKU, aggressive school boys, sugar-sensitive children Healthy adults, airplane pilots, adults with Parkinson’s disease, adults with depression No effect on learning, cognitive performance, behavior, seizures, or any other neurological parameter Aspartame controversies

11 16 chronic animal studies: multiple species –14 found no evidence of carcinogenic or promoting effects of aspartame –Only studies reporting positive results by Soffritti et al. Detailed review of protocol and data of Soffritti by: –EFSA, 2006; Agence Franciase de Securite Santarie des Aliments (2006); US National Toxicology Program; FDA, Health Canada; Expert panel (Crit Rev Toxicology, 2007) All agreed that: –“there is no credible evidence that aspartame is carcinogenic” –“no need to further review the safety of aspartame” –“no need to revise previously established ADI” Does aspartame cause cancer?

12 Metabolism of aspartame –1 yr infants and older children; –No difference between children and adult Effect on behavior assessed –No effect even with habitual use Effect on childhood cancers –No association Aspartame is safe for children (>1 yr) at levels consumed Is aspartame safe for children?

13 Acesulfame K Discovered in times sweeter than sucrose Commonly blended with aspartame JECFA ADI = 15 Consumption studies: Australia, Canada, France, Netherlands, New Zealand, Spain, Sweden, UK, US Average users: <10% ADI; Highest users: ~30% ADI No report of highest user exceeding ADI

14 Acesulfame K: Metabolism Rapidly absorbed Excreted unchanged in the urine within 24 hours in rats, dogs, and humans No accumulation in the body

15 Acesulfame K: Safety Can acesulfame K cause cancer? –No evidence in preclinical studies with healthy animals –No evidence of carcinogenicity in cancer- prone mice Does acesulfame K increase insulin secretion? –No effects observed in in vivo studies

16 Sucralose Discovered in times sweeter than sucrose Heat-stable – can be used in various food applications Approved for use in over 60 countries JECFA ADI = 15 Consumption studies: Australia, Canada, New Zealand, Average users: <3% ADI; Highest users: ~15% ADI No report of highest user exceeding ADI

17 Sucralose: Metabolism Approximately 85% of ingested sucralose is not absorbed and is eliminated in the faeces unchanged Of the absorbed sucralose (15%): –2 to 3% glucuronidated and excreted in urine –Remainder excreted unchanged in urine No bioaccumulation. Gut microflora unable to hydrolyse sucralose

18 Sucralose : SAFETY Large body of research Preclinical studies have not demonstrated any toxicities Human tolerance studies have demonstrated no adverse effects at dosages equivalent to ADI for up to 6 months

19 Stevia extracts Hot-water extracts from the leaves of the Brazilian shrub Stevia rebaudiana Contains many steviol glycosides, with highest percentage of stevioside and rebaudioside A JECFA ADI = 4 mg/kg/day, as steviol equivalents Rebaudoside A preparation permitted in U.S. for food use Rebaudioside A Stevioside

20 Stevia extracts: Metabolism Glucosides not absorbed Steviol glycosides hydrolysed to steviol by gut microflora –Rate depends on number of glucose moieties attached to steviol backbone Steviol absorbed in large intestine, glucuronidated and excreted –Rats: faeces –Humans: urine Steviol Backbone

21 Stevia extracts: Safety Effect on blood glucose homeostasis, blood pressure, reproduction or kidneys? –Studies conducted with crude or low-purity extracts have demonstrated that extracts may have these effects –Studies conducted with high-purity extracts (>95% steviol glycosides) have shown no adverse effects JECFA confirmed the safety of steviol glycosides in 2008, changing temporary ADI to full ADI, based on the new studies

22 Conclusions A large body of evidence is required to support safety, and is critically reviewed by health authorities. All approved sweeteners are safe. No evidence of adverse effects of non-nutritive sweeteners at levels of human consumption, by even highest users.

23 Consultants in Human Health, Toxicology & Regulatory Affairs THANK YOU! QUESTIONS?

24 Neotame Derivative of Aspartame 7000x sweeter than sugar Metabolized by removal of methyl group, to desterified neotame No adverse effects ADI: 2 mg/kg/day, FDA


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