A combination of two compounds found in red grapes and oranges could be used to improve the health of people with diabetes, and reduce cases of obesity and heart disease.
The find has been made by University of Warwick researchers who now hope that their discovery will be developed to provide a treatment for patients.
A team led by Paul Thornalley, Professor in Systems Biology at Warwick Medical School, studied two compounds found in fruits but not usually found together.
The compounds are trans-resveratrol (tRES) – found in red grapes, and hesperetin (HESP) – found in oranges.
When given jointly at pharmaceutical doses the compounds acted in tandem to decrease blood glucose, improve the action of insulin and improve the health of arteries.
The researchers noted an improvement in insulin resistance in trial participants produced by the compounds in 8-week treatment that was similar to that achieved with bariatric surgery after 6 months.
Currently, Metformin is considered for the treatment of overweight/obese people at high risk of developing type 2 diabetes.
However, in the study the combination of the fruit compounds was found to be more effective than Metformin at reducing blood sugar in the obese and overweight trial participants.
The compounds act by increasing a protein called glyoxalase 1 (Glo1) in the body which neutralises a damaging sugar-derived compound called methylglyoxal (MG).
MG is a major contributor to the damaging effects of sugar. Increased MG accumulation with a high energy diet intake is a driver of insulin resistance leading to type 2 diabetes, and also damages blood vessels and impairs handling of cholesterol associated with increased risk of cardiovascular diseases.
Blocking MG improved health in overweight and obese people and will likely help patients with diabetes and high risk of cardiovascular disease too. It has already been proven experimentally that blocking MG improves health impairment in obesity and type 1 and type 2 diabetes.
Although the same compounds are found naturally in some fruits, the amounts and type required for health improvement are hard to be obtained from increased fruit consumption.
The compounds that increase Glo1 and are called a ‘Glo1 inducer’. Pharmaceutical doses for patients with obesity, diabetes and high risk of heart disease could be given to patients in capsule form.
Thirty-two overweight and obese people within the 18-80 age range who had a BMI between 25-40 took part in the trial. They were given the supplement in capsule form once a day for eight weeks.
They were asked to maintain their usual diet and their food intake was monitored via a dietary questionnaire and they were also asked not to alter their daily physical activity.
The team found that the highly overweight subjects who had BMIs of over 27.5 with treatment displayed increased Glo1 activity, decreased glucose levels, improved working of insulin, improved artery function and decreased blood vessel inflammation. There was no effect of placebo.