Inhibition of the gut enzyme intestinal alkaline phosphatase may explain how aspartame promotes glucose intolerance and obesity in mice.

Published

Journal Article

Diet soda consumption has not been associated with tangible weight loss. Aspartame (ASP) commonly substitutes sugar and one of its breakdown products is phenylalanine (PHE), a known inhibitor of intestinal alkaline phosphatase (IAP), a gut enzyme shown to prevent metabolic syndrome in mice. We hypothesized that ASP consumption might contribute to the development of metabolic syndrome based on PHE's inhibition of endogenous IAP. The design of the study was such that for the in vitro model, IAP was added to diet and regular soda, and IAP activity was measured. For the acute model, a closed bowel loop was created in mice. ASP or water was instilled into it and IAP activity was measured. For the chronic model, mice were fed chow or high-fat diet (HFD) with/without ASP in the drinking water for 18 weeks. The results were that for the in vitro study, IAP activity was lower (p < 0.05) in solutions containing ASP compared with controls. For the acute model, endogenous IAP activity was reduced by 50% in the ASP group compared with controls (0.2 ± 0.03 vs 0.4 ± 0.24) (p = 0.02). For the chronic model, mice in the HFD + ASP group gained more weight compared with the HFD + water group (48.1 ± 1.6 vs 42.4 ± 3.1, p = 0.0001). Significant difference in glucose intolerance between the HFD ± ASP groups (53 913 ± 4000.58 (mg·min)/dL vs 42 003.75 ± 5331.61 (mg·min)/dL, respectively, p = 0.02). Fasting glucose and serum tumor necrosis factor-alpha levels were significantly higher in the HFD + ASP group (1.23- and 0.87-fold increases, respectively, p = 0.006 and p = 0.01). In conclusion, endogenous IAP's protective effects in regard to the metabolic syndrome may be inhibited by PHE, a metabolite of ASP, perhaps explaining the lack of expected weight loss and metabolic improvements associated with diet drinks.

Full Text

Duke Authors

Cited Authors

  • Gul, SS; Hamilton, ARL; Munoz, AR; Phupitakphol, T; Liu, W; Hyoju, SK; Economopoulos, KP; Morrison, S; Hu, D; Zhang, W; Gharedaghi, MH; Huo, H; Hamarneh, SR; Hodin, RA

Published Date

  • January 2017

Published In

Volume / Issue

  • 42 / 1

Start / End Page

  • 77 - 83

PubMed ID

  • 27997218

Pubmed Central ID

  • 27997218

Electronic International Standard Serial Number (EISSN)

  • 1715-5320

International Standard Serial Number (ISSN)

  • 1715-5312

Digital Object Identifier (DOI)

  • 10.1139/apnm-2016-0346

Language

  • eng