Diabetes and Alzheimer’s Disease: Can Tea Phytochemicals Play a Role in Prevention?

Article type: Review Article

Authors: Fernando, Warnakulasuriya M.A.D.B.^{a; 1} | Somaratne, Geeshani^{c; d; 1} | Goozee, Kathryn G.^{a; b; f; g; h; i} | Williams, Shehan^e | Singh, Harjinder^{c; d} | Martins, Ralph N.^{a; b; f; g; h; i; *}

Affiliations: [a] Centre of Excellence in Alzheimer’s Disease Research and Care, School of Medical Sciences, Edith Cowan University, Joondalup, Australia | [b] School of Biomedical Science, Macquarie University, Sydney, NSW, Australia | [c] Massey Institute of Food Science and Technology, Massey University, Palmerston North, New Zealand | [d] Riddet Institute, Massey University, Palmerston North, New Zealand | [e] Faculty of Medicine, University of Kelaniya, Colombo, Sri Lanka | [f] KARVIAH Research Centre, Anglicare, Castle Hill, NSW, Australia | [g] School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Nedlands, WA, Australia | [h] Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia | [i] KaRa Institute of Neurological Diseases, Sydney, NSW, Australia

Correspondence: [*] Correspondence to: Professor R.N. Martins, Centre of Excellence in Alzheimer’s Disease Research and Care, School of Medical Sciences, Edith Cowan University, Joondalup,Australia. Tel.: +61 8 6304 5456; Fax: +61 8 93474299; E-mail: [email protected].

Note: [1] These authors contributed equally to this work.

Abstract: Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer’s disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties. It is rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, which is considered to be the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer’s disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-β plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer’s disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.

Keywords: Alzheimer’s disease, cognitive impairment, diabetes, phytochemicals, tea

DOI: 10.3233/JAD-161200

Journal: Journal of Alzheimer's Disease, vol. 59, no. 2, pp. 481-501, 2017