Review Evaluation of the effects of anthocyanins in type 2 diabetes Renata A. Soriano Sancho ⁎, Glaucia Maria Pastore Department of Food Science, School of Food Engineering, State University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, ZIP code 13083-862, Campinas, SP, Brazil abstract article info Article history: Received 2 September 2011 Accepted 29 November 2011 Keywords: Anthocyanin Type 2 diabetes Oxidative stress Insulin β cells The number of cases of type 2 diabetes (T2D) is increasing worldwide. This disease can be characterized by insulin resistance and pancreatic β cell dysfunction, which lead to macro- and microvascular complications. Anthocyanins are flavonoids that occur naturally in plants and are responsible for their color. Studies with cell lines and animal models and clinical trials in humans suggest that anthocyanins exhibit antidiabetic properties. However, variation in the structure of anthocyanins makes it difficult to determine their effects on T2D. Understanding the absorption and metabolism of anthocyanins is important for understanding their role in the improvement of this disease. Published data suggest that anthocyanins may lower blood glu- cose by improving insulin resistance, protecting β cells, increasing secretion of insulin and reducing digestion of sugars in the small intestine. The mechanisms of action are primarily related to their antioxidant proper- ties, but enzymatic inhibition and other pathways may also be relevant. © 2011 Elsevier Ltd. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 2. Chemical structure and antioxidant action of anthocyanins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 2.1. Absorption, metabolism and bioavailability of anthocyanins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 2.2. Properties of anthocyanin-related type 2 diabetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 2.2.1. Oxidative stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 2.2.2. β cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 2.2.3. Insulin secretion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 2.2.4. Insulin resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 2.2.5. α-Glucosidase inhibitory action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384 1. Introduction The improvement of living conditions has contributed to the in- creased longevity of people worldwide. As a result, population aging is no longer a phenomenon restricted to developed countries. Medical advances have decreased the impact of infectious diseases, and chronic degenerative diseases (CDDs), such as diabetes mellitus, car- diovascular disease, Alzheimer's and Parkinson's, have become more important in the context of health. Unlike infectious diseases, CDDs are multifactorial and often de- velop through exposure to different risk factors and unhealthy lifestyles. The incidence of diabetes is increasing worldwide. The number of people with diabetes will increase from 171 million in 2000 to a pro- jected 366 million in 2030. Brazil is among the 10 countries with the greatest number of people with diabetes and is expected to rank sixth in the year 2030, with a projected total of 11.3 million people with the disease (Wild, Roglic, Green, Sicree, & King, 2004). An inadequate diet is a risk factor for the development of CDD. However, a proper diet can prevent or delay the manifestation of dis- ease or improve the condition of individuals with an established dis- ease. The benefits associated with a healthy diet are due, at least in part, to higher concentrations of antioxidants found in fruits and Food Research International 46 (2012) 378–386 ⁎ Corresponding author at: State University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, CEP: 13083-862, Campinas, SP, Brazil. Tel.: +55 19 37883887; fax: +55 19 32891513. E-mail address: resancho@fea.unicamp.br (R.A.S. Sancho). 0963-9969/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2011.11.021 Contents lists available at SciVerse ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres