Regular daily intake of black tea improves oxidative stress biomarkers and decreases serum C-reactive protein levels in type 2 diabetic patients.
BACKGROUND
This study was undertaken to evaluate the possible effects of different daily doses of black tea intake on certain oxidative stress, inflammatory and metabolic biomarkers in patients with type 2 diabetes mellitus (T2DM).


METHODS
Forty-six patients with known T2DM were randomly assigned either to the test (n = 23, 57.0 +/- 7.9 years) or the control (n = 23, 55.4 +/- 8.3 years) group. Following a one-week 'run-in' period, the test group received 150, 300, 450 and 600 ml of black tea extract (BTE) during the weeks 1, 2, 3 and 4, respectively. The control group received 150 ml BTE a day throughout the intervention period. Dietary, anthropometric and biochemical assessments were performed at the end of each week.


RESULTS
Serum total antioxidant capacity was enhanced similarly in both test and control groups. However, daily intake of 2 cups of BTE by the test group showed a suppressing effect on serum malondialdehyde. Serum C-reactive protein significantly decreased and glutathione levels increased following the intake of 4 cups (600 ml) of BTE a day.


CONCLUSIONS
Regular intake of BTE had anti-oxidative and anti-inflammatory effects in patients with T2DM. These findings may, to some extent, explain the mechanisms underlying the protective effects of drinking tea against cardiovascular disease.
Neyestani
Tirang R
TR
National Nutrition and Food Technology Research Institute, Shaheed Beheshti University of Medical Sciences, Tehran, Iran. neytra@yahoo.com
Shariatzade
Nastaran
N
Kalayi
Ali
A
Gharavi
A'azam
A
Khalaji
Niloufar
N
Dadkhah
Monireh
M
Zowghi
Telma
T
Haidari
Homa
H
Shab-bidar
Sakineh
S
D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers; D002097:C-Reactive Protein / Q000187:drug effects*; D028241:Camellia sinensis / Q000737:chemistry; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D013662:Tea / Q000737:chemistry*
D000975:Antioxidants; D015415:Biomarkers; D010936:Plant Extracts; D013662:Tea; D008315:Malondialdehyde; D002097:C-Reactive Protein